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利用拉长晶粒和再结晶两种组织搅拌头对X70管线钢进行搅拌摩擦焊,通过使用寿命试验、拉伸试验和冲击试验,研究了搅拌头组织不同对其使用寿命和焊接接头力学性能的影响,结合硬度测量、金相组织观察和扫描电镜分析探究了其影响机理。结果表明:两种组织搅拌头焊接接头的力学性能相当,均因焊缝金属中出现马氏体组织而使强度升高、塑性和韧性下降;再结晶组织搅拌头焊后其本身组织产生变形,出现晶粒间缺陷使其使用寿命低于拉长晶粒搅拌头,两种搅拌头焊接过程中磨损机理均为磨料磨损。
X70 pipeline steel was treated by friction stir welding with elongated grains and recrystallized two kinds of tissue mixing heads. The service life, tensile test and impact test of X70 steel were studied. Influence, combined with hardness measurement, microstructure observation and scanning electron microscopy analysis of its impact mechanism. The results show that the mechanical properties of the welding joints of the two kinds of structure mixing heads are quite similar, the strength increases due to the presence of martensite in the weld metal, and the plasticity and toughness of the welded joints decrease. After recrystallization, Intergranular defects appear to make their service life is lower than the elongated grain mixing head, the wear mechanism of the two kinds of mixing head welding process are abrasive wear.