What measures are taken to deal with high temperatures in steel pressure vessels/pipes?
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I think situations of high temperature and high pressure must be encountered often. It seems that there are many factors to consider in this situation: high-temperature strength, corrosion resistance, and wear resistance (in gas-solid or liquid-solid phases, in certain specific areas such as valves and elbows). I’ve done some research and found that several approaches could be considered; could everyone discuss this from the perspectives of cost and feasibility? 1. Change the process and structure (for example, reduce flow velocity, lower temperature, or modify the structure). 2. Use stainless steel that can withstand higher temperatures, or even superalloys. 3. Lining – I think this is basically the method used in rooms, where some insulating material such as cement is applied inside the pipes. 4. Surface strengthening, such as surfacing, thermal spraying, self-propagating synthesis, nitriding, shot blasting, laser cladding, etc.
Regarding the strengthening of stainless steel surfaces, this is something I came into frequent contact with during my work in the machinery industry, and I find it to be very useful. However, since I started working on pressure vessel/pipeline design, I’ve found that the company basically doesn’t use any other methods aside from surfacing welding. I wonder for what reason, ah? 1. Is surface strengthening too costly? 2. Is surface strengthening not suitable for the chemical industry? I think it is feasible to carry out surface treatment on stainless steel in some specific areas and under particular conditions. For example, 1. It is difficult to use linings at certain valves, and using superalloys would be too expensive ； Moreover, if the valve is also subjected to liquid-solid or vapor-solid impacts, wear will be severe. 2. For some small-diameter pipes, it is even impossible to apply a lining; instead, high-temperature alloys must be used throughout, which also results in high costs.
Lining——I think this is basically the method used in rooms, where some insulating material such as cement is applied inside the pipes. Surface strengthening methods include surfacing, thermal spraying, self-propagating synthesis, nitriding, shot blasting, laser cladding, etc. The first two of these are relatively common; however, they are too costly and complicated to use, which is why they are generally not employed