考虑相变影响的电阻点焊数字模拟
Numerical simulation of resistance spot welding considering phase transition effect
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摘要: 热膨胀作用于焊接整个过程,考虑相变对线膨胀系数的影响,建立了考虑相变影响的电阻点焊二维轴对称有限元数值分析模型.以双相高强度钢DP600为研究对象,考虑相变潜热的影响,得到焊接过程温度场分布结果.利用热弹塑性理论和线性混合法则,考虑相变对线膨胀系数的影响,对双相钢电阻点焊应力场及工件焊接变形进行了分析研究.结果表明,考虑相变对线膨胀系数的影响,计算分析结果更接近实际.Abstract: Al/Fe clad materials joining with Al alloy were successfully realized at intermediate temperature without flux in air by using ultrasonic-assisted brazing.Mechanical properties and microstructure of joints with Zn-Al and Al-Si filler metals were studied.The experiment showed that the oxide film of Al film at clad materials were effectively removed when Al/Fe clad materials were brazed with 5A06 alloy by using Zn-Al filler metal.Diffusion of Al film was easily controlled.There were not Fe- Al intermetallic compounds in the joins.Shear strength of joints was higher than 70 MPa when the Al film was not completely dissolved.The joints were composed of α-Al,η-Zn,Zn-Al eutectic and Zn-Al eutectoid.When Al/Fe clad materials were brazed with 1100 Al by using Al-Si filler metal,the Al film was completely dissolved in a short time.Fe-Al-Si intermetallic compounds and microcracks were observed and the shear strength was only 20 MPa.