| 固溶处理对S32707特超级双相不锈钢析出相、组织及性能影响 |
| |
| 作者姓名： | 沈伟 孙丽娟 李长荣 杨占兵 王福明 |
| |
| 作者单位： | 1.北京科技大学冶金与生态工程学院，北京 100083 |
| |
| 基金项目： | 国家自然科学基金资助项目（51974017） |
| |
| 摘 要： | 通过Thermo-Calc热力学计算、OM和FE-SEM观察、力学性能和腐蚀性能试验对不同固溶温度下的特超级双相不锈钢进行分析和研究。结果表明:σ相和非平衡氮化物是固溶水冷组织中的主要析出相，当固溶温度低于1050 ℃时，σ相优先沿双相界面析出，显著降低双相不锈钢的冲击韧性；当固溶温度高于1100 ℃，非平衡氮化物开始在铁素体晶粒内部析出，且随着固溶温度的升高，非平衡氮化物析出数量增加。这是由于固溶水冷过程中氮在铁素体中的溶解度快速降低，过饱和的氮来不及扩散到相邻奥氏体中，只能以氮化物的形式析出。随固溶温度升高，铁素体含量增加，奥氏体含量降低，实验钢的强度增加，冲击韧性降低。在1080～1120 ℃之间固溶时，双相比例接近1∶1，S32707特超级双相不锈钢具有优良的综合力学性能和耐晶间腐蚀性能。
|
| 关 键 词： | 特超级双相不锈钢 组织演变 σ相 非平衡氮化物 力学性能 |
| 收稿时间： | 2021-03-25 |
Solution treatment effect on precipitates,microstructure,and properties of S32707 hyper-duplex stainless steel |
| |
| Authors: | SHEN Wei SUN Li-juan LI Chang-rong YANG Zhan-bing WANG Fu-ming |
| |
| Affiliation: | 1.School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China2.School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China |
| |
| Abstract: | Duplex stainless steel (DSS) has been widely used in some harsh environments, such as flue gas shedding and seawater desalination, because of its high strength and corrosion resistance. These excellent properties rely on a high alloy content (Cr, Mo, N, etc.) and perfect dual-phase equilibrium. The dual-phase equilibrium mainly includes dual-phase proportion balance, properties balance, and absence of clear secondary phase in the solid solution structure. As one of the main developmental directions of DSS, hyper-duplex stainless steel (HDSS) has attracted much attention in recent years. In this paper, the effects of solution treatment on precipitates, microstructure, and properties of S32707 HDSS were studied by Thermo-Calc thermodynamic calculation, OM and FE-SEM observation, mechanical properties, and corrosion property tests. The results showed that σ phase and non-equilibrium nitrides were the main precipitates of solution-treated HDSS. When the solution temperature was lower than 1050 ℃, the σ phase precipitated preferentially along the dual-phase boundaries, which significantly reduced the impact toughness of HDSS. When the solution temperature was higher than 1100 ℃, non-equilibrium nitrides precipitated in ferrite grains, and the number of non-equilibrium nitrides increased with an increase in solution temperature. The reason for the non-equilibrium nitride precipitation was that the nitrogen content in the ferrite increased with an increase in temperature. This led to the supersaturation of nitrogen in the ferrite grains during the rapid cooling process. Under such conditions, the finely dispersed non-equilibrium nitrides precipitated in the ferrite grains. With increasing solution temperature, the content of the ferrite increased, the content of austenite decreased, the strength increased, and the impact toughness decreased. The optimal solution temperature of HDSS was 1080?1120 ℃. Under this condition, the ratio of duplex was close to 1∶1, and the S32707 hyper duplex stainless steel presented excellent comprehensive mechanical properties and intergranular corrosion resistance. |
| |
| Keywords: | |
| 本文献已被 CNKI 万方数据 等数据库收录！ |
| 点击此处可从《》浏览原始摘要信息 |
|
点击此处可从《》下载全文 |
|
