( 1. 北京工業(yè)大學 材料科學與工程學院, 北京 100022；
2. 北京航空制造工程研究所, 北京 100024)
摘 要: 采用數(shù)值模擬和實驗相結合的方法研究了鈦合金TC4薄板常規(guī)及帶熱沉的鎢極氬弧焊焊接過程中溫度及應力應變的分布，考察了熱沉對溫度場和應力應變場的影響規(guī)律， 探討了使用該技術實現(xiàn)應力和變形控制的機理。 結果表明： 帶熱沉的鎢極氬弧焊焊接過程中， 緊隨熱源之后熱沉急冷作用使得試件形成馬鞍形溫度場，而熱沉作用部位溫度最低。 熱沉作用部位的急冷收縮對周圍金屬產(chǎn)生拉伸作用， 使得焊縫及近縫區(qū)金屬升溫過程中產(chǎn)生的壓縮塑性應變減小， 冷卻過程中產(chǎn)生的拉伸塑性應變增大，接頭中不協(xié)調應變減小， 殘余應力降低。 實驗測量與有限元模擬結果吻合良好， 證實了采用熱沉控制應力與變形的有效性和有限元模型的正確性。
關鍵字: 鈦合金； 鎢極氬弧焊； 熱沉； 溫度場； 應力場； 應變場； 有限元法
trailing spot heat sink for titanium alloy
DU Yu-xiao2, SUN Yong-chun2
（ 1. School of Materials Science and Engineering,
Beijing Polytechnical University, Beijing 100022, China;
2. Beijing Aeronautical Manufacturing Technology Research Institute, China）
Abstract: The distribution of temperature, stress and strain of titanium alloy Ti-6Al-4V thin sheet were studied with numerical simulation and experiment during conventional gas tungsten arc welding and gas tungsten arc welding with trailing spot heat sink behind welding arc, also named dynamically controlled low stress no-distortion gas tungsten arc welding, the influences of heat sink on temperature, stress and strain fields were investigated, the stress and distortion controlling mechanism of dynamically controlled low stress no-distortion technique was discussed. The results show that, during dynamically controlled low stress no-distortion gas tungsten arc welding, the saddle shape temperature field is formed due to the intense cool effects of heat sink, there exists the lowest temperature in the heat sink applied region. High tensile action of metals is generated by sharp cooling of the heat sink applied region, which decreases the compressive plastic strains in heating process and increases the tensile plastic strains in cooling process within and near the weld. The incompatible strains in the joint decrease and the residual stresses reduce. The simulation results are in good agreement with the experimental results, which proves the effectiveness of DC-LSND technique and the validity of the finite element model.
Key words: titanium alloy; gas tungsten arc welding; heat sink; temperature field; stress field; strain field; finite element method
