共查询到17条相似文献,搜索用时 78 毫秒
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试验研究了超高强度硼钢板/镀锌双相钢板的电阻点焊接头质量缺陷及其产生原因,通过正交试验设计,重点讨论了焊接电流、通电时间和电极压力对点焊接头强度的影响.结果表明:超高强度硼钢板/镀锌双相钢点焊中超高强度钢板侧更易出现飞溅和烧穿问题,通电时间和焊接电流强度时点焊接头拉剪强度影响显著,这类钢板组合的焊接应优先采用大电流、短... 相似文献
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研究了DP600高强钢的电阻点焊工艺,采用正交试验设计,利用Minitab回归分析后规划求解得到的最优解满足最大强度性能要求,并对点焊接头的微观组织、力学性能进行了分析。得出最佳焊接参数为:电极压力2.058 kN,焊接时间17 cyc,焊接电流10.14kA。DP600钢点焊熔核的微观组织为柱状晶,以板条状马氏体为主。在拉剪条件下,DP600高强钢电阻点焊接头主要有熔核剥离断裂和界面断裂2种断裂模式。 相似文献
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针对2.0 mm厚的AZ31B镁合金以及1.0 mm厚的SPHC镀锌钢板,采用kDWJ-17型三相次级整流电阻焊机进行焊接试验,通过对接头的金相观察、扫描电镜分析,结合原子结合能研究点焊接头拉剪断裂特征.结果表明,点焊接头断裂的形式呈现结合面断裂和纽扣断裂两种方式,纽扣断裂抗拉剪力学性能优于结合面断裂,纽扣断裂断口是以韧性断口为主,脆性断裂为辅的混合断口.熔核区以Fe-Al化合物为主时发生纽扣断裂,熔合线边缘晶粒尺寸粗大以及熔核区Fe-Al化合物结合能大,使其断裂位置在熔合线边缘.熔核区以Mg-Zn化合物为主时发生结合面断裂,其Mg-Zn化合物结合能偏小,容易被拉断. 相似文献
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以汽车车身DH980-GI钢板电阻点焊为研究对象,通过参数实验优化设计,接头强度、接头硬度和接头抗点焊液态金属脆(LME)分析等手段,研究了焊接电流等参数对钢板电阻点焊接接头性能的影响,并对板材的点焊液态金属脆敏感性进行测试研究。试验结果显示,在电极压力4.5 kN、焊接时间380 ms的条件下,焊接电流在6.8~8.1 kA内,不同电流的接头熔核区域显微硬度值相近,均在470~510 HV内,熔核直径均满足标准要求。LME测试结果显示,在6.8~10.5 kA电流范围内未出现LME裂纹,而11~14.5 kA电流范围内出现了A类LME裂纹。力学性能测试结果显示,在焊接电流6.8 kA时,接头抗剪强度为901~911 MPa,在焊接电流8.1 kA时,为738~783 MPa,抗剪力均达到21 kN以上,均满足标准要求。 相似文献
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Christopher DiGiovanni Elliot Biro Norman Y. Zhou 《Science & Technology of Welding & Joining》2013,18(3):218-224
ABSTRACTAdvanced high strength steels used in automotive structural components are commonly protected using zinc coatings. However, the steel/zinc system creates the potential for liquid metal embrittlement (LME) during welding. Although LME cracks are known to form, limited research has found any detrimental impact of LME cracks on weld strength. In this work, a comparison of zinc coated and uncoated advanced high strength steel joints showed LME decreased strength in welds from transformation induced plasticity type microstructures and an 1100?MPa ultimate tensile strength by 43.6%. LME cracks were observed to propagate until final fracture. However, only cracks located in the periphery of the weld area were found contribute to a loss in strength. 相似文献
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Christoph Böhne Gerson Meschut Max Biegler Julian Frei Michael Rethmeier 《Science & Technology of Welding & Joining》2020,25(4):303-310
ABSTRACTAdvanced high strength steels are usually coated by a zinc layer for an increased resistance against corrosion. During the resistance spot welding of zinc coated steel grades, liquid metal embrittlement (LME) may occur. As a result, cracking inside and around the spot weld indentation is observable. The extent of LME cracks is influenced by a variety of different factors. In this study, the impact of the used electrode geometry is investigated over a stepwise varied weld time. A spot welding finite element simulation is used to analyse and explain the observed effects. Results show significant differences especially for highly increased weld times. Based on identical overall dimensions, electrode geometries with a larger working plane allow for longer weld times, while still preventing LME within the investigated material and maintaining accessibility. 相似文献
