US20030145694A1 - Apparatus and method for machining of hard metals with reduced detrimental white layer effect - Google Patents

Apparatus and method for machining of hard metals with reduced detrimental white layer effect Download PDF

Info

Publication number
US20030145694A1
US20030145694A1 US10/066,830 US6683002A US2003145694A1 US 20030145694 A1 US20030145694 A1 US 20030145694A1 US 6683002 A US6683002 A US 6683002A US 2003145694 A1 US2003145694 A1 US 2003145694A1
Authority
US
United States
Prior art keywords
workpiece
cutting tool
machined
component
hard
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US10/066,830
Inventor
Zbigniew Zurecki
Ranajit Ghosh
John Frey
James Taylor
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Air Products and Chemicals Inc
Original Assignee
Air Products and Chemicals Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Air Products and Chemicals Inc filed Critical Air Products and Chemicals Inc
Priority to US10/066,830 priority Critical patent/US20030145694A1/en
Assigned to AIR PRODUCTS AND CHEMICALS, INC. reassignment AIR PRODUCTS AND CHEMICALS, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: FREY, JOHN HERBERT, GHOSH, RANAJIT, TAYLOR, JAMES BRYAN, ZURECKI, ZBIGNIEW
Priority to EP03705833A priority patent/EP1472046A2/en
Priority to KR1020047012058A priority patent/KR100612067B1/en
Priority to AU2003207616A priority patent/AU2003207616A1/en
Priority to CA002474790A priority patent/CA2474790A1/en
Priority to PCT/US2003/001682 priority patent/WO2003066916A2/en
Priority to BR0307437-4A priority patent/BR0307437A/en
Priority to JP2003566261A priority patent/JP2005516785A/en
Priority to MXPA04007487A priority patent/MXPA04007487A/en
Priority to CNA038077523A priority patent/CN1646259A/en
Priority to US10/502,835 priority patent/US8220370B2/en
Priority to TW092101701A priority patent/TW583051B/en
Publication of US20030145694A1 publication Critical patent/US20030145694A1/en
Priority to ZA200407017A priority patent/ZA200407017B/en
Priority to JP2007009201A priority patent/JP2007118184A/en
Priority to JP2007182361A priority patent/JP2007260904A/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23QDETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q11/00Accessories fitted to machine tools for keeping tools or parts of the machine in good working condition or for cooling work; Safety devices specially combined with or arranged in, or specially adapted for use in connection with, machine tools
    • B23Q11/10Arrangements for cooling or lubricating tools or work
    • B23Q11/1038Arrangements for cooling or lubricating tools or work using cutting liquids with special characteristics, e.g. flow rate, quality
    • B23Q11/1053Arrangements for cooling or lubricating tools or work using cutting liquids with special characteristics, e.g. flow rate, quality using the cutting liquid at specially selected temperatures
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23QDETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q11/00Accessories fitted to machine tools for keeping tools or parts of the machine in good working condition or for cooling work; Safety devices specially combined with or arranged in, or specially adapted for use in connection with, machine tools
    • B23Q11/10Arrangements for cooling or lubricating tools or work
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23PMETAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
    • B23P25/00Auxiliary treatment of workpieces, before or during machining operations, to facilitate the action of the tool or the attainment of a desired final condition of the work, e.g. relief of internal stress
    • B23P25/003Auxiliary treatment of workpieces, before or during machining operations, to facilitate the action of the tool or the attainment of a desired final condition of the work, e.g. relief of internal stress immediately preceding a cutting tool
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S82/00Turning
    • Y10S82/90Lathe thermal regulation
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T407/00Cutters, for shaping
    • Y10T407/14Cutters, for shaping with means to apply fluid to cutting tool
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T82/00Turning
    • Y10T82/10Process of turning
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T82/00Turning
    • Y10T82/16Severing or cut-off
    • Y10T82/16065Combined with means to apply fluid

