高速动车组用超厚度车钩座板的焊接工艺研究

Research of the welding procedures for the ultra-thick coupler seat board on a high speed EMU

文章以高速动车组的超厚度车钩座板部件的焊接为例,选用84 mm厚度的6082-T4状态的母材材料,进行超厚度铝合金材料的焊接工艺研究。采用搅拌摩擦焊的方法进行焊接,焊接完成后进行人工时效热处理,通过无损检测、拉伸试验、弯曲试验、硬度试验、宏观金相组织分析、微观金相组织分析的试验方法,进行超厚度车钩座板焊接接头性能的研究。结果表明,所述工艺的超厚板铝合金焊接接头具有良好性能和组织。焊接接头强度平均值为218.45 MPa,达到母材强度的70%,拉伸断口全貌呈纤维状,韧性良好;弯曲180°无缺陷,具备良好的弯曲性能;焊缝金相组织熔合良好,无孔洞、夹杂等内部缺陷;焊缝各层的水平硬度分布均为“W”形,硬度最低值均出现在热影响区,焊核区硬度较高,但仍低于母材;在焊缝厚度方面,上表面层的硬度高于中间层,焊核区各层硬度分布差异大,中心的硬度明显低于外侧的硬度。

Taking the welding of 84mm-thick 6082-T4 coupler seat board for high speed EMU as the example,this paper studies the welding procedures for ultra-thick aluminum alloy components.After the FSW operation and artificial aging heat treatment,NDT,tensile test,bending test,hardness test,macrostructural analysis and microstructural structural analysis is conducted to investigate the performance of welded joints on the ultra-thick coupler seat board.Test results show that the welded joints on the ultra-thick aluminum plates processed with the above-mentioned techniques exhibit excellent performance and structure.The average strength of the welded joints reaches 218.45 MPa,up to 70%of that of the base material;the tensile fracture morphology presents fiber state with excellent toughness;the welded joints show good bending performance,no defects appear after bending 180°;good fusion is reflected in the microstructure of the joint without any internal defects,including pores or inclusions;the horizontal hardness of each layer of the weld distributes in the shape of“W”with minimum value of hardness appearing in the heat-affected-zone,the hardness at the weld nugget zone(WNZ)is comparatively high,but is still lower than the base material;in terms of throat thickness,the hardness at the top layer is higher than that of the interlayer,the hardness distribution at each layer of the weld nugget zone differs greatly,with the central hardness obviously lower than the outer one.