摘要
In the present study,the effects of microstructure,grain size,and texture after thermomechanical processing on the corrosion behavior of AISI 321 austenitic stainless steel(ASS)were studied.The as-received,coarse-grained steel((35±3)μm)was subjected to 20%,50%and 90%thickness reduction through cold rolling at liquid nitrogen temperature,followed by annealing at 750,950 and 1050℃for 15 min.Recrystallization occurred after annealing at 750℃,and with the increasing of annealing temperature to 950℃and 1050℃,secondary recrystallization(abnormal grain growth)and grain growth were observed.The results showed that,after 20%thickness reduction,corrosion resistance increased significantly(21.1 kΩ·cm^(2))compared with the as-received condition(3.9 kΩ·cm^(2))due to the enhancement ofγ-fiber and the creation ofΣ3 boundaries.In contrast,the corrosion resistance decreased with the increasing of thickness reduction to 90%during rolling,but still depicted higher corrosion resistance compared with the as-received specimen.After annealing the 90%cold rolled(CR)specimens at 750 and 950℃,the corrosion resistance increased in comparison with the as-received sample as a result of the more uniform microstructure,appearance of Goss and brass texture components,and grain refinement.However,significant grain growth((112±76)μm)followed by a non-uniform structure was observed after annealing at 1050℃and resulted in the lowest corrosion resistance(1.3 kΩ·cm^(2)).
本文研究了热处理对AISI 321奥氏体不锈钢(ASS)管微观结构、晶粒尺寸和纹理及其腐蚀行为的影响。将原始的粗粒径钢试样((35±3)μm)先在液氮温度下冷轧减厚20%、50%和90%,随后在750、950和1050℃下退火处理15 min。试样在750℃退火后发生再结晶,随着退火温度升高至950和1050℃,出现二次再结晶(晶粒异常生长)和晶粒生长。结果表明,在厚度减少20%后,由于γ-纤维的增强和Σ3边界的形成,试样的耐蚀性(21.1 kΩ·cm^(2))较初始条件(3.9 kΩ·cm^(2))显著提高。当轧制厚度减少90%时,试样的耐蚀性降低,但仍表现出比原始试样更高的耐蚀性。在750和950℃退火处理冷轧减厚90%的试样中,微观组织分布更加均匀,Goss和黄铜纹理成分出现,晶粒细化,耐蚀性比原始试样更高。经1050℃退火处理后,试样粒径明显增大((112±76)μm),微观组织分布不均匀,耐蚀性最低(1.3 kΩ·cm^(2))。
基金
Project(scu.EM1400.30796)supported by the Shahid Chamran University of Ahvaz,Iran。
