论文部分内容阅读
精确分析熔化极气体保护电弧焊 (GMAW)焊接传热过程的前提是对施加于工件表面上的焊接热输入分布模式有一个恰当的、合乎实际的描述。本文作者根据电弧物理的基本原理和熔滴与熔池的交互作用 ,建立了双峰分布的电弧热流密度分布模型 ,确定了熔滴热焓量在熔池内部的分布区域。以此为基础 ,建立了GMAW焊接传热的数学模型 ,给出了焊接热影响区奥氏体晶粒长大的动力学方程。采用数值模拟技术研究了低碳钢和HQ130钢HAZ的奥氏体晶粒长大过程 ,得到了焊接热输入对HAZ不同部位奥氏体晶粒尺寸的影响规律。试验表明 ,焊接热循环及HAZ奥氏体晶粒尺寸的计算值和实测值吻合良好。
A prerequisite for accurate analysis of GMAW welding heat transfer processes is an appropriate, realistic description of the welding heat input distribution pattern applied to the workpiece surface. According to the basic principle of arc physics and the interaction between droplet and weld pool, the author established a bimodal distribution of arc heat flux density distribution model and determined the distribution area of enthalpy of droplet in the weld pool. Based on this, a mathematical model of GMAW welding heat transfer was established, and the kinetic equation of austenite grain growth in HAZ was given. The process of austenite grain growth in HAZ of low carbon steel and HQ130 steel was studied by numerical simulation. The influence of welding heat input on the austenite grain size in different parts of HAZ was obtained. Tests show that the calculated values of the welding heat cycle and the HAZ austenite grain size are in good agreement with the measured values.