Yang Wen-Sheng, Liu Shuai, Han Shao-Wei, Wang Jia-Wei, Guo Jing, Yan Yan, Guo Han-Jie
School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing (USTB), Beijing 100083, China.
Steelmaking Department, Beijing Shougang Co., Ltd, Qian'an 064400, China.
Materials (Basel). 2020 Nov 27;13(23):5396. doi: 10.3390/ma13235396.
Evolutions of two typical types of nonmetallic inclusions, i.e., inclusions based on CaO-SiO-AlO and MnO-SiO-AlO of 304 stainless steel were investigated in laboratory-scale experiments under isothermal heat treatment at 1250 °C for 0, 30, 60 and 120 min. Results show inclusion population density increases at the first stage and then decreases while their average size decreases and then increases. Moreover, almost no CrO content within the inclusion before the heat treatment, but CrO content increases gradually along with increasing heat treatment time. Furthermore, the increasing of CrO content in the inclusions would increase their melting points and reduce their plasticities. The experimental results and thermodynamic analysis indicate that there are three steps for inclusion evolution during the heat treatment process, in which Ostwald ripening plays an important role in inclusion evolution, i.e., inclusions grow by absorbing the newly formed small-size MnO-CrO inclusions.
在实验室规模的实验中，研究了304不锈钢两种典型类型的非金属夹杂物（即基于CaO-SiO-AlO和MnO-SiO-AlO的夹杂物）在1250℃等温热处理0、30、60和120分钟时的演变情况。结果表明，夹杂物数量密度在第一阶段增加，然后减少，而其平均尺寸则先减小后增大。此外，热处理前夹杂物中几乎没有CrO含量，但CrO含量随着热处理时间的增加而逐渐增加。此外，夹杂物中CrO含量的增加会提高其熔点并降低其可塑性。实验结果和热力学分析表明，热处理过程中夹杂物演变有三个步骤，其中奥斯特瓦尔德熟化在夹杂物演变中起重要作用，即夹杂物通过吸收新形成的小尺寸MnO-CrO夹杂物而生长。
