Cr4Mo4V轴承钢滚动接触疲劳和磨损性能研究

通过球棒滚动接触疲劳(RCF)试验机,研究了Cr4Mo4V轴承钢在4050润滑油润滑和0.18滑滚比条件下的滚动接触疲劳和磨损性能.结果表明:Cr4Mo4V钢的应力-寿命(S-N)曲线数据分散性较大,疲劳寿命随着应力增加呈下降趋势.Cr4Mo4V钢滚动接触磨损主要为磨料磨损,黏着磨损和疲劳磨损,随着应力和时间增加磨损体积增加,滚道凹槽深度达到17μm.通过光学显微镜(OM)和扫描电子显微镜(SEM)观察试样棒剖面与滚道交界处疲劳裂纹,发现疲劳破坏类型主要有两种:起源于表面的剥落(SOF)和起源于白蚀区的剥落(WSF).通过滚道径向切割抛光酸蚀显示Cr4Mo4V钢滚动接触疲劳影响区,随着应力和循环接触次数的增加,在次表层依次发现黑蚀区(DER)、白蚀区(WEA)和蝴蝶组织(BW).表面碳化物的剥落坑,黏着磨损和疲劳磨损的凹坑导致了表面起裂、白蚀区和蝴蝶组织中的碳化物和夹杂导致微裂纹的产生,链状碳化物使裂纹往深处扩展.

Rolling Contact Fatigue and Wear Characteristics of Cr4Mo4V Bearing Steel

The fatigue and wear characteristics of Cr4Mo4V steel under lubrication of 4050 lubricant were evaluated.Tests were conducted using a rolling contact fatigue(RCF)test rig of the ball-on-rod type with 0.18 slide-to-roll ratio.S-N data showed continuous gradual decline and large dispersion.Rolling contact wear of Cr4Mo4V steel involved mainly abrasive wear,adhesive wear and fatigue wear.Wear volume became larger when time and stress increased.The maximum depth of raceway groove reached up to 17 μ rn.The rolling contact fatigue mechanism analysis of steel with different stress was investigated in detail by observing fatigue cracks of the junction of cross section and wear surface of rod specimens using optical microscopy and scanning electronic microscopy.It is found that there were two kinds of flaking,i.e.surface originated flaking (SOF) and white etching area originated flaking (WSF).The initial etching clearly reveals the RCF affected plastically deformed area at the edges of the test track of Cr4Mo4V steel rod material.With increasing contact cycles and contact stress,dark etching regions (DER),white etching area (WEA) and butterfly wings (WB) formed in the subsurface in sequence.Carbide peeling pits,adhesive wear and fatigue wear pits caused surface originated flaking.Carbides and inclusions in WEA and BW led to the generation of micro-cracks.Cracks extended deeper due to the presence of chain-carbide.