【摘要】 为改善超细晶粒钢焊缝热影响区(HAZ)组织软化问题,对不同Al含量的Fe-Mn-Si超细晶粒钢进行了热模拟研究。结果表明,在一定冷速条件下,此类钢随Al元素添加量的变化,组织从上贝氏体转变为无碳化物贝氏体,且随Al含量的不同,无碳化物贝氏体中残留奥氏体含量及其形态存在明显变化。另一方面,适当Al含量可增加此类钢种焊接条件下贝氏铁素体的形核数量,造成晶粒细化。残留奥氏体相数量与形态变化及晶粒细化是含Al超细晶粒钢HAZ区韧性提高的根本原因。更多还原

【Abstract】 In order to improve toughness of the weld heat affected zone(HAZ)of ultra-fine grained(UFG)steel,a thermal simulation procedure of Fe-Mn-Si UFG steels with different Al addition was conducted and the corresponding microstructure was characterized and investigated.The results indicate that the structure in the simulated HAZ tends from upper bainite to carbon-free bainite for the steel by increasing Al addition.The proper amount of Al addition is of beneficial to the nucleation of bainite ferrite,leading to the grain refinement.Different amounts and morphology of retained austenite are observed in the Fe-Mn-Si UFG steel with different amount of aluminium.The formation of strie retained austenite and grain refinement of bainite ferrite in Fe-Mn-Si UFG steels with Al addition results in the increasing toughness of weld HAZ.更多还原