The National Shipbuilding Research Program 1985 Ship Production Symposium Volume 2 Paper No. 3: Evaluate the Benefit of New Higher-Strength HSLA (High Strength, Low Alloy)Steels
2006
West, J. C.
As the continuing search for offshore oil heads toward deeper water, the need for sturdier designs and stronger steels multiplies. Thus the costs to build mobile drilling units and fixed platforms rise exponentially. Steels with 50, 60, 65, 75, 80, and 100 ksi (thousand pounds per square inch) yield points in both the HSLA normalized and C-Mn-Si (Carbon- Manganese-Silicon) quenched and tempered conditions are available from various producers. Most of these steels above l-1/2 inches in thickness must be welded to themselves or other steels by using sustained preheat and controlled interpass temperatures, plus controlled welding heat input of approximately 50 to 60 KJ/inch (kilo joules per inch). These two items will add as much as 50 percent to the cost of welding when using the submerged-arc process. Cost increases up to 30 percent can be expected when stick welding under these conditions. The practice of using hand-held oxy-gas torches, by the welder, to drive out moisture or raise the steel above freezing conditions is considered as normal, with its cost usually included in the standard welding costs.
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