NO TURNING BACK:
PIPE WELDING SYSTEM KICKS IT UP A NOTCH

Using an advanced pipe welding system, this fabricator has increased their pipe fabrication quality and productivity with flatter bead profiles, good sidewall tie-in for 30 percent less grinding, and superior weld puddle control – with no wire rejects in over a year.

Founded in 1994, Shinn Mechanical, Inc. (Kent, WA) serves the industrial piping, processing, HVAC, refrigeration and plumbing markets, welding everything from ½ in diameter 316L stainless steel to A106 double-containment pipe to 34 in diameter A53 black pipe. They also fabricate complete platforms or skids. Located only minutes from the Seattle Sea-Tac airport, customers include those in the aerospace and military industries, as well as in healthcare construction.

“It’s always better to have the right tools,” smiles Mike Shinn, president of Shinn Mechanical. “My philosophy is that even if you can save two or three percent on every job, and you do that over time, it’s a big percentage at the end of the year.” Considering that the overhead rate for pipefitter/welders in the Pacific Northwest exceeds $1 per minute, those sorts of savings add up pretty quickly.

Among its recent money-saving accomplishments, this fabricator reduced material handling time by at least 10 percent – and increased safety – by building and designing “the ultimate welding boom”. On the welding side of operations, Shinn Mechanical has increased MIG weld quality to the point where operators cannot remember their last rejected weld, reducing grinding time by 30 percent and process changeover time to “two seconds.”

That’s not all. Shop operators here complete joints three to four times faster than shops that rely solely on stick and TIG technology. How? They use a pipe-specific multi-process welding system from Miller Electric Mfg. Co. (Appleton, WI) called PipeWorxä that was recommended by Jim Hedberg, a representative from Pacific Welding Supply (Tacoma, WA).

The PipeWorx system uses Pro-Pulse™ pulsed MIG and RMD™(regulated metal deposition) processes, as well as stick, TIG and flux cored processes that have been optimized specifically for pipe fabrication. The system also provides traditional MIG processes. Switching between processes requires only the push of one button, with no need to manually switch polarity, cables or hoses, thus increasing productivity and eliminating a potential source of errors.

FAST AND GOOD
While some code requirements and weld procedure specifications require TIG and/or stick welding, Shinn Mechanical has worked with its customers to qualify as many applications as possible for RMD and Pro-Pulse.

For example, welding 4 in and 6 in diameter pipe generally requires two passes. “We would run an RMD root with a Pro-Pulse cap. We go to Pro-Pulse on every size that requires more than two passes whenever codes and procedures allow,” explains Steve Sayers, a pipefitter/welder with UA Local 32 who has worked at Shinn Mechanical since 2005. “It would be a minimum of double, if not three times, faster to put in an RMD root as opposed to a standard TIG or Stick weld. Because of how much metal you can put down with Pro-Pulse and still have an X-ray-quality weld, your production times [are] three to four times faster [with] the same quality of work you could [do] with a TIG or stick procedure. We haven’t had a wire [welding] reject in well over a year.”

Miller engineers have confirmed Sayers’ estimates for RMD. While productivity rates vary depending upon joint configuration, diameter, schedule, material, etc., general travel speeds for root pass welding are as follows:
• TIG: 2 ipm to 4 ipm
• Stick: 5 ipm to 8 ipm
• RMD: 6 ipm to 12 ipm

Sayers notes that RMD puts in a “heavier deposit of metal than you do with short arc. When you grind your bead out, you are still able to put a good [second] pass in with less chance of blowing through your initial bead and still maintaining a quality bead on the inside without distorting it with too much heat from your secondary pass.”