Welding of 304H and issues related to post-weld treatment
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Dear all Haoyou users, I have a question: for the heated surface tubes welded from 304H material, what pressure is used for the pressure test? 1.5 times? 2 times? What medium is being used? Will tap water work? Must it be demineralized water? I saw on other websites that if water is drained immediately after the pressure test, chlorination measures may not be necessary. Then, 304H is welded using A102 TIG welding wire with argon shielding; is heat treatment required after welding? Tube with φ76*5.5 dimensions, at a pressure of 6.3MPa
Drain it thoroughly after the hydrostatic test, and there is no need to control the chloride ion content. For austenitic stainless steel, heat treatment should be avoided as much as possible after welding; if heat treatment is necessary, solution treatment must be carried out, which is not feasible for shaped pipes!
The specification requires that the Cl ion content in stainless steel be less than 25 ppm
A102 is a welding rod grade used for arc welding; its corresponding model is E308. It is not an TIG welding wire, with the corresponding model for TIG welding wires being ER308H. Welding materials with a ‘H’ in their designation are generally hard to find. If a carbon content of more than 0.04% is required, then welding materials with an actual measured carbon content of 0.04% or higher can be selected.
Wouldn’t 25 ppm result in a conductivity of 0? . . Is it 25mg/L? Was the unit careless?
So, may I ask which new regulation states that control is not required? Our inspection agency is insisting on this point and refusing to allow pressure testing, so we need a document explaining it
1ppm = 1mg/L
It depends on the standards applicable to your pipeline; currently, the pressure vessel standard GBT 150 already permits this.