Definitions

  • the present invention relates to the field of machining of hard metallic materials by cutting (e.g., shaping parts by removing excess material in the form of chips) with hard cutting tools, and more particularly to machining methods that reduce the thickness of a thermomechanically-affected layer (e.g., white layer) on as-machined surfaces of hard metal workpieces and/or mitigate the detrimental effects in machined surfaces of hard metal workpieces due to the thermomechanical load of a hard cutting tool machining the workpiece.
  • a thermomechanically-affected layer e.g., white layer
  • the invention concerns machining of hard metallic parts, characterized by the surface hardness exceeding 42 Rockwell on Scale C, with hard cutting tools, characterized by the edge hardness exceeding 1500 Vickers. Machining of hard or hardened metallic parts brings about significant cost savings to the manufacturing industries through the reduction of heat-treating and machining steps in the production cycle and minimizing the extent of slow, finish-grinding operations.
  • ceramic cutting tools and tool coatings which include alumina (Al 2 O 3 ), cubic boron nitride (CBN) and many other advanced materials, machining of hard metals has become feasible and includes outer diameter (OD) turning, inner diameter turning (boring), grooving, parting, facing, milling, drilling, and numerous other cutting operations.
  • thermomechanically-affected workpiece surface comprising an etching-resistant white layer is undesired because of associated tensile stresses, e.g., reduced fatigue-resistance, lower fracture toughness, and/or reduced wear resistance of parts produced. See, B. J. Griffins, White Layer Formation at Machined Surfaces and Their Relationship to White Layer Formations at Worn Surfaces, J. of Tribology , April 1985, Vol. 107/165.
  • thermomechanically-affected layer e.g., “white layer”
  • Applicants' invention is an apparatus and a method for reducing a thickness of a thermomechanically-affected layer on an as-machined surface of a hard metal workpiece, and an apparatus and a method for mitigating a detrimental effect of a thermomechanical load in a machined surface of a hard metal workpiece.
  • Another aspect of the invention is an apparatus and a method for machining a hard metal workpiece using the aforesaid apparatuses and methods.
  • Other aspects of the invention are the workpieces machined by the apparatus and method for machining.
  • a first embodiment of the method for reducing a thickness of a thermomechanically-affected layer on an as-machined surface of a hard metal workpiece being machined by a hard cutting tool exerting a thermomechanical load on a surface of the workpiece includes reducing the thermomechanical load.
  • the hard metal workpiece includes an iron-containing alloy.
  • the hard cutting tool is made at least in part of a material selected from a group containing a ceramic compound; a ceramic-ceramic composite; a ceramic-metal composite; a diamond-like, metal-free material; an alumina-based ceramic; a cubic boron nitride-based ceramic material; a tungsten carbide-based material; and a cermet-type material.
  • the cutting tool initially has a first temperature prior to contacting the surface of the workpiece, and the thermomechanical load is reduced by cooling the cutting tool to a second temperature lower than the first temperature before the cutting tool contacts the surface of the workpiece or while the workpiece is being machined.
  • the cutting tool is cooled by an external cooling means.
  • the cooling means includes at least one cryogenic fluid.
  • the cooling means includes at least one inert, water-free coolant.
  • the cutting tool has a hardness and a resistance to cracking, and cooling the cutting tool with the cooling means results in an increase in the hardness or an increase in the resistance to cracking.
  • thermomechanical load is a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, and the thermomechanical load is reduced by reducing the component of the cutting force.
  • the cutting tool has an inclination angle, and the component of the cutting force is reduced by making the inclination angle more positive. (The phrase “making the inclination angle more positive” is defined and discussed in the Detailed Description of the Invention section below.)
  • the cutting tool has a rake angle, and the component of the cutting force is reduced by making the rake angle more positive.
  • a second embodiment of the method for reducing a thickness of a thermomechanically-affected layer on an as-machined surface of a hard metal workpiece being machined by a hard cutting tool includes multiple steps.
  • the cutting tool initially has a first temperature prior to contacting the surface of the workpiece and exerts a thermomechanical load on a surface of the workpiece, at least a portion of the thermomechanical load being a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece.
  • the first step of the method is to cool the cutting tool to a second temperature lower than the first temperature before the cutting tool contacts the surface of the workpiece or while the workpiece is being machined.
  • the second step is to reduce the component of the cutting force.
  • a first embodiment of the method for mitigating a detrimental effect of a thermomechanical load in a machined surface of a hard metal workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool machining the workpiece, thereby forming the machined surface includes cooling the machined surface by a cooling means having an initial temperature in a range of about ⁇ 250° C. to about +25° C.
  • the cooling means includes at least one inert, water-free coolant.
  • the cooling means includes at least one stream containing a cryogenic fluid or at least one ice particle having a temperature less than about ⁇ 75° C.
  • the hard metal workpiece includes an iron-containing alloy.
  • the hard cutting tool is made at least in part of a material selected from a group containing a ceramic compound; a ceramic-ceramic composite; a ceramic-metal composite; a diamond-like, metal-free material; an alumina-based ceramic; a cubic boron nitride-based ceramic material; a tungsten carbide-based material; and a cermet-type material.
  • a second embodiment of the method for mitigating the detrimental effect is similar to the first embodiment, but also includes cooling the cutting tool simultaneously by the cooling means.
  • thermomechanical load is a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece.
  • the method in this third embodiment includes reducing the component of the cutting force.
  • the component of the cutting force is reduced by making the inclination angle more positive and the cooling means includes at least one stream containing a cryogenic fluid or at least one ice particle having a temperature less than about ⁇ 75° C.
  • a fourth embodiment of the method for mitigating the detrimental effect is similar to the third embodiment, but includes cooling the cutting tool simultaneously by the cooling means.
  • the component of the cutting force is reduced by making the inclination angle more positive and the cooling means includes at least one stream containing a cryogenic fluid with at least one ice particle having a temperature less than about ⁇ 75° C.
  • Another aspect of the invention is a method for machining a hard metal workpiece. There are several embodiments of this method.
  • a first embodiment of the method for machining a hard metal workpiece whereby a thickness of a thermomechanically-affected layer on an as-machined surface of the workpiece is reduced, the workpiece being machined with a hard cutting tool initially having a first temperature prior to contacting the surface of the workpiece, the hard cutting tool exerting a thermomechanical load on a surface of the workpiece, includes cooling the cutting tool to a second temperature lower than the first temperature before the cutting tool contacts the surface of the workpiece or while the workpiece is being machined.
  • a second embodiment of the method for machining a hard metal workpiece whereby a detrimental effect of a thermomechanical load is mitigated in a machined surface of the workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool forming the machined surface of the workpiece, includes cooling the machined surface by a cooling means having an initial temperature in a range of about ⁇ 250° C. to about +25° C.
  • a third embodiment of the method for machining a hard metal workpiece whereby a thickness of a thermomechanically-affected layer on an as-machined surface of the workpiece is reduced, the workpiece being machined with a hard cutting tool, the hard cutting tool exerting a thermomechanical load on a surface of the workpiece, at least a portion of the thermomechanical load being a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, includes reducing the component of the cutting force.
  • thermomechanical load is a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece.
  • the fourth embodiment includes reducing the component of the cutting force.
  • a fifth embodiment of the method for machining is similar to the second embodiment, but includes cooling the cutting tool simultaneously by the cooling means.
  • thermomechanical load is a component of the cutting force, the component being applied in a direction normal to the surface of the workpiece.
  • the sixth embodiment includes reducing the component of the cutting force.
  • a seventh embodiment of the method for machining is similar to the sixth embodiment, but includes cooling the cutting tool simultaneously by the cooling means.
  • Another aspect of the invention is a workpiece machined by a method for machining as in any of the aforesaid embodiments and characterized by an improved surface or an improved property.
  • a first embodiment of the apparatus for reducing a thickness of a thermomechanically-affected layer on an as-machined surface of a hard metal workpiece being machined by a hard cutting tool exerting a thermomechanical load on a surface of the workpiece includes a means for reducing the thermomechanical load.
  • the hard metal workpiece includes an iron-containing alloy.
  • the hard cutting tool is made at least in part of a material selected from a group containing a ceramic compound; a ceramic-ceramic composite; a ceramic-metal composite; a diamond-like, metal-free material; an alumina-based ceramic; a cubic boron nitride-based ceramic material; a tungsten carbide-based material; and a cermet-type material.
  • a first embodiment of the apparatus for mitigating a detrimental effect of a thermomechanical load in a machined surface of a hard metal workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool machining the workpiece, thereby forming the machined surface includes a means for cooling the machined surface by at least one stream of a coolant having an initial temperature in a range of about ⁇ 250° C. to about +25° C.;
  • the stream contains at least one inert, water-free coolant.
  • the at least one stream contains a cryogenic fluid or at least one ice particle having a temperature less than about ⁇ 75° C.
  • thermomechanical load in the machined surface of a hard metal workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool machining the workpiece, thereby forming the machined surface, wherein at least a portion of the thermomechanical load is a component of the cutting force, the component being applied in a direction normal to the surface of the workpiece, includes: a means for cooling the machined surface by at least one stream containing at least one inert, water-free coolant having an initial temperature in a range of about ⁇ 250° C. to about +25° C.; a means for cooling the cutting tool simultaneously by at least another stream containing at least one inert, water-free coolant; and a means for reducing the component of the cutting force.
  • Another aspect of the invention is an apparatus for machining a hard metal workpiece. There are several embodiments of the apparatus for machining.
  • a first embodiment of the apparatus for machining a hard metal workpiece whereby a thickness of a thermomechanically-affected layer on an as-machined surface of the workpiece is reduced, the workpiece being machined by a hard cutting tool initially having a first temperature prior to contacting the surface of the workpiece, the hard cutting tool exerting a thermomechanical load on a surface of the workpiece, includes a means for cooling the cutting tool to a second temperature lower than the first temperature before the cutting tool contacts the surface of the workpiece or while the workpiece is being machined.
  • a second embodiment of the apparatus for machining a hard metal workpiece whereby a detrimental effect of a thermomechanical load is mitigated in a machined surface of the workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool forming the machined surface of the workpiece, includes a means for cooling the machined surface by a stream of a fluid having an initial temperature in a range of about ⁇ 250° C. to about +25° C.
  • a third embodiment of the apparatus for machining a hard metal workpiece whereby a thickness of a thermomechanically-affected layer on an as-machined surface of the workpiece is reduced, the workpiece being machined by a hard cutting tool exerting a thermomechanical load on a surface of the workpiece, at least a portion of the thermomechanical load being a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, includes a means for reducing the component of the cutting force.
  • thermomechanical load is a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece.
  • the fourth embodiment includes a means for reducing the component of the cutting force.
  • the fifth embodiment of the apparatus for machining is similar to the second embodiment, but includes a means for simultaneously cooling the cutting tool with at least one other stream of the fluid, the means for cooling being means for spraying the streams of the fluid.
  • a sixth embodiment of the apparatus for machining is similar to the third embodiment, but includes a means for spraying the machined surface with at least one stream of a fluid having an initial temperature in a range of about ⁇ 250° C. to about +25° C.
