摘要
利用Gleeble热模拟试验机模拟研究了X80钢焊接热影响区粗晶区组织在不同冷却速度下的变化规律,研究了冷却时间、组织和性能之间的关系。结果表明,X80钢焊接热影响区粗晶区组织主要由板条贝氏体和粒状贝氏体组成。随冷却时间t8/5时间增加,板条贝氏体含量逐渐减少,由细长状转变成粗大片状、并趋于平行;粒状贝氏体含量逐渐增加,其间的马氏体M/奥氏体A组元数量增加,间距缩短,面积增大。随冷却时间t8/5时间增加,焊接热影响区粗晶区冲击韧性先增加后减小;当t8/5=7 s时,X80钢焊接热影响区粗晶区组织为少量的粒状贝氏体,且弥散分布于大量板条贝氏体之间,细化板条贝氏体,增加有效晶界,起到细化和强化作用,冲击断口分布着大量的细小韧窝,为明显的韧性断裂。
The change of the coarse grain heat-affected zone( CGHAZ) of X80 steel at different cooling rates was investigated by a Gleeble thermal simulation testing machine,and the relationship of cooling time,microstructure and property was investigated. The results show that the microstructure of heat-affected zone( CGHAZ) of X80 steel is mainly composed of granular bainite and lath bainite. The amount of lath bainite decreases and granular bainite increases with the increasing t8 /5time,and the shape of lath bainite tends to be coarser and parallel. The M / A constituents in granular bainite gradually increase with the spacing decreasing and area increasing. The impact toughness of CGHAZ firstly increases and then decreases with the increasing t8 /5time. The granular bainite dispersed-distributes in large amount of lath bainite when t8 /5time is 7 s,the dispersed granular bainite refines,the grain boundaries among the lath bainite and increase,and has refined and strengthened. The large amount of tiny dimples appear in the impact fractures and is typical ductile fracture mechanism.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2014年第S2期129-133,共5页
Transactions of Materials and Heat Treatment
基金
四川省高等学校油气田材料重点实验项目(12YQT025)
关键词
X80钢
热模拟
焊接热影响区粗晶区
贝氏体
冲击韧性
X80 steel
thermal simulation
coarse grain heat-affected zone
bainite
impact toughness
