Pay attention to the alkali embrittlement of sodium hydroxide in petrochemical plants
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Sodium hydroxide (NaOH) is a commonly used medium in petrochemical production facilities; under certain conditions, it can cause stress corrosion cracking in carbon steel materials (often referred to as alkali embrittlement). The factors affecting stress corrosion cracking of carbon steel in NaOH solution are concentration, temperature, and residual stress. Generally, when the temperature of NaOH exceeds 40 degrees and its concentration is above 60%, stress-relief heat treatment should be applied to it after welding.
When using sodium hydroxide in petrochemical plants, attention must be paid to the alkali embrittlement problem it may cause. To prevent stress corrosion cracking of carbon steel materials in a sodium hydroxide environment, especially when the temperature of sodium hydroxide is above 40 degrees and its concentration is above 60%, stress-relief heat treatment is required for the welded material. .
It is described in detail in the pressure vessel standards for SH and HG
General alkaline wires need to undergo heat treatment