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Improved HSLA-80 T-Beams

Parameters have been determined for hybrid laser arc welding HSLA-80 T-Beams that will reduce production and assembly costs as well as improve T-Beam quality for DDG 1000. Applied Thermal Sciences photo

Objective

The project objective was to determine optimum parameters for hybrid laser arc welding (HLAW) of HSLA-80 T-Beams that will reduce production and assembly costs as well as improve T-Beam quality for DDG 1000.

Background

T-Beam stiffeners are used extensively in ship construction for decks, bulkheads, shells, and other structural applications. As the need for weight and cost reduction grows, alternate production methods are being considered to improve beam quality, to weld thinner plate materials and to minimize distortion and the cost and availability of beams for ship construction.

Technical Approach

This project will develop a procedure for combining gas metal arc welding and laser welding processes to weld HSLA-80 T-beams. This hybrid laser arc welding procedure will be submitted to ABS for approval. Once approved, the process will be made available to manufacturers for use in HSLA-80 T-beam production for DDG-1000.

Benefits

The hybrid laser arc welding process allows higher weld travel speeds and reduced distortion, which result in less rework and lower beam production costs. In addition, the improved beam quality provides better fit-up during shipyard construction, which reduces assembly costs. The higher travel speed and reduced distortion are expected to reduce T-beam fabrication costs by 45% and reduce ship construction costs by $647K.

Implementation

This project has developed a HLAW process that has been approved by the American Bureau of Shipping. The process will be implemented at American Tank and Fabricating Company to produce HLAW HSLA-80 T-beams for DDG 1000.  Other potential platforms that could benefit from this project include the Littoral Combat Ship, which uses a variety of thin section materials including ASTM A710, a material very similar to HSLA-80.

Status

Completed