15CrMoV钢拘束状态多层焊近缝区M-A组织的精细结构与韧性

RELATIONSHIP BETWEEN THE TOUGHNESS AND FINE MICROSTRUCTURES OF M-A CONSTITUENTS IN RESTRAINED MULTIPASS TIG WELDED HAZS OF 15CrMoV BAINITIC STEEL

摘要: 本文研究了5CrMoV 钢拘束与非拘束TIG多层焊近缝区组织,特别是M-A岛状组织精细结构与韧性的对应关系。研究结果证明:拘束接头的韧性高于非拘束接头的韧性。主要原因是拘束接头的M-A岛状组织数量少,岛内孪晶马氏体少而位错马氏体多,铁素体基体的位错密度高以及有极细的碳化物(直径约200×10^-10m)从基体上弥散析出。

Abstract: This paper studies the relationship between the toughness and fine microstructures of M-A constituents in the multipass TIG welding of 15CrMoV Steel under restrained and non-restrained conditions.It is found thai the restrained condition gives rise to better HAZ toughness,due to less M-A constituents,less twin martensite but more dislocation martensite in M-A constituents,higher dislocation density in ferrite and larger amount of V₄C₃ fine carbides precipitated from matrix.