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用搅拌摩擦焊方法成功焊接了 10 mm 厚的紫铜与低碳钢板,得到了内部无缺陷、外观成形良好的接头.紫铜位于搅拌摩擦焊返回边时,能使焊缝形成良好接头.反之,位于前进边时则有沟槽和未焊合等缺陷.右旋螺纹搅拌针会使焊缝材料向上作螺旋形运动,接头有明显的轴肩影响区,缺陷容易在焊缝底部出现.左旋螺纹搅拌针使搅拌针周围的塑化金属向下迁移,在焊缝下部形成明显的呈"洋葱环"形焊核区,缺陷容易在焊缝上部出现.搅拌针偏移量对焊缝形貌有较大影响.接头抗拉强度达 233 MPa,为铜母材强度的 95%,断裂位置在铜侧热影响区.焊核区抗拉强度达 296 MPa,远超过紫铜母材的强度.Abstract: The joining of dissimilar metals, T2 copper and Q235 mild steel plates with 10 mm thickness, is carried out in friction stir welding. Excellent welds can be gained when copper is fixed at the retreating side, but defects can be produced in welds when copper is fixed at the advancing side. The pin shapes influence the flow of the plasticized metal in the weld, which results in the variety of the morphology of the weld. If the screw thread on the pin is clockwise, the metal around the pin will move upwards to the root of the pin, which causes that the shoulder affected zone is clear and the weld defects would form at the lower part of the weld section. If the screw thread on the pin is counter-clockwise, the metal around the pin will move downwards, which drives the metal around the pin tip to move around and upwards. The onion ring pattern, which appears like lamellar structure, is observed in the stir zone. The shoulder-affected zone is not clear; the weld defects will form at the upper part of the weld section. Various pin offsets will affect the flow of weld metal. If an optimization of the process parameters is performed, defeet-free joints can be formed. The tensile test results show that the maximum joint tensile strength can reach 233 MPa, which is 95% of the parent materials of copper, and the fracture happens in the HAZ of copper. The maximum tensile strength of the nugget zone can reach 296 MPa, which is very considerably larger than that of the parent materials of copper. 相似文献
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在铝合金中镶嵌标识材料进行搅拌摩擦焊试验,分析了焊缝中S曲线的形成原因;并用圆锥光面搅拌针的搅拌头,研究了焊接工艺参数对LY12铝合金焊缝中S曲线形貌的影响.结果表明,焊缝中S曲线是原始界面与其周边金属一起位移、变形的结果;S曲线的形状取决于焊缝上部金属的旋转运动、搅拌针与原焊接面之间的相互作用以及焊缝底部金属朝远离焊缝中心线的方向和板材上方移动的综合作用.对于圆锥光面搅拌针,当焊接速度一定时,增大搅拌头的旋转速度;或当搅拌头旋转速度一定时,降低焊接速度,S曲线在焊缝厚度方向的贯穿区域减小并最终消失. 相似文献
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采用3种焊丝对2519铝铜合金进行MIG焊,研究了孕育剂Ti、Zr对焊缝组织和性能的影响。结果表明:Ti和Zr的细化作用是相容的,当焊丝中单独添加孕育剂Ti或Zr时,焊缝几乎由粗大的柱状晶组成;焊丝中复合添加少量的孕育剂Ti和Zr时,Ti和Zr在熔池中分别形成Al3Ti和Al3Zr,促进了α(Al)非均质形核;随着焊丝中Ti和Zr含量的增加,焊缝组织逐步细化,当焊丝中Ti和Zr含量较高时,Ti和Zr还在熔池中形成大量的Al3(Ti,Zr)质点,促进α(Al)非均质形核;焊缝组织由细小均匀的等轴晶组成,显著提高了接头强度和塑性。 相似文献
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