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采用激光电弧复合焊对Q450NQR1高强度耐候钢进行焊接。试验结果表明:当热输入为3.54 k J/cm时,焊缝组织主要是马氏体,热输入为4.06 k J/cm时,组织主要为针状铁素体,热输入为4.93 k J/cm时,组织主要为粒状贝氏体。粗晶区组织由马氏体和粒状贝氏体组成,随着热输入的增加,粗晶区的晶粒尺寸增加,马氏体含量减少,粒状贝氏体含量增加,焊缝和粗晶区的显微硬度减小。不同热输入下焊缝金属的屈服强度和抗拉强度均高于母材,断裂位置位于母材,热输入为4.06 k J/cm的焊缝金属低温冲击韧性最高。
Q450NQR1 high strength weathering steel is welded by laser arc welding. The experimental results show that when the heat input is 3.54 kJ / cm, the microstructure of the weld is mainly martensite. When the heat input is 4.06 kJ / cm, the microstructure is acicular ferrite and the heat input is 4.93 kJ / cm, the organization is mainly granular bainite. The coarse grain structure consists of martensite and granular bainite. With the increase of heat input, the grain size of coarse grain increases, the content of martensite decreases and the content of granular bainite increases. The weld and coarse grain The microhardness decreases. Under different heat input, the yield strength and tensile strength of the weld metal are higher than the base metal, the fracture position is located in the base metal, the weld metal with heat input of 4.06 k J / cm has the highest low temperature impact toughness.