TECHNICAL PROGRESS REPORT OF THE SHIP STRUCTURE COMMITTEE (2ND).
SHIP STRUCTURE COMMITTEE WASHINGTON D C
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Justification of the various structural modifications employed is indicated by the service record of Liberty ships and T-2 Tankers, based on reduction of frequency of major casualties. Brittle fractures may be initiated in welded ships if the steel used in the main hull girder absorbs less than 15 ft.-lb. of energy in the standard V-notch Charpy impact test at a temperature of 60 F. It is not known, however, how much more notch-tough the steel must be in order to remove the danger of brittle fracture. This statement is based on the investigation of failures during the past eight years and consequently is established only for the types of vessels covered by the investigation and the operating conditions that existed for these same vessels. Based on the conclusion 3 above, some ship plates in 34-in. thickness would appear to be undesirable for use in welded ship construction. Either preheating or postheating generally lowers the transition temperature of ship steel weldments. Author
- Metallurgy and Metallography
- Marine Engineering