US3770595A - Method of treatment of steel parts in order to increase their resistance to wear and abrasion - Google Patents

Method of treatment of steel parts in order to increase their resistance to wear and abrasion Download PDF

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US3770595A
US3770595A US00200965A US3770595DA US3770595A US 3770595 A US3770595 A US 3770595A US 00200965 A US00200965 A US 00200965A US 3770595D A US3770595D A US 3770595DA US 3770595 A US3770595 A US 3770595A
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cold
treatment
depth
working
deformation
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US00200965A
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G Cros
G Mazet
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CENTRE STEPHANOIS RECH MECAN HYDROMECAN ET FROTTEMENT FR
STEPHANOIS RECH
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STEPHANOIS RECH
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Priority claimed from FR7041921A external-priority patent/FR2115505A5/fr
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    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/04Ferrous alloys, e.g. steel alloys containing manganese
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D7/00Modifying the physical properties of iron or steel by deformation
    • C21D7/02Modifying the physical properties of iron or steel by deformation by cold working
    • C21D7/04Modifying the physical properties of iron or steel by deformation by cold working of the surface
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/02Pretreatment of the material to be coated
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23FNON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F17/00Multi-step processes for surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by subclass C21D or C22F or class C25
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25DPROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D9/00Electrolytic coating other than with metals
    • C25D9/04Electrolytic coating other than with metals with inorganic materials
    • C25D9/06Electrolytic coating other than with metals with inorganic materials by anodic processes
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M61/00Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/16Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • F02M61/166Selection of particular materials
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M61/00Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/16Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • F02M61/168Assembling; Disassembling; Manufacturing; Adjusting

