不平衡因子对药芯焊丝CO2气体保护焊焊缝金属韧度的影响

研究了由氮化物形成元素Al,Ti等控制的不平衡因子B对低合金药芯焊丝CO2气体保护焊缝金属韧度的作用.结果表明,在药芯具有氧化性的条件下,不平衡因子B对焊缝金属韧度的作用仍然明显.并且相比实心焊丝CO2气体保护焊而言,不平衡因子B的最佳值增大了.分析表明,药芯焊丝自身的氧化性是不平衡因子B增大的原因.在不平衡因子B由小增加到最佳值的过程中,焊缝金属组织由粒状贝氏体 板条铁素体逐渐向以夹杂物为核心的针状铁素体组织发展,由此其韧度逐渐改善;而当不平衡因子B超过最佳值较多时,过剩的氮化物形成元素进入铁素体固溶而导致脆化.

Effect of unbalance factor on toghness of weld metal by CO2 arc welding with flux cored wire

The effects of unbalance factor B controlled by nitride forming elements Al,Ti etc on the impact toghness of weld metal by CO_2 arc welding with flux cored wire were studied.The experimental results showed that as the B increases,the impact toghness increases at first and than deacreases.Because of the fluxes oxidability,the optimal value of B raised as compared by CO_2 arc welding with solid wire.As the increases from the first to optimal value,the main microstructure of the weld metal changed from granular bainite and ferrite side-plate to acicular ferrite,so the impact toghness was improved.But in case of the B over the optimal value very much,the toghness deacreased because the surplus nitride forming elements resided in the parent of ferrite.