扫描速度对硼铸铁气缸套表面钨极氩弧硬化效果的影响

研究了钨极氩弧扫描速度对硼铸铁表面硬化效果的影响规律。结果表明：扫描速度增加。硬化层宽度、深度减小，而硬度提高，裂纹率增大；硬化层硬度沿层深的分布是从表及里由高而低，在过渡区下降缓慢；沿层宽的分布是层中心最高。向两侧逐渐降低，直至硼铸铁基体达到最低值；在保证不出现裂纹的条件下，硬化层表面的最高硬度值可达61．4HRC，硬化层最高显微硬度值可达1156．4HV0．1；硼铸铁材料采用氩弧热源淬火时。淬硬层与基体之间过渡区明显，硬化区组织为莱氏体，过渡区为马氏体、残余奥氏体和少量石墨。

Influence of Scanning Speed on Argon Arc Hardening Effect of Boron Cast Iron Cylinder Surface

The influence disciplinarian of scanning speed on tungstic electrode argon arc hardening effect on surface of boron cast iron was investigated. The results show that along with the working current increasing the width and depth of hardening layer reduces, the hardness and crack rate increases. The hardness distributing rule along the hardened layer depth direction is that the microhardness change tendency is from high to low from the surface to inner.The hardness distributing rule along the hardening layer width direction is that the hardness of hardened layer center is highest and reduces gradually to two sides, until the boron cast iron substrate achieves the minimum value. Under the condition of ensuring no the crack, the highest hardness on the hardened layer surface may reach 61.4 HRC, the highest microhardness may reach 1156.4 HV0.1; When the boron cast iron material uses argon arc heat source quenching, the transition region between hardening layer and base metal is obvious, microstructure of hardening path is ledeburite, microstructure of transition region is martensite, remaining austenite and few graphite.