摘要
对典型成分的S32750双相不锈钢进行了一次固溶+冷变形+二次固溶处理,获得了不同组织形态的样品,对其进行组织演变、力学性能和耐点蚀性能表征与测试,并利用EBSD、EPMA手段对试验钢的晶体学信息、元素分布进行了分析。结果表明:经过上述处理后试验钢的相比例和晶粒尺寸差异明显,二次固溶后,相比于冷变形状态,二次固溶后两相晶粒尺寸变化情况不一致。由于两相再结晶能力和晶粒长大速度存在差异,1100℃+50%+1100℃和1150℃+50%+1100℃工艺下,二次固溶后试验钢组织以铁素体晶粒长大为主,约为22μm,奥氏体晶粒尺寸变化不明显,在10μm附近;1050℃+50%+1100℃工艺二次固溶后奥氏体晶粒得到进一步细化,降低至5μm;1250℃+50%+1100℃工艺下,二次固溶后两相晶粒均进一步细化,铁素体和奥氏体晶粒尺寸分别降低至11和4μm。相比于一次固溶状态,二次固溶后所有晶粒均得到细化。前后2次固溶温度差异较大时,在前期冷变形储能作用下,在二次固溶时促进了新的固态相变行为,并获得更为细化的晶粒组织。二次固溶后,试验钢强度与冷变形态相比整体降低,但断后伸长率升高,与一次固溶相比整体强度和断后伸长率均上升。1050℃+50%+1100℃工艺下屈服强度达到641 MPa,断后伸长率为39%,1250℃+50%+1100℃工艺下,屈服强度为619 MPa,断后伸长率达到44%。加权平均PREN值可反应出试验钢的整体耐点蚀性能。二次固溶后,试验钢点蚀电位提高,达到1056~1075 mV,钝化膜的稳定性增强,与一次固溶态和冷轧态相比,回扫阳极曲线无滞回现象。
S32750 duplex stainless steel with typical composition was subjected to a treatment process consisting of primary solid solution+cold deformation+secondary solid solution treatment,resulting in samples with different microstructures.The microstructure evolution,mechanical properties and pitting resistance were characterized and tested,while the crystallographic information and elemental distribution of the test steels were analyzed by means of EBSD and EPMA.The results show that the phase ratio and grain size of the test steel are significantly altered after the above treatment.After the secondary solid solution,the changes in grain size of the two phases were inconsistent compared to the cold deformed state.Due to the differences in two-phase recrystallization capacity and grain growth rate,in the 1100℃+50%+1100℃and 1150℃+50%+1100℃processes,the ferrite grains grew to approximately 22μm after secondary solution treatment,whereas the austenite grain size remained about 10μm with no significant change.For the 1250℃+50%+1100℃process,both phases exhibited further refinement after secondary solution treatment,with ferrite and austenite grain sizes reducing to 11 and 4μm,respectively.Compared with the state of primary solution,all grains were refined after secondary solution treatment.Under the action of pre-cold deformation energy storage,the new solid-state phase transformation behavior is promoted during secondary solution,and more refined grain structure is obtained.After the second solid solution,the strength of the test steel decreased totally compared to the cold deformation form,but the elongation rate increased.Compared with the first solid solution,both the strength and elongation rate increased totally.At 1050℃+50%+1100℃,the yield strength is 641 MPa and the elongation is 39%;at 1250℃+50%+1100℃,the yield strength is 619 MPa and the elongation is 44%.The weighted average PREN value can reflect the overall pitting resistance of the test steel.After the second solution,the pitting potential of the test steel is increased,up to 1056-1075 mV,and the stability of the passivation film is enhanced.Compared with the first solution state and the cold rolling state,there is no hysteresis phenomenon in the swept-back anode curve.
作者
顾洋
丰涵
何建国
宋志刚
郑文杰
朱玉亮
GU Yang;FENG Han;HE Jianguo;SONG Zhigang;ZHENG Wenjie;ZHU Yuliang(Research Institute of Special Steels,Central Iron and Steel Research Institute Co.,Ltd.,Beijing 100081,China;Hebei Province Key Laboratory of Corrosion-Resistant Alloy Materials,Xingtai 054800,Hebei,China)
出处
《钢铁研究学报》
北大核心
2025年第4期497-508,共12页
Journal of Iron and Steel Research
基金
河北省重点研发计划资助项目(23311004D)。
关键词
双相不锈钢
固溶处理
冷变形
晶粒尺寸
耐点蚀性能
duplex stainless steel
solid solution treatment
cold deformation
grain size
pitting resistance
