How to Corrode and Protect Metal-Alkali Line Pipelines
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The alkali solution in the pipeline has a concentration of 30%–40% (NaOH); the pipeline is made of carbon steel, and welding is used for connection. The operating pressure is 0.6–0.7 Mpa, and the operation mode is intermittent. During winter operations, steam heating at a pressure of 0.3 Mpa (around 100 degrees Celsius) is required. Due to the high temperature of the alkaline solution, the welds in the pipes crack, resulting in frequent leaks of the alkaline solution. What measures can be taken to resolve this issue?
Switch to hot water heating (around 50~60 degrees Celsius).
We know that carbon steel becomes brittle in alkaline solutions of NaOH at temperatures above 50 degrees Celsius, and thus it is not reliable.
Heat treatment of welds； If that still doesn’t work, upgrade to Cr-Ni stainless steel
I’m looking forward to the poster’s subsequent solutions. Under consideration……
Heat treatment of the weld seam yields a better effect in reducing the hardness of the weld bead and the heat-affected zone.
Using an iron-based alloy memory metal pipe joint can completely solve the problem, with very good results.
I wonder if pipes made of 304 material will be suitable? Has it been experimented on?
The temperature is at its limit; you could try conducting a hanging slice experiment