Can a backing plate be heat-treated without ventilation holes?
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I have a question: we have a high-pressure vessel with a working pressure of 15 MPa, operating temperatures ranging from -20 to 50°C. Its diameter is 4000 mm and its wall thickness is 150 mm. On the outside, gussets with dimensions of 250×300×100 mm have been welded on – these are located on the surface of the steel plate, without covering the welds. The weld angles are 30 mm, and the welder has welded around the entire perimeter, creating an enclosed space inside. The equipment is now ready for final heat treatment. Are there any issues? Is it necessary to cut a hole for ventilation? If heat treatment is carried out in this way, is the force in a confined space high? What problems will arise? In addition to these larger shims, there are many other shims with a diameter of 30 mm and a thickness of 20 mm; none of them have ventilation holes. Won’t there be any problems in such a confined space? If it is only after the final heat treatment of the device that it is discovered that no vent hole was left, but the welds around the gasket have passed inspection, is it still necessary to create a vent hole (by planing or grinding)?
The gasket does not have any ventilation holes, so it’s likely that the final welding points will not be airtight either; there should still be some air leakage. ——One’s own opinions are not necessarily correct and can be corrected; please do not use abusive language.
Vent holes must be left; heating in a sealed space can cause a sudden rise in pressure, and equipment is particularly vulnerable to external pressure, which may lead to deformation. Vent holes are usually required when welding gaskets, let alone when heat treatment is involved. Since it is a heat treatment device, it is not recommended to cut it open; instead, grinding it open is suggested
I agree with the person above; it’s better to leave something that allows air to pass through, otherwise it might cause some unnecessary problems.
For high-voltage equipment, the welds should not be subjected to secondary heat treatment; instead, use a cutting machine to grind the welds or drill holes in the backing plate.
It was ground open, but I didn’t dare to drill in, fearing I wouldn’t be able to control the depth.
The fillet weld has high peaks; the enclosed space is small, so it shouldn’t crack, right? I heard that our design was calculated accordingly.