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分析了厚钢板大线能量焊接后热影响区(HAZ)的失效机理,介绍了利用微细夹杂物改善HAZ性能的研究情况。粗晶热影响区脆化是由于晶粒粗大及不良组织而引起,粗大的奥氏体晶粒是焊接热影响区韧性恶化的主要原因。抑制焊接HAZ晶粒长大是改善厚钢板可焊性的关键因素。用真空感应炉分别冶炼了不同成分的钢,研究Mg对低碳钢HAZ性能的影响。结果表明含Mg钢HAZ的低温韧性较比不含Mg钢有较大幅度提高。通过激光高温显微镜原位观察发现,含Mg钢在1400℃保温300s后奥氏体晶粒仍然保持着细小的结构,这主要归功于Mg添加后生成的细小粒子所产生的钉扎作用,该发现为改善厚板HAZ韧性提供了一种方法。
The failure mechanism of heat-affected zone (HAZ) after heavy-gauge steel welding is analyzed, and the research on improving the HAZ performance by using fine inclusions is introduced. Embrittlement of the coarse heat-affected zone is caused by coarse grains and poor microstructure, and the coarse austenite grains are the main reason for the toughness deterioration of the weld HAZ. Suppressing weld HAZ grain growth is to improve the weldability of thick steel key factor. Different components of steel were smelted by vacuum induction furnace to study the effect of Mg on the properties of HAZ of mild steel. The results show that the low temperature toughness of Mg-containing steel HAZ is higher than that of Mg-free steel. In-situ observation by laser pyrolysis microscope showed that austenite grains retained fine structure after Mg-containing steel was heated at 1400 ℃ for 300s, which is mainly due to the pinning effect of fine particles generated after the addition of Mg. To improve the toughness of HAZ plate provides a way.