SELECTION OF BRITTLE WELD ELECTRODES FOR CRACK ARREST TOUGHNESS DETERMINATION

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Authors
  1. Pussegoda, L.N.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN);Fleet Technology Ltd, Kanata ONT (CAN)
Abstract
In crack arrest tests fast running cracks are usually initiated from either brittle weld deposits or strain age embrittled notches. A previous study of the crack arrest toughness of ship plate indicated that for different specimen sizes and material toughness, the crack starters need to have different degrees of embrittlement. For a successful test, larger and tougher specimens require a higher stored energy before crack initiation, and the crack starter should be able to delay triggering the crack run. Similarly, smaller less tough specimens need a lower stored energy. The suitability of several selected weld electrodes with different hardness and/or toughness has been assessed in terms of their ability to initiate running cracks. Two sizes of full thickness compact crack arrest (CCA) specimens with crack starter weld beads were machined from 15 mm thick 350WT ship plate. They were oriented L-T with W = 300 and 100 and an a sub o/W ratio of 0.35. The anticipated crack arrest toughness values corresponding to the two specimen sizes were Kv = 155 and 95 MPa root m at -15 and -40C, respectively. The results indicate that at the test temperatures the three most promising crack starters had toughness values of about 100, 180 and 270 MPa root m. For the larger specimen the ideal crack starter had the intermediate toughness. For the smaller specimen, the best starter option was the one with the lowest toughness.
Keywords
350WT steel;Brittleness;Crack arrest;Crack initiation
Report Number
DREA-CR-98-425 — Contract Report
Date of publication
01 May 1998
Number of Pages
27
DSTKIM No
98-02213
CANDIS No
509065
Format(s):
Hardcopy;Document Image stored on Optical Disk

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