Q690C低碳粒贝钢多层MAG焊接头组织与性能

发布时间：2018-01-31 19:34

  本文关键词： QC低合金高强钢 等匹配 低碳贝氏体 全自动MAG焊 贝氏体回火　出处：《焊接学报》2015年01期 　论文类型：期刊论文

【摘要】：为提高效率、获得理想断裂位置并改善热影响区韧性,对控扎控冷工艺生产的8 mm厚Q690C低碳粒贝钢,选用等强度匹配的焊丝,采用无预热、低热输入(10 k J/cm以下)三层全自动MAG工艺施焊.结果表明,无裂纹与成形缺陷;拉、弯与冲击性能均合格.焊缝为针状铁素体,韧性优异;仅在较窄的部分相变区(单道约0.2~0.4mm)因回火而出现软化,但未对抗拉性能形成危害;因热输入低,拉伸断裂位置距焊缝更远;虽然熔合区与粗晶区为粗大平行上贝板条束+M-A组元,出现了硬化,但低热输入的低过热效果与两次后续焊道对贝氏体基体的明显回火作用改善了熔合区在0℃的冲击韧性.
[Abstract]:In order to improve the efficiency, obtain the ideal fracture position and improve the toughness of the heat affected zone, the 8mm thick Q690C low carbon grain beige steel produced by the controlled zoning and cooling process was selected as the welding wire with equal strength matching and without preheating. The three-layer fully automatic MAG process with low heat input less than 10kJ / cm is applied. The results show that there are no cracks and forming defects. The tensile, bending and impact properties are all qualified. The weld is acicular ferrite with excellent toughness. Only in the narrow partial phase transition zone (about 0.2 ~ 0.4mm single channel) softened due to tempering, but did not harm the tensile properties. Because of the low heat input, the tensile fracture position is farther away from the weld. Although the fusion zone and the coarse crystal region are coarse parallel to the upper shell strip beam M-A component appears hardening. However, the low superheating effect of low heat input and the obvious tempering of bainite matrix by two subsequent welding passes improved the impact toughness of the fusion zone at 0 鈩，

本文编号：1479834