Journal Published Online: 26 September 2018
Volume 47, Issue 5

A Study of Precipitation-Strengthened Creep-Resistant Austenitic Stainless Steel for Supercritical and Ultra-Supercritical Power Plants

CODEN: JTEVAB

Abstract

The properties of precipitation-hardened austenitic stainless steels are adversely affected by the precipitation of unwanted brittle phases, like sigma (nonmagnetic intermetallic phase that is composed of iron and chromium) and Laves (Fe2Nb). These stainless steels are also susceptible to stress corrosion cracking. The induced residual stress in the material in turn reduces its creep strength. The strain beyond a certain limit affects its creep-resistant property appreciably, and hence, beyond a certain strain, these stainless steels are to be solution-treated for stress relief. Characterization studies on precipitation-strengthened creep-resistant austenitic stainless steel are presented in this article. Effects of strain and aging on microstructures are also evaluated. In order to understand the precipitation-strengthening behavior and effect of strain on Super304H (CC2328-2), the material was strained and aged at 650°C for a period ranging from 7 h to 4 weeks, and then the microstructures were studied using an optical microscope. Experiments were carried out on tubes with no strain and tubes with strain, which were aged at 650°C. The results show that beyond a threshold strain of ∼17 %, the material becomes deteriorated, and to regain its original microstructure, solid solution treatment is necessitated.

Author Information

Shrivastava, Dharmendra
Department of Applied Mechanics, Indian Institute of Technology Delhi, Noida, India
Aravindan, Sivanandam
Department of Mechanical Engineering, Indian Institute of Technology Delhi, Hauz Khas, India
Prasad, Rajesh
Department of Applied Mechanics, Indian Institute of Technology Delhi, Hauz Khas, India
Pages: 18
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Details
Stock #: JTE20170418
ISSN: 0090-3973
DOI: 10.1520/JTE20170418