Definitions

  • ABSTRACT PP N05 200,965 A method of treatment of steel parts in order to increase their resistance to wear and abrasion, comprises [30] Foreign Application p i i Dam essentially a mechanical operation of cold-deformation NOV 23 1970 France 7041921 of the material effecting cold-working to a depth of 971 France 7140884 about 1.5 mm. to 3 mm. and a complementary mechanical operation of cold-working at the surface, effected 7 up to about 0.2 mm.
  • the knurling operation results in a dimensional variation which is not the same from one part to the other. 3.
  • the cold-working operation leaves on the surface of cause damage during running-in if they are set free by friction.
  • the present invention has for its object a method of treatment of steel parts in order to increase their resistance to wear and to abrasion, characterized by at least two mechanical operations of cold deformation, one a cold-working in depth, for example up to about 2 or 3 mm., the other to increase the cold-working at the surface, for example up to about 0.2 mm. to 0.5 mm. If so desired, these operations may be followed by an electro-chemical treatment in a bath of salts at low temperature.
  • the mechanical operations are such that on the one hand there is produced a gradient of residual stresses such that the value of these stresses at the surface is greater than 80 daN/sq.mm. and then decreases gradu ally so as to reach 30 daN/sq.mm. at about 0.4 mm. in depth, and such that on the other hand there is produced a cold-working gradient such that at at least 0.2 mm. in depth, the vickers hardness is greater than 550.
  • the electro-chemical operation is such that it leads to the formation at the surface of a superficial layer which inhibits welding, composed of a compound between a metalloid and the iron of the steel base, and such that this layer is obtained by immersion of the parts in a bath of salts at a temperature less than 400C., and preferably lower than 250C.
  • the mechanical operations consist of a knurling and a rollering, and are followed by a sulphuration at low temperature.
  • the knurling operation has the object of coldworking the part to a depth of at least 1.5 mm., and. also to impress by forging on the surface of the part, patterns in a direction substantially perpendicular to the direction subsequently followed by the friction.
  • the rollering operation has the object, on the one hand of obtaining a surface vickers hardness greater than 700, and on the other hand to bring the part, which had increased in diameter after knurling, very exactly back to the dimension which it had before the first knurling operation, that is to say upon completion of machining.
  • the operation of sulphuration by electro-ch'emical means has the object, on the one hand of forming at the surface of the parts a layer of iron sulphide of about ten the metal fragmented zones or burrs which are liable to v microns, known as the weld-inhibitor layer, making it possible to prevent any risk of the part becoming welded during the running-in period on the other piece with which it is intended to co-operate in friction, and on the other hand to eliminate by chemical composition the burrs formed as a result of the first knurling operation.
  • This sulphuration is carried out at very low temperature, namely below 400C., advantageously below 250C. and preferably below 200C., and does not in any way modify the characteristics of resilience of the parts.
  • a sulphuration of this kind can be effected for example by electrolysis in a bath containing for the major part alkaline thiocyanates.
  • each of the three above operations individually makes it possible to improve the qualities of the part, the first by deep cold-working, the second by surface hardening, the third by the creation of a weld-inhibiting layer, and that furthermore there exist ties of co-operation between them having an effect of combination, in this sense that the second restores the limits and dimensions that the first has altered, while the third directly suppresses the burrs resulting from the first said operation and left by the second.
  • the mechanical operations of cold deformation are effected by rolling and coiling.
  • the mechanical operations of cold deformation are effected by rolling and hammering to shape.
  • the mechanical operations of cold deformation are effected by stamping and chasing.
  • F161 is a diagram illustrating the gradient of residual stresses, in which there has been plotted as abscissae 0D the distance from the surface, or depth, in microns, and as ordinates OR the compression stress in daN/sq.mm.;
  • FIG.2 is a diagram illustrating the gradient of coldworking, in which there has been plotted as abscissae OD the distance from the surface or depth in microns, and as ordinates 0V, the vickers hardness HV under a load of grams.
  • EXAMPLE 1 There are treated a shaft and a ring of 40 mm. in diameter which are made from a HADFIELD steel containing 1.2 percent of carbon, 12 percent of manganese, in the supertempered state at l050C. with a powerful cooling.
  • the knurling tools carry two 'knurling wheels of 20 mm. in diameter, producing on the parts two families of striations, the depth of which is comprised between 0.3 mm. and 1.0 mm. and preferably in the vicinity of 0.7 mm.
  • the striations are spaced apart from each other by a distance comprised between 1 mm. and 2 mm. and preferably in the vicinity of l mm.
  • the striations are transverse with respect to the direction specified for the friction and are advantageously inclined with respect to this direction. This inclination is preferably 60, which amounts to saying that the striations are inclined by 30 to the direction of the generator lines;
  • Each knurling wheel passes 20 times in front of the same point of the part to be cold-worked
  • the force of application of the knurled wheels (length of generator line of the wheel: 10 mm.) on the part is comprised between 200 kg and 1000 kg and preferably in the vicinity of 600 kg.
  • the tool carries two smooth wheels, that is to say without striations and cambered with a radius of camber comprised between 100 mm. and 300 mm., and preferably in the vicinity of 200 mm.;
  • the force of application of the wheels on the part is comprised between 100 kg and 5 00 kg and preferably in the vicinity of 300 kg;
  • Each wheel passes 20 times opposite a same point of the part.
  • the shaft and ring parts of HADFIELD steel show in cross-section, under metallographic examination, extremely dense systems of slip lines penetrating to a depth of more than 1 mm.
  • the micro-hardness indicates on the one hand hardnesses greater than 700 HV for the first three-tenths of a millimetre from the surface, and on the other hand a progressive fall in this hardness beyond 0.3 mm., the hardness of the base metal (250 HV) being found only at a depth of between 1 mm. and 1.5 mm.
  • the parts are then subjected to an electro-chemical sulphuration at a low temperature, less than 250C.
  • This sulphuration is effected in an electrolytic bath containing for the major part alkaline thio-cyanates, the temperature of which is advantageously comprised between 150 and 200C. for a duration comprised between 2 and 30 minutes and preferably in the vicinity of 10 minutes.
  • the anode is formed by each part treated and the anode current has a density comprised between 1A and 10 A per sq.dm. and preferably in the vicinity of 3 A per sq.dm.
