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本文采用光学与电子显微镜研究了不同热处理条件下低合金高强度钢及其埋弧焊焊缝金属的微观组织与机械性能。冲击试验结果表明,无论钢板和焊缝金属,调质状态下的冲击韧性最高,而正火状态下的冲击韧性最低。焊态下的焊缝韧性比正火状态有明显的提高。组织观察结果表明,无论是钢板还是焊缝金属,调质状态下的组织是回火马氏体、正火状态下的组织是上贝氏体;焊态下的焊缝组织是粒状或条状贝氏体。在组织成分相同的条件下,焊缝冲击功远低于钢板,其原因与材质中硫、磷含量,气体含量及夹杂物形态、分布等密切相关。
In this paper, the microstructure and mechanical properties of low alloy high strength steel and its submerged arc welded metal under different heat treatment conditions were studied by optical and electron microscope. Impact test results show that, regardless of steel and weld metal, the highest impact toughness under quenched and tempered conditions, and the lowest impact toughness under normal conditions. Weld under the weld toughness than the normalized state has significantly improved. Tissue observations show that the microstructure of the quenched and tempered steel is tempered martensite both in steel and weld metal and in the normalized state as upper bainite. Weld microstructure in the as-welded state is granular or strip-like Bainite. Under the same composition, the impact energy of the weld is much lower than that of the steel plate, which is closely related to the content of sulfur and phosphorus, the gas content and the morphology and distribution of inclusions in the material.