Back gouging carbon steel 1

[WOtx]

Can someone tell me if it is required to preheat before back gouging carbon steel of any thickness?

 

[Duwe6]

Look at an applicable Welding Procedure. Thermal cutting/backgouging requires the same preheat as welding does. Typical minimum temps for mild steel [P1 grout] are
50°F for up to 1.5-inches thick
150°F for 1.5-inches, up to 2.5-inches
225°F for 2.5-inches and over.

These numbers are slightly conservative, but I do not allow the Welder to go below them more than 10°F. Preheat is cheap compaired to cracking.

 

[Guest102023]

My rule is always that thermal gouging should be treated the same way as the welding. You're usually going to be welding shortly after that anyway.

 

[duongwe]

@sending Mr Duwe6 (Industrial): where does it ordain those???

 

[Mr168]

duongwe: Those values are from Table 3.2 in AWS D1.1.

 

[Duwe6]

A proper WPS will have some sort of preheat that increases with thickness. If you are working to one you are does, those are the 'official' temperatures.

If your WPS fails to address preheat of thick sections, these numbers work on mild carbon steel. They have been proven out by the American Welding Society at least 50 years ago. AWS puts these values in a number of their welding Codes. ASME assumes that you will put proper preheat into your WPS's based on industry standard, and does not give you much guidance.