Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING 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
  • C23C—COATING 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
  • C23C8/00—Solid 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
  • C23C8/06—Solid 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 using gases
  • C23C8/08—Solid 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 using gases only one element being applied
  • C23C8/20—Carburising
  • C23C8/22—Carburising of ferrous surfaces
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING 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
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/40—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rings; for bearing races

Definitions

• the invention relates to a method for producing a hardened component consisting of a non-magnetizable austenitic material by carburizing the near-surface material layer at high temperature in an oxygen-free, gaseous hydrocarbon-containing atmosphere and then cooling it.
• Such components are such.
• a method for producing rolling bearing components of this type is already known, which provides for the hardness of the rolling bearing component to be increased by work hardening.
• the known method is only of limited use, since work hardening, which leads to hardnesses of more than 450 HV, leads to the formation of forming martensite in the structure of the rolling bearing component, which makes it magnetisable, for applications in which non-magnetisable rolling bearing components require a higher load capacity is no longer usable.
• non-magnetizable rolling bearing components produced by the known method have only about 25% of the load capacity of comparable conventional rolling bearing components.
• the present invention has for its object to provide a method of the type mentioned, which makes it possible to produce components made of austenitic material which, while maintaining their non-magnetizability, have a load capacity comparable to roller bearing components made of roller bearing steel.
• the component is a roller bearing component, the oxygen-free atmosphere containing CH4, or C3H8, or a mixture of both.
• the method according to the invention creates a structure in the surface area of the rolling bearing component, which consists of a cementite-rich phase, which is comparable in terms of metallurgy and crystallography with leather burit and is largely non-magnetic and can have a hardness of up to 700 HV.
• the core area of the component consists of the austenitic starting material.
• roller bearing components produced by the process according to the invention surprisingly retain their strength and hardness up to temperatures of 600 ° C., so that they are suitable not only for applications in which an unmagnetizable rolling bearing is required, but also for such applications that require high temperature resistance of the rolling bearing.
• roller bearings made from roller bearing components produced by the method according to the invention are suitable for those applications in which roller bearings interact with adjacent components made of aluminum alloys, since the thermal expansion coefficient of austenitic materials corresponds to that of aluminum alloys. The fitting problems that occur in conventional roller bearings due to the different thermal expansion coefficients can thus be avoided by using roller bearing components produced by the method according to the invention.
• Rolling bearing components with a hardness of more than 700 HV can be produced if the oxygen-free atmosphere contains atomic nitrogen according to an embodiment of the invention. It then diffuses nitrogen into the near-surface material layer of the rolling bearing component, which forms nitrides there, which further increase the hardness of the near-surface structure.
• a particularly uniform structure of the near-surface material layer of the roller bearing component is achieved if, according to one embodiment of the invention, the roller bearing component is carburized at temperatures between 800 and 100 ° C., but preferably between 880 and 960 ° C.
• roller bearing component produced by the method according to the invention meets the requirements to a particularly high degree if the carbon content in the near-surface material layer according to one embodiment of the invention has at least 1.5% and the roller bearing component according to a further embodiment of the invention has a surface hardness of at least 550 HV .
• the rolling bearing component produced by the method according to the invention consists of one of the austenitic materials X 5 CrNi 18 9, X 12 CrNiS 18 8, X 12 CrNi 17 7 or X 10 CrNiTi 18 9, which, as has been shown, for the method according to the invention are particularly suitable.
• roller bearing component made of an austenitic material which has a hardness in its material layer close to the surface which is sufficient for the typical roller bearing stresses and which is nevertheless non-magnetizable.
• the roller bearing component produced by the method according to the invention has high heat resistance and also has increased corrosion resistance compared to conventional roller bearing components.
• the rolling bearing component produced by the method according to the invention can interact with components consisting of aluminum alloys without fitting problems, since both have approximately the same coefficient of thermal expansion.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Rolling Contact Bearings (AREA)
• Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=6284238

Family Applications (1)

Country Status (4)

Families Citing this family (5)

Family Cites Families (21)

• 1985
  • 1985-10-23 DE DE19853537658 patent/DE3537658A1/de active Granted
• 1986
  • 1986-09-11 US US06/906,365 patent/US4888065A/en not_active Expired - Fee Related
  • 1986-10-02 DE DE8686113601T patent/DE3681137D1/de not_active Expired - Lifetime
  • 1986-10-02 EP EP86113601A patent/EP0226729B1/de not_active Expired - Lifetime
  • 1986-10-23 JP JP61250948A patent/JPS6299454A/ja active Pending

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events