残余应力对焊接结构应力腐蚀行为影响机理研究

Influence Mechanism of Residual Stress on Stress Corrosion Behavior of Welded Structure

针对焊接结构的应力腐蚀行为,提出了耐腐蚀常数公式,得到了残余应力对焊接结构耐腐蚀性能的影响机理。结果表明:耐腐蚀常数公式可以解释残余应力对焊接结构应力腐蚀行为的影响机理。焊接残余拉应力会同时减小金属的活化能和表面原子密度,导致焊接结构耐腐蚀性能的降低;在焊接残余压应力作用下,金属的表面原子密度升高,抵消了残余压应力对金属腐蚀速率的促进作用,提高了焊接结构的耐腐蚀性能。

The corrosion resistance constant formula was put forward for the stress corrosion behavior of welded structure, and the influence mechanism of residual stress on the corrosion resistance of welded structure was obtained. The results show that the influence mechanism of residual stress on the corrosion resistance of welded structure can be explained by the corrosion resistance constant formula. The welding residual tensile stress can decrease the metal activation energy and surface atomic density, resulting in the decrease of the corrosion resistance of welded structure. The welding residual compressive stress increases the metal surface atomic density, which counteracts the effect of residual compressive stress on the metal corrosion rate and increases the corrosion resistance of welded structure.