摘要
通过热处理工艺均化并改善R-31耐热接头组织。采用金相显微镜、显微硬度计、扫描电镜(SEM)和能谱仪(EDS)、电化学综合测试系统结合腐蚀实验分析焊接接头组织、力学性能以及组织转变对CO2腐蚀发生规律的影响。结果显示:未经热处理的焊缝熔合区组织为细小的粒状珠光体,中间有少量的先共析铁素体呈岛状分布。热处理后,接头热影响区的组织长大,且熔合区有少许的弥散碳化物析出,硬度增加。热处理使接头腐蚀电位增大,抵御腐蚀的能力增强。分析腐蚀形貌发现热影响区、粗晶区以及由铁素体和渗碳体共析而成的珠光体区最易发生CO2局部腐蚀,其中热影响区腐蚀速率较大,EDS能谱分析显示蚀坑中具有很高的碳含量。
The structure of R-31 welded joints are homogenized and improved by post-weld heat treatment（PWHT）. Some researches like microstructure of the welded joints, mechanical properties and effect on CO2 corrosion by those changes are investigated by metallurgical microscope, micro-hardness tester, SEM and EDS,electrochemical test system in corrosion experiment. Results show that organization of weld fusion zone without heat treatment is the fine granular pearlite and dotted with a few island ferrite. After heat treatment,the structure in heat-affected zone（HAZ）occur grain coarsening and precipitate a little dispersed carbide,this leads hardness to increase. In addition,the higher corrosion potential obtained from PWHT makes it has a better performance on CO2 corrosion resistance. Corrosion morphology analysis shows that HAZ,coarsen zone and eutectoid pearlite combined by ferrite and cementite are mo st prone to corrosion,HAZ has the maximum corrosion rate,there are high carbon content in the corrosion pits though EDS analysis.
出处
《电焊机》
2015年第10期140-144,共5页
Electric Welding Machine
