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Title: Fracture toughness of thick section dissimilar electron beam weld joints

Abstract

Microstructural investigations as well as crack tip opening displacement (CTOD) fracture toughness test based on elastic-plastic fracture mechanics were performed on single pass, full penetration similar and dissimilar electron beam (EB) welds of 40 mm thick 316L type austenitic steel and high alloyed fine tempered martensitic 9Cr 1Mo Nb V (P91 -ASTM A213) steel. The latter modified steel has been developed to fill up the gap between 12Cr steel and austenitic stainless steels with respect to the high temperature properties and better weldability. Furthermore, it shows a small thermal expansion coefficient and is not susceptible to stress corrosion cracking like the austenitic steel. The weldment properties were evaluated by microstructural analysis, microhardness, Charpy V- notch impact, and by newly developed flat microtensile specimens (0.5 mm thick). The dissimilar EB weld metal and HAZ of P91 steel has been shown to be microstructurally and mechanically distinct from both austenitic and martenistic parent metals. The use of microsized rectangular tensile specimens provides unique solution to the problem of the mechanical property determination of the narrow EB weld joint. The HAZ of the 9Cr1Mo steel exhibits extremely poor CTOD toughness properties in as-welded condition at room temperature. The CTOD values obtained were believedmore » to be represent the intrinsic property of this zone, since the distance of the crack tip to the austenitic steel part was too large to receive a stress relaxation effect from low strength side on the crack tip (by accommodating the applied strains in the high toughness, lower strength 316L plate).« less

Authors:
;
Publication Date:
OSTI Identifier:
115433
Report Number(s):
CONF-9404233-
TRN: 95:002927-0011
Resource Type:
Conference
Resource Relation:
Conference: 75. American Welding Society (AWS) annual meeting, Philadelphia, PA (United States), 10-15 Apr 1994; Other Information: PBD: 1994; Related Information: Is Part Of 75th Diamond anniversary American Welding Society annual meeting; PB: 273 p.
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; MARTENSITIC STEELS; ELECTRON BEAM WELDING; FRACTURE PROPERTIES; MECHANICAL PROPERTIES; STAINLESS STEEL-316L; MICROSTRUCTURE; CHARPY TEST; MICROHARDNESS; THERMAL EXPANSION

Citation Formats

Kocak, M, and Junghans, E. Fracture toughness of thick section dissimilar electron beam weld joints. United States: N. p., 1994. Web.
Kocak, M, & Junghans, E. Fracture toughness of thick section dissimilar electron beam weld joints. United States.
Kocak, M, and Junghans, E. Sat . "Fracture toughness of thick section dissimilar electron beam weld joints". United States.
@article{osti_115433,
title = {Fracture toughness of thick section dissimilar electron beam weld joints},
author = {Kocak, M and Junghans, E},
abstractNote = {Microstructural investigations as well as crack tip opening displacement (CTOD) fracture toughness test based on elastic-plastic fracture mechanics were performed on single pass, full penetration similar and dissimilar electron beam (EB) welds of 40 mm thick 316L type austenitic steel and high alloyed fine tempered martensitic 9Cr 1Mo Nb V (P91 -ASTM A213) steel. The latter modified steel has been developed to fill up the gap between 12Cr steel and austenitic stainless steels with respect to the high temperature properties and better weldability. Furthermore, it shows a small thermal expansion coefficient and is not susceptible to stress corrosion cracking like the austenitic steel. The weldment properties were evaluated by microstructural analysis, microhardness, Charpy V- notch impact, and by newly developed flat microtensile specimens (0.5 mm thick). The dissimilar EB weld metal and HAZ of P91 steel has been shown to be microstructurally and mechanically distinct from both austenitic and martenistic parent metals. The use of microsized rectangular tensile specimens provides unique solution to the problem of the mechanical property determination of the narrow EB weld joint. The HAZ of the 9Cr1Mo steel exhibits extremely poor CTOD toughness properties in as-welded condition at room temperature. The CTOD values obtained were believed to be represent the intrinsic property of this zone, since the distance of the crack tip to the austenitic steel part was too large to receive a stress relaxation effect from low strength side on the crack tip (by accommodating the applied strains in the high toughness, lower strength 316L plate).},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1994},
month = {12}
}

Conference:
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