  • the sulphuration treatment has the following characteristics:
  • Cathode crucible of ferritic stainless steel
  • composition of the bath in percentage by weight isomer of the bath in percentage by weight:
  • Density of anode current 3.5 A/sq.dm.
  • Parts thus conditioned are capable of greatly increased performances under friction as compared with those which could be obtained with parts of the same grade but which were not subjected to the three operations referred to above.
  • the shaft of 40 mm. in diameter is allowed to oscillate in a ring of 40 mm. in length under a pressure of 200 bars.
  • the assembly is mounted with very slight lubrication and with an initial play of 0.1 mm.
  • the amplitude of the oscillations is 90 and their frequency is l Hertz.
  • the shaft and the ring treated according to the present example of embodiment have oscillated for 1450 hours. When they were dismantled, the wear on the shaft was 0.2 mm. and on the ring 0.3 mm.
  • one of the mechanical operations of cold deformation effects cold-working in depth, for example up to 2 mm. in the example shown in FlG.2 (this could be more, for example 2.5 mm. or 3 mm., or less, for example 1.5 mm.) while the other mechanical operation completes the cold working on the surface, for example and without any limitation, up to about 0.2 mm. or 0.5 mm.
  • the operations are such that the gradient of the residual stresses corresponds to a curve comprised between the curves C and C of P101, and that the gradient of cold working corresponds to a curve comprised between the curves C and C of P162.
  • the residual stress gradient is such that the value of these stresses at the surface is greater than daN/sq.mm. and then gradually decreases so as to reach 30 daN/sq.mm. at about 0.4 mm. of depth.
  • the cold-working gradient is such that below at least 0.2 mm. in depth, the hardness is greater than 550 HV.
  • the electro-chemical operation leads to the formation on the surface of a surface layer which inhibits welding, made of a compound between a metalloid and the iron of the steel base, and that this layer is obtained by immersion of the parts in a bath of salts at a temperature less than 400C, and preferably less than 250C.
  • Cathode crucible of ferritic stainless steel; Composition of the bath in percentage by weight:
  • EXAMPLE III This concerns a method of treatment of a tape, comprising a succession in the order given, of the three following operations:
  • a coiling operation having the purpose on the one hand of increasing the cold-working by deformation (drawing, bending) and on the other hand of obtaining the desired geometrical shape;
  • Example l The two mechanical operations of rolling and laminating are such that the characteristics described in Example l are obtained (FIGS.1 and 2) while the electrochemical operation may also be carried out as described in the said Example 1.
  • EXAMPLE IV This is concerned with a method of treatment of a ribbon, comprising the succession, in the order given, of three operations:
  • Example 1 The two mechanical operations of rolling and hammer-shaping are such that the characteristics described in Example 1 are obtained (see FIGSJ and 2) while the electro-chemical operation can also be effected as described in the said Example 1.
  • EXAMPLE V This relates to a method of treatment of a metal sheet, comprising the succession, in the order stated, of the following operations:
  • a stamping-chasing operation on the metal sheet in a deforming machine This operation makes it possible on the one hand to obtain cold-working at the surface and in depth by deformation of the material, and on the other hand to preserve a definite 1 geometric shape while respecting close tolerances.
  • This method may be applied for example by means of a deforming machine on which is mounted a mandrel, the material to be deformed being imprisoned in this mandrel and by a plate-clamp.
  • a mechanical or hydraulic system makes it possible to chase the plate to be deformed and to give it'the desired geometrical shape.
  • a gradient of residual stresses (FIG.1) such that the values of these stresses at the surface are higher than daN/sq.mm. and then progressively decrease so as to reach 30 daN/sq.mm. at about 0.4 mm. in depth.
  • a gradient of residual stresses of this kind may be obtained either by allotropic surface conversion of the metal (change of phase 1 a), or by cold-working properly so-called. This gradient of values of residual stresses makes it possible to avoid surface destruction of the parts by over-stresses of tension arising behind the zone of contact of the two parts in frictional contact.
  • This weldinhibiting layer which must on the other hand he obtained at a low temperature (less than 400C. and preferably less than 250C may be a sulphide or a telluride or an iodide of iron, etc., and its function is particularly beneficial in the case of parts working under large stresses and operating under conditions of doubtful lubrication.
  • Non-limitative' tests of the method according to the invention are described below. These tests were carried out on a simulator utilizing a shaft of 50 mm. in diameter oscillating in a ring of 50 mm. in diameter and 50 mm. in length, under a pressure of 100 bars, the whole unit being mounted with slight lubrication and with an initial play of 0.1 mm. The amplitude of the oscillations was and their frequency was l Hertz.
  • the ring is produced by rolling and then winding of a steel ribbon with 1.2 percent of carbon and 12 percent of manganese previously super-tempered. There are thus obtained residual compression stresses at the surface equal to 90 daN/sq.mm. and a surface hardness of 750 HV. These tests were stopped after 1450 hours working. No sign of seizure could be observed. The wear on the shaft and on the ring was of the order of 2/10 mm.
  • a method of treatment of steel parts in order to increase their resistance to wear and abrasion comprising cold deforming the material effecting cold-working to a depth of about 1.5-3 mm, and further cold-working the surface of said material to a depth of about 0.2-0.5 mm.
  • a method of treatment as claimed in claim I in which a gradient of residual stresses is obtained, such that the value of said stresses on the surface is higher than daN/sq.mm. and then progressively decreases so as to reach 30 daN/sq.mm. at a depth of about 0.4
  • a method of treatment as claimed in claim I and thereafter forming on the surface of the material a superficial layer composed of a sulphur-containing compound between a metalloid and the iron of the steel base.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • General Engineering & Computer Science (AREA)
  • Inorganic Chemistry (AREA)
  • Electrochemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Heat Treatment Of Articles (AREA)
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  • Heat Treatment Of Sheet Steel (AREA)
US00200965A 1970-11-23 1971-11-22 Method of treatment of steel parts in order to increase their resistance to wear and abrasion Expired - Lifetime US3770595A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR7041921A FR2115505A5 (en) 1970-11-23 1970-11-23 Increasing wear and abrasion resistance of steel workpieces - using t mechanical cold hardening operations
FR7140884A FR2161155A6 (xx) 1970-11-23 1971-11-16

