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对国内自主研发的核级304NG控氮不锈钢板材埋弧焊接头力学性能进行了工程应用评价,并对接头的高温断裂行为进行了研究。结果表明,304NG接头各项指标远高于RCC-M规范的要求;焊接接头和焊缝试样均无晶间腐蚀裂纹,N含量偏高未对耐晶间腐蚀性能产生明显影响;焊接接头高温拉伸断裂机制为微孔聚集型韧性断裂,韧窝中的金属氧化物球形夹杂是导致焊接接头塑性指标偏低的主要因素。304NG不锈钢弧焊前,应对待焊表面及焊丝进行彻底的清洁去污,严格控制焊剂的烘干,以控制O元素的引入,减少金属氧化物夹杂的形成。
The mechanical properties of submerged arc welded joints of 304NG nitrogen-controlled stainless steel plate independently researched and developed in China were evaluated, and the high-temperature fracture behavior of joint was studied. The results show that the indexes of 304NG joint are much higher than the requirements of RCC-M. No intergranular corrosion cracking is found in the welded joint and the welded joint. The high N content has no obvious effect on the intergranular corrosion resistance. Tensile fracture mechanism is microporous aggregate ductile fracture. The spherical inclusions of metal oxide in dimples are the main factors leading to the low plasticity of welded joints. 304NG stainless steel arc welding, the surface to be welded and welding wire to conduct a thorough cleaning decontamination, strict control of flux drying, in order to control the introduction of O elements to reduce the formation of metal oxide inclusions.