  • the seventh embodiment of the apparatus for machining is similar to the sixth embodiment, but includes a means for spraying at least one other stream of the fluid simultaneously on the cutting tool.
  • Another aspect of the invention is a workpiece machined by an apparatus for machining as in any of the aforesaid embodiments and characterized by an improved surface or an improved property.
  • FIG. 1A is a schematic diagram illustrating an OD-hardturning operation using a solid barstock and a round cutting tool, plus a schematic representation of a detail illustrating a cross-sectional view of a typical subsurface microstructure of an as-machined workpiece;
  • FIG. 1B is a schematic diagram illustrating an embodiment of the present invention used with an OD-hardturning operation similar to that shown in FIG. 1A;
  • FIG. 2 is a graph showing the measurement of white layer thickness for eight test conditions using different cutting speeds, cutting tool materials and cooling conditions;
  • FIG. 3A is a graph showing the change of subsurface hardness as a result of hardturning with different cutting tool materials and cooling conditions at a cutting speed of 700 feet per minute;
  • FIG. 3B is a graph showing the results of residual stress measurements on four types of samples as shown in FIG. 3A;
  • FIG. 4A is a schematic diagram illustrating a conventional method of hardturning where the inclination angle A-O-B is negative;
  • FIG. 4B is a schematic diagram illustrating an embodiment of the present invention wherein the inclination angle is increased from the negative value shown in FIG. 4A to a positive value B-O-C shown in FIG. 4B;
  • FIG. 4C is a schematic diagram illustrating another embodiment of the present invention.
  • the present invention involves machining hard metallic workpieces with hard cutting tools using a method which reduces the thickness of, or eliminates, thermomechanically-affected layers, including but not limited to white layer, and allows cutting at higher speeds without an excessive white layer using CBN tool materials, as well as less expensive Al 2 O 3 , carbide, cermet, or other hard tool materials.
  • white layer refers to all types of “thermomechanically-affected layers,” including but not limited to those associated with surface tensile stresses (e.g., reduced fatigue-resistance, lower fracture toughness, and/or reduced wear resistance).
  • thermomechanical load exerted by the cutting tool at the machined surface is reduced using one or a combination of the three techniques (A, B, C) discussed below.
  • the temperature of the tool cooling jet may vary between +25° C. and ⁇ 250° C., with the lower, cryogenic jet temperatures preferred.
  • the tool cooled with such a jet makes the surface of a machined part colder.
  • the use of inert and water-free cooling jets enhances the life of Al 2 O 3 , CBN and other, hard cutting tools and, consequently, allows the use of sharper cutting edges which generate lower cutting forces and thinner white layers.
  • the surface-cooling jet of technique B may be separate from the tool-cooling jet of technique A; or just a single jet can be aimed in such a way that it cools both the tool and the surface simultaneously.
  • Persons skilled in the art will recognize that multiple cooling jets or sprays of technique A and technique B could be used according to the present invention.
  • the cutting force component normal to the as-machined workpiece surface appears to be a significant source of heat flux entering the surface and generating white layer.
  • the normal force is the radial force
  • a more positive tool inclination angle results in a reduced thermomechanical load entering the surface.
  • the normal force is the feed force
  • a more positive rake angle will be more important.
  • both the inclination angle and the rake angle are made more positive than the conventional, negative values that are used in current hard machining operations. Since the life of hard cutting tools scales inversely with the positive inclination and rake angle, the increase in the value of these angles is most advantageous if practiced in combination with technique A, which also enhances tool life during hard machining.
  • FIG. 1A is a schematic diagram of an OD-hardturning operation involving a solid barstock as the workpiece 12 and a round cutting tool 14 (with a cutting insert marked as CT) viewed from the topside of the tool rake surface.
  • This view is referred to as the X-Z plane view.
  • the X-Z projection of the major cutting forces that have to be applied to the workpiece via the cutting tool is denoted as F xz feed or feed force, and F xz radial or radial force, where the feed force is less than the radial force.
  • the location of the thermomechanically-affected layers 16 on the as-machined surface of the workpiece is illustrated in FIG. 1A.
  • the detail on the right of the figure shows a cross-sectional view of the typical subsurface microstructure of the as-machined workpiece that can be observed under a scanning electron microscope (SEM) using magnifications ranging from 3,000 to 12,000 times.
  • SEM scanning electron microscope
  • OS outer surface that was in direct contact with the cutting tool during hardturning
  • WL white layer
  • DL dark layer
  • BM base metal base metal representing the parent or unaffected structure of the barstock.
  • the white layer (WL) is a thin band of poorly etching material with broadly dispersed, spherical carbides.
  • the underlying dark layer (DL) is thicker than the white layer, and contains more and bigger carbide particles, as well as microfeatures suggesting martensitic needles and latches.
  • the thermomechanically-affected layer includes both the white layer (WL) and the dark layer (DL) but also extends even deeper into the base metal and cannot be measured using simple microscopic methods.
  • thermomechanically-affected layer is usually based on (1) a microscopic measurement of the well contrasting white layer (WL), combined with (2) additional measurements of the mechanical properties of the material below the as-machined surface, e.g., residual stress and microhardness measurements.
  • FIG. 1B shows the same X-Z view of the cutting tool 14 and the workpiece 12 (barstock), but does not include the cross-sectional details of the subsurface microstructure as in FIG. 1A.
  • Points CJ xz 1 and CJ xz 2 are X-Z plane projections of the preferred locations of cold jet-discharging orifices (not shown) that aim the cooling jets ( 18 , 20 ) at the rake of the cutting tool, at the as-machined surface of the workpiece and, optionally, into the clearance gap between the cutting tool and the workpiece surface, just below the rake surface and the cutting tool-workpiece contact area.
  • the cold jet impact is limited to the cutting tool and the as-machined workpiece surface area.
  • the CJ xz 1 jet may be positioned higher or lower, above the rake along the Y-axis, and may impact only the rake surface along the contact length. This represents technique A, discussed earlier.
  • the CJ xz 1 jet may spray both the rake and the as-machined surface downstream of the cutting tool. This alternate approach combines techniques A and B.
  • the CJ xz 2 jet may be positioned behind or below the cutting tool, along the Y and the Z axes, in order to work according to technique B.
  • the CJ xz 2 jet can be eliminated as well if the spray 18 from the CJ xz 1 jet is sufficiently effective in cooling the machined surface.
  • Table 1 The results of comparative tests carried out to evaluate the effectiveness of techniques A, B, and C are summarized in Table 1, which details the conditions of the tests.
  • Cutting tool Cutting insert CBN, a “low-content PCBN” type Al 2 O 3 -based ceramic type, system Al 2 O 3 —TiCN composition Insert designation BNC80, 4NC-CNMA432, 4 cutting KY4400, CNGA432, 4 cutting and description: edges, PVD-TiN coated edges, PVD-TiN coated Supplier/toolmaker: Sumitomo Kennametal Edge chamfer 25° +/ ⁇ 3° 25° +/ ⁇ 3° Chamfer width, 0.00325 inches 0.00425 inches measured: Toolholder for MCLNL-164C, Kennametal MCLNL-164C, Kennametal cutting insert: Toolholder's angles: ⁇ 5° rake angle and ⁇ 5° inclination ⁇ 5° rake and ⁇ 5° angle inclination angle Cutting Cutting speed in 400 and 700 400 and 700 parameters ft/minute: Feedrate in 0.004 0.004 inches/revolution, see: comment (1) below Depth of cut in 0.015 0.015 inches: Cutting (feed)
  • thermomechanical load at as-machined work surface i.e. # a thinner thermomechanically-affected surface including white layer.
  • the 2 nd factor influencing white layer is # the temperature at the tool-work contact area. Thermal conductivity of the low-PCBN tool is somewhat # higher than that of the Al 2 O 3 —TiCN tool which means the contact area is cooler in the former case.
  • FIG. 2 shows the results of SEM measurements of the white layer thickness for eight (8) test conditions.
  • the results show that the sharper and more conductive CBN tool tends to produce a thinner white layer than that produced by the Al 2 O 3 tool.
  • the reduction of the normal component of the cutting force coming with the sharper tools, and the reduction of tool temperature with more conductive tool materials, are consistent with our techniques A and C.
  • the most significant factor in reducing white layer thickness was the cooling jet applied according to techniques A and B, which was capable of reducing the white layer by about 40% regardless of the tool and cutting speed used.
  • the most important and surprising finding is that the white layer produced with the jet-cooled Al 2 O 3 tool is significantly thinner than the white layer produced by the CBN tool operated the conventional way (i.e., dry).
  • the white layer produced with the Al 2 O 3 tool at 700 feet/minute is thinner than the white layer produced with the dry CBN tool at 400 ft/minute.
  • the present invention enables hard machining operators to produce better parts faster and at lower tooling cost
  • FIG. 3A shows the change of subsurface hardness as a result of hardturning with the CBN and Al 2 O 3 tools at the cutting speed of 700 feet/minute. Undesired softening of workpiece material observed within the first 15 micrometers under the as-machined surface after the conventional dry hardturning is prevented when the cryogenic cooling jet is used according to techniques A and B of the invention.
  • FIG. 3B plots results of residual stress measurements on the same four types of samples as in FIG. 3A.
  • the cryojet cooling eliminates a steep tensile stress resulting from the conventional dry hardturning.
  • the cryojet makes the subsurface stress slightly more compressive and, just as in the case of Al 2 O 3 , flattens the fluctuation of stress with depth.
  • FIGS. 3A and 3B show that the techniques A and B of the invention bring an unexpected improvement in the mechanical properties of a hard machined surface.
  • FIGS. 4A, 4B and 4 C present the same operation but in the X-Y plane showing a section of the face of the barstock or workpiece 12 and the side of the cutting insert (CT).
  • FIG. 4A shows the conventional method of hardturning where the inclination angle A-O-B is negative.
  • the X-Y projection of the work-material reaction force that resists machining operation, R xy mach can be presented with some degree of simplification as a sum of two forces projected on the same plane X-Y: tangential reaction cutting force, R xy tan, and radial reaction force, R xy rad.
  • the radial reaction force is larger than zero, usually larger than the tangential or the feed force (extending along the Z-axis), and in some hardturning cases larger than the tangential and feed forces combined.
  • the radial force applied via the cutting tool to the workpiece surface, F xz rad must be equally large, which leads to a high thermomechanical load being applied by the cutting tool to the workpiece surface and contributes to the formation of thick white layers.
  • FIG. 4B presents a modification of the conventional cutting geometry (in FIG. 4A) as the inclination angle, B-O-C, is increased from the initial negative value (represented by A-O-B) in FIG. 4A to a new positive value, which results in reversing the direction of the radial reaction force, R xy rad.
  • the increased or more positive inclination angle reduces the required radial force of the cutting tool to zero or below zero, resulting in a reduction of the thermomechanically-affected layer at the workpiece surface.
  • This modification of the cutting geometry represents technique C of the present invention. This technique may be extended to hard facing and hard orthogonal cutting operations where, if effective rake angles are made more positive than the conventionally used negative angles, then the thermomechanical load at the workpiece surface is reduced, and the thermomechanically-affected layer is thinner.
  • the increased inclination and/or rake angles may produce tensile stresses around the cutting edges of typically brittle tools used in hard machining. Such tensile stresses may lead to premature tool failures in the case of the conventional technology that teaches dry cutting conditions. As observed, the failures are less frequent and tool life is extended when at least one cooling jet or spray is aimed at the rake of the cutting tool during hard machining, and the cooling fluid used is inert, water-free, and preferably cryogenic. (The term “inert” means that the cooling fluid does not react with the hard metal and does not degrade the mechanical properties of the hard metal or the hard cutting tool.)
  • FIG. 4C shows the X-Y plane projection of two cooling jets, CJ xy 1 and CJ xy 2 , corresponding to the jets shown in FIG. 1B in the X-Z plane view.
  • the application of technique C is most advantageous from the production and cost standpoint, when CJ 1 or, alternatively, CJ 1 and CJ 2 are spraying coolant during the hard cutting, as shown in FIG. 4C.
  • the present invention minimizes detrimental white layer and other thermomechanically-affected layers in an as-machined workpiece surface by reducing the thermomechanical load exerted by the cutting tool on the workpiece material surface during hard machining.
  • the present invention includes three techniques (A, B, C) which may be used separately or in combination (AB, AC, BC, ABC).

