US2277428A - Diamond abrasive tool - Google Patents

Diamond abrasive tool Download PDF

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Publication number
US2277428A
US2277428A US276585A US27658539A US2277428A US 2277428 A US2277428 A US 2277428A US 276585 A US276585 A US 276585A US 27658539 A US27658539 A US 27658539A US 2277428 A US2277428 A US 2277428A
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United States
Prior art keywords
matrix
diamond
silver
diamond particles
cobalt
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Expired - Lifetime
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US276585A
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Edgar W Engle
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Carboloy Co Inc
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Carboloy Co Inc
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Publication date
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Priority to US276585A priority Critical patent/US2277428A/en
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D3/00—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents
    • B24D3/02—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent
    • B24D3/04—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic
    • B24D3/06—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic metallic or mixture of metals with ceramic materials, e.g. hard metals, "cermets", cements
    • B24D3/08—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic metallic or mixture of metals with ceramic materials, e.g. hard metals, "cermets", cements for close-grained structure, e.g. using metal with low melting point

Definitions

  • the present invention relates to diamond impregnated hard metal compositions and more particularly to an abrasive composition which consists of diamond particlesembedded in a hard metal composition matrix which contains metal from the group copper and silver.
  • abrasive compositions which consist of dia mond particles embedded in a hard metal composition matrix consisting for example of tungsten carbide and cobalt.
  • a composition of this character is disclosed in Taylor Patent 1,996,598.
  • Diamond particles employed in any grinding wheel or drill constitute a large portion of the cost of such articles and it is highly desirable that the diamonds be .held firmly in position. While the cemented carbide matrix disclosed in the Taylor patent holds the diamonds firmly in position in drills, wheel dressers and the like, I have found that in abrasive wheels, cutting-off wheels, laps, and the like, it is possible to obtain even greater gripping action on the diamond particles if the cemented carbide matrix for the diamonds contains a relatively small quantity of metal from the group copper and silver.
  • I employ as the matrix for the diamond particles a mixture of tungsten carbide and metal of the iron group suchas cobalt to which a few per cent of copper, or silver, or both has been added.
  • the cobalt content of the matrix may constitute from about 3 to about 25% by weight of the mixture of tungsten carbide and cobalt, the quantity of cobalt employed depending upon the work to be performed.
  • a tool consisting of about 75 %'of a mixture of WC and 16% Co, /2% of metal from the group copper and silver and 19% diamond particles gives very satisfactory results.
  • the quantity of diamond particles employed in an abrasive tool may vary but in general the quantity employed will be the maximum quantity which the matrix will hold together securely. In cut-oif wheels where-considerable toughness is contain less cobalt, since'there will be a greater thickness of matrix surrounding each diamond particle. With a given amount of wheel wear there will be more binder to be removed with wheels containing a lesser percentage by volume of diamond with the result that if the binder is too tough the tendencyto glaze over theexposed diamond particles will be increased.
  • the matrix can be less tough, that is,
  • the matrix Another factor which determines the composition of the matrix is the peripheral speed at which the wheel operates.
  • the matrix must have sufiicient strength and toughness so that the wheel will not fracture from the forces developed in rotation.
  • the quantity of copper or silver or both employed in the cemented carbide matrix may vary but if too much is employed the copper or silver will glaze the wheel and prevent cutting action.
  • a matrix consisting of about 92% or 93% of a mixture of tungsten carbide and 16% cobalt with about 7% copper or 8% silver gives very satisfactory results.
  • the diamond particles which I employ are capable of passing through a 20 to 120 mesh or 'even finer screen but preferably are capable of passing through a 40 to mesh Grams of test Wheel wear block in change of diameter moved r .001 re uction in wheel diameter Weight in grams of cemented carbide removed from test block Inches Similar wheels containing the same quantity and size of diamond particles embedded in a cemented carbide matrix consisting of 91.9% of a mixture of WC and 16% Co. with 8.1% silver gave the following results:
  • test block removed r .001" re uction in wheel diameter Wheel wear in change of diameter Wcight in grams of cemented carbide removed from test block Inches 6.200 .(Xi2 3.145
  • the tungsten carbide and cobalt is thoroughly mixed for example in a ball mill.
  • the mixed material is then spread out in a thin layer and powdered copper or silver or both added and mixed therewith, usually by hand. Thereafter the diamond-particles are added. These also are hand mixed with the powdered matrix material.
  • the material is placed in a mold care being taken that the diamond particles remain evenly distributed throughodt the powdered metal matrix.
  • a pressure'oi' about 2500 to 3000 lbs. per square inch is applied to the powdered material in the mold while it has a temperature of about 1400 to 1700" C.
  • the pressed material may be heated in any suitable atmosphere, for example in hydrogen.
  • An abrading tool' having a portion thereof consisting of diamond particles distributed in a matrix which consistsof a cemented carbide containing an appreciable quantity and up to about 8% silver.
  • An abrading tool having a portion thereof consisting of diamond particles distributed in a matrix which consists of a cemented carbide containing about 8% silver, said cemented carbide consisting of about 16% cobalt with the remainder tungsten carbide.

