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新一代钢铁材料为晶粒尺寸在微米或亚微米级的铁素体钢,其强度比普通铁素体钢提高一倍,同时又具有较好的韧性。解决该钢的焊接问题,是新一代钢铁材料成功的关键。本文采用CO_2激光进行SS400钢的不填丝焊接,获得了强韧性高于母材的接头。当焊缝和热影响区金属主要由下贝氏体组成时,冲击功最高。当出现侧板条铁素体或低碳马氏体含量较多,冲击功下降,但都高于母材。接头硬度值低于HV330,无软化区,具有良好的弯曲塑性,强度高于母材金属。
A new generation of steel is a ferrite steel with a grain size in the micron or sub-micron range, twice the strength of conventional ferritic steels and at the same time has good toughness. Solving the welding problems of this steel is the key to the success of the new generation of steel materials. In this paper, CO_2 laser was used for SS400 steel wire-free welding, obtained a toughness higher than the base metal joints. The impact energy is highest when the weld metal and the heat affected zone consist mainly of lower bainite. When there is more side ferrite or low-carbon martensite content, impact energy decreased, but higher than the base metal. Joint hardness value is lower than the HV330, no softening zone, has a good plastic bending, strength is higher than the base metal.