2020年12月8日 · For welding stainless steel pipe, Dixie Mechanical followed the traditional process of using a TIG root pass with an argon back purge followed by flux-cored fill and cap passes. The back purge on stainless steel was an especially time-consuming process, typically requiring 20 to 30 minutes depending on the pipe size to set up the argon ...

2008年3月2日 · The techniques for welding carbon steel pipe are the same as those described here for welding stainless. However, to qualify procedures for welding 300 series stainless steel pipe without backing gas, fabricators must do the following: Ensure a minimum 1/8-in. gap around the entire circumference of the joint.

2013年1月22日 · Welding stainless steel tube and pipe traditionally requires a back purge of argon. In non-critical applications, where cost is a driving factor, operations can also use nitrogen as a back purge. However, this may lead to the formation of some nitride compounds in the weld root, which sacrifices some corrosion resistance.

2020年4月3日 · Figure 8 shows sugaring on the backside of a stainless steel weld, a common TIG welding problem. Sugaring (oxidation) occurs around the weld when it is exposed to oxygen in the air. The best way to prevent sugaring is to back purge the weld with argon shielding gas or reduce welding amperage.

2017年12月12日 · Proper post-flow time in seconds is determined by dividing welding amps by 10. A minimum of eight seconds is recommended. When running longer gas lines, the initial shielding gas released upon starting the arc will be a much higher flow rate. Decrease this by using shorter gas lines, or by increasing pre-flow time to purge the lines before arc ...

2016年6月9日 · Typically, when TIG welding P91 pipe, it requires an argon back purge during the root pass. Eliminating this saves in wasted gas and the time it takes for the purge. Also, with advanced waveform MIG the thicker root deposit helps eliminate the hot pass, reducing the risk of burnthrough on the subsequent fill passes.

Dixie Mechanical eliminated back purge and cut welding time by more than 30% with a process change and the PipeWorx 400. aCD8lgJGmlo 97dc9e6e-9250-4065-9cba-006ebca329cb

2013年4月26日 · The majority of titanium pipe welding is done in open-air environments. A purged gas chamber offers extreme protection, but is expensive (in terms of cost and the shielding gas required to purge it), potentially cumbersome to weld in and does not always accommodate large work pieces. It is also more time-intensive.

The Bernard PipeWorx 300-15 gun with a tapered tip and nozzle is recommended for root pass welding, especially in fixed-position applications where visibility is difficult. Switch to a standard tip and nozzle for fill and cap pass welding with flux-cored or pulsed MIG welding processes. This allows one gas and one wire to make the weld.

This is a basic set-up and technique guide to welding the root pass on pipe with the Miller PipeWorx 400 System or the PipeWorx 350 FieldPro™ System using RMD® (Regulated Metal Deposition). RMD® Root Pass Welding Start and Stop the arc on a tack at the 1:30 position. Rotate pipe away while maintaining the arc at the 1:30 to 2:00 position.