喷丸处理对55SiCr弹簧钢低温气体渗氮的影响

Influence of shot peening on low temperature gas nitriding of 55SiCr spring steel

对55Si Cr弹簧钢表面进行不同强度的喷丸处理,并在390℃进行低温气体渗氮12 h。利用超景深显微镜、显微硬度计、直读光谱仪以及X射线衍射仪(XRD)分析了渗氮层的显微组织、厚度、氮含量和相组成。结果表明,渗氮层主要由γ'-Fe4N和αN相组成,并有少量的Cr N和Fe3O4。随喷丸强度增加,渗氮层组织更加均匀致密,渗氮层厚度、表面硬度和渗层氮含量均增加。

Surface of 55SiCr spring steel was shot peened with different intensity , then gas nitrided at 390 ℃ for 12 h.Microstructure, thickness, nitrogen content and phase composition of the nitrided layer were analyzed by optical microscopy , microhardness tester , direct reading spectrograph and XRD , respectively.The results show that the nitrided layer is composed of αN and γ′-Fe4 N phases, and also contains a little CrN and Fe 3 O4 .with the shot peening intensity increasing , the microstructure of the nitrided layer becomes more compact and homogeneous , and the thickness of the nitrided layer , surface hardness and the N content in layer increase .