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Title: Correlation of the microstructure and fracture toughness of the heat-affected zones of an SA 508 steel

Abstract

In this study, microstructures of a heat-affected zone (HAZ) of an SA 508 steel were identified by Moessbauer spectroscopy in conjunction with microscopic observations, and were correlated with fracture toughness. Specimens with the peak temperature raised to 1350 C showed mostly martensite. With the peak temperature raised to 900 C, the martensite fraction was reduced, while bainite or martensite islands were formed because of the slow cooling from the lower austenite region and the increase in the prior austenite grain size. As the martensite fraction present inside the HAZ increased, hardness and strength tended to increase, whereas fracture toughness decreased. The microstructures were not changed much from the base metal because of the minor tempering effect when it was raised to 650 C or 700 C. However, fracture toughness of the subcritical HAZ with the peak temperature raised to 650 C to 700 C was seriously reduced after postweld heat treatment (PWHT) because carbide particles were of primary importance in initiating voids. Thus, the most important microstructural factors affecting fracture toughness were the martensite fraction before PWHT and the carbide fraction after PWHT.

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Pohang Univ. of Science and Technology (KR)
OSTI Identifier:
20050544
Resource Type:
Journal Article
Journal Name:
Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science
Additional Journal Information:
Journal Volume: 31; Journal Issue: 4; Other Information: PBD: Apr 2000; Journal ID: ISSN 1073-5623
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; MICROSTRUCTURE; FRACTURE PROPERTIES; STEEL-ASTM-A508; HEAT AFFECTED ZONE; MARTENSITE; BAINITE; AUSTENITE; TEMPERATURE DEPENDENCE; CORRELATIONS

Citation Formats

Kim, S, Kang, S Y, Oh, S J, Kwon, S J, Lee, S, Kim, J H, and Hong, J H. Correlation of the microstructure and fracture toughness of the heat-affected zones of an SA 508 steel. United States: N. p., 2000. Web. doi:10.1007/s11661-000-0106-2.
Kim, S, Kang, S Y, Oh, S J, Kwon, S J, Lee, S, Kim, J H, & Hong, J H. Correlation of the microstructure and fracture toughness of the heat-affected zones of an SA 508 steel. United States. https://doi.org/10.1007/s11661-000-0106-2
Kim, S, Kang, S Y, Oh, S J, Kwon, S J, Lee, S, Kim, J H, and Hong, J H. 2000. "Correlation of the microstructure and fracture toughness of the heat-affected zones of an SA 508 steel". United States. https://doi.org/10.1007/s11661-000-0106-2.
@article{osti_20050544,
title = {Correlation of the microstructure and fracture toughness of the heat-affected zones of an SA 508 steel},
author = {Kim, S and Kang, S Y and Oh, S J and Kwon, S J and Lee, S and Kim, J H and Hong, J H},
abstractNote = {In this study, microstructures of a heat-affected zone (HAZ) of an SA 508 steel were identified by Moessbauer spectroscopy in conjunction with microscopic observations, and were correlated with fracture toughness. Specimens with the peak temperature raised to 1350 C showed mostly martensite. With the peak temperature raised to 900 C, the martensite fraction was reduced, while bainite or martensite islands were formed because of the slow cooling from the lower austenite region and the increase in the prior austenite grain size. As the martensite fraction present inside the HAZ increased, hardness and strength tended to increase, whereas fracture toughness decreased. The microstructures were not changed much from the base metal because of the minor tempering effect when it was raised to 650 C or 700 C. However, fracture toughness of the subcritical HAZ with the peak temperature raised to 650 C to 700 C was seriously reduced after postweld heat treatment (PWHT) because carbide particles were of primary importance in initiating voids. Thus, the most important microstructural factors affecting fracture toughness were the martensite fraction before PWHT and the carbide fraction after PWHT.},
doi = {10.1007/s11661-000-0106-2},
url = {https://www.osti.gov/biblio/20050544}, journal = {Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science},
issn = {1073-5623},
number = 4,
volume = 31,
place = {United States},
year = {Sat Apr 01 00:00:00 EST 2000},
month = {Sat Apr 01 00:00:00 EST 2000}
}