【摘要】 本文首先对焊接接头焊前预热产生附加热应力的机理进行了分析,得到两端刚性固定对接接头模型预热时附加热应力的计算公式,即:附加热应力Δσ_r的大小与拘束度 R、加热宽度 L_Q、预热温度与室温之差(T-T_R)成正比,与焊缝的厚度 hw 成反比。接着分析了在不同预热条件下实际结构产生附加热应力的趋势,提出了在不同情况下附加热应力的估算方法。通过实验室的平板刚性拘束裂纹试验(PRRC)和在实际焊接结构上的验证,说明有关分析和公式是正确的。最后,提出了减小或消除实际焊接结构上的附加热应力的具体措施。更多还原

【Abstract】 In this article,the theoretical analyses for the mechanism of extra heat stress produced in preheating procedure before welding are given firstthen a formula for calculating extra heat stree during preheating of butt joint model having 2 ends fixed rigidly is set up,The degree of extra heat stress is directly proportional to the restraint degree,the heating width. and the difference between preheating temperature and room temperature,and is the inver, sely proportional to the thickness of weld seam.This article also analyses the tendency of producing extra heat stress from the actual structure under different preheat conditions analysed and puts forward a calculating method .Through the rigidity restrain crack test of flat plate in laboratory and the actual welding structure,the above analysis and formula were verified to be correct.Finally,the article suggests concrete measures for minimizing or eliminating the extra heat stress of practical welding structures.更多还原