Ai Xingyu, Liu Zhengjun, Wu Dan
Department of Material Science and Engineering, Shenyang University of Technology, Shenyang 110870, China.
Materials (Basel). 2020 Feb 17;13(4):892. doi: 10.3390/ma13040892.
Q960 high-strength steel is widely used in pressure vessels, bridges, offshore platforms and other important steel structural components because of its high strength and good plastic toughness, but alloy elements added to this kind of steel have strong hardenability, especially after welding, so the strength and toughness cannot meet the requirements, which limits its application in a wider range. In this paper, from the point of view of the metallurgical treatment of the weld, the goal is to improve the strength and toughness of the Q960 high strength steel weld metal In order to analyze the influence of Zr on the welding process of Q960 steel and the strengthening and toughening effect of weld metal, this paper takes Fe-Mn-Mo-Cr-Ni as the main alloy system, BaF-CaF-Al-Mg as the basic slag system, and adopts the method of melting consumable electrode self-shielded for welding, and analyzes the welding process, microstructure, tensile property and impact toughness of the welded joint. The experimental results show that when the weld metal contains 0.0061% Zr, the minimum spatter rate is only 7%, the maximum slag removal rate is 95%, the maximum hardness is 357HV, the maximum elongation is 34%, and the impact toughness is the highest. At this time, the acicular ferrite content in the weld microstructure is the highest, and there is a certain amount of equiaxed fine-grained ferrite, and the content of proeutectoid ferrite is the least, which effectively improves the strength and toughness of the weld metal.
Q960高强度钢因其高强度和良好的塑韧性而广泛应用于压力容器、桥梁、海洋平台等重要钢结构构件，但这类钢中添加的合金元素具有很强的淬透性，尤其是焊接后，强度和韧性无法满足要求，这限制了其在更广泛范围内的应用。本文从焊缝冶金处理的角度出发，目的是提高Q960高强度钢焊缝金属的强度和韧性。为了分析Zr对Q960钢焊接过程及焊缝金属的强化增韧效果，本文以Fe-Mn-Mo-Cr-Ni为主要合金体系，BaF-CaF-Al-Mg为碱性渣系，采用熔化极自保护焊方法进行焊接，并对焊接接头的焊接工艺、微观组织、拉伸性能和冲击韧性进行了分析。实验结果表明，当焊缝金属中Zr含量为0.0061%时，飞溅率最小仅为7%，最大清渣率为95%，最大硬度为357HV，最大伸长率为34%，冲击韧性最高。此时，焊缝微观组织中针状铁素体含量最高，并有一定量的等轴细晶铁素体，先共析铁素体含量最少，有效提高了焊缝金属的强度和韧性。
