Jiaxing bearing, bearing steel heat treatment microstructure of relevant knowledge

There is rotational, have HRB bearing ( ) Jiaxing bearing, bearing steel heat treatment microstructure of relevant knowledge. Jiaxing bearing group sales co. , LTD. ( The company) Is jiaxing bearing factory set up in the spot sales window, specializing in HRB brand bearings, facing the whole country, the existing stock 50 million yuan, covers the whole bearing, have very strong cash supply ability. Bearing steel heat treatment microstructure of knowledge: martensite: under normal circumstances, GCr15 quenching temperature is about 840 ℃, and usually does not exceed 850 ℃. GCr15SiMn quenching temperature is about 820 ℃, generally does not exceed 835 ℃. Too high or too low will cause the temperature of martensite overheating or less heat. Qualification standard martensite 15 ( Miniature components level 13) 。 Add strict level is 14 for the wall thickness is small ( The six - 7 mm below) Products to level 13. Martensite thickness is mainly related to the heating temperature and heating time. Bainite isothermal quenching bainite: general use of the material is GCr15 and GCr18Mo, effective thickness of GCr15 steel processing parts is more control within 30 mm, GCr18Mo heating temperature can be extended to 65 mm: whether GCr15 or GCr18Mo, temperature 865 ℃ ~ 890 ℃ isothermal temperature, whether is it GCr15 GCr18Mo, the Ms point is 225 ℃, commonly used 235 - isothermal temperature 245℃。 Holding time: generally should not be less than 4 hours according to standard JB/T1255 assessment 1 - Level 3 qualification, bainite and heating temperature and heating time, isothermal temperature and time on the troostite: troostite is produced when heated or hardening of the martensite and bainite organization, do not want it to exist. Standard stipulated in the effective wall thickness is not more than 12 mm, the core is not more than 12 level; Greater than 12 mm, 3 mm on the surface of the ministry of external control, surface within 3 mm to allow a small amount of troostite troostite produces mainly poor cooling or heating is insufficient, mainly cooling bad reason: oil quenching heart department generally don't appear troostite effective wall thickness is about 8 mm, the quenching salt core generally don't appear troostite effective wall thickness is 15 mm or so, strengthen the medium flow, improve the quenching temperature, increase the clearance between the tooling and parts or components, such as salt water can reduce the generation of troostite, sometimes can be found that the surface has troostite, and the core is not, too much of water content in general is medium caused by residual austenite, the residual austenite is caused by the martensitic transformation is incomplete, the amount of residual austenite is good for the life of the parts. General 710% cryogenic treatment after quenching tempering can have 4% 58% after the cold processing special requirements can be achieved 1530% generally there is a requirement for reducing austenitic, to increase the cold water processing ( Line with refrigerator) The less, the lower the temperature, the paralympic reduce the residence time in the quenching medium, will also reduce the paralympic. Residual austenite request below 5%, to adopt cryogenic processing ( - 70℃- 90℃） 。 24-hour customer service hotline: if you are more interested in jiaxing bearing the author introduced the industry information or have any questions, please click on contact us page on the right side of the online customer service, or call:, you close the way of jiaxing bearing purchasing advisors. - - - - - - Editor: jiaxing bearing sourcing consultant LTD. All rights reserved, The company) Reprint please indicate the source