等离子改性工艺对含硼铸铁组织和性能的影响

Effects of Plasma Modified Treatment on Microstructure and Property of Boron Cast Iron

针对柴油机气缸套磨损失效现象,采用高能等离子束在常压下快速扫描含硼铸铁气缸套内表面,对缸套内壁进行局部硬化改性处理,获得了高硬度淬火硬化层,分析了等离子改性对硼铸铁汽缸套表面组织的影响,研究表明．工作电流越大、扫描速度越低,硬化区表层残余奥氏体含量越少;在扫描速度不变的情况下,工作电流越大,硬化层深度越大、硬度越高;工作电流不变．扫描速度越低,硬化层深度越大、硬度越高。通过磨损实验对比,可知等离子硬化后的硼铸铁的耐磨性高于含硼铸铁基体,而含硼铸铁基体的耐磨性又高于灰铸铁。

In order to overcome abrasion failure of diesel engine cylinder liner, a quenching layer with high hardness was obtained by rapidly scanning internal surface of the boron cast iron cylinder liner with high energy plasma beam under atmospheric pressure, and the effect of plasma beam on the surface microstructure of cylinder liner was analyzed. The results show that the residual austenite on the surface of hardened layer is smaller at higher electricity and slower scanning speed; the case depth becomes much more thicker and the hardness becomes larger at higher electric current with the constant scanning speed; the case depth is thicker and the hardness is larger at slower speed of scanning with the constant electric current. Comparison of the wear test results indicates that the wear resistance of the boron cast iron plasma beam hardening layer is higher than that of the matrix with boron cast iron, and the wear resistance of its as-cast is higher than that of the gray cast iron.