摘要
用Gleeble-3800热模拟试验机模拟了09MnNiDR低温压力容器钢焊接临界粗晶区（intercriticallyrehea—tedcoarse-grainedheat—affectedzone），并对其进行了焊后热处理（post-weldingheattreatment）工艺研究。采用力学性能检测及结构表征方法研究了热处理前后焊接临界粗晶区的力学性能及影响机制。试验分析表明，尺寸较大的M—A岛（martensite-austeniteisland）是材料受力时裂纹的启裂源，是引起试验钢焊接临界粗晶区冲击韧性较差的主要原因。经过焊后热处理，临界粗晶区的冲击韧性明显改善，并且热处理温度工艺窗口（560～640℃）较宽。热处理后M—A岛的分解、碳化物的球化及大角度晶界对裂纹扩展的阻碍作用是韧性提高的主要原因。
The pressure vessel steel 09MnNiDR, which is used to manufacture equipment serving at --70℃, usual- ly use multi-pass welding in industrial production. In order to ensure the safe application performance of equip- ment, the post-welding heat treatment （PWHT） is carried out usually. So, the intercritically reheated coarse- grained heat-affected zone （ICCGHAZ） of the low temperature pressure vessel steel 09MnNiDR was simulated by Gleeble-3800, and the effect of post-welding heat treatment （PWHT） process was also investigated, aiming to provide experimental basis for industrial production to some extent. And then, the mechanical properties and mechanism of ICCHAZ after and before PWHT was investigated by mechanical properties testing and microstruc- ture characterization. The result shows that the existence of coarse martensite-austenite （M-A） islands, acting as the crack initiation sources when external stress is applied, is the main reason for the poor impact toughness of the ICCGHAZ. After a post-welding heat treatment, with a wide operating window （560--640 ℃）, the impact prop- erty is improved, primarily due to the decomposition of M-A islands, spheroidization of carbides and the impedi- ment of crack propagation by high-angle grain boundaries.
出处
《钢铁研究学报》
CAS
CSCD
北大核心
2014年第4期46-52,共7页
Journal of Iron and Steel Research
关键词
09MnNiDR)焊接临界粗晶区
焊后热处理
M—A岛
09MnNiDR steel
intercritically reheated coarse-grained heat-affected zone
post-welding heat treat-ment
M-A island
