高强度耐候钢Q450NQR1激光复合焊接头组织与性能

Microstructure and Properties of Laser Hybrid Welded Joints for High Strength Weathering Steel Q450NQR1

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 was welded by laser arc hybrid welding. The experimental results show that the weld metal is mainly composed of martensite when the heat input is 3.54 k J/cm, the weld metal primarily consists of acicular ferrite when the heat input is 4.06 k J/cm, and the weld metal is mainly composed of granular bainite when the heat input is 4.93 k J/cm. The coarse grained region mainly includes martensite and granular bainite. With the increase of heat input, the grain size in coarse grained region increases, the content of martensite decreases, the content of granular bainite increases, and the microhardness in the weld metal and coarse grained region reduces. The yield strength and tensile strength of the weld metal under different heat inputs are higher than those of the base metal, and fracture appears in base metal. When the heat input is 4.06 k J / cm, the low temperature impact toughness of the weld metal is the highest.