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Title: Effect of welding conditions on transformation and properties of heat-affected zones in LWR (light-water reactor) vessel steels

Abstract

The continuous cooling transformation behavior (CCT) and isothermal transformation (IT) behavior were determined for SA-508 and SA-533 materials for conditions pertaining to standard heat treatment and for the coarse-grained region of the heat-affected zone (HAZ). The resulting diagrams help to select welding conditions that produce the most favorable microconstituent for the development of optimum postweld heat treatment (PWHT) toughness levels. In the case of SA-508 and SA-533, martensite responds more favorably to PWHT than does bainite. Bainite is to be avoided for the optimum toughness characteristics of the HAZ. The reheat cracking tendency for both steels was evaluated by metallographic studies of simulated HAZ structures subjected to PWHT cycles and simultaneous restraint. Both SA-533, Grade B, Class 1, and SA-508, Class 2, cracked intergranularly. The stress rupture parameter (the product of the stress for a rupture life of 10 min and the corresponding reduction of area) calculated for both steels showed that SA-508, Class 2, was more susceptible to reheat cracking than SA-533, Grade B, Class 1. Cold cracking tests (Battelle Test and University of Tennessee modified hydrogen susceptibility test) indicated that a higher preheat temperature is required for SA-508, Class 2, to avoid cracking than is required for SA-533,more » Grade B, Class 1. Further, the Hydrogen Susceptibility Test showed that SA-508, Class 2, is more susceptible to hydrogen embrittlement than is SA-533, Grade B, Class 1.« less

Authors:
;  [1]
  1. Tennessee Univ., Knoxville, TN (USA). Welding Research and Engineering
Publication Date:
Research Org.:
US Nuclear Regulatory Commission (NRC), Washington, DC (United States). Div. of Engineering; Tennessee Univ., Knoxville, TN (USA). Welding Research and Engineering; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USNRC
OSTI Identifier:
6337784
Report Number(s):
NUREG/CR-3873; ORNL/Sub-78-7637/1
ON: TI91004247; TRN: 90-036969
DOE Contract Number:  
AC05-84OR21400
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; BWR TYPE REACTORS; PRESSURE VESSELS; WELDED JOINTS; PWR TYPE REACTORS; STEELS; MECHANICAL PROPERTIES; CHARPY TEST; CRACKS; EMBRITTLEMENT; HEAT TREATMENTS; HYDROGEN; ISOTHERMAL PROCESSES; MICROSTRUCTURE; STANDARDS; STEEL-ASTM-A508; STEEL-ASTM-A533; STRESSES; WELDING; ALLOYS; CONTAINERS; CRYSTAL STRUCTURE; DESTRUCTIVE TESTING; ELEMENTS; FABRICATION; IMPACT TESTS; IRON ALLOYS; IRON BASE ALLOYS; JOINING; JOINTS; LOW ALLOY STEELS; MATERIALS TESTING; MECHANICAL TESTS; NONMETALS; REACTORS; TESTING; WATER COOLED REACTORS; WATER MODERATED REACTORS; 360103* - Metals & Alloys- Mechanical Properties; 210100 - Power Reactors, Nonbreeding, Light-Water Moderated, Boiling Water Cooled; 210200 - Power Reactors, Nonbreeding, Light-Water Moderated, Nonboiling Water Cooled

Citation Formats

Lundin, C D, and Mohammed, S. Effect of welding conditions on transformation and properties of heat-affected zones in LWR (light-water reactor) vessel steels. United States: N. p., 1990. Web. doi:10.2172/6337784.
Lundin, C D, & Mohammed, S. Effect of welding conditions on transformation and properties of heat-affected zones in LWR (light-water reactor) vessel steels. United States. https://doi.org/10.2172/6337784
Lundin, C D, and Mohammed, S. 1990. "Effect of welding conditions on transformation and properties of heat-affected zones in LWR (light-water reactor) vessel steels". United States. https://doi.org/10.2172/6337784. https://www.osti.gov/servlets/purl/6337784.
@article{osti_6337784,
title = {Effect of welding conditions on transformation and properties of heat-affected zones in LWR (light-water reactor) vessel steels},
author = {Lundin, C D and Mohammed, S},
abstractNote = {The continuous cooling transformation behavior (CCT) and isothermal transformation (IT) behavior were determined for SA-508 and SA-533 materials for conditions pertaining to standard heat treatment and for the coarse-grained region of the heat-affected zone (HAZ). The resulting diagrams help to select welding conditions that produce the most favorable microconstituent for the development of optimum postweld heat treatment (PWHT) toughness levels. In the case of SA-508 and SA-533, martensite responds more favorably to PWHT than does bainite. Bainite is to be avoided for the optimum toughness characteristics of the HAZ. The reheat cracking tendency for both steels was evaluated by metallographic studies of simulated HAZ structures subjected to PWHT cycles and simultaneous restraint. Both SA-533, Grade B, Class 1, and SA-508, Class 2, cracked intergranularly. The stress rupture parameter (the product of the stress for a rupture life of 10 min and the corresponding reduction of area) calculated for both steels showed that SA-508, Class 2, was more susceptible to reheat cracking than SA-533, Grade B, Class 1. Cold cracking tests (Battelle Test and University of Tennessee modified hydrogen susceptibility test) indicated that a higher preheat temperature is required for SA-508, Class 2, to avoid cracking than is required for SA-533, Grade B, Class 1. Further, the Hydrogen Susceptibility Test showed that SA-508, Class 2, is more susceptible to hydrogen embrittlement than is SA-533, Grade B, Class 1.},
doi = {10.2172/6337784},
url = {https://www.osti.gov/biblio/6337784}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Nov 01 00:00:00 EST 1990},
month = {Thu Nov 01 00:00:00 EST 1990}
}