摘要:
A roller bearing that provides ball and roller bearing elements comprised of M50 steel and M50NiL steel having surface hardnesses above 60 HRC, and in the range of 65-72 HRC. The hardness in the surface region is achieved by nitriding the surface to achieve a high hardness and extended life. This improvement is brought about by controlling the microstructure of the alloy by minimizing the formation of retained austenite. The material is tempered as required. The surface is then nitrided, but the nitriding operation is carefully controlled to avoid the formation of intergranular nitrides. Because of the method used to prevent the formation of intergranular nitrides, some carbon may be present to prevent the surface of the steel from becoming depleted of carbon. The hardening element in this nitro-carburizing operation is nitrogen, which forms iron nitride as Fe3N or Fe4N intragranularly. The purpose of the carbon in the operation is to maintain the concentration of carbon in the surface of the bearing so that the properties are not altered by decarburizing the surface. Standard gaseous and plasma nitriding techniques also may be used for the nitriding operation.
摘要翻译:一种滚动轴承,其提供由M50钢和M50NiL钢组成的球和滚子轴承元件,其表面硬度高于60HRC,并且在65-72HRC的范围内。 表面区域的硬度是通过对表面进行氮化而实现的,以达到高硬度和延长使用寿命。 通过最小化残余奥氏体的形成来控制合金的微观结构,可以实现这种改进。 材料根据需要回火。 然后将表面氮化,但是精心控制氮化操作以避免形成晶间氮化物。 由于用于防止形成晶间氮化物的方法,可能存在一些碳以防止钢的表面变成碳。 该硝基渗碳操作中的硬化元素是氮,其形成Fe 3 N 3或Fe 4 N N的氮化铁。 操作中的碳的目的是保持轴承表面中碳的浓度,使得通过对表面进行脱碳来改变其性能。 标准的气体和等离子体氮化技术也可用于氮化操作。