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Welding Smarter on Stainless Steel Pipe
- An apprentice welder can become proficient with the processes in less than two days; an experienced welder can become proficient in less than two hours
- Welding travel speeds of 6 to 12 inches per minute (vs. 3 to 8 ipm for Stick and 3 to 5 ipm for TIG, both in the fixed position)
- Potential to eliminate the hot pass
- Potentially no backing gas for some of the 300 series stainless steel grades.
- Superior quality welds
- Reduced rework costs (which can cost up to $500 to fix a serious flaw)
- Exceptional tolerance for high-low misalignment between pipe sections
- Minimal clean-up time (no slag to chip, little or no spatter)
- Same wire and shielding gas for subsequent passes with a pulsed GMAW process, reducing downtime associated with process changeover
Customer Testimonial
“High-speed video proves that stable short circuits create only small ripples in the weld puddle, which in turn allow consistent tie-in to the sidewall. As a result of a stable and more controllable weld puddle, apprentice operators can quickly and easily learn to create uniform, high quality welds.”
— Jim Cuhel, welding engineer, Miller Electric Mfg. Co.
Application
Welding stainless steel pipe.
Key Business Issue
- Keeping up with strong industry demand for welded stainless steel pipe.
Challenge
- Finding a way to increase productivity when adding more welding operators isn't an option due to the chronic shortage of skilled welders.
Previous System & Process
- Traditional root pass welding with the manual TIG or Stick process.
New Solution
- Root pass welding using Miller's innovative RMD Pro process.
Results
- Productivity improvements of 100 to 400 percent. Because RMD Pro is a wire welding process (modified short circuit transfer), it greatly increases travel speeds compared to TIG or Stick.
- Better puddle control. With RMD Pro technology, the welding system anticipates and controls the short circuit, then reduces available welding current to create a consistent metal transfer. Precisely controlled metal transfer provides uniform droplet deposition, making it easier for the welder to control the puddle.
- Easier to train operators. An apprentice welder can become proficient with the processes in less than two days; an experienced welder can become proficient in less than two hours.
- Potential to eliminate backing gas. The shielding gas coming out of the gun remains relatively undisturbed by the controlled metal transfer of the RMD Pro process. As a result, enough shielding gas gets pushed through the root opening to prevent sugaring (oxidation) on the backside of the weld. Some fabricators have qualified procedures to weld some of the 300 series stainless steels without a backing gas, improving productivity by up to 400 percent.
- Potential to eliminate the hot pass. The RMD Pro process creates a root pass weld with a 1/8- to 1/4-in. throat. In many instances, the amount of root pass metal deposited will be sufficient to support the heat input requirements of the first pulsed MIG or fill pass. Fabricators can eliminate the TIG hot pass, saving about $15 on a 12-in., schedule 40 pipe.
