盐浴渗氮对G80Cr4Mo4V高温轴承钢组织与性能的影响

Effect of Salt Bath Nitriding on Microstructure and Properties of G80Cr4Mo4V High Temperature Bearing Steel

研究了盐浴渗氮对G80Cr4Mo4V高温轴承钢组织和性能的影响,在520℃条件下分别保温1,4,8 h制备渗氮层,并对渗层的组织形貌、相结构、厚度、硬度及结合力进行了研究。结果表明:与渗氮1 h相比,4,8 h渗氮下渗层均匀性大幅提高;不同渗氮时间下,渗层表面相组成均以过饱和马氏体(α′N)、铁氮化合物、铬氮化合物为主,且铁氮化合物含量随渗氮时间的增加而增加;碳化物与氮化物呈大块状分布,铁的氮-碳化合物呈脉状分布,渗氮前后基体组织无明显变化;随渗氮时间的增加,渗层厚度增加,硬度升高,表面硬度较渗氮前提高了1.3~1.6倍,试样直线度和表面粗糙度Ra少量增大;渗层与基体结合力良好,在不同渗氮时间下压痕均属HF1级。

The effect of salt bath nitriding is studied on microstructure and properties of G80Cr4Mo4V high temperature bearing steel.The nitriding layers are prepared under 520℃for 1,4 and 8 h,and the microstructure,phase structure,thickness,hardness and bonding force of the layers are studied.The results show that compared with nitriding for 1 h,the uniformity of the layers under nitriding for 4,8 h are greatly improved.Under different nitriding times,the surface phase composition of the layers is mainly supersaturated martensite(α′N),iron nitrogen compound and chromium nitrogen compound,and the content of iron nitrogen compound increases with increase of nitriding time.The carbides and nitrides are distributed in bulk,and the nitrogen carbon compounds of iron are distributed in vein.The matrix structure has no obvious change before and after nitriding.With increase of nitriding time,the thickness and hardness of the layers are increased,the surface hardness is increased by 1.3~1.6 times compared with untreated sample,the straightness and surface roughness of sample are increased slightly.The bonding force between infiltrated layers and matrix is excellent,and the indentations belong to HF1 grade under different nitriding times.