Abstract

An apparatus and a method are disclosed for reducing a thickness of a thermomechanically-affected layer on an as-machined surface of a hard metal workpiece being machined by a hard cutting tool exerting a thermomechanical load on a surface of the workpiece. The method involves reducing the thermomechanical load on the surface of the workpiece, and the apparatus includes a means for reducing the thermomechanical load on the surface of the workpiece.

Description

    BACKGROUND OF THE INVENTION
  • The present invention relates to the field of machining of hard metallic materials by cutting (e.g., shaping parts by removing excess material in the form of chips) with hard cutting tools, and more particularly to machining methods that reduce the thickness of a thermomechanically-affected layer (e.g., white layer) on as-machined surfaces of hard metal workpieces and/or mitigate the detrimental effects in machined surfaces of hard metal workpieces due to the thermomechanical load of a hard cutting tool machining the workpiece. [0001]
  • Specifically, the invention concerns machining of hard metallic parts, characterized by the surface hardness exceeding 42 Rockwell on Scale C, with hard cutting tools, characterized by the edge hardness exceeding 1500 Vickers. Machining of hard or hardened metallic parts brings about significant cost savings to the manufacturing industries through the reduction of heat-treating and machining steps in the production cycle and minimizing the extent of slow, finish-grinding operations. With the advent of hard, ceramic cutting tools and tool coatings, which include alumina (Al[0002] 2O3), cubic boron nitride (CBN) and many other advanced materials, machining of hard metals has become feasible and includes outer diameter (OD) turning, inner diameter turning (boring), grooving, parting, facing, milling, drilling, and numerous other cutting operations.
  • A significant limitation of the widespread use of hard metal machining is the so-called “white layer” effect, a microscopic alteration of the as-machined surface of a workpiece, which effect is produced in response to an extremely high thermomechanical load exerted at the as-machined surface by the cutting tool. Although not fully understood, the thermomechanically-affected workpiece surface comprising an etching-resistant white layer is undesired because of associated tensile stresses, e.g., reduced fatigue-resistance, lower fracture toughness, and/or reduced wear resistance of parts produced. See, B. J. Griffins, White Layer Formation at Machined Surfaces and Their Relationship to White Layer Formations at Worn Surfaces, [0003] J. of Tribology, April 1985, Vol. 107/165.
  • It has been reported that a sharper and/or not worn cutting edge, as well as the conventional flooding of a cutting tool with a water-based, emulsified oil coolant, contribute to the reduction in the detrimental tensile stresses and white layer. W. Konig, M. Klinger, and R. Link, Machining Hard Materials with Geometrically Defined Cutting Edges—Field of Applications and Limitations, [0004] Annals of CIRP, 1990, Vol. 57, pp. 61-64. Hard machining with conventional flood cooling has been reexamined but found to be ineffective. H. K. Tonshoff and H. G. Wobker, Potential and Limitations of Hard Turning, 1st Int. Machining and Grinding Conf., Sep. 12-14, 1995, Dearborn, Mich., SME Technical Paper MR95-215. Moreover, sharp-finished cutting edges easily fracture in the case of inexpensive, Al2O3-based tools, leaving expensive CBN tools as the only current option. It has been noted that the use of coolants in hard machining should be avoided since cooling accelerates the edge wear and shortens overall life of CBN tools used for finish-hardturning. T. J. Broskea, PCBN Tool Failure Mode Analysis, Intertech 2000, Vancouver B. C., Canada, Jul. 17-21, 2000. Numerous other publications and machining textbooks have indicated that the use of coolants with inexpensive Al2O3 tools brings about a rapid fracture. Using non-cooled CBN tools (dry turning), the effect of cutting speed on white layer thickness during hardturning of a popular hardened bearing steel 52100 has been examined. Y. K. Chou and C. J. Evans, Process Effects on White Layer Formation in Hard Turning, Trans. of NAMRI/SME, Vol. XXVI, 1998, pp.117-122. Results showed that only relatively low cutting speeds, translating into reduced productivity rates, assure an acceptably thin white layer. Thus, the machining technology of today offers no solution for making hard, white layer-free parts quickly and at reduced costs.
  • It is desired to have an apparatus and a method which minimize the alteration of workpiece surfaces during hard machining, and more specifically, which eliminate or minimize tensile and/or fluctuating surface stresses and etch-resistant white layer (i.e., the detrimental effects of “white layer”). [0005]
  • It is further desired to have an apparatus and method which produce better parts having less of the detrimental effects of a thermomechanically-affected layer (e.g., “white layer”) and which do so faster, at lower costs, and with less expensive tools. [0006]
  • BRIEF SUMMARY OF THE INVENTION
  • Applicants' invention is an apparatus and a method for reducing a thickness of a thermomechanically-affected layer on an as-machined surface of a hard metal workpiece, and an apparatus and a method for mitigating a detrimental effect of a thermomechanical load in a machined surface of a hard metal workpiece. Another aspect of the invention is an apparatus and a method for machining a hard metal workpiece using the aforesaid apparatuses and methods. Other aspects of the invention are the workpieces machined by the apparatus and method for machining. [0007]
  • A first embodiment of the method for reducing a thickness of a thermomechanically-affected layer on an as-machined surface of a hard metal workpiece being machined by a hard cutting tool exerting a thermomechanical load on a surface of the workpiece includes reducing the thermomechanical load. [0008]
  • There are several variations of the first embodiment of that method. In one variation, the hard metal workpiece includes an iron-containing alloy. In another variation, the hard cutting tool is made at least in part of a material selected from a group containing a ceramic compound; a ceramic-ceramic composite; a ceramic-metal composite; a diamond-like, metal-free material; an alumina-based ceramic; a cubic boron nitride-based ceramic material; a tungsten carbide-based material; and a cermet-type material. [0009]
  • In another variation, the cutting tool initially has a first temperature prior to contacting the surface of the workpiece, and the thermomechanical load is reduced by cooling the cutting tool to a second temperature lower than the first temperature before the cutting tool contacts the surface of the workpiece or while the workpiece is being machined. In a variant of that variation, the cutting tool is cooled by an external cooling means. In one variant of that variant, the cooling means includes at least one cryogenic fluid. In another variant, the cooling means includes at least one inert, water-free coolant. In yet another variant, the cutting tool has a hardness and a resistance to cracking, and cooling the cutting tool with the cooling means results in an increase in the hardness or an increase in the resistance to cracking. [0010]
  • In another variation of the method, at least a portion of the thermomechanical load is a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, and the thermomechanical load is reduced by reducing the component of the cutting force. There are several variants of this variation. In one variant, the cutting tool has an inclination angle, and the component of the cutting force is reduced by making the inclination angle more positive. (The phrase “making the inclination angle more positive” is defined and discussed in the Detailed Description of the Invention section below.) In another variant, the cutting tool has a rake angle, and the component of the cutting force is reduced by making the rake angle more positive. [0011]
  • A second embodiment of the method for reducing a thickness of a thermomechanically-affected layer on an as-machined surface of a hard metal workpiece being machined by a hard cutting tool includes multiple steps. In this embodiment, the cutting tool initially has a first temperature prior to contacting the surface of the workpiece and exerts a thermomechanical load on a surface of the workpiece, at least a portion of the thermomechanical load being a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece. The first step of the method is to cool the cutting tool to a second temperature lower than the first temperature before the cutting tool contacts the surface of the workpiece or while the workpiece is being machined. The second step is to reduce the component of the cutting force. [0012]
  • A first embodiment of the method for mitigating a detrimental effect of a thermomechanical load in a machined surface of a hard metal workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool machining the workpiece, thereby forming the machined surface, includes cooling the machined surface by a cooling means having an initial temperature in a range of about −250° C. to about +25° C. [0013]
  • There are several variations of the first embodiment of that method. In one variation, the cooling means includes at least one inert, water-free coolant. In another variation, the cooling means includes at least one stream containing a cryogenic fluid or at least one ice particle having a temperature less than about −75° C. In another variation, the hard metal workpiece includes an iron-containing alloy. In another variation, the hard cutting tool is made at least in part of a material selected from a group containing a ceramic compound; a ceramic-ceramic composite; a ceramic-metal composite; a diamond-like, metal-free material; an alumina-based ceramic; a cubic boron nitride-based ceramic material; a tungsten carbide-based material; and a cermet-type material. [0014]
  • A second embodiment of the method for mitigating the detrimental effect is similar to the first embodiment, but also includes cooling the cutting tool simultaneously by the cooling means. [0015]
  • In a third embodiment of the method for mitigating the detrimental effect, which is similar to the first embodiment, at least a portion of the thermomechanical load is a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece. The method in this third embodiment includes reducing the component of the cutting force. In a variation of this embodiment, wherein the cutting tool has an inclination angle, the component of the cutting force is reduced by making the inclination angle more positive and the cooling means includes at least one stream containing a cryogenic fluid or at least one ice particle having a temperature less than about −75° C. [0016]
  • A fourth embodiment of the method for mitigating the detrimental effect is similar to the third embodiment, but includes cooling the cutting tool simultaneously by the cooling means. In a variation of the fourth embodiment, wherein the cutting tool has an inclination angle, the component of the cutting force is reduced by making the inclination angle more positive and the cooling means includes at least one stream containing a cryogenic fluid with at least one ice particle having a temperature less than about −75° C. [0017]
  • Another aspect of the invention is a method for machining a hard metal workpiece. There are several embodiments of this method. [0018]
  • A first embodiment of the method for machining a hard metal workpiece, whereby a thickness of a thermomechanically-affected layer on an as-machined surface of the workpiece is reduced, the workpiece being machined with a hard cutting tool initially having a first temperature prior to contacting the surface of the workpiece, the hard cutting tool exerting a thermomechanical load on a surface of the workpiece, includes cooling the cutting tool to a second temperature lower than the first temperature before the cutting tool contacts the surface of the workpiece or while the workpiece is being machined. [0019]
  • A second embodiment of the method for machining a hard metal workpiece, whereby a detrimental effect of a thermomechanical load is mitigated in a machined surface of the workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool forming the machined surface of the workpiece, includes cooling the machined surface by a cooling means having an initial temperature in a range of about −250° C. to about +25° C. [0020]
  • A third embodiment of the method for machining a hard metal workpiece, whereby a thickness of a thermomechanically-affected layer on an as-machined surface of the workpiece is reduced, the workpiece being machined with a hard cutting tool, the hard cutting tool exerting a thermomechanical load on a surface of the workpiece, at least a portion of the thermomechanical load being a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, includes reducing the component of the cutting force. [0021]
  • In a fourth embodiment of the method for machining, which is similar to the first embodiment, at least a portion of thermomechanical load is a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece. The fourth embodiment includes reducing the component of the cutting force. [0022]
  • A fifth embodiment of the method for machining is similar to the second embodiment, but includes cooling the cutting tool simultaneously by the cooling means. [0023]
  • In a sixth embodiment of the method for machining, which is similar to the second embodiment, at least a portion of the thermomechanical load is a component of the cutting force, the component being applied in a direction normal to the surface of the workpiece. The sixth embodiment includes reducing the component of the cutting force. [0024]
  • A seventh embodiment of the method for machining is similar to the sixth embodiment, but includes cooling the cutting tool simultaneously by the cooling means. [0025]
  • Another aspect of the invention is a workpiece machined by a method for machining as in any of the aforesaid embodiments and characterized by an improved surface or an improved property. [0026]
  • A first embodiment of the apparatus for reducing a thickness of a thermomechanically-affected layer on an as-machined surface of a hard metal workpiece being machined by a hard cutting tool exerting a thermomechanical load on a surface of the workpiece, includes a means for reducing the thermomechanical load. [0027]
  • There are several variations of the first embodiment of that apparatus. In one variation, the hard metal workpiece includes an iron-containing alloy. In another variation, the hard cutting tool is made at least in part of a material selected from a group containing a ceramic compound; a ceramic-ceramic composite; a ceramic-metal composite; a diamond-like, metal-free material; an alumina-based ceramic; a cubic boron nitride-based ceramic material; a tungsten carbide-based material; and a cermet-type material. [0028]
  • A second embodiment of the apparatus for reducing a thickness of a thermomechanically-affected layer on an as-machined surface of a hard metal workpiece being machined by a hard cutting tool initially having a first temperature prior to contacting the surface of the workpiece, the hard cutting tool exerting a thermomechanical load on a surface of the workpiece, at least a portion of the thermomechanical load being a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, includes: a means for cooling the cutting tool to a second temperature lower than the first temperature before the cutting tool contacts the surface of the workpiece or while the workpiece is being machined; and a means for reducing the component of the cutting force. [0029]
  • A first embodiment of the apparatus for mitigating a detrimental effect of a thermomechanical load in a machined surface of a hard metal workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool machining the workpiece, thereby forming the machined surface, includes a means for cooling the machined surface by at least one stream of a coolant having an initial temperature in a range of about −250° C. to about +25° C.; In one variation of this embodiment, the stream contains at least one inert, water-free coolant. In another variation, the at least one stream contains a cryogenic fluid or at least one ice particle having a temperature less than about −75° C. [0030]
  • A second embodiment of the apparatus for mitigating a detrimental effect of a thermomechanical load in the machined surface of a hard metal workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool machining the workpiece, thereby forming the machined surface, wherein at least a portion of the thermomechanical load is a component of the cutting force, the component being applied in a direction normal to the surface of the workpiece, includes: a means for cooling the machined surface by at least one stream containing at least one inert, water-free coolant having an initial temperature in a range of about −250° C. to about +25° C.; a means for cooling the cutting tool simultaneously by at least another stream containing at least one inert, water-free coolant; and a means for reducing the component of the cutting force. [0031]
  • Another aspect of the invention is an apparatus for machining a hard metal workpiece. There are several embodiments of the apparatus for machining. [0032]
  • A first embodiment of the apparatus for machining a hard metal workpiece, whereby a thickness of a thermomechanically-affected layer on an as-machined surface of the workpiece is reduced, the workpiece being machined by a hard cutting tool initially having a first temperature prior to contacting the surface of the workpiece, the hard cutting tool exerting a thermomechanical load on a surface of the workpiece, includes a means for cooling the cutting tool to a second temperature lower than the first temperature before the cutting tool contacts the surface of the workpiece or while the workpiece is being machined. [0033]
  • A second embodiment of the apparatus for machining a hard metal workpiece, whereby a detrimental effect of a thermomechanical load is mitigated in a machined surface of the workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool forming the machined surface of the workpiece, includes a means for cooling the machined surface by a stream of a fluid having an initial temperature in a range of about −250° C. to about +25° C. [0034]
  • A third embodiment of the apparatus for machining a hard metal workpiece, whereby a thickness of a thermomechanically-affected layer on an as-machined surface of the workpiece is reduced, the workpiece being machined by a hard cutting tool exerting a thermomechanical load on a surface of the workpiece, at least a portion of the thermomechanical load being a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, includes a means for reducing the component of the cutting force. [0035]
  • In a fourth embodiment, which is similar to the first embodiment, at least a portion of the thermomechanical load is a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece. The fourth embodiment includes a means for reducing the component of the cutting force. [0036]
  • The fifth embodiment of the apparatus for machining is similar to the second embodiment, but includes a means for simultaneously cooling the cutting tool with at least one other stream of the fluid, the means for cooling being means for spraying the streams of the fluid. [0037]
