DELAYED CRACKING IN NAVAL STRUCTURAL STEELS

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Authors
  1. Pussegoda, L.N.
  2. Granville, B.A.
  3. Malik, L.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN);Fleet Technology Ltd, Kanata ONT (CAN)
Abstract
In spite of the continuing efforts to develop steels and welding consumables that provide increased resistance to hydrogen induced delayed cracking in welds, such cracking still occurs, especially in multipass welds in high strength steels and in repaired welds. Since multipass welds present a much larger number of variables compared to the existing schemes for estimating preheat to prevent hydrogen cracking in essentially single pass welds, it is suggested that a simple modeling approach, appropriately verified is best suited to study delayed cracking in multipass welds. Such a model has been previously developed in the context of delayed cracking in pipeline girth welds, and in the present study, it has been used to predict the delay time in a simulated repair weld in a 9 mm thick, ASTM A517 Gr F steel. The delay time of 24 hours predicted by the model agreed quite well with the experimentally measured times of 12 to 18 hours in constant deflection tests. Examination of metallographic sections confirmed that the specimens which cracked developed relatively large cracks and those that did not had no evidence of micro-cracks. Also, specimens that survived the critical (maximum) time for delay cracking did not show any evidence of micro-crack formation, even after seven days of test duration. TRUNCATED
Keywords
Hydrogen cracking;Delay time;ASTM A517 Grade F steel
Report Number
DREA-CR-97-420;4529-DFR — Contractor Report
Date of publication
01 Dec 1996
Number of Pages
36
DSTKIM No
97-03928
CANDIS No
503849
Format(s):
Hardcopy;Document Image stored on Optical Disk

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