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  • ISSN：0577-6686
机械工程学报

机械工程学报 ›› 2017, Vol. 53 ›› Issue (8): 91-98.doi: 10.3901/JME.2017.08.091

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TRIP980高强钢/SPCC低碳钢的异种钢电阻 点焊工艺优化及接头性能分析

岑耀东1,2, 陈芙蓉1   

  1. 1. 内蒙古工业大学材料科学与工程学院 呼和浩特 010051;
    2. 包钢(集团)公司集团管理部 包头 014010);
  • 出版日期:2017-04-15 发布日期:2017-04-15
  • 作者简介:

    岑耀东，男，1982年出生，博士研究生，工程师。主要研究方向为汽车板焊接新工艺、新技术。

    E-mail：yaodong118@163.com

    陈芙蓉(通信作者)，女，1971年出生，博士，教授，博士研究生导师。主要研究方向为材料焊接性及其表面改性。

    E-mail：cfr7075@imut.edu.cn

Properties and Optimized Process of TRIP980 High Strength Steel and SPCC Low Carbon Steel Resistance Spot Welding of Dissimilar Steel

CEN Yaodong1,2, CHEN Furong1   

  1. 1. School of Materials Science and Engineering， Inner Mongolia University of Technology， Hohhot 010051;
    2. Group Management Department， Baotou Steel(Group)Corp.， Baotou 014010);
  • Online:2017-04-15 Published:2017-04-15

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摘要：

以厚度均为1.5 mm的TRIP980高强钢/SPCC低碳钢的异种钢板电阻点焊接头为研究对象，以接头剪切拉伸载荷为评价指标，运用正交试验优化其焊接参数，采用极差法和方差法对结果进行分析，随后增加焊前预热条件，分析对比相同焊接电流、焊接时间、电极压力参数下采用预热和无预热时点焊接头的剪切拉伸载荷，利用电子拉伸试验机、金相显微镜和显微硬度仪分别对预热和无预热两种条件下较优焊接参数时的点焊接头性能及显微组织进行测试和分析，研究TRIP980高强钢/SPCC低碳钢的异种钢板电阻点焊接头力学性能及接头各区域的金相组织、硬度特点。结果表明：运用焊前预热能够获得性能良好的点焊接头，相同焊接参数情况下，预热点焊接头的剪切拉伸载荷比无预热高5.5%以上;两种条件下较优焊接参数时，无预热点焊接头为脆性断裂，预热点焊接头为韧-脆混合断裂;采用预热获得的点焊接头组织比无预热更为致密;预热点焊接头熔核和母材的硬度比无预热时有所下降，熔合线硬度过渡平缓。其主要机理是，预热使点焊接头熔核周边优先发热，热影响区扩大，熔核韧性提高和熔核周边应力集中缓解，从而提高了点焊接头的强度。

关键词: 电阻点焊, 异种钢, 高强钢

Abstract:

TRIP980 high strength steel and SPCC low carbon steel of 1.5 mm thickness are connected by resistance spot welding. As joint shear tensile load for evaluation indexes, the results are analyzed by the range analysis and variance methods and the welding parameters are optimized by using orthogonal test. As adding the preheating before welding conditions, the shear tensile load of spot welding joint with the preheating and without preheating are comparatively analyzes under parameters of the same welding current, welding time and electrode pressure. Using electronic tensile testing machine, metallographic microscope and microhardness meter, the performance and microstructure of spot welding joint are tested and analyzed under the optimal welding parameters with the preheating and without preheating conditions. The results show that using preheating before welding could get spot welding joint of good performance and under the same welding parameters, shear tensile load of spot welding joint with preheating is more 5.5% than that of without preheating. Under the optimal welding parameters, spot welding joint without preheating is brittle fracture, and the joint with preheating is ductile-brittle mixed fracture. The spot welding joint organization with preheating is denser than that without preheating. Hardness of molten nuclear and the parent metal for spot welding joint with preheating is less than that without preheating, and the hardness of the fusion line is transition smooth. The main mechanism is that preheating makes molten nuclear surrounding of spot welding joint priority have a heat, and with the heat affected zone expands, the molten nuclear toughness will enhance and the stress of molten nuclear surrounding centrally relieve, thus improving the strength of the spot welding joint.

Key words: dissimilar steel plate, resistance spot welding, high strength steel

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