  • A sixth embodiment of the apparatus for machining is similar to the third embodiment, but includes a means for spraying the machined surface with at least one stream of a fluid having an initial temperature in a range of about −250° C. to about +25° C. [0038]
  • The seventh embodiment of the apparatus for machining is similar to the sixth embodiment, but includes a means for spraying at least one other stream of the fluid simultaneously on the cutting tool. [0039]
  • Another aspect of the invention is a workpiece machined by an apparatus for machining as in any of the aforesaid embodiments and characterized by an improved surface or an improved property.[0040]
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • The invention will be described by way of example with reference to the accompanying drawings, in which: [0041]
  • FIG. 1A is a schematic diagram illustrating an OD-hardturning operation using a solid barstock and a round cutting tool, plus a schematic representation of a detail illustrating a cross-sectional view of a typical subsurface microstructure of an as-machined workpiece; [0042]
  • FIG. 1B is a schematic diagram illustrating an embodiment of the present invention used with an OD-hardturning operation similar to that shown in FIG. 1A; [0043]
  • FIG. 2 is a graph showing the measurement of white layer thickness for eight test conditions using different cutting speeds, cutting tool materials and cooling conditions; [0044]
  • FIG. 3A is a graph showing the change of subsurface hardness as a result of hardturning with different cutting tool materials and cooling conditions at a cutting speed of 700 feet per minute; [0045]
  • FIG. 3B is a graph showing the results of residual stress measurements on four types of samples as shown in FIG. 3A; [0046]
  • FIG. 4A is a schematic diagram illustrating a conventional method of hardturning where the inclination angle A-O-B is negative; [0047]
  • FIG. 4B is a schematic diagram illustrating an embodiment of the present invention wherein the inclination angle is increased from the negative value shown in FIG. 4A to a positive value B-O-C shown in FIG. 4B; and [0048]
  • FIG. 4C is a schematic diagram illustrating another embodiment of the present invention.[0049]
  • DETAILED DESCRIPTION OF THE INVENTION
  • The present invention involves machining hard metallic workpieces with hard cutting tools using a method which reduces the thickness of, or eliminates, thermomechanically-affected layers, including but not limited to white layer, and allows cutting at higher speeds without an excessive white layer using CBN tool materials, as well as less expensive Al[0050] 2O3, carbide, cermet, or other hard tool materials. As used hereinafter, the term “white layer” refers to all types of “thermomechanically-affected layers,” including but not limited to those associated with surface tensile stresses (e.g., reduced fatigue-resistance, lower fracture toughness, and/or reduced wear resistance).
  • According to the present invention, the thermomechanical load exerted by the cutting tool at the machined surface is reduced using one or a combination of the three techniques (A, B, C) discussed below. [0051]
  • A. Cooling Cutting Tool with a Precisely Aimed Jet or Spray of Inert, Water-Free Coolant, so that the Heat Transferred from the Hot Tool Interface to the Workpiece is Reduced and, Most preferably, the Tool Becomes a Heat Sink for the Workpiece Surface. [0052]
  • The temperature of the tool cooling jet may vary between +25° C. and −250° C., with the lower, cryogenic jet temperatures preferred. The tool cooled with such a jet makes the surface of a machined part colder. In addition, as observed during hard machining tests, in contrast to conventional machining technology teachings, the use of inert and water-free cooling jets enhances the life of Al[0053] 2O3, CBN and other, hard cutting tools and, consequently, allows the use of sharper cutting edges which generate lower cutting forces and thinner white layers.
  • B. Cooling the As-Formed or As-Machined Workpiece Surface with the Same Type of Direct Impinging Cooling Jet or Spray as in Technique A. [0054]
  • Based on observations, it appears that cooling of the as-machined workpiece surface reduces the depth of heat penetration into machined material and, consequently, the extent of undesired material transformations. The surface-cooling jet of technique B may be separate from the tool-cooling jet of technique A; or just a single jet can be aimed in such a way that it cools both the tool and the surface simultaneously. Persons skilled in the art will recognize that multiple cooling jets or sprays of technique A and technique B could be used according to the present invention. [0055]
  • C. Reducing the Cutting Force Component in the Direction Normal to the As-Machined Workpiece Surface. [0056]
  • As observed during tests, the cutting force component normal to the as-machined workpiece surface appears to be a significant source of heat flux entering the surface and generating white layer. In the case of the most frequently practiced OD-hardturning operations, where the normal force is the radial force, a more positive tool inclination angle results in a reduced thermomechanical load entering the surface. In the case of orthogonal cutting, where the normal force is the feed force, a more positive rake angle will be more important. In the most generic cutting case, both the inclination angle and the rake angle are made more positive than the conventional, negative values that are used in current hard machining operations. Since the life of hard cutting tools scales inversely with the positive inclination and rake angle, the increase in the value of these angles is most advantageous if practiced in combination with technique A, which also enhances tool life during hard machining. [0057]
  • FIG. 1A is a schematic diagram of an OD-hardturning operation involving a solid barstock as the [0058] workpiece 12 and a round cutting tool 14 (with a cutting insert marked as CT) viewed from the topside of the tool rake surface. This view is referred to as the X-Z plane view. The X-Z projection of the major cutting forces that have to be applied to the workpiece via the cutting tool is denoted as Fxzfeed or feed force, and Fxzradial or radial force, where the feed force is less than the radial force. The location of the thermomechanically-affected layers 16 on the as-machined surface of the workpiece is illustrated in FIG. 1A. The detail on the right of the figure shows a cross-sectional view of the typical subsurface microstructure of the as-machined workpiece that can be observed under a scanning electron microscope (SEM) using magnifications ranging from 3,000 to 12,000 times. The following designations are used: OS—outer surface that was in direct contact with the cutting tool during hardturning, WL—white layer, DL—dark layer, and BM—base metal base metal representing the parent or unaffected structure of the barstock.
  • Based on SEM examinations carried out on a popular bearing steel grade, AISI 52100 (1 wt % C and 1.5 wt % Cr), hardened to 61 Rockwell on scale C and hard machined, the white layer (WL) is a thin band of poorly etching material with broadly dispersed, spherical carbides. The underlying dark layer (DL) is thicker than the white layer, and contains more and bigger carbide particles, as well as microfeatures suggesting martensitic needles and latches. The thermomechanically-affected layer includes both the white layer (WL) and the dark layer (DL) but also extends even deeper into the base metal and cannot be measured using simple microscopic methods. Consequently, the evaluation of the thickness of a thermomechanically-affected layer is usually based on (1) a microscopic measurement of the well contrasting white layer (WL), combined with (2) additional measurements of the mechanical properties of the material below the as-machined surface, e.g., residual stress and microhardness measurements. [0059]
  • FIG. 1B shows the same X-Z view of the [0060] cutting tool 14 and the workpiece 12 (barstock), but does not include the cross-sectional details of the subsurface microstructure as in FIG. 1A. Points CJxz 1 and CJ xz 2 are X-Z plane projections of the preferred locations of cold jet-discharging orifices (not shown) that aim the cooling jets (18, 20) at the rake of the cutting tool, at the as-machined surface of the workpiece and, optionally, into the clearance gap between the cutting tool and the workpiece surface, just below the rake surface and the cutting tool-workpiece contact area. Thus, the cold jet impact is limited to the cutting tool and the as-machined workpiece surface area. It is important not to cool the barstock upstream of the cutting tool, since such cooling increases the mechanical energy required for cutting, i.e., cancels the cooling effect and simultaneously shortens the life of the cutting tool. As shown in FIG. 1B, the CJxz 1 jet may be positioned higher or lower, above the rake along the Y-axis, and may impact only the rake surface along the contact length. This represents technique A, discussed earlier. Alternatively, the CJxz 1 jet may spray both the rake and the as-machined surface downstream of the cutting tool. This alternate approach combines techniques A and B. The CJ xz 2 jet may be positioned behind or below the cutting tool, along the Y and the Z axes, in order to work according to technique B. The CJ xz 2 jet can be eliminated as well if the spray 18 from the CJxz 1 jet is sufficiently effective in cooling the machined surface. The results of comparative tests carried out to evaluate the effectiveness of techniques A, B, and C are summarized in Table 1, which details the conditions of the tests.
    TABLE 1
    Cutting tool Cutting insert: CBN, a “low-content PCBN” type Al2O3-based ceramic type,
    system Al2O3—TiCN composition
    Insert designation BNC80, 4NC-CNMA432, 4 cutting KY4400, CNGA432, 4 cutting
    and description: edges, PVD-TiN coated edges, PVD-TiN coated
    Supplier/toolmaker: Sumitomo Kennametal
    Edge chamfer 25° +/− 3° 25° +/− 3°
    Chamfer width, 0.00325 inches 0.00425 inches
    measured:
    Toolholder for MCLNL-164C, Kennametal MCLNL-164C, Kennametal
    cutting insert:
    Toolholder's angles: −5° rake angle and −5° inclination −5° rake and −5°
    angle inclination angle
    Cutting Cutting speed in 400 and 700 400 and 700
    parameters ft/minute:
    Feedrate in 0.004 0.004
    inches/revolution,
    see: comment (1)
    below
    Depth of cut in 0.015 0.015
    inches:
    Cutting (feed) Radial (along X-axis), facing Radial (along X-axis), facing
    direction:
    Cooling Two cooling (1) Dry (no cooling), and (1) Dry (no cooling), and
    conditions methods: (2) CJxz 1 jet aimed at the tool rake (2) CJxz 1 jet aimed at the tool
    and at as-matchined surface rake and at as-machined
    according to techniques A and B surface according to techniques
    A and B
    Cooling medium for Cryogenic liquid nitrogen jet Crogenic liquid nitrogen jet
    case (2), above: impacting rake and as-machined impacting rake and as-
    surface in form of a 2-phase fluid machined surface in form of a
    which is boiling at −197° C. 2-phase fluid which is boiling at
    −197° C.
    Workpiece AISI 52100 bearing Oil quenched and low-tempered to Oil quenched and low-tempered
    material steel, 1.0 wt % 61 HRC +/− 1 HRC to 61 +/− 1 HRC
    carbon, 1.5 wt %
    chromium
    White layer Workpiece material 1.06 cubic inches 1.06 cubic inches
    examination volume removed by
    conditions a new cutting edge
    before taking as-
    machined
    workpiece surface
    samples for
    examination
    of white
    layer, see comment
    (2) below
    Number of 8 8
    interruptions during
    workpiece material
    cutting prior to
    white
    layer examination:
    Surface roughness Ra = 15-20 Ra = 15-30
    range of as- microinches/inch microinches/inch
    machined
    workpiece surface
    samples transferred
    for white layer
    evaluations
    Residual stress Incremental hole drilling with 1 Incremental hole drilling with 1
    measurement mm diameter drill, extensometer mm diameter drill,
    method: rosette extensometer rosette
    Direction of Perpendicular to as-machined Perpendicular to as-machined
    metallographic cut workpiece surface and in the workpiece surface and in the
    for image evaluation radial direction (along X-axis) radial direction (along X-axis)
    and microhardness
    measurements:
    Microhardness Profiling hardness as a function of Profiling hardness as a function
    measurement depth under as-machined of depth under as-machined
    method-Knoop, workpiece surface with blade- workpiece surface with blade-
    100G load applied shaped indenter shaped indenter
    for 15 seconds
    Etchant used for Nital-5% HNO3 in ethanol applied Nital-5% HNO3 in ethanol
    developing white to sample surface for 10 seconds applied to sample surface for 10
    layer contrast on seconds
    cross-sectional
    metallographic
    samples of as-
    machined
    workpiece surface:
    # the CBN tool was larger, i.e. more positive or sharper, than the effective rake angle of the Al2O3 tool.
    # Consequently, the CBN insert used generated lower normal force during face cutting than the Al2O3 insert
    # which, according to technique C results in a lower thermomechanical load at as-machined work surface, i.e.
    # a thinner thermomechanically-affected surface including white layer. The 2nd factor influencing white layer is
    # the temperature at the tool-work contact area. Thermal conductivity of the low-PCBN tool is somewhat
    # higher than that of the Al2O3—TiCN tool which means the contact area is cooler in the former case.
  • FIG. 2 shows the results of SEM measurements of the white layer thickness for eight (8) test conditions. The results show that the sharper and more conductive CBN tool tends to produce a thinner white layer than that produced by the Al[0061] 2O3 tool. The reduction of the normal component of the cutting force coming with the sharper tools, and the reduction of tool temperature with more conductive tool materials, are consistent with our techniques A and C. However, the most significant factor in reducing white layer thickness was the cooling jet applied according to techniques A and B, which was capable of reducing the white layer by about 40% regardless of the tool and cutting speed used. The most important and surprising finding is that the white layer produced with the jet-cooled Al2O3 tool is significantly thinner than the white layer produced by the CBN tool operated the conventional way (i.e., dry). Moreover, the white layer produced with the Al2O3 tool at 700 feet/minute is thinner than the white layer produced with the dry CBN tool at 400 ft/minute. Thus, the present invention enables hard machining operators to produce better parts faster and at lower tooling cost.
  • FIG. 3A shows the change of subsurface hardness as a result of hardturning with the CBN and Al[0062] 2O3 tools at the cutting speed of 700 feet/minute. Undesired softening of workpiece material observed within the first 15 micrometers under the as-machined surface after the conventional dry hardturning is prevented when the cryogenic cooling jet is used according to techniques A and B of the invention.
  • FIG. 3B plots results of residual stress measurements on the same four types of samples as in FIG. 3A. In the case of Al[0063] 2O3, the cryojet cooling eliminates a steep tensile stress resulting from the conventional dry hardturning. In the case of CBN, the cryojet makes the subsurface stress slightly more compressive and, just as in the case of Al2O3, flattens the fluctuation of stress with depth. Both FIGS. 3A and 3B show that the techniques A and B of the invention bring an unexpected improvement in the mechanical properties of a hard machined surface.
  • As FIG. 1B presented the X-Z plane view of OD-hardturning, FIGS. 4A, 4B and [0064] 4C present the same operation but in the X-Y plane showing a section of the face of the barstock or workpiece 12 and the side of the cutting insert (CT). FIG. 4A shows the conventional method of hardturning where the inclination angle A-O-B is negative. The X-Y projection of the work-material reaction force that resists machining operation, Rxymach, can be presented with some degree of simplification as a sum of two forces projected on the same plane X-Y: tangential reaction cutting force, Rxytan, and radial reaction force, Rxyrad. The radial reaction force is larger than zero, usually larger than the tangential or the feed force (extending along the Z-axis), and in some hardturning cases larger than the tangential and feed forces combined. To balance the radial reaction force, the radial force applied via the cutting tool to the workpiece surface, Fxzrad, must be equally large, which leads to a high thermomechanical load being applied by the cutting tool to the workpiece surface and contributes to the formation of thick white layers.
  • FIG. 4B presents a modification of the conventional cutting geometry (in FIG. 4A) as the inclination angle, B-O-C, is increased from the initial negative value (represented by A-O-B) in FIG. 4A to a new positive value, which results in reversing the direction of the radial reaction force, R[0065] xyrad. In effect, the increased or more positive inclination angle reduces the required radial force of the cutting tool to zero or below zero, resulting in a reduction of the thermomechanically-affected layer at the workpiece surface. This modification of the cutting geometry represents technique C of the present invention. This technique may be extended to hard facing and hard orthogonal cutting operations where, if effective rake angles are made more positive than the conventionally used negative angles, then the thermomechanical load at the workpiece surface is reduced, and the thermomechanically-affected layer is thinner.
  • The increased inclination and/or rake angles may produce tensile stresses around the cutting edges of typically brittle tools used in hard machining. Such tensile stresses may lead to premature tool failures in the case of the conventional technology that teaches dry cutting conditions. As observed, the failures are less frequent and tool life is extended when at least one cooling jet or spray is aimed at the rake of the cutting tool during hard machining, and the cooling fluid used is inert, water-free, and preferably cryogenic. (The term “inert” means that the cooling fluid does not react with the hard metal and does not degrade the mechanical properties of the hard metal or the hard cutting tool.) [0066]
  • FIG. 4C shows the X-Y plane projection of two cooling jets, CJ[0067] xy 1 and CJ xy 2, corresponding to the jets shown in FIG. 1B in the X-Z plane view. The application of technique C is most advantageous from the production and cost standpoint, when CJ1 or, alternatively, CJ1 and CJ2 are spraying coolant during the hard cutting, as shown in FIG. 4C.
  • The present invention minimizes detrimental white layer and other thermomechanically-affected layers in an as-machined workpiece surface by reducing the thermomechanical load exerted by the cutting tool on the workpiece material surface during hard machining. As discussed above, the present invention includes three techniques (A, B, C) which may be used separately or in combination (AB, AC, BC, ABC). [0068]
  • Although illustrated and described herein with reference to certain specific embodiments, the present invention is nevertheless not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the spirit of the invention. [0069]

