Project Participants: Alcoa Defense, Inc., Marinette Marine & Austal USA
Project Start: February 2012
Currently, aluminum butt welding for each Littoral Combat Ship (LCS) is a labor-intensive and costly process. This is due to the number of weld passes required to complete welds in aluminum of varying thicknesses. The numerous welding passes add unnecessary labor and can result in added distortion and rework. In addition, current aluminum panels and modules require welding from both sides due to incomplete welding penetration from a single side. This represents a time-consuming and labor-intensive operation for completing each panel joint.
The objectives for this project are to develop and demonstrate a High-Deposition Gas Metal Arc (HDGMA) aluminum welding system and associated welding processes and procedures that will enable single-sided and single-pass welding of select aluminum primary structures for both LCS classes of ships (Freedom and Independence). When demonstrated to be successful, the process will be approved by ABS and NAVSEA for implementation on aluminum ship structures.
Creating an approved one-sided welding process will eliminate several of the current processing steps and will deliver a more controlled and mechanized welding approach. The one-sided weld process will be fully developed for flat down-hand welding position and could also transition into an out-of position butt weld procedure (horizontal and vertical) that will have the potential of significantly reducing the cost of erecting modules. Predevelopment estimates of the cost savings are in the range of 30 to 35% savings for every dollar currently spent on aluminum butt welding in the flat down-hand position.
When successfully implemented, the HDGMA welding process will offer specific reductions in money, time, and material expenditures, which will result in more effective resource utilization compared to the current process.