预热和焊后热处理对T23钢接头力学性能的影响  

Effects of Preheating and Post-Weld Heat Treatment on the Mechanical Properties of T23 Steel Weldment

作　　者：李夕强[1] 王学[2] 杨超[1] 葛兆祥[1] 杨贤彪[1] 任遥遥[2] 

机构地区：[1]江苏方天电力技术有限公司,江苏南京211102 [2]武汉大学动力与机械学院,湖北武汉430072

出　　处：《中国电力》2016年第2期1-5,66,共6页Electric Power

基　　金：国家自然科学基金资助项目(51574181);先进焊接与连接国家重点实验室开放课题重点资助项目(AWJ-Z15-02)~~

摘　　要：为优化焊接工艺,解决水冷壁T23接头焊缝在运行中容易出现裂纹的问题,测试了T23接头在4种不同工艺(不预热、焊后不热处理,不预热、焊后热处理,预热、焊后不热处理,预热、焊后热处理;预热温度为150℃,焊后热处理工艺为740℃、0.5 h)下的硬度和冲击韧性,并观察了显微组织的变化。研究结果表明,预热对T23接头硬度的影响不大,但增大晶粒尺寸和过热区的宽度,对焊缝和热影响区(HAZ)的韧性均有不利影响;焊后热处理明显降低焊缝和HAZ的硬度,虽然对HAZ韧性影响很小,但可改善焊缝的韧性。建议预热温度不超过150℃或取消预热,进行焊后热处理以保证接头的长期服役性能。In order to optimize the welding techniques of T23 steel and avoid the cracking in its welded joints in the water-wall of ultra supereritical （USC） boilers, the hardness and toughness are tested for the joints welded with four different welding techniques, which are the ones of without preheating and post-weld heat treatment （PWHT）, PWHT without preheating, preheating without PWHT, preheating and PWHT. The preheating is set at 150 ℃ and PWHT being at 740 ℃ for 0.5 h. The changes of their microstructures are also observed. The results show that preheating has little effect on the hardness of the weldments, but it makes the grain size and width of the over-heated zone enlarge, which lowers the toughness of the weld metal and the heat-affected zone （HAZ）. PWHT significantly reduces the hardness of the weld metal and HAZ, and improves the toughness of the weld metal even though it has little effect on that of HAZ. In order to avoid the occuring of cold cracking, preheating with the temperatures below 150 ℃ or no prheating is recommended for the welding of T23 steel. For the sake of long-term operating properities of the T23 steel joints, PWHT is still necessary for the improvement.

关 键 词：T23钢 焊接接头 预热 焊后热处理 力学性能 

分 类 号：TG457.11[金属学及工艺—焊接]