Claims (50)

1. A method for reducing a thickness of a thermomechanically-affected layer on an as-machined surface of a hard metal workpiece being machined by a hard cutting tool exerting a thermomechanical load on a surface of the workpiece, comprising reducing the thermomechanical load.
2. A method as in claim 1, wherein the cutting tool initially has a first temperature prior to contacting the surface of the workpiece, and wherein the thermomechanical load is reduced by cooling the cutting tool to a second temperature lower than the first temperature before the cutting tool contacts the surface of the workpiece or while the workpiece is being machined.
3. A method as in claim 2, wherein the cutting tool is cooled by an external cooling means.
4. A method as in claim 3, wherein the cooling means comprises at least one inert, water-free coolant.
5. A method as in claim 3, wherein the cooling means comprises at least one cryogenic fluid.
6. A method as in claim 1, wherein at least a portion of the thermomechanical load is a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, and wherein the thermomechanical load is reduced by reducing the component of the cutting force.
7. A method as in claim 6, wherein the cutting tool has an inclination angle, and wherein the component of the cutting force is reduced by making the inclination angle more positive.
8. A method as in claim 6, wherein the cutting tool has a rake angle, and wherein the component of the cutting force is reduced by making the rake angle more positive.
9. A method as in claim 4, wherein the cutting tool has a hardness and a resistance to cracking, and wherein cooling the cutting tool with the cooling means results in an increase in the hardness or an increase in the resistance to cracking.
10. A method as in claim 1, wherein the hard metal workpiece comprises an iron-containing alloy.
11. A method as in claim 1, wherein the hard cutting tool is made at least in part of a material selected from a group containing a ceramic compound; a ceramic-ceramic composite; a ceramic-metal composite; a diamond-like, metal-free material; an alumina-based ceramic; a cubic boron nitride-based ceramic material; a tungsten carbide-based material; and a cermet-type material.
12. A method for reducing a thickness of a thermomechanically-affected layer on an as-machined surface of a hard metal workpiece being machined by a hard cutting tool initially having a first temperature prior to contacting the surface of the workpiece, the hard cutting tool exerting a thermomechanical load on a surface of the workpiece, at least a portion of the thermomechanical load being a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, comprising the steps of:
cooling the cutting tool to a second temperature lower than the first temperature before the cutting tool contacts the surface of the workpiece or while the workpiece is being machined; and
reducing the component of the cutting force.
13. A method for mitigating a detrimental effect of a thermomechanical load in a machined surface of a hard metal workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool machining the workpiece, thereby forming the machined surface, comprising cooling the machined surface by a cooling means having an initial temperature in a range of about −250° C. to about +25° C.
14. A method as in claim 13, wherein the cooling means comprises at least one stream containing a cryogenic fluid or at least one ice particle having a temperature less than about −75° C.
15. A method as in claim 13, wherein the cooling means comprises at least one inert, water-free coolant.
16. A method as in claim 13, wherein the hard metal workpiece comprises an iron-containing alloy.
17. A method as in claim 13, wherein the hard cutting tool is made at least in part of a material selected from a group containing a ceramic compound; a ceramic-ceramic composite; a ceramic-metal composite; a diamond-like, metal-free material; an alumina-based ceramic; a cubic boron nitride-based ceramic material; a tungsten carbide-based material; and a cermet-type material.
18. A method for mitigating a detrimental effect of a thermomechanical load in a machined surface of a hard metal workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool machining the workpiece, thereby forming the machined surface, comprising the steps of:
cooling the machined surface by a cooling means having an initial temperature in a range of about −250° C. to about +25° C.; and
cooling the cutting tool simultaneously by the cooling means.
19. A method for mitigating a detrimental effect of a thermomechanical load in a machined surface of a hard metal workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool machining the workpiece, thereby forming the machined surface, wherein at least a portion of the thermomechanical load is a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, comprising the steps of:
cooling the machined surface by a cooling means having an initial temperature in a range of about −250° C. to about +25° C.; and
reducing the component of the cutting force.
20. A method as claim 19 wherein the cutting tool has an inclination angle, and wherein the component of the cutting force is reduced by making the inclination angle more positive and the cooling means comprises at least one stream containing a cryogenic fluid or at least one ice particle having a temperature less than about −75° C.
21. A method for mitigating a detrimental effect of a thermomechanical load in a machined surface of a hard metal workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool machining the workpiece, thereby forming the machined surface, wherein at least a portion of the thermomechanical load is a component of the cutting force, the component being applied in a direction normal to the surface of the workpiece, comprising the steps of:
cooling the machined surface by a cooling means having an initial temperature in a range of about −250° C. to about +25° C.;
cooling the cutting tool simultaneously by the cooling means; and
reducing the component of the cutting force.
22. A method as in claim 21, wherein the cutting tool has an inclination angle, and wherein the component of the cutting force is reduced by making the inclination angle more positive and the cooling means comprises at least one stream containing a cryogenic fluid with at least one ice particle having a temperature less than about −75° C.
23. A method for machining a hard metal workpiece, whereby a thickness of a thermomechanically-affected layer on an as-machined surface of the workpiece is reduced, the workpiece being machined with a hard cutting tool initially having a first temperature prior to contacting the surface of the workpiece, the hard cutting tool exerting a thermomechanical load on a surface of the workpiece, comprising cooling the cutting tool to a second temperature lower than the first temperature before the cutting tool contacts the surface of the workpiece or while the workpiece is being machined.
24. A workpiece machined by a method as in claim 23 and characterized by an improved surface or an improved property.
25. A method for machining a hard metal workpiece, whereby a detrimental effect of a thermomechanical load is mitigated in a machined surface of the workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool forming the machined surface of the workpiece, comprising cooling the machined surface by a cooling means having an initial temperature in a range of about −250° C. to about +25° C.
26. A workpiece machined by a method as in claim 25 and characterized by an improved surface or an improved property.
27. A method for machining a hard metal workpiece, whereby a thickness of a thermomechanically-affected layer on an as-machined surface of the workpiece is reduced, the workpiece being machined with a hard cutting tool, the hard cutting tool exerting a thermomechanical load on a surface of the workpiece, at least a portion of the thermomechanical load being a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, comprising reducing the component of the cutting force.
28. A workpiece machined by a method as in claim 27 and characterized by an improved surface or an improved property.
29. A method for machining a hard metal workpiece, whereby a thickness of a thermomechanically-affected layer on an as-machined surface of the workpiece is reduced, the workpiece being machined with a hard cutting tool initially having a first temperature prior to contacting the surface of the workpiece, the hard cutting tool exerting a thermomechanical load on a surface of the workpiece, at least a portion of the thermomechanical load being a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, comprising the steps of:
cooling the cutting tool to a second temperature lower than the first temperature before the cutting tool contacts the surface of the workpiece or while the workpiece is being machined; and
reducing the component of the cutting force.
30. A method for machining a hard metal workpiece, whereby a detrimental effect of a thermomechanical load is mitigated in a machined surface of the workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool forming the machined surface of the workpiece, comprising the steps of:
cooling the machined surface by a cooling means having an initial temperature in a range of about −250° C. to about +25° C.; and
cooling the cutting tool simultaneously by the cooling means.
31. A method for machining a hard metal workpiece, whereby a detrimental effect of a thermomechanical load is mitigated in a machined surface of the workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool forming the machined surface of the workpiece, wherein at least a portion of the thermomechanical load is a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, comprising the steps of:
cooling the machined surface by a cooling means having an initial temperature in a range of about −250° C. to about +25° C.; and
reducing the component of the cutting force.
32. A method for machining a hard metal workpiece, whereby a detrimental effect of a thermomechanical load is mitigated in a machined surface of the workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool forming the machined surface of the workpiece, wherein at least a portion of the thermomechanical load is a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, comprising the steps of:
cooling the machined surface by a cooling means having an initial temperature having a range of about −250° C. to about +25° C.;
cooling the cutting tool simultaneously by the cooling means; and
reducing the component of the cutting force.
33. An apparatus for reducing a thickness of a thermomechanically-affected layer on an as-machined surface of a hard metal workpiece being machined by a hard cutting tool exerting a thermomechanical load on a surface of the workpiece, comprising a means for reducing the thermomechanical load.
34. An apparatus as in claim 33, wherein the hard metal workpiece comprises an iron-containing alloy.
35. An apparatus as in claim 33, wherein the hard cutting tool is made at least in part of a material selected from a group containing a ceramic compound; a ceramic-ceramic composite; a ceramic-metal composite; a diamond-like, metal-free material; an alumina-based ceramic; a cubic boron nitride-based ceramic material; a tungsten carbide-based material; and a cermet-type material.
36. An apparatus for reducing a thickness of a thermomechanically-affected layer on an as-machined surface of a hard metal workpiece being machined by a hard cutting tool initially having a first temperature prior to contacting the surface of the workpiece, the hard cutting tool exerting a thermomechanical load on a surface of the workpiece, at least a portion of the thermomechanical load being a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, comprising:
a means for cooling the cutting tool to a second temperature lower than the first temperature before the cutting tool contacts the surface of the workpiece or while the workpiece is being machined; and
a means for reducing the component of the cutting force.
37. An apparatus for mitigating a detrimental effect of a thermomechanical load in a machined surface of a hard metal workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool machining the workpiece, thereby forming the machined surface, comprising a means for cooling the machined surface by at least one stream of a coolant having an initial temperature in a range of about −250° C. to about +25° C.
38. An apparatus as in claim 37, wherein the at least one stream contains a cryogenic fluid or at least one ice particle having a temperature less than about −75° C.
39. An apparatus as in claim 37, wherein the stream contains at least one inert, water-free coolant.
40. An apparatus for mitigating a detrimental effect of a thermomechanical load in the machined surface of a hard metal workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool machining the workpiece, thereby forming the machined surface, wherein at least a portion of the thermomechanical load is a component of the cutting force, the component being applied in a direction normal to the surface of the workpiece, comprising:
a means for cooling the machined surface by at least one stream containing at least one inert, water-free coolant having an initial temperature in a range of about −250° C. to about +25° C.;
a means for cooling the cutting tool simultaneously by at least another stream containing at least one inert, water-free coolant; and
a means for reducing the component of the cutting force.
41. An apparatus for machining a hard metal workpiece, whereby a thickness of a thermomechanically-affected layer on an as-machined surface of the workpiece is reduced, the workpiece being machined by a hard cutting tool initially having a first temperature prior to contacting the surface of the workpiece, the hard cutting tool exerting a thermomechanical load on a surface of the workpiece, comprising a means for cooling the cutting tool to a second temperature lower than the first temperature before the cutting tool contacts the surface of the workpiece or while the workpiece is being machined.
42. A workpiece machined by an apparatus as in claim 41 and characterized by an improved surface or an improved property.
43. An apparatus for machining a hard metal workpiece, whereby a detrimental effect of a thermomechanical load is mitigated in a machined surface of the workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool forming the machined surface of the workpiece, comprising a means for cooling the machined surface by a stream of a fluid having an initial temperature in a range of about −250° C. to about +25° C.
44. A workpiece machined by an apparatus as in claim 43 and characterized by an improved surface or an improved property.
45. An apparatus for machining a hard metal workpiece, whereby a thickness of a thermomechanically-affected layer on an as-machined surface of the workpiece is reduced, the workpiece being machined by a hard cutting tool exerting a thermomechanical load on a surface of the workpiece, at least a portion of the thermomechanical load being a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, comprising a means for reducing the component of the cutting force.
46. A workpiece machined by an apparatus as in claim 45 and characterized by an improved surface or an improved property.
47. An apparatus for machining a hard metal workpiece, whereby a thickness of a thermomechanically-affected layer on an as-machined surface of the workpiece is reduced, the workpiece being machined by a hard cutting tool initially having a first temperature prior to contacting the surface of the workpiece, the hard cutting tool exerting a thermomechanical load on a surface of the workpiece, at least a portion of the thermomechanical load being a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, comprising:
a means for cooling the cutting tool to a second temperature lower than the first temperature before the cutting tool contacts the surface of the workpiece or while the workpiece is being machined; and
a means for reducing the component of the cutting force.
48. An apparatus for machining a hard metal workpiece, whereby a detrimental effect of a thermomechanical load is mitigated in a machined surface of the workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool forming the machined surface of the workpiece, comprising:
a means for spraying the machined surface with at least one stream of a fluid having an initial temperature in a range of about −250° C. to about +25° C.; and
a means for spraying at least one other stream of the fluid simultaneously on the cutting tool.
49. An apparatus for machining a hard metal workpiece, whereby a detrimental effect of a thermomechanical load is mitigated in a machined surface of the workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool forming the machined surface of the workpiece, wherein at least a portion of the thermomechanical load is a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, comprising:
a means for spraying the machined surface with at least one stream of a fluid having an initial temperature in a range of about −250° C. to about +25° C.; and
a means for reducing the component of the cutting force.
50. An apparatus for machining a hard metal workpiece, whereby a detrimental effect of a thermomechanical load is mitigated in a machined surface of the workpiece, the thermomechanical load being exerted on a surface of the workpiece by a hard cutting tool forming the machined surface of the workpiece, wherein at least a portion of the thermomechanical load is a component of a cutting force, the component being applied in a direction normal to the surface of the workpiece, comprising:
a means for spraying the machined surface with at least one stream of a fluid having an initial temperature in a range of about −250° C. to about +25° C.;
a means for spraying at least one other stream of the fluid simultaneously on the cutting tool; and
a means for reducing the component of the cutting force.
US10/066,830 2002-02-04 2002-02-04 Apparatus and method for machining of hard metals with reduced detrimental white layer effect Abandoned US20030145694A1 (en)

Priority Applications (15)

Application Number Priority Date Filing Date Title
US10/066,830 US20030145694A1 (en) 2002-02-04 2002-02-04 Apparatus and method for machining of hard metals with reduced detrimental white layer effect
US10/502,835 US8220370B2 (en) 2002-02-04 2003-01-21 Apparatus and method for machining of hard metals with reduced detrimental white layer effect
BR0307437-4A BR0307437A (en) 2002-02-04 2003-01-21 Method for reducing a thermomechanically affected layer thickness on an as-machined surface of a tempered metal workpiece, Method for machining a tempered metal workpiece, Apparatus for reducing a thermodynamically affected layer thickness on a "as-machined" surface of a tempered metal workpiece, method and apparatus for smoothing out a detrimental defect of a thermomechanical load on a machined surface of a tempered metal workpiece, machined workpiece, apparatus for machining a metal workpiece seasoned
MXPA04007487A MXPA04007487A (en) 2002-02-04 2003-01-21 Apparatus and method for machining of hard metals with reduced detrimental white layer effect.
AU2003207616A AU2003207616A1 (en) 2002-02-04 2003-01-21 Apparatus and method for machining of hard metals with reduced detrimental white layer effect
CA002474790A CA2474790A1 (en) 2002-02-04 2003-01-21 Apparatus and method for machining of hard metals with reduced detrimental white layer effect
PCT/US2003/001682 WO2003066916A2 (en) 2002-02-04 2003-01-21 Apparatus and method for machining of hard metals with reduced detrimental white layer effect
EP03705833A EP1472046A2 (en) 2002-02-04 2003-01-21 Apparatus and method for machining of hard metals with reduced detrimental white layer effect
JP2003566261A JP2005516785A (en) 2002-02-04 2003-01-21 Apparatus and method for processing hard metal with reduced adverse effects of white layer
KR1020047012058A KR100612067B1 (en) 2002-02-04 2003-01-21 Apparatus and method for machining of hard metals with reduced detrimental white layer effect
CNA038077523A CN1646259A (en) 2002-02-04 2003-01-21 Apparatus and method for machining of hard metals with reduced detrimental white layer effect
TW092101701A TW583051B (en) 2002-02-04 2003-01-27 Apparatus and method for machining of hard metals with reduced detrimental white layer effect
ZA200407017A ZA200407017B (en) 2002-02-04 2004-09-02 Apparatus and methods for machining of hard metals with reduced detrimental white layer effect
JP2007009201A JP2007118184A (en) 2002-02-04 2007-01-18 Apparatus and method for machining hard metal with reduced adverse affect of white layer effect
JP2007182361A JP2007260904A (en) 2002-02-04 2007-07-11 Apparatus and method for machining of hard metal with reduced detrimental white layer effect

