What potential hazards can arise if the support pads of heat treatment equipment are not heat-treated?
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One absorption tower in a petrochemical plant, as well as the overall heat treatment equipment, are suffering from hydrogen sulfide stress corrosion! Due to the incorrect placement of the bracket shims, several additional shims have been welded onto the tower. The tower needs to be lifted as soon as possible, and what problems could arise if these shims are not subjected to heat treatment? The tower body is 20 thick! 3 meters in diameter!
What the poster means is, after the entire equipment underwent heat treatment, welding was carried out on it as well? This requires local heat treatment of the cylinder at the gasket area; refer to GB150.4 7.4.3 and 7.4.4. Once it’s in place, local heat treatment should be straightforward to carry out
The purpose of heat treatment in the absorption tower is to eliminate welding stress and reduce the hardness of the welds. Wet hydrogen sulfide tends to cause stress corrosion in the harder weld areas. Local heat treatment should be applied to the cylinder at the gasket location.
Gaskets are non-compressive components; unlike weld seams, they do not come into contact with the medium either! Is it stress corrosion or welding stress that causes the cracking? I need a response from a theoretical perspective!
For such a large tower, when performing local heat treatment, it is necessary to carry it out on all the ring sections, including the gussets, and it is difficult to ensure that no secondary stresses will be generated. It is recommended to use low-wire-energy multi-pass welding when welding the bracket gussets, and to perform preheating in order to reduce welding shrinkage stresses; no heat treatment is required after welding.
After local heat treatment, how can one check the results of the treatment?
I’m not sure what test you are referring to? Generally, it’s just about measuring hardness.
After local heat treatment, how can we determine whether the heat treatment was successful? The only way is to conduct a hardness test!
First is a visual inspection to check for overheating, deformation, etc., as well as examinations of curves and hardness tests.
You’re very professional; it must be convenient to conduct hardness tests now! Is it expensive?
Just perform a local heat treatment and that’s it!