氩弧硬化对硼铸铁表面组织和性能的影响

采用氩弧重熔技术在硼铸铁表面进行表面硬化改性处理,研究了钨极氩弧硬化工艺参数对硼铸铁表面组织和性能的影响.结果表明,硼铸铁表面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,过渡区组织为马氏体 残留奥氏体 少量石墨.氩弧硬化工艺参数对硬化层的深度、硬度和裂纹率影响较大,工作电流增加或扫描速度减小时,硼铸铁表面硬化层深度增加,硬度降低,裂纹率下降.在保证不出现裂纹的条件下,硬化层表面的硬度值最高可达64 HRC,硬化层显微硬度值最高可达1196 HV0.1,其耐磨性明显高于未经处理和经激光表面处理的硼铸铁.

Influence of Argon Arc Hardening Process on Microstructure and Properties of Boron Cast Iron Surface

Surface modification was carried out on boron cast surface by argon arc remelting technology.Effect of tungstic electrode argon arc hardening parameters on microstructure and mechanical properties of boron cast iron surface was investigated.The results show that the transition zone is obvious between hardening layer and matrix metal when the surface is hardened by argon arc heat source.Microstructures of the hardened layer and the transition zone are ledeburite,and martensite retained austenite a little graphite,respectively.The process parameters obviously influence the depth,hardness and crack rate of the hardened layer.With increasing the working current or decreasing the scanning speed,the hardened layer depth increases,and the hardness and crack rate decreases.The maximum hardness and microhardness of hardened layer surface without cracks reach 64 HRC and 1196 HV0.1,respectively.The wearability of the argon arc hardened boron cast iron is much better than that of the boron cast iron either without hardening or laser hardened.