金属热处理 ›› 2022, Vol. 47 ›› Issue (1): 172-177.DOI: 10.13251/j.issn.0254-6051.2022.01.029

• 组织与性能 • 上一篇    下一篇

Mn18Cr18N高氮奥氏体不锈钢的高温力学性能

王英虎1, 郑淮北1, 白青青1, 宋令玺1, 胡进2, 黄博2   

  1. 1.成都先进金属材料产业技术研究院股份有限公司, 四川 成都 610000;
    2.攀钢集团江油长城特殊钢有限公司, 四川 江油 621704
  • 收稿日期:2021-06-28 修回日期:2021-08-30 出版日期:2022-01-25 发布日期:2022-02-18
  • 作者简介:王英虎(1992—),男,工程师,硕士,主要研究方向为先进金属材料及加工技术,E-mail:hihihowareyou@163.com

High temperature mechanical properties of Mn18Cr18N high nitrogen austenitic stainless steel

Wang Yinghu1, Zheng Huaibei1, Bai Qingqing1, Song Lingxi1, Hu Jin2, Huang Bo2   

  1. 1. Chengdu Advanced Metal Material Industry Technology Research Institute Co., Ltd., Chengdu Sichuan 610000, China;
    2. Pangang Group Jiangyou Changcheng Special Steel Co., Ltd., Jiangyou Sichuan 621704, China
  • Received:2021-06-28 Revised:2021-08-30 Online:2022-01-25 Published:2022-02-18

摘要: 采用Gleeble-2000热模拟试验机对Mn18Cr18N高氮奥氏体不锈钢进行高温拉伸试验,利用扫描电镜-能谱仪对拉伸试样断口形貌及断口附近的显微组织进行观察,用Thermo-Calc软件计算试验钢的相变及析出相,研究了Mn18Cr18N高氮奥氏体不锈钢的高温力学性能。结果表明,试验钢的第Ⅰ脆性区>1200 ℃,第Ⅲ脆性区为850~950 ℃,未出现第Ⅱ脆性区,第Ⅰ脆性区的出现主要是在加热过程中试验钢由γ奥氏体向δ铁素体转变引起的,第Ⅲ脆性区的出现是因为沿晶析出M23C6、M2(C, N)等硬脆相引起的;试验钢的抗拉强度随着拉伸温度升高而降低,断面收缩率在1000~1200 ℃温度范围内逐渐增大并表现出极佳的热塑性,断面收缩率均在70%以上,温度超过1200 ℃后断面收缩率急剧下降;Mn18Cr18N高氮奥氏体不锈钢的热锻温度应选择在1000~1150 ℃之间,在此温度范围内试验钢的断面收缩率均在70%以上,并且可以避开第Ⅰ与第Ⅲ脆性区。

关键词: 高氮奥氏体不锈钢, 高温力学性能, 高温拉伸试验, 强塑性, Thermo-Calc软件

Abstract: High temperature mechanical properties of the Mn18Cr18N high nitrogen austenitic stainless steel were studied, with the high temperature tensile test being carried out by Gleeble-2000 thermal simulation testing machine, the fracture morphology and vicinity microstructure of the tensile specimens being observed by scanning electron microscopy-energy dispersive spectrometer, and the phase transformation and precipitated phases of the tested steel being studied by Thermo-Calc calculation. The results show that the corresponding temperature of brittle zone Ⅰ of the tested steel is higher than 1200 ℃, and that of brittle zone Ⅲ is 850-950 ℃, while the brittle zone Ⅱ does not appear. The appearance of the brittle zone Ⅰ is mainly caused by the transformation from γ austenite to δ ferrite during heating process of the tested steel, and that of the brittle zone Ⅲ is caused by the intergranular hard and brittle precipitated phases such as M23C6 and M2(C, N). With the increase of tensile test temperature, the tensile strength of the tested steel decreases. The reduction of area gradually increases in the temperature range of 1000-1200 ℃ and shows excellent thermoplasticity, which is above 70%. While when the temperature exceeds 1200 ℃, the reduction of area decreases sharply. The hot forging temperature of the Mn18Cr18N high nitrogen austenitic stainless steel should be selected between 1000 ℃ and 1150 ℃, during which the reduction of area of the tested steel is above 70%, and the brittle zones Ⅰ and Ⅲ can be avoided.

Key words: high nitrogen austenitic stainless steel, high temperature mechanical properties, high temperature tensile test, strength and plasticity, Thermo-Calc software

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