Study of Phase Transformation in Martensitic Stainless Steel AISI 422 During Continuous Cooling

Subject Areas : journal of New Materials

سعیده Ghanbari ¹ , کامران Amini ² , علی Shafyei ³ , M.A Soltani ⁴

1 - مرکز تحقیقات مواد پیشرفته، دانشکده مهندسی مواد، واحد نجف آباد، دانشگاه آزاد اسلامی، نجف آباد.
2 - دانشیار، دانشکده مهندسی مکانیک، واحد تیران، دانشگاه آزاد اسلامی، تیران، اصفهان، ایران.
3 - دانشیار، گروه مهندسی مواد، واحد نجف آباد، دانشگاه آزاد اسلامی، نجف آباد، ایران.
4 - کارشناس ارشد فولاد آلیاژی اصفهان،اصفهان،ایران.

Received: 2016-05-20 Accepted : 2016-05-20 Published : 2015-12-22

Keywords: Phase Transformation, Dilatometery, Steel AISI 422, CCT Diagram,

Abstract :

In this research the behavior of the steel AISI 422 has been investigated during the various continuous cycle of cooling in dilatometer and CCT diagram has been obtained. The standard test samples were prepared in accordance with the requirements of the standard Dilatometers SEP 1681 in cylinders with a diameter of 4 mm and length of 10 mm. In the dilatometer test, heating the samples were conducted in controlled vacuum atmosphere. The results showed that after reaching the austenitizing temperature of 1040°C, holding time of 15 minutes , cooling time of 5, 15, 30 minutes, 1, 3, 6, 12 and 18 hours, martensite was formed in range of 238-300 °C. Colling In 24, 36 and 48 hours, pearlite phase was formed. The start temperature range of this transformation was 472-621°C and the final temperature rang of perlite transformation was 367-504°C. The martensite transformation for this cooling times was 300-310°C. In the cooling time of 36 hours, the bainite phase was formed in the temperature rang of 402-451°C. The results of this steel's hardenability test showed high hardenability and the jominy curve showed constant line

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