Description

Patented Mar. 24, 1942 DIAMOND ABRASIVE TOOL Edgar W. Engle, Grosse Pointe Park, Mich., as-
signor to Carboloy Company, 1110., Detroit, Mich., a corporation of New York No Drawing. Application May 31, 1939, Serial No. 276,585
2 Claims.
The present invention relates to diamond impregnated hard metal compositions and more particularly to an abrasive composition which consists of diamond particlesembedded in a hard metal composition matrix which contains metal from the group copper and silver.
Prior to the presentinvention abrasive compositions have been made which consist of dia mond particles embedded in a hard metal composition matrix consisting for example of tungsten carbide and cobalt. A composition of this character is disclosed in Taylor Patent 1,996,598.
Diamond particles employed in any grinding wheel or drill constitute a large portion of the cost of such articles and it is highly desirable that the diamonds be .held firmly in position. While the cemented carbide matrix disclosed in the Taylor patent holds the diamonds firmly in position in drills, wheel dressers and the like, I have found that in abrasive wheels, cutting-off wheels, laps, and the like, it is possible to obtain even greater gripping action on the diamond particles if the cemented carbide matrix for the diamonds contains a relatively small quantity of metal from the group copper and silver.
In carrying out my invention, I employ as the matrix for the diamond particles a mixture of tungsten carbide and metal of the iron group suchas cobalt to which a few per cent of copper, or silver, or both has been added. The cobalt content of the matrix may constitute from about 3 to about 25% by weight of the mixture of tungsten carbide and cobalt, the quantity of cobalt employed depending upon the work to be performed. A tool consisting of about 75 %'of a mixture of WC and 16% Co, /2% of metal from the group copper and silver and 19% diamond particles gives very satisfactory results.
The quantity of diamond particles employed in an abrasive tool may vary but in general the quantity employed will be the maximum quantity which the matrix will hold together securely. In cut-oif wheels where-considerable toughness is contain less cobalt, since'there will be a greater thickness of matrix surrounding each diamond particle. With a given amount of wheel wear there will be more binder to be removed with wheels containing a lesser percentage by volume of diamond with the result that if the binder is too tough the tendencyto glaze over theexposed diamond particles will be increased. In pro ducing a thin disc cutting wheel with a volume relation of two parts matrix and one part diamond, I use an inherently tougher matrix than in the case of a surface grinding wheel with approximately equal volumes of diamond and required the volume of diamond particles may ployed, it maybe found that with diamonds within mesh limits of 20 to 120, there is not enough matrix material to grip all the diamonds.
As the percentage volume of diamonds decreases the matrix can be less tough, that is,
matrix. Another factor which determines the composition of the matrix is the peripheral speed at which the wheel operates. The matrix must have sufiicient strength and toughness so that the wheel will not fracture from the forces developed in rotation.
The quantity of copper or silver or both employed in the cemented carbide matrix may vary but if too much is employed the copper or silver will glaze the wheel and prevent cutting action. A matrix consisting of about 92% or 93% of a mixture of tungsten carbide and 16% cobalt with about 7% copper or 8% silver gives very satisfactory results. The diamond particles which I employ are capable of passing through a 20 to 120 mesh or 'even finer screen but preferably are capable of passing through a 40 to mesh Grams of test Wheel wear block in change of diameter moved r .001 re uction in wheel diameter Weight in grams of cemented carbide removed from test block Inches Similar wheels containing the same quantity and size of diamond particles embedded in a cemented carbide matrix consisting of 91.9% of a mixture of WC and 16% Co. with 8.1% silver gave the following results:
Grams of tcst block "re-' moved r .001" re uction in whccl diameter \\'heel wear in change in diameter Weight in grams of cemented carbide removed from test block Inclm 5.003 s. we
Similar wheels containing the same quantity and size of diamond particles embedded in a cemented carbide matrix consisting of 93% of a mixture of tungsten carbide and 16% cobalt with 7% copper gave the following results:
Grams of test block removed r .001" re uction in wheel diameter Wheel wear in change of diameter Wcight in grams of cemented carbide removed from test block Inches 6.200 .(Xi2 3.145
In the manufacture of the above abrasive tools the tungsten carbide and cobalt is thoroughly mixed for example in a ball mill. The mixed material is then spread out in a thin layer and powdered copper or silver or both added and mixed therewith, usually by hand. Thereafter the diamond-particles are added. These also are hand mixed with the powdered matrix material. When mixed to the desired extent the material is placed in a mold care being taken that the diamond particles remain evenly distributed throughodt the powdered metal matrix. A pressure'oi' about 2500 to 3000 lbs. per square inch is applied to the powdered material in the mold while it has a temperature of about 1400 to 1700" C. The pressed material may be heated in any suitable atmosphere, for example in hydrogen.
What I claim as new and desire to secure by Letters Patent of the United States is:
1. An abrading tool'having a portion thereof consisting of diamond particles distributed in a matrix which consistsof a cemented carbide containing an appreciable quantity and up to about 8% silver.
2. An abrading tool having a portion thereof consisting of diamond particles distributed in a matrix which consists of a cemented carbide containing about 8% silver, said cemented carbide consisting of about 16% cobalt with the remainder tungsten carbide.
EDGAR W. ENGLE.
US276585A 1939-05-31 1939-05-31 Diamond abrasive tool Expired - Lifetime US2277428A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US276585A US2277428A (en) 1939-05-31 1939-05-31 Diamond abrasive tool

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US276585A US2277428A (en) 1939-05-31 1939-05-31 Diamond abrasive tool

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