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US10/066,830 US20030145694A1 (en) 2002-02-04 2002-02-04 Apparatus and method for machining of hard metals with reduced detrimental white layer effect

Publications (1)

Publication Number Publication Date
US20030145694A1 true US20030145694A1 (en) 2003-08-07

Family

ID=27658740

Family Applications (2)

Application Number Title Priority Date Filing Date
US10/066,830 Abandoned US20030145694A1 (en) 2002-02-04 2002-02-04 Apparatus and method for machining of hard metals with reduced detrimental white layer effect
US10/502,835 Active 2028-06-26 US8220370B2 (en) 2002-02-04 2003-01-21 Apparatus and method for machining of hard metals with reduced detrimental white layer effect

Family Applications After (1)

Application Number Title Priority Date Filing Date
US10/502,835 Active 2028-06-26 US8220370B2 (en) 2002-02-04 2003-01-21 Apparatus and method for machining of hard metals with reduced detrimental white layer effect

Country Status (12)

Country Link
US (2) US20030145694A1 (en)
EP (1) EP1472046A2 (en)
JP (3) JP2005516785A (en)
KR (1) KR100612067B1 (en)
CN (1) CN1646259A (en)
AU (1) AU2003207616A1 (en)
BR (1) BR0307437A (en)
CA (1) CA2474790A1 (en)
MX (1) MXPA04007487A (en)
TW (1) TW583051B (en)
WO (1) WO2003066916A2 (en)
ZA (1) ZA200407017B (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050211029A1 (en) * 2004-03-25 2005-09-29 Zbigniew Zurecki Apparatus and method for improving work surface during forming and shaping of materials
US20060207080A1 (en) * 2005-03-17 2006-09-21 Keate Robert A Process of refurbishing brake components
US7434439B2 (en) 2005-10-14 2008-10-14 Air Products And Chemicals, Inc. Cryofluid assisted forming method
US7634957B2 (en) 2004-09-16 2009-12-22 Air Products And Chemicals, Inc. Method and apparatus for machining workpieces having interruptions
US7637187B2 (en) 2001-09-13 2009-12-29 Air Products & Chemicals, Inc. Apparatus and method of cryogenic cooling for high-energy cutting operations
US8220370B2 (en) 2002-02-04 2012-07-17 Air Products & Chemicals, Inc. Apparatus and method for machining of hard metals with reduced detrimental white layer effect
WO2016099375A1 (en) * 2014-12-16 2016-06-23 Aktiebolaget Skf Bearing component and method of manufacture

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7419498B2 (en) * 2003-10-21 2008-09-02 Nmt Medical, Inc. Quick release knot attachment system
US7390240B2 (en) * 2005-10-14 2008-06-24 Air Products And Chemicals, Inc. Method of shaping and forming work materials
US7290471B2 (en) * 2005-11-15 2007-11-06 3M Innovative Properties Company Cutting tool having variable rotation about a y-direction transversely across a work piece for making microstructures
CN102517539A (en) * 2012-01-09 2012-06-27 西南大学 Method for improving bonding strength of interface between hard coating and substrate
CN103894911B (en) * 2014-04-19 2017-04-05 上海上大热处理有限公司 A kind of axial workpiece cutting equipment
CN112756636A (en) * 2020-12-29 2021-05-07 浙江金固股份有限公司 Turning method for plate-shaped workpiece

Family Cites Families (112)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US145894A (en) * 1873-12-23 Improvement in hub-boring machines
US174528A (en) * 1876-03-07 Improvement in curry-combs
US110761A (en) * 1871-01-03 Improvement in devices for nicking screw-caps
US2635399A (en) 1951-04-19 1953-04-21 Thompson Prod Inc Method for grinding carbide tools
US2641047A (en) 1951-07-19 1953-06-09 Waterbury Farrel Foundry & Mac Cutting tool
DE1049661B (en) 1952-12-31 1900-01-01
US3751780A (en) * 1965-06-22 1973-08-14 H Villalobos Ultra sharp diamond edges for ultra thin sectioning and as point cathode
US3433028A (en) 1966-09-02 1969-03-18 Air Prod & Chem Cryogenic fluid conveying system
US3571877A (en) 1968-04-04 1971-03-23 Neal P Jefferies Cooling system for cutting tool and the like
US3650337A (en) 1969-07-31 1972-03-21 Aerojet General Co Cryogenically cooled drill
US3696627A (en) 1971-01-18 1972-10-10 Air Prod & Chem Liquid cryogen transfer system
US3971114A (en) * 1972-01-27 1976-07-27 Dudley George M Machine tool having internally routed cryogenic fluid for cooling interface between cutting edge of tool and workpiece
US3889520A (en) 1973-02-13 1975-06-17 Theodor Stoferle Fluidic system for monitoring machine tool wear during a machining operation
US3900976A (en) * 1974-01-24 1975-08-26 Jr William H Kitts Device for supporting a coated abrasive
US3979981A (en) 1974-05-20 1976-09-14 Union Carbide Corporation Cryogenic shearing of metal
US3900975A (en) 1974-05-20 1975-08-26 Union Carbide Corp Cryogenic grinding of copper
DE2617289C3 (en) * 1975-04-21 1981-03-19 Hitachi, Ltd., Tokyo Process for the plastic deformation of face-centered cubic metals
US4296610A (en) 1980-04-17 1981-10-27 Union Carbide Corporation Liquid cryogen delivery system
US4404827A (en) 1981-07-10 1983-09-20 Union Carbide Corporation Method and apparatus for drawing wire
US4336689A (en) 1981-07-10 1982-06-29 Union Carbide Corporation Process for delivering liquid cryogen
JPS59199579A (en) 1983-04-25 1984-11-12 三菱マテリアル株式会社 Abrasion resistant sialon base ceramics
JPS6088791A (en) 1983-10-18 1985-05-18 三井建設株式会社 Acute curve shield construction method
US4510760A (en) 1984-03-02 1985-04-16 Messer Griesheim Industries, Inc. Compact integrated gas phase separator and subcooler and process
JPS6210105A (en) 1985-07-08 1987-01-19 Japan Exlan Co Ltd Production of hard polyvinyl alcohol gel
DE3542966A1 (en) 1985-12-05 1987-06-11 Hasenclever Maschf Sms METHOD AND DEVICE FOR FREE-FORMING WORKPIECES
US4829869A (en) * 1986-01-29 1989-05-16 Yamaha Corporation Tone control apparatus for electronic musical instrument
US4666665A (en) 1986-01-30 1987-05-19 Federal-Mogul Corporation Hot-forging small inner diameter powdered metal parts
US4716738A (en) 1986-08-04 1988-01-05 Cv International, Inc. Apparatus and method for delivering cryogenic liquid from a supply vessel to receiver vessels
US4829859A (en) 1986-08-29 1989-05-16 Ulticon Systems, Inc. Method of high speed machining
US4715187A (en) 1986-09-29 1987-12-29 Vacuum Barrier Corporation Controlled cryogenic liquid delivery
DE3640645A1 (en) 1986-11-28 1988-06-09 Wacker Chemitronic METHOD FOR SAWING CRYSTAL RODS OR BLOCKS BY MEANS OF INTERNAL HOLE SAWS IN THIN WINDOWS
CN1010466B (en) 1987-04-09 1990-11-21 哈尔滨工业大学 Superfinish cutting process with diamond for ferrous metals and hard alloys
US4848198A (en) 1988-04-21 1989-07-18 Kennametal Inc. Chip breaking tool holder
US5123250A (en) 1990-04-10 1992-06-23 Union Carbide Canada Limited Cryogenic apparatus
US5025547A (en) * 1990-05-07 1991-06-25 Aluminum Company Of America Method of providing textures on material by rolling
WO1992016464A1 (en) 1991-03-15 1992-10-01 Aga Aktiebolag Method for cooling and lubricating of tools for cutting of molten glass
US5103701A (en) * 1991-04-01 1992-04-14 The United States Of America As Represented By The United States Department Of Energy Diamond tool machining of materials which react with diamond
US5237894A (en) 1991-10-22 1993-08-24 Cleveland State University Material machining with improved fluid jet assistance
JPH0631502A (en) 1992-07-13 1994-02-08 Genichi Sato Cutting tool
US5265505A (en) 1992-10-29 1993-11-30 Frechette Eugene L Turret-lathe coolant system
US5392608A (en) 1993-03-26 1995-02-28 The Boc Group, Inc. Subcooling method and apparatus
JPH06330077A (en) 1993-05-18 1994-11-29 Kobe Steel Ltd Lubricant for cryogenic temperature working of aluminum and its alloy and method for cryogenic temperature working
DE4326517C2 (en) 1993-08-06 1998-06-10 Linde Ag Process for machining metal workpieces with cooling
SE507706C2 (en) 1994-01-21 1998-07-06 Sandvik Ab Silicon carbide whisker reinforced oxide based ceramic cutter
US5509335A (en) * 1994-02-25 1996-04-23 Value Tech Engineering, Inc. Cryogenic vapor oxygen free machining method
US5597272A (en) 1994-04-27 1997-01-28 Sumitomo Electric Industries, Ltd. Coated hard alloy tool
US5432132A (en) 1994-05-25 1995-07-11 The Electrofuel Manufacturing Co. Silicon nitride based cutting tool insert
AU3323695A (en) * 1994-08-09 1996-03-07 Edison Materials Technology Center, The Cryogenic machining
FR2724337A1 (en) 1994-09-09 1996-03-15 Anhydride Carbonique Ind System for cooling material to be machined
US5477691A (en) 1994-09-30 1995-12-26 Praxair Technology, Inc. Liquid cryogen delivery system
JPH08276564A (en) 1994-11-09 1996-10-22 Ichinose Internatl:Kk Automatic rotary screen printer and screen washing method
JP3354024B2 (en) 1994-12-22 2002-12-09 株式会社神戸製鋼所 Lubricants for low-temperature forming of aluminum and aluminum alloy sheets
US5662266A (en) 1995-01-04 1997-09-02 Zurecki; Zbigniew Process and apparatus for shrouding a turbulent gas jet
US5799553A (en) 1995-02-08 1998-09-01 University Of Connecticut Apparatus for environmentally safe cooling of cutting tools
SE9502687D0 (en) * 1995-07-24 1995-07-24 Sandvik Ab CVD coated titanium based carbonitride cutting tool insert
GB9517546D0 (en) 1995-08-26 1995-10-25 Secr Defence Quick release cryogenic coupling
US5592863A (en) * 1995-09-25 1997-01-14 Xerox Corporation Cryogenic machining of soft/ductile materials
AU1162897A (en) 1995-11-22 1997-06-11 Mike Kenney Tool, Inc. Distribution valve for high pressure coolant used in a metalworking machine application
US5762381A (en) * 1995-12-08 1998-06-09 The Perkin-Elmer Corporation Connecting apparatus for conveyance of cryogenic fluid
DE19600172C2 (en) 1996-01-04 1997-12-11 Vandurit Vdh Gmbh Hartmetall U Indexable insert with thermal barrier coating for metalworking
US5878496A (en) 1996-04-09 1999-03-09 Purdue Research Foundation Method of manufacturing a component
US5761974A (en) * 1996-07-22 1998-06-09 Board Of Regents Of The University Of Nebraska System and method for machining heat resistant materials
US5810942A (en) 1996-09-11 1998-09-22 Fsi International, Inc. Aerodynamic aerosol chamber
SE510284C2 (en) 1996-11-18 1999-05-10 Sandvik Ab Internally chilled cutter for chip separating machining
DE19730539C1 (en) 1997-07-16 1999-04-08 Fraunhofer Ges Forschung Lathe tool
US6010283A (en) 1997-08-27 2000-01-04 Kennametal Inc. Cutting insert of a cermet having a Co-Ni-Fe-binder
JP3050183B2 (en) * 1997-09-09 2000-06-12 住友電気工業株式会社 Ceramic tip clamp type cutting tool
US6200198B1 (en) * 1997-10-20 2001-03-13 Enshu Limited Method of cutting of metal materials and non-metal materials in a non-combustible gas atmosphere
US6454877B1 (en) * 1998-01-02 2002-09-24 Dana Corporation Laser phase transformation and ion implantation in metals
US6202525B1 (en) 1998-02-25 2001-03-20 Johns Manville International, Inc. Chopping apparatus
JPH11267902A (en) 1998-03-23 1999-10-05 Hiroshi Hashimoto Tool having ultra-fine cutting blade and processing tool having ultra-fine cutting blade
WO1999060079A2 (en) 1998-05-21 1999-11-25 The Trustees Of Columbia University In The City Of New York Milling tool with rotary cryogenic coolant coupling
JP2955661B1 (en) * 1998-05-29 1999-10-04 東京大学長 Low temperature coupler
SE9803111L (en) * 1998-06-15 2000-03-16 Seco Tools Ab Method
JP2000024801A (en) * 1998-07-08 2000-01-25 Sony Corp Machining method for noble metal
US6105374A (en) 1998-07-28 2000-08-22 Nu-Bit, Inc. Process of nitriding metal-containing materials
JP3449929B2 (en) * 1998-09-08 2003-09-22 日本スピードショア株式会社 Machining method
JP3244072B2 (en) * 1998-09-09 2002-01-07 豊田工機株式会社 Cooling method in grinding
US6330818B1 (en) 1998-12-17 2001-12-18 Materials And Manufacturing Technologies Solutions Company Lubrication system for metalforming
JP2000296438A (en) 1999-04-15 2000-10-24 Ebara Corp Cooling gas spray device
JP2000343427A (en) * 1999-06-07 2000-12-12 Sony Corp Glass press forming die machining device by single point grinding and method therefor
US6360577B2 (en) 1999-09-22 2002-03-26 Scimed Life Systems, Inc. Apparatus for contracting, or crimping stents
DE19953230C2 (en) * 1999-11-04 2003-08-28 C D Waelzholz Produktionsgmbh Cold rolling process
US20020066830A1 (en) * 1999-12-21 2002-06-06 Mullings Lester Earl Vibrational air mover (V. A. M. )
FR2804492B1 (en) 2000-02-02 2002-06-07 Carboxyque Francaise LUBRICATION PROCESS USING LIQUID CARBON DIOXIDE
US6415486B1 (en) 2000-03-01 2002-07-09 Surface Technology Holdings, Ltd. Method and apparatus for providing a residual stress distribution in the surface of a part
US6622570B1 (en) * 2000-03-01 2003-09-23 Surface Technology Holdings Ltd. Method for reducing tensile stress zones in the surface of a part
SE520088C2 (en) 2000-04-06 2003-05-20 Skf Sverige Ab Method for chip cutting machining of a workpiece
JP2002036115A (en) * 2000-07-31 2002-02-05 Sintokogio Ltd Shot peening processing method and processed article thereof
JP2002059336A (en) 2000-08-23 2002-02-26 Mitsubishi Heavy Ind Ltd Cooling air feeder
US6544669B2 (en) 2000-08-24 2003-04-08 Clad Metals Llc Cryogenic treatment of cookware and bakeware
EP1347852B1 (en) * 2000-10-28 2007-08-15 Purdue Research Foundation Method of forming nano-crystalline structures
US6564682B1 (en) * 2000-11-14 2003-05-20 Air Products And Chemicals, Inc. Machine tool distributor for cryogenic cooling of cutting tools on a turret plate
US6513336B2 (en) 2000-11-14 2003-02-04 Air Products And Chemicals, Inc. Apparatus and method for transferring a cryogenic fluid
US6675622B2 (en) * 2001-05-01 2004-01-13 Air Products And Chemicals, Inc. Process and roll stand for cold rolling of a metal strip
US6815362B1 (en) 2001-05-04 2004-11-09 Lam Research Corporation End point determination of process residues in wafer-less auto clean process using optical emission spectroscopy
EP1262280B1 (en) * 2001-05-28 2005-11-02 Hegenscheidt-MFD GmbH & Co. KG Apparatus for deep rolling recesses and radii of journal bearings of crankshafts
US20020189413A1 (en) * 2001-05-31 2002-12-19 Zbigniew Zurecki Apparatus and method for machining with cryogenically cooled oxide-containing ceramic cutting tools
DE10130445A1 (en) * 2001-06-23 2003-01-02 Sms Demag Ag Method and arrangement of nozzles for variable width lubrication of a roll stand
DE10131369A1 (en) 2001-06-28 2003-01-09 Sms Demag Ag Method and device for cooling and lubricating rolls of a roll stand
DE10140718A1 (en) 2001-08-27 2003-04-03 Walter Jaeger Process and tool for machining workpieces with cooling
US20030110781A1 (en) 2001-09-13 2003-06-19 Zbigniew Zurecki Apparatus and method of cryogenic cooling for high-energy cutting operations
US7290397B2 (en) 2001-10-22 2007-11-06 Air Products & Chemicals, Inc. Linearly-actuated cryo-fluid connection (LACC) for manufacturing machines
US6652200B2 (en) 2001-11-01 2003-11-25 Rolf H. Kraemer Tool holder with coolant system
US20030145694A1 (en) 2002-02-04 2003-08-07 Zbigniew Zurecki Apparatus and method for machining of hard metals with reduced detrimental white layer effect
US7252024B2 (en) 2002-05-23 2007-08-07 Air Products & Chemicals, Inc. Apparatus and method for machining with cryogenically cooled oxide-containing ceramic cutting tools
US6767836B2 (en) 2002-09-04 2004-07-27 Asm Japan K.K. Method of cleaning a CVD reaction chamber using an active oxygen species
US7513121B2 (en) 2004-03-25 2009-04-07 Air Products And Chemicals, Inc. Apparatus and method for improving work surface during forming and shaping of materials
DE102004040375A1 (en) * 2004-06-09 2005-12-29 Sms Demag Ag Method and rolling stand for cold rolling of metallic rolling stock, in particular of rolled strip, with nozzles for gaseous or liquid treatment media
US7634957B2 (en) 2004-09-16 2009-12-22 Air Products And Chemicals, Inc. Method and apparatus for machining workpieces having interruptions
US7434439B2 (en) 2005-10-14 2008-10-14 Air Products And Chemicals, Inc. Cryofluid assisted forming method
JP6362637B2 (en) 2016-03-15 2018-07-25 三菱重工業株式会社 Dimensional tolerance analysis system, dimensional tolerance analysis method, three-dimensional model generation program, and recording medium