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US (1) US3770595A (xx)
JP (1) JPS5635731B1 (xx)
BE (1) BE775652A (xx)
CA (1) CA958202A (xx)
DE (1) DE2157823A1 (xx)
FR (1) FR2161155A6 (xx)
GB (1) GB1374116A (xx)
IT (1) IT942917B (xx)
LU (1) LU64311A1 (xx)
NL (1) NL7116084A (xx)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0115046A2 (de) * 1983-01-03 1984-08-08 Asea Ab Eisenbahnrad
EP0381648A1 (en) * 1989-02-02 1990-08-08 Sandvik Aktiebolag Method to increase the strength of an element for percussive drilling
US5826453A (en) * 1996-12-05 1998-10-27 Lambda Research, Inc. Burnishing method and apparatus for providing a layer of compressive residual stress in the surface of a workpiece
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
US20030085257A1 (en) * 2001-11-02 2003-05-08 The Boeing Company Apparatus and method for forming weld joints having compressive residual stress patterns
US6589412B1 (en) * 1999-10-20 2003-07-08 Dowa Mining Co., Ltd. Method for producing a sliding member having excellent seizure resistance
US6622570B1 (en) 2000-03-01 2003-09-23 Surface Technology Holdings Ltd. Method for reducing tensile stress zones in the surface of a part
AU775549B2 (en) * 1998-10-08 2004-08-05 Surface Technology Holdings, Ltd., Burnishing method and apparatus for providing a layer of compressive residual stress in the surface of a workpiece
US20100044234A1 (en) * 2006-11-24 2010-02-25 H.E.F. Sulphuration method of ferrous alloy parts in an aqueous solution
US9789582B2 (en) 2012-07-05 2017-10-17 Surface Technology Holdings Ltd. Method and compression apparatus for introducing residual compression into a component having a regular or an irregular shaped surface
CN111774822A (zh) * 2020-08-13 2020-10-16 无锡金峰园弹簧制造有限公司 一种热卷弹簧芯轴的加工工艺
US20210092856A1 (en) * 2019-09-23 2021-03-25 Apple Inc. Surface nanograin for improved durability of metal bands

