Under what circumstances is heat treatment required for tube boxes?
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Under what circumstances is heat treatment required for tube boxes? After the tube boxes are welded, is it necessary to leave a machining allowance on the flanges, and if so, how much?
GB151 specifies that for tube boxes and floating head covers made of carbon steel or low-alloy steel, as well as those with lateral openings exceeding 1/3 of the cylinder’s inner diameter, stress-relief heat treatment is required after welding. Both the flange sealing surface of the equipment and the partition should have a machining allowance; we generally leave 5-10 mm.
I agree with the person above; the flange sealing surface is machined after heat treatment, usually leaving a margin of 5-10 mm. The specific allowance depends on the machining equipment and material quality.