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7637187B2 (en) 2001-09-13 2009-12-29 Air Products & Chemicals, Inc. Apparatus and method of cryogenic cooling for high-energy cutting operations
US8220370B2 (en) 2002-02-04 2012-07-17 Air Products & Chemicals, Inc. Apparatus and method for machining of hard metals with reduced detrimental white layer effect
US20050211029A1 (en) * 2004-03-25 2005-09-29 Zbigniew Zurecki Apparatus and method for improving work surface during forming and shaping of materials
US7513121B2 (en) 2004-03-25 2009-04-07 Air Products And Chemicals, Inc. Apparatus and method for improving work surface during forming and shaping of materials
US7634957B2 (en) 2004-09-16 2009-12-22 Air Products And Chemicals, Inc. Method and apparatus for machining workpieces having interruptions
US20060207080A1 (en) * 2005-03-17 2006-09-21 Keate Robert A Process of refurbishing brake components
US7676897B2 (en) 2005-03-17 2010-03-16 Keate Robert A Process of refurbishing brake components
US7434439B2 (en) 2005-10-14 2008-10-14 Air Products And Chemicals, Inc. Cryofluid assisted forming method
WO2016099375A1 (en) * 2014-12-16 2016-06-23 Aktiebolaget Skf Bearing component and method of manufacture
US10385919B2 (en) 2014-12-16 2019-08-20 Aktiebolaget Skf Bearing component and method

Also Published As

Publication number Publication date
TW583051B (en) 2004-04-11
KR100612067B1 (en) 2006-08-14
ZA200407017B (en) 2006-06-28
BR0307437A (en) 2005-01-04
US20050016337A1 (en) 2005-01-27
JP2007260904A (en) 2007-10-11
WO2003066916A3 (en) 2004-02-19
AU2003207616A8 (en) 2003-09-02
AU2003207616A1 (en) 2003-09-02
WO2003066916A2 (en) 2003-08-14
JP2005516785A (en) 2005-06-09
JP2007118184A (en) 2007-05-17
EP1472046A2 (en) 2004-11-03
KR20040091009A (en) 2004-10-27
CA2474790A1 (en) 2003-08-14
MXPA04007487A (en) 2004-11-10
US8220370B2 (en) 2012-07-17
TW200302764A (en) 2003-08-16
CN1646259A (en) 2005-07-27

Similar Documents

Publication Publication Date Title
De Oliveira et al. Hard turning in continuous and interrupted cut with PCBN and whisker-reinforced cutting tools
Dhar et al. Cutting temperature, tool wear, surface roughness and dimensional deviation in turning AISI-4037 steel under cryogenic condition
Hong et al. New cooling approach and tool life improvement in cryogenic machining of titanium alloy Ti-6Al-4V
Bosheh et al. White layer formation in hard turning of H13 tool steel at high cutting speeds using CBN tooling
JP2007118184A (en) Apparatus and method for machining hard metal with reduced adverse affect of white layer effect
Wang et al. Hybrid machining of Inconel 718
EP1395391B1 (en) Apparatus and method for machining with cryogenically cooled, oxide containing ceramic cutting tools
Kishawy et al. Tool wear and surface integrity during high-speed turning of hardened steel with polycrystalline cubic boron nitride tools
Sobiyi et al. Performance of mixed ceramics and CBN tools during hard turning of martensitic stainless steel
Aruna et al. Wear analysis of ceramic cutting tools in finish turning of Inconel 718
Rahim et al. Investigation on tool life and surface integrity when drilling Ti-6Al-4V and Ti-5Al-4V-Mo/Fe
de Oliveira et al. Effect of PCBN tool grade and cutting type on hard turning of high-chromium white cast iron
Abrão et al. Surface integrity
Dhar et al. Wear behavior of uncoated carbide inserts under dry, wet and cryogenic cooling conditions in turning C-60 steel
Jacobson Surface integrity of hard-turned M50 steel
Braghini Jr et al. An investigation of the wear mechanisms of polycrystalline cubic boron nitride (PCBN) tools when end milling hardened steels at low/medium cutting speeds
Mou et al. Vibration, tool wear and surface roughness characteristics in turning of Inconel 718 alloy with ceramic insert under LN2 machining
Wang et al. Cryogenic machining of tantalum
KR20060033718A (en) Method for toughening surface of sintered material cutting tool and sintered material cutting tool having long life
Qadri et al. Influence of tool tip temperature on crater wear of ceramic inserts during turning process of inconel-718 at varying hardness
Burhanuddin et al. The effect of tool edge geometry on tool performance and surface integrity in turning Ti-6Al-4V alloys
Han et al. Investigation of tool wear in pull boring of pure niobium tubes
Hung et al. Micromachining of advanced materials
Kamruzzaman et al. Effect of high-pressure coolant on temperature, chip, force, tool wear, tool life and surface roughness in turning AISI 1060 steel
Bonney High-speed machining of nickel-base, Inconel 718, alloy with ceramic and coated carbide cutting tools using conventional and high-pressure coolant supplies

Legal Events

Date Code Title Description
AS Assignment

Owner name: AIR PRODUCTS AND CHEMICALS, INC., PENNSYLVANIA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ZURECKI, ZBIGNIEW;GHOSH, RANAJIT;FREY, JOHN HERBERT;AND OTHERS;REEL/FRAME:012576/0204;SIGNING DATES FROM 20020129 TO 20020204

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION