Prior Situation

A pressure vessel manufacturer in Denver asked General Air for assistance in improving the output of their thin wall tank line while reducing the number of “leakers.” In depositing circumferential and longitudinal lap welds (14g to 12g A36 steel), the challenge was to find a high speed solution that also had the punch to burn through the tacks from where leaks came. Upon request, the end-user allowed us to perform a thorough walk through to ask questions and look for additional cost reduction opportunities and/or identify areas of quality improvement. We observed that their cutting gas, acetylene, was not optimal from both a safety and cutting standpoint. Our solution, metal-cored wire conversion and HPG on pressure vessels.

PE Solution

Leaks seemed to be located at the tacks, and the tack welds were made with 6010 stick which is not just slow but left a slag inclusion when covered with a gas shielded flux-cored wire. Also, 6010 penetrates too much on sheet metal, breaching the inner wall. So we metal-cored wire conversion was applied for tacking and also used it at high deposition on the lap welds, increasing travel speed from 25 IPM to 40 IPM. “Leakers” were cut in half.

We converted them to a neutral sub-arc flux to avoid potential cracking and also converted them to high purity cutting gas (HPG) to achieve much faster cutting speeds and greater safety. Many of the solutions on the menu of opportunities were implemented and the customer’s output has increased substantially.

Success Highlights: Over $38,590 in annual savings

• Increased lap weld travel speeds 60%
• Cut tank lap tack leaks in half
• Decreased tacking time by replacing manual 6010 w/semi-auto wire
• Changed sub-arc flux prone to multiple weld cracking

For an introduction into metal-cored wire, check out our video on our YouTube. Metal-Cored Wire Introduction