摘要
电弧增材制造是成形高性能HSLA钢构件的重要新方法。为了明晰HSLA钢在电弧增材制造时的组织演变行为,研究了构件在堆积成形时的温度场、热循环、热影响区分区及其组织转变。结果表明,电弧增材制造过程中,HSLA钢堆积金属包含凝固区与热影响区,热影响区可分为粗晶区、正火区和回火区。凝固区在热循环作用下先后转变为粗晶区、正火区,最终成为回火区;同时,堆积金属中的残留铁素体晶核、夹杂物附近的高密度位错、铁素体感生形核、第二相质点钉扎晶界和连续动态再结晶共同促进组织细化,使粗大的柱状晶、块状铁素体、侧板条铁素体以及少量针状铁素体、珠光体演变为细小的等轴铁素体和珠光体,有利于提高构件强韧性并抑制力学性能各向异性。构件垂直与水平抗拉强度分别为519.6、520.8MPa,-20℃冲击功分别为124.7、122.1J。
Wire arc additive manufacturing(WAAM)is a novel and important method for forming high-performance HSLA steel components.In order to reveal the microstructural evolution behavior of HSLA steel during WAAM,the temperature field,thermal cycle,heat affected zone partition and its microstructure transformation of component during deposition were investigated.The results showed that in WAAM process,the deposited metal of HSLA steel consisted of solidification zone(SZ)and heat affected zone,and the latter could be divided into coarse austenitic-grain zone(CAZ),normalizing zone(NZ)and tempering zone(TZ).Under the action of thermal cycle,SZ successively turned into CAZ,NZ,and finally became TZ.Meanwhile,Residual ferrite nuclei,high-density dislocations near inclusions,ferrite sympathetic nucleation,grain boundaries pinning by second-phase particles,and continuous dynamic recrystallization all facilitated the microstructure refinement,making coarse columnar grains,grain boundary ferrites,ferrite slide plates,a small amount of acicular ferrites and pearlites evolved into fine equiaxed ferrites and pearlites,beneficial for improving strength,toughness and inhibiting mechanical anisotropy.The vertical,horizontal tensile strength of WAAMed component were 519.6,520.8 MPa respectively,and impact energy at-20 ℃ was 124.7,122.1 Jrespectively.
作者
禹润缜
余圣甫
齐膑
代轶励
YU Run-zhen;YU Sheng-fu;QI Bin;DAI Yi-li(State Key Laboratory of Materials Processing and Die and Mould Technology,Huazhong University of Science and Technology,Wuhan 430074,Hubei,China)
出处
《钢铁》
CAS
CSCD
北大核心
2021年第10期136-145,共10页
Iron and Steel
基金
国家重点研发计划资助项目(2017YFB1103200)。
关键词
HSLA钢
电弧增材制造
温度场
热循环
组织演变
晶粒细化
力学性能
HSLA steel
wire arc additive manufacturing
temperature field
thermal cycle
microstructural evolution
grain refinement
mechanical property
