焊接热循环和拘束应变对粗晶区组织和性能的影响

籍助于热模拟技术、光学金相和透射电子显徽镜、微型拉伸和冲击试验研究了焊接热循环和拘束应变对ＥＨ３６ＭＯＤ控轧钢焊接粗晶区的显微组织和力学性能的影响。试验结果表明，在２种热循环制度下，粗晶区具有不同的显微组织，当ｔ８／５＝６ｓ时，以下贝氏体和板条马氏体为主，而ｔ８／５＝５０ｓ时，则以先共析铁素体和上贝氏体为主。拘束应变的存在，不仅可细化粗晶区的奥氏体晶粒，而且可使组织形态及其相对量发生改变，相应地提

INFLUENCE OF WELD THERMAL CYCLE AND RESTRAINT STKAIN ON STRUCTURE AND PROPERTIES OF COARSE GRAINED REGION

Influence of weld thermal cycle and restraint strain on microstructure and mechanicalproperties of welding coarse grained region of EH36MOD controlled rolling steel has been in-vestigated by means of thermal simulative technique,optical metalloscope and transmissionelectron microscope,microtensile and impact test.The experimental results show that thereare different microstructure in welding coarse grained region under two different thermal cy-cle conditions.when t8/5=6 s,the microstructure is primarily low bainite and lath marten-site,while for t8/5=50 s,pre-eutectoid ferrite and upper bainite are the main,The restraintstrain not only fines austenite grain,but changes structrual morphology and their relativeamount in coarse grained region also. The tensile strength, ductile and impact toughness ofcoarse grained region are increased correspondingly when t8/5=6s,but the tensile strength isdecreased and ductile as well as impact toughness are improved for t8/5=50 s.