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采用自动埋弧焊机对超低碳贝氏体钢(ULCB钢)进行直缝双面焊双面成型焊接试验,分析了焊接热输入对其焊接接头组织及性能的影响。结果表明:焊缝显微组织主要是针状铁素体和粒状贝氏体,这两种相组成和相比例,极大地影响了接头的强韧性。随着焊接热输入增大,焊缝区针状铁素体含量先减少后增加,粒状贝氏体含量先增大后减少,热影响区晶粒变得粗大,ULCB钢接头强韧性呈现一定规律的变化。在较小的焊接线能量(24.81 k J/cm)下,焊接接头具有优良的强韧性,抗拉强度达到803.63 MPa,为母材抗拉强度的94.3%,焊缝和热影响区冲击韧性分别为193、232 J。
An automatic submerged arc welding machine was used to test the welding of ULCB steel with straight seam double-sided welding. The effects of welding heat input on the microstructure and properties of the welded joints were analyzed. The results show that the microstructure of the weld is mainly acicular ferrite and granular bainite. The phase composition and phase ratio of the two phases greatly affect the strength and toughness of the joint. With the increase of welding heat input, the content of acicular ferrite in the weld zone first decreased and then increased, the content of granular bainite first increased and then decreased, and the grains in the heat affected zone became coarse. The strength and toughness of ULCB steel joints showed a certain rule The change. Under the condition of smaller welding line energy (24.81 kJ / cm), the welded joint has excellent toughness, tensile strength reaches 803.63 MPa, 94.3% of the tensile strength of the base metal, impact toughness of the weld and heat affected zone For 193,232 J.