在自行研制的锰-镍-钼-铬系自保护药芯焊丝化学成分的基础上同时加入质量分数分别为0.09%和0.045%的钛和锆元素研制出一种新型焊丝, 采用该焊丝以及未加入钛、锆元素的焊丝对Q235钢进行焊接试验, 研究了钛和锆元素对熔敷金属显微组织和力学性能的影响, 并对钛和锆元素的作用机理进行了讨论。结果表明: 加入微合金元素钛和锆后, 熔敷金属的组织更细小,针状铁素体含量更多,但硬度变化不大,抗拉强度和伸长率较未加入微合金元素的分别提高了7%和13%, -20 ℃冲击韧性提高了1.42倍;微量钛元素的加入能够起到脱氧、脱氮和促进针状铁素体形核的作用; 微量锆元素的加入能够起到脱氧和细化组织的作用。

On the basis of Mn-Ni-Mo-Cr system self-developed self-shielded flux cored wire, a new-typed welding wire was developed through adding elements titanium and zirconium with mass fraction 0.09% and 0.045% respectively into flux cored wire. Welding test was carried out on Q235 steel by using flux cored wires with/without micro-alloy elements, and then the effects of micro-alloy elements titanium and zirconium on microstructure and mechanical properties of the deposited metal were studied. And, the effects mechanism of micro-alloy elements titanium and zirconium on deposited metal was discussed. The results show that after adding titanium and zirconium elements, microstructure of the deposited metal was smaller, acicular ferrite was more, but its hardness changed little, and its tensile strength and elongation increased by respectively 7% and 13% compared to the deposited metal of welding wire without micro-alloy elements; Meanwhile, the impact toughness of the deposited metal at -20 ℃ increased by 1.42 times. The micro-alloy titanium element in the flux cored wire will be beneficial to remove oxygen and remove nitrogen and promote the nucleation and growth of acicular ferrite, as well as the micro-alloying zirconium element will be beneficial to remove oxygen and refine microstructure.