通过光学显微镜和扫描电镜等研究了固溶、时效热处理对堆焊钴基合金后2507双相不锈钢母材及堆焊热影响区组织的影响。结果表明: 在1 050~1 200 ℃之间进行固溶处理时, 随着固溶温度的升高, 母材中铁素体的体积分数从46%增加到了58%, 奥氏体含量降低; 堆焊热影响区的奥氏体垂直于熔合线生成和长大, 并在奥氏体晶界处有黑色析出相产生; 在850 ℃时效处理后, 母材和热影响区中均有σ相析出, 但热影响区铁素体基体上有位向交错的针状γ2相析出; 在620 ℃时效处理后, 母材和热影响区中均没有σ相析出, 但有点状连续碳化物在热影响区的奥氏体晶界上析出。

The effects of heat treatment (solid solution and aging) on microstructure of base metal and surfacing welding heat affected zone (HAZ) of 2507 DSS (duplex stainless steel) by the means of optical microscopy and scanning electron microscopy. The results show that, after the steel was solid soluted at 1 050-1 200 ℃, the volum fraction of ferrite in base metal increased from 46% to 58% with increasing of the solid solution temperture, and the content of austenite increased. The sustenite grew perpendicular to fusion line in surfacing welding HAZ, and some black precipitated phases were found at the austenitic grain boundaries. σ phase appeared in both base metal and HAZ after aging at 850 ℃, and interlaced needle-shaped γ2 phase could be found in ferrite base in HAZ. Continous and point like carbides could be found at the austenitic grain boundaries in HAZ, and σ phase was not found in base metal and heat affected zone after aging at 620 ℃.