We all know that heat treatment technology, the application how many people really understand it? Today I put the bearing application of heat treatment technology made it clear to everyone.
(1) expand the range of applications of GCr15 steel, general the GCr15 steel M quenching ferrule effective wall thickness 12mm, BL quenching ability of nitrate cooling, stirring, string action, add water, and other measures, the ferrule effective wall thickness can be extended to about 28 mm.
(2) hardness and stability, good uniformity BL change is a slow process, generally GCr15 steel need 4h the steel GCr18Mo need 5h rings nitrate in the long isothermal surface the heart organized by the Ministry of transition almost simultaneously, so the hardness and stability, good uniformity, GCr15 steel BL after quenching hardness of 59 to 61HRC, uniformity ≤ 1 HRC, not like quenching ferrule wall thickness slightly larger low hardness, soft spots, poor uniformity problems.
(3) to reduce quenching, grinding cracks Railway, rolling bearings production, obtained after quenching The high hardness often take strong cooling measures, resulting in quenching micro-cracks; BL quenching due to the ferrule size, weight, brittleness the oil quenching M organization, BL organization toughness better than M organization, up to -400 to 500 MPa of the compressive stress is formed on the surface at the same time, greatly reduces the tendency to crack quenching offset some of the grinding stress; grinding surface compressive stress, so that the overall level of stress decreased greatly reduces the grinding cracks.
(4) bearing service life by Withstand large impact loads railway, rolling mill bearings, and M after quenching from the main failure in the form of: assembling sets of cracks within the course of the the impact outer wall off the block, the inner ring fragmentation, Austempering bearing the impact toughness, surface compressive stress, regardless of the assembly sets of cracks within, or the jacket wall off the block the use of the process, within the set of fragmentation tendency is greatly reduced, and can reduce the stress concentration edge of roller. By austempering after than after quenching M average life and increased reliability.
