Improved construction processes involving thin plates are expected to reduce labor costs by $5 million over five years. (CTC photo)
To reduce significant levels of distortion that Ingalls Shipbuilding is experiencing in thin plates used in DDG 51 Class ship construction.
Thin steel plates (plates less than 3/8-inch thick) used for DDG 51 Class ship panel production are subject to excessive distortion during plasma cutting. This distortion results in significant rework costs associated with the required flattening and excessive weld joint gaps caused by distortion-related shapes during ship fabrication.
After evaluation, NMC will develop recommended plate procurement specifications to assist the supplying steel mills in reducing plate residual stress. To address thermal-cutting distortion, NMC is investigating the shipyard’s plasma cutting equipment and practices and is establishing a set of guidelines for plate nesting, cutting, sequencing and equipment to improve the process.
Reducing thin plate distortion will improve part accuracy and will diminish weld gaps, heat input, and heat straightening. Huntington Ingalls Industries –Ingalls Shipbuilding estimates that labor savings resulting from this project’s recommendations will be more than $5M over the next five years.
Pending successful development and acceptance of plate procurement specifications and cutting guidelines, Ingalls expects to implement these results for the procurement and cutting of all thin steel plates. Initial implementation is scheduled to begin in the first quarter of 2014 for construction of DDG 114.
ESAB Welding and Cutting
Naval Surface Warfare Center, Carderock Division
The University of New Orleans / PD Technologies
PMS 400D - DDG 51 Program Office
ArcelorMittal Burns Harbor