Some detrimental phases, such as nitrides, carbides and intermetallics may precipitate due to improper manufacturing or fusion welding process and affect the mechanical properties and corrosion resistance of duplex stainless steels (DSSs) dramatically. In this work, the solution-annealed 2205 DSS samples were aged at 850 °C for different time to stimulate typical welding microstructures at different cooling rates and their corrosion resistance were assessed by methods of cyclic potentiodynamic polarization and electrochemical impedance tests. Microstructural characterization indicates that chromium nitrides and carbides lamellas precipitate first in the initial several minutes and chi phase nucleates and grows at ferrite grain boundaries or austenite/ferrite phase boundaries then. With aging time prolonged to 60 min plentiful sigma phase together with the secondary austenite precipitates alongside prior austenite/ferrite phase boundaries and propagates into ferrite. Electrochemical tests demonstrate that chromium nitrides and carbides precipitates accelerate the activated corrosion of matrix and have less impact on its pitting potential. Precipitation of chi and sigma can cause chromium and molybdenum depletion in surrounding areas and increase the susceptibility dramatically. So, it is necessary to optimize the welding specifications in practice to obtain microstructure that combines mechanical strength and corrosion resistance excellently.

某些有害相，例如氮化物，碳化物和金属间化合物，可能由于不正确的制造或熔焊工艺而析出，并严重影响双相不锈钢（DSS）的机械性能和耐蚀性。在这项工作中，将固溶退火的2205 DSS样品在850°C的温度下老化不同的时间，以刺激不同冷却速率下的典型焊接微观结构，并通过循环电势极化和电化学阻抗测试方法评估了它们的耐腐蚀性。显微组织表征表明，氮化铬和碳化物薄片首先在最初的几分钟内析出，然后chi相成核，然后在铁素体晶界或奥氏体/铁素体相界生长。随着时效时间延长至60分钟，大量的σ相与次级奥氏体一起在先前的奥氏体/铁素体相界附近析出并传播到铁素体中。电化学测试表明，氮化铬和碳化铬沉淀加速了基体的活化腐蚀，并且对其点蚀电位的影响较小。chi和sigma的沉淀会导致周围区域的铬和钼消耗，并大大增加磁化率。因此，有必要在实践中优化焊接规格，以获得兼具机械强度和耐蚀性的显微组织。电化学测试表明，氮化铬和碳化铬沉淀加速了基体的活化腐蚀，并且对其点蚀电位的影响较小。chi和sigma的沉淀会导致周围区域的铬和钼消耗，并大大增加磁化率。因此，有必要在实践中优化焊接规格，以获得兼具机械强度和耐蚀性的显微组织。电化学测试表明，氮化铬和碳化铬沉淀加速了基体的活化腐蚀，并且对其点蚀电位的影响较小。chi和sigma的沉淀会导致周围区域的铬和钼消耗，并大大增加磁化率。因此，有必要在实践中优化焊接规格，以获得兼具机械强度和耐蚀性的显微组织。