Is heat treatment required for the butt welding of 20G (Q245R) DN32 steel pipes? ? Is flaw detection needed? ?
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As stated in the title: butt welding of 20G (Q245R) DN32 steel pipes, with a wall thickness of 5 mm; the medium temperature is around 200 degrees, and the pipeline pressure is 25 MPa. Is heat treatment required? ? Is flaw detection needed? ? After reading GBT 30583-2014 \"Rules for Post-Weld Heat Treatment of Pressure Equipment\", there is a clause in 4.1.3 stating that \"for carbon steel, no post-weld heat treatment is required when the temperature is below 490°C.\" What exactly does \"heat treatment at 490°C\" mean? ? Does it refer to the medium temperature? ? I’m seeking help from all the experts; thank you
Yes, it refers to the temperature of the runtime medium
Whether heat treatment is required depends on the medium.
It is clearly not referring to the temperature of the medium; rather, it means that during manufacturing and installation processes such as welding, heat treatment, and pipe bending, when the temperature is kept below 490°C, heat treatment and flaw detection are not necessary. Since the temperature has not exceeded the eutectoid line, take a look at the iron-carbon phase diagram yourself.
You have overlooked the most important factor, which is the medium. If the medium is hydrogen, carbon steel pipes must undergo degassing heat treatment
I found an experienced welder who made it clear that no heat treatment was needed, as the wall was thin. But it would be even better if heat treatment is possible, to eliminate welding stress.
This time it’s either hydrogen or water. Last time, high-temperature and high-pressure welding of 15CrMo was carried out, along with hydrogen-removal heat treatment
Excuse me, on the sixth floor, can the welding temperature also be controlled at such a low level?