【摘要】 本文进行了45钢激光铬合金化研究。通过对硬度、成分、残余应力及相组织的定量测量,结合形貌观察和工艺参数,对合金层进行了综合分析。结果表明,45钢激光铬合金化强化机理主要是马氏体相变强化;由于马氏体相变,合金层内存在残余压应力;由于合金层内C、Cr分布均匀,抑制了奥氏体的转变,从而使合金层内残存亚稳态的奥氏体相;熔化深度也影响奥氏体的转变,对含铬量低(～11Cr%)的合金层,当熔化深度很深(780μm)或熔化层深且相互搭叠时,残余奥氏体量减少。更多还原

【Abstract】 In this paper, surface alloying of 45 carbon steel with chromium using CO₂ laser has been investigated. Through the measurement microhardness, content of alloying element, residual stress, phase structure, combining morphology observaation and process parameters, a comprehensive analysis has been made on the alloyed layer. It was shown that the principal strengthening mechanism of laser surface alloying of 45 steel with chromium is martensite transformation strengthening. Because of martensite transformation, there exists a residual compressive stress in alloyed layer. Because the uniform distribution of C and Cr retarded the transformation of austenite, so there exists residual metastable austenite phase in alloyed layer. The transformation of austenite is also influnced by melting depth. For alloying layers having lower chromium content（Cr～l1%）, when melting depth is deeper （～780μm） or the deep melt strips ovetlapped each other, the coutets of residual austenite will be decreased.更多还原