A super duplex stainless steel was subjected to solution annealing at 1323 K. This led to grain coarsening, ‘limited’ (~ 7 pct by area) austenite-to-ferrite phase transformation and changes in phase-specific chemistry. No changes in the phase boundary nature or galvanic coupling between phases were, however, noted. The general corrosion behavior was determined by the electrochemical performance of the individual phases. The corrosion performance of the ferrite phase degraded monotonically with annealing time. This was related to a combined effect of grain coarsening and dilution in alloying (chromium and molybdenum content) elements. Corrosion of the austenite phase was, however, non-monotonic: as the effects of grain coarsening was counter-balanced, at least during the initial stages of annealing, by relative molybdenum enrichment. This study thus provided clear experimental data relating phase-specific corrosion performance with annealing induced changes in grain size and local chemistry in a super duplex stainless steel.

超级双相不锈钢在1323 K下进行了固溶退火。这导致晶粒粗化，“受限”（约7 pct面积）奥氏体到铁素体的相变以及特定相化学的变化。但是，没有注意到相界性质的改变或相之间的电流耦合。总体腐蚀行为由各个相的电化学性能决定。铁素体相的腐蚀性能随退火时间单调降低。这与合金元素（铬和钼含量）中晶粒粗化和稀释的综合作用有关。但是，奥氏体相的腐蚀不是单调的：至少在退火的初始阶段，通过相对富集钼可以抵消晶粒粗化的影响。