(現代焊接生產技術國家重點實驗室，哈爾濱工業(yè)大學 150001)
摘 要: 提出采用橫向預置擠壓載荷進行隨焊同步防止鋁合金薄板焊接熱裂紋的新方法。對處于脆性溫度區(qū)間的焊縫金屬施加一適當的橫向擠壓載荷，可以減小焊縫金屬凝固收縮時產生的橫向拉伸應力和應變，使其總應變被限制在最低延性值范圍內，改變了熱裂紋產生的力學條件。建立橫向預置壓應力模型、采用彈塑性有限元方法闡明橫向預置應力法防止熱裂紋的原理，在自制的裝置上對常規(guī)焊和橫向預置壓應力工藝條件下焊接試件裂紋率進行比較分析。魚骨狀裂紋試驗結果表明：在加載寬度一定時，隨著預置載荷的增加，在焊縫處產生的擠壓應力也隨之增加，裂紋率和裂紋長度逐漸降低，當橫向預置壓應力達到一定數值(0.3σ0.2)后，能夠完全防止焊接熱裂紋的產生。
關鍵字: 預置橫向擠壓載荷；焊接熱裂紋；裂紋率；數值模擬
（National Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology,
Harbin 150001, China）
Abstract: A new technique was presented to prevent welding hot cracking of aluminum thin plate by employing transverse compressive pre-load(TCPL)during welding. A proper transverse compressive load that is applied to the weld metal in brittle temperature range (BTR) can reduce the transverse tensile stress and strain when the weld metal is contracted during its solidifying so as to limit its total strain below the minimum plastic value, and the mechanical condition of welding hot cracking is changed. The model of TCPL was established and the principle of preventing welding hot cracking was illuminated by means of elasto-plastic finite element method. The cracking rates of conventional welding and welding with transverse compressive pre-stress were compared with each other. The experimental results of fish-bone samples show that with the TCPL increasing, the compressive stress in weld increases and the cracking length and cracking rate are reduced when the load region has a given value. When TCPL reaches a certain value (0.3σ0.2), the cracking is prevented completely.
Key words: transverse pre-stress; welding hot cracking; cracking rate; numerical simulation
