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I. Typical corrosion rates under different operating conditions The corrosion rate of steel in this system varies significantly depending on factors such as medium concentration, temperature, pH value, and type of steel. The measured values are as follows: For carbon steel (Grade 20), at low temperatures – specifically at 90°C in an environment with a high HCl concentration of pH=1 – the corrosion rate can reach 35.27 mm/a； When the pH rises to 3, the corrosion rate drops to about 10% of the previous value; when pH > 5, it is only about 5% of the previous value. High-temperature conditions for carbon steel: In a mixed gas phase environment at 310–360°C, the average corrosion rate of Grade 20 steel is 0.06–0.46 mm/year. Low-alloy steel conditions: The uniform corrosion rate of 12Cr2AlMoV steel in this environment is approximately 0.2 mg/(cm²·h), and its corrosion resistance is far superior to that of ordinary carbon steel. Under normal stainless steel operating conditions: 304L suffers severe pitting after just 6 months in this environment with high Cl⁻ levels, while 316L can only resist stress corrosion cracking for 18 months before failing. II. Key influence patterns: At low pH levels, the corrosion rate is primarily determined by the HCl concentration, while the H₂S concentration has little effect on the overall corrosion rate. An increase in temperature accelerates the hydrogen depolarization reaction and electrochemical reactions, causing the corrosion rate to increase significantly as temperature rises. An increase in HCl concentration destroys the FeS protective film formed on the steel surface, reducing its density and even causing it to peel off, thereby accelerating the corrosion process.