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L. He C. DiGiovanni X. Han C. Mehling E. Wintjes E. Biro 《Science & Technology of Welding & Joining》2013,18(6):579-586
ABSTRACTThird-generation advanced high strength steels are typically given a zinc coating that provides excellent resistance to corrosion. During the resistance spot welding process, the melted zinc coating enables liquid metal embrittlement (LME) that causes cracking in the weld indent. In this study, LME in TRIP 1100 and TRIP 1200 steels was suppressed by placing aluminium interlayers added between the electrode and steel contact surface. Compared to welds exhibiting LME, TRIP 1100 with aluminium interlayers showed complete strength recovery while TRIP 1200 with aluminium interlayers resulted in a recovery of strength by 90%. Aluminium interlayers suppress LME by the formation of iron aluminides that hinder liquid zinc from coming in contact with the steel substrate, thus preventing LME. 相似文献
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采用电阻点焊对TRIP980高强钢进行焊接. 通过单因素法和焊后回火优化了焊接参数和工艺,研究了较优焊接参数和工艺时的接头熔核显微组织及力学性能,结果表明,优化参数为9.5 kA,22 cycle,3 kN,接头熔核为粗大的马氏体组织,接头硬度为617.1 HV,最大拉剪载荷为17.8 kN;在此基础上增加焊后回火,回火电流6.3 kA、回火时间13 cycle,接头组织显著细化,接头硬度降低至574 .0 HV,接头最大拉剪载荷提高到19.5 kN,增幅为9.6%,断口形式由原先的界面断裂转变为纽扣断裂. 相似文献
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采用电阻点焊实现了对镁合金和钢的焊接,研究焊接电流、焊接时间和焊接压力对镁/钢点焊接头拉剪力和熔核直径的影响。结果表明,随着焊接压力、焊接电流或焊接时间的增加,镁/钢点焊接头拉剪力先增加后减小。在预压时间300ms,焊接电流30kA,焊接时间180ms,焊接压力6kN时,得到镁/钢点焊接头最大拉剪力6.64 kN。 相似文献
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《Science & Technology of Welding & Joining》2013,18(1):25-31
AbstractIn normal production of resistance spot welded galvanised structures, it is difficult to completely avoid surface breaking cracks. Known key factors to cause cracking are zinc coating, electrode wear during subsequent welding and insufficient electrode cooling. In this report, an embrittlement mechanism was investigated that could be coupled to the galvanisation method for dual phase steels. With identical bulk material and weld parameters, the first 50 spot welds were crack free with electrogalvanised coating, while only 10 out of 50 were crack free with hot dip galvanised coating. Energy dispersive X-ray spectroscopy analysis of the worn electrode surfaces used for welding of the hot dip galvanised coating revealed areas of aluminium oxide. Since aluminium oxide is a very strong isolator, the electrical resistance will increase, which in turn is suggested to increase the surface temperature of the spot weld and thereby increase the probability for liquid metal embrittlement and surface cracks. 相似文献
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采用纯铝作为中间层对铝合金与低碳钢进行了电阻点焊,分析中间夹层厚度对界面反应层厚度和接头抗拉强度的影响。在钢/中间夹层界面观察到有界面反应层生成,其主要由靠近钢侧的Fe2Al5和靠近中间夹层铝侧的FeAl3两种金属间化合物组成。与不加中间夹层相比,利用纯铝作为中间夹层点焊的铝合金与低碳钢的接头具有较薄的界面反应层和较高的接合强度。随着中间夹层厚度的增加,界面反应层厚度逐渐减小,而接头抗拉强度则呈增大趋势。结果表明,采用纯铝作为中间夹层点焊铝合金与钢具有一定的有效性。 相似文献