The effects of repeated weld repairs on the mechanical properties of high strength steel plate joints

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Authors
  1. Munro, C.
Corporate Authors
Defence Research and Development Canada, Atlantic Research Centre, Halifax NS (CAN)
Abstract
Repetitive weld repairs of structural steels such as those used for ships and submarines can compromise the performance of the repaired joint. In order to determine how many weld repairs should be permitted on one location, HY-80 steel plate was subjected to repeated welding operations. Plate sections were fabricated and welded a total of one, three and five times. Two orientations were tested, with welds made either parallel or perpendicular to the base plate rolling direction. Analysis of samples taken from these plates indicated repeat welding led to negligible differences in weld and heat affected zone (HAZ) microstructure and microhardness, and also showed that chemical dilution of the HAZ was not a concern. Weld metal and HAZ yield strengths were slightly decreased by repeat welding, but were still adequate after five total welds. Repeat welding did, however, lead to significant decreases in impact energy absorption when welding was conducted perpendicular to the base plate rolling direction. Evidence suggested that coarsening of oxide inclusions was responsible for the compromised impact energy. Ultimately HY-80 welds continued to meet the applicable American military standard when a total of three welds were performed; subsequent welds did not meet the impact energy requirement. It is therefore recommended that a three-weld limit (i.e., one fabrication weld plus two repair welds) be enforced in practice when multiple repairs of this alloy are required.
Keywords
repair welding;HY-80 steel;impact testing;tensile testing;fatigue testing
Report Number
DRDC-RDDC-2014-R184 — Scientific Report
Date of publication
01 Oct 2014
Number of Pages
54
DSTKIM No
CA040325
CANDIS No
801314
Format(s):
Electronic Document(PDF)

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