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通过调整与控制600 MPa级高强钢药芯焊丝中的稀土元素含量,研制了适用于921A钢的气保护焊接用药芯焊丝,并利用制备出的药芯焊丝焊接921A钢。测定了焊缝金属的力学性能、显微硬度及低温冲击韧性,同时利用扫描电镜和金相显微镜对其拉伸试样断口以及焊缝金属的组织形貌进行了观察。结果表明,在一定含量范围内,稀土元素的添加可以明显改善焊缝金属组织,提高低温冲击韧性和综合力学性能。稀土含量过高时,组织反而朝着不利于力学性能提升的方向转变。
By adjusting and controlling the content of rare earth elements in flux cored wire of 600 MPa high strength steel, flux-cored wire suitable for gas-shielded welding of 921A steel was developed and the 921A steel was welded by using the prepared flux-cored wire. The mechanical properties, microhardness and low temperature impact toughness of the weld metal were measured. Meanwhile, the fracture of the tensile specimen and the microstructure of the weld metal were observed by scanning electron microscopy and metallographic microscope. The results show that, within a certain range of contents, the addition of rare earth elements can significantly improve the weld metal structure, improve the low temperature impact toughness and mechanical properties. Rare earth content is too high, but the organization is not conducive to the improvement of mechanical properties in the direction of change.