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3567062D1 (en) * 1985-10-22 1989-02-02 Voest Alpine Automotive Method of manufacturing an injection nozzle housing

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US147502A (en) * 1874-02-17 Improvement in the methods of treating sheet-iron for rolling
US2078434A (en) * 1935-04-11 1937-04-27 Sutton Eng Co Method of finishing rounds
US2116107A (en) * 1937-06-08 1938-05-03 Wheeling Steel Corp Container, container stock, and method of making the same
US2260779A (en) * 1937-10-28 1941-10-28 Hoffmann Ernst Method of making ferroconcrete reinforcing elements
US2626532A (en) * 1951-11-21 1953-01-27 Motch Merryweather Machinery Cutting tool mounting and method of making
US3073022A (en) * 1959-04-03 1963-01-15 Gen Motors Corp Shot-peening treatments
US3321338A (en) * 1963-12-11 1967-05-23 Berliet Automobiles Friction elements especially resistant to wear by abrasion

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US147502A (en) * 1874-02-17 Improvement in the methods of treating sheet-iron for rolling
US2078434A (en) * 1935-04-11 1937-04-27 Sutton Eng Co Method of finishing rounds
US2116107A (en) * 1937-06-08 1938-05-03 Wheeling Steel Corp Container, container stock, and method of making the same
US2260779A (en) * 1937-10-28 1941-10-28 Hoffmann Ernst Method of making ferroconcrete reinforcing elements
US2626532A (en) * 1951-11-21 1953-01-27 Motch Merryweather Machinery Cutting tool mounting and method of making
US3073022A (en) * 1959-04-03 1963-01-15 Gen Motors Corp Shot-peening treatments
US3321338A (en) * 1963-12-11 1967-05-23 Berliet Automobiles Friction elements especially resistant to wear by abrasion

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0115046A3 (en) * 1983-01-03 1985-03-20 Asea Ab Railroad wheel
EP0115046A2 (de) * 1983-01-03 1984-08-08 Asea Ab Eisenbahnrad
EP0381648A1 (en) * 1989-02-02 1990-08-08 Sandvik Aktiebolag Method to increase the strength of an element for percussive drilling
US5826453A (en) * 1996-12-05 1998-10-27 Lambda Research, Inc. Burnishing method and apparatus for providing a layer of compressive residual stress in the surface of a workpiece
WO2000020170A1 (en) * 1996-12-05 2000-04-13 Lambda Research, Inc. Burnishing method and apparatus for providing a layer of compressive residual stress in the surface of a workpiece
AU775549B2 (en) * 1998-10-08 2004-08-05 Surface Technology Holdings, Ltd., Burnishing method and apparatus for providing a layer of compressive residual stress in the surface of a workpiece
US6589412B1 (en) * 1999-10-20 2003-07-08 Dowa Mining Co., Ltd. Method for producing a sliding member having excellent seizure resistance
US6622570B1 (en) 2000-03-01 2003-09-23 Surface Technology Holdings Ltd. Method for reducing tensile stress zones in the surface of a part
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
US20030085257A1 (en) * 2001-11-02 2003-05-08 The Boeing Company Apparatus and method for forming weld joints having compressive residual stress patterns
US6926970B2 (en) 2001-11-02 2005-08-09 The Boeing Company Apparatus and method for forming weld joints having compressive residual stress patterns
US20100044234A1 (en) * 2006-11-24 2010-02-25 H.E.F. Sulphuration method of ferrous alloy parts in an aqueous solution
US8562812B2 (en) * 2006-11-24 2013-10-22 H.E.F. Sulphuration method of ferrous alloy parts in an aqueous solution
US9789582B2 (en) 2012-07-05 2017-10-17 Surface Technology Holdings Ltd. Method and compression apparatus for introducing residual compression into a component having a regular or an irregular shaped surface
US20210092856A1 (en) * 2019-09-23 2021-03-25 Apple Inc. Surface nanograin for improved durability of metal bands
CN111774822A (zh) * 2020-08-13 2020-10-16 无锡金峰园弹簧制造有限公司 一种热卷弹簧芯轴的加工工艺
CN111774822B (zh) * 2020-08-13 2024-06-11 无锡金峰园弹簧制造有限公司 一种热卷弹簧芯轴的加工工艺

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Publication number Publication date
CA958202A (en) 1974-11-26
IT942917B (it) 1973-04-02
DE2157823A1 (de) 1972-05-31
GB1374116A (en) 1974-11-13
BE775652A (fr) 1972-03-16
FR2161155A6 (xx) 1973-07-06
NL7116084A (xx) 1972-05-25
JPS5635731B1 (xx) 1981-08-19
LU64311A1 (xx) 1972-06-13

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