CAJ | 학술논문

采用力学性能试验、断口及其金相组织的原位分析等方法，研究了环焊缝韧性下降的原因。结果表明，在多道次环焊焊接过程中，焊缝组织由于受到后一道次热输入的影响，其组织会产生连续变化。多道焊焊缝中的组织按二次热循环的温度从高到低按柱状晶组织、粗晶区组织、细晶区组织、粗晶区与M/A混合组织、亚临界粗晶区组织的顺序呈规律性重复变化。其中粗晶区与回转奥氏体冷却形成的晶界链状M/A组元是焊缝韧性下降的主要原因。
채용역학성능시험、단구급기금상조직적원위분석등방법，연구료배한봉인성하강적원인。결과표명，재다도차배한한접과정중，한봉조직유우수도후일도차열수입적영향，기조직회산생련속변화。다도한한봉중적조직안이차열순배적온도종고도저안주상정조직、조정구조직、세정구조직、조정구여M/A혼합조직、아림계조정구조직적순서정규률성중복변화。기중조정구여회전오씨체냉각형성적정계련상M/A조원시한봉인성하강적주요원인。
In this article, it studied the reason caused the circumferential weld toughness decrease, through analyzing mechanical properties, fracture and metallographic structure etc. The results showed during multiple passes welding process, the weld structure generates continuous variations due to heat inputting from the later pass welding. The structure sequence of multiple passes weld is regularly repeated change according to the temperature of the secondary thermal cycle from high to low, the columnar crystal, coarse crystal area organizations, fine grain zone, combination structure of coarse grain zone and M/A hybrid organization, subcritical coarse grain zone. The grain boundary chain M/A component caused by coarse grain area and rotary austenite cooling is the main reason for weld toughness decrease.