搅拌针几何形态对无倾角搅拌摩擦焊焊缝成形的影响及其机制分析

发布时间：2018-12-12 03:06

【摘要】：无倾角搅拌摩擦焊工艺是保障平面二维及空间三维复杂焊缝焊接质量的关键技术。分别采用含有光面搅拌针、光面带切台搅拌针和螺纹带切台搅拌针的焊具进行无倾角焊接试验,对比研究焊缝形貌、缺陷分布和接头性能,以期阐明搅拌针几何形态对无倾角搅拌摩擦焊焊缝的影响及其机制,从而为无倾角搅拌摩擦焊工艺的高质量应用奠定技术基础。试验结果表明,在无倾角焊接条件下,光面搅拌针容易导致焊缝根部出现孔洞缺陷,难以形成优质接头;带切台搅拌针增强了焊缝中上部材料的塑性流动,由此间接促进了焊缝根部匙孔的填充,在较低焊速下可以获得无缺陷接头;搅拌针螺纹结构直接增强了焊缝根部材料的塑性流动,因而能在更宽的参数范围内形成无缺陷接头。与光面搅拌针相比,搅拌针切台结构增大了接头软化区宽度,提高了焊缝上部的软化程度,所得无缺陷接头的抗拉强度最高可达母材的86%。对比而言,在带切台搅拌针上进一步加工螺纹能够降低焊接热软化效应,减小软化区宽度并提高焊核区硬度,接头最高强度系数由此增大到了90%。
[Abstract]:Non-obliquity friction stir welding (FSW) is a key technology to ensure the welding quality of planar 2D and 3D complex welds. The welding tools containing smooth surface stirring needle, smooth belt cutting table stirring needle and thread belt cutting table stirring needle were used to carry out inclinless welding tests respectively. The weld appearance, defect distribution and joint properties were compared and studied. The aim of this paper is to clarify the effect and mechanism of the geometry of the agitation needle on the weld seam of friction stir welding without dip angle, thus laying a technical foundation for the high quality application of the non-dip friction stir welding process. The test results show that, under the condition of no dip welding, smooth surface stirring needle can easily lead to hole defects in the weld root, and it is difficult to form high quality joint. The plastic flow of the material in the upper and middle parts of the weld is enhanced by the stirring needle with the cutting table, thus indirectly promoting the filling of the keyhole in the root of the weld, and the non-defective joint can be obtained at lower welding speed. The agitated needle thread structure directly enhances the plastic flow of the material at the weld root, so that the non-defect joint can be formed in a wider range of parameters. Compared with the smooth surface mixing needle, the structure of the mixing needle cutting table increases the width of the softening zone of the joint and the softening degree of the upper part of the weld, and the tensile strength of the non-defective joint can reach the maximum of 86% of the base metal. In contrast, further processing of thread on agitated needle with cutting table can reduce the softening effect of welding heat, decrease the width of softening zone and increase the hardness of nugget zone, thus the maximum strength coefficient of the joint increases to 90%.
【作者单位】：中国科学院沈阳自动化研究所机器人学国家重点实验室;
【基金】：国家自然科学基金(51505471) 中国科学院青年创新促进会专项基金(2015162)资助项目
【分类号】：TG453.9

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