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Title: Low Distortion Welded Joints for NCSX

Abstract

The National Compact Stellarator Experiment (NCSX) required precise positioning of the field coils in order to generate suitable magnetic fields. A set of three modular field coils were assembled to form the Half Field-Period Assemblies (HPA). Final assembly of the HPA required a welded shear plate to join individual coils in the nose region due to the geometric limitations and the strength constraints. Each of the modular coil windings was wound on a stainless steel alloy (Stellalloy) casting. The alloy is similar to austenitic 316 stainless steel. During the initial welding trials, severe distortion, of approximately 1/16", was observed in the joint caused by weld shrinkage. The distortion was well outside the requirements of the design. Solutions were attempted through several simultaneous routes. The joint design was modified, welding processes were changed, and specialized heat reduction techniques were utilized. A final joint design was selected to reduce the amount of weld material needed to be deposited, while maintaining adequate penetration and strength. Several welding processes and techniques using Miller Axcess equipment were utilized that significantly reduced heat input. The final assembly of the HPA was successful. Distortion was controlled to 0.012", well within the acceptable design tolerance range of 0.020"more » over a 3.5 foot length.« less

Authors:
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
964192
Report Number(s):
PPPL-4453
TRN: US0904114
DOE Contract Number:  
DE-ACO2-09CH11466
Resource Type:
Conference
Resource Relation:
Conference: 23rd Symposium on Fusion Engineering, San Diego, CA May 31-June 4, 2009
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ALLOYS; CASTING; DESIGN; MAGNETIC FIELDS; PLATES; POSITIONING; SHEAR; SHRINKAGE; STAINLESS STEELS; STELLARATORS; TOLERANCE; WELDED JOINTS; WELDING; WOUNDS; NCSX

Citation Formats

M. Denault, M Viola, W. England. Low Distortion Welded Joints for NCSX. United States: N. p., 2009. Web.
M. Denault, M Viola, W. England. Low Distortion Welded Joints for NCSX. United States.
M. Denault, M Viola, W. England. Thu . "Low Distortion Welded Joints for NCSX". United States. https://www.osti.gov/servlets/purl/964192.
@article{osti_964192,
title = {Low Distortion Welded Joints for NCSX},
author = {M. Denault, M Viola, W. England},
abstractNote = {The National Compact Stellarator Experiment (NCSX) required precise positioning of the field coils in order to generate suitable magnetic fields. A set of three modular field coils were assembled to form the Half Field-Period Assemblies (HPA). Final assembly of the HPA required a welded shear plate to join individual coils in the nose region due to the geometric limitations and the strength constraints. Each of the modular coil windings was wound on a stainless steel alloy (Stellalloy) casting. The alloy is similar to austenitic 316 stainless steel. During the initial welding trials, severe distortion, of approximately 1/16", was observed in the joint caused by weld shrinkage. The distortion was well outside the requirements of the design. Solutions were attempted through several simultaneous routes. The joint design was modified, welding processes were changed, and specialized heat reduction techniques were utilized. A final joint design was selected to reduce the amount of weld material needed to be deposited, while maintaining adequate penetration and strength. Several welding processes and techniques using Miller Axcess equipment were utilized that significantly reduced heat input. The final assembly of the HPA was successful. Distortion was controlled to 0.012", well within the acceptable design tolerance range of 0.020" over a 3.5 foot length.},
doi = {},
url = {https://www.osti.gov/biblio/964192}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2009},
month = {2}
}

Conference:
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