Application conditions of 304 and 304L stainless steel in chlorinated aqueous solutions
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1. Type 304 stainless steel: This is the cheapest and most widely used austenitic stainless steel (used in industrial equipment in industries such as food processing, chemicals, and nuclear energy). Suitable for general organic and inorganic media. For example, nitric acid with a concentration of <30%, temperature ≤100°C, or a concentration of ≥30% and temperature <50°C ； Carbonic acid, ammonia water, and alcohols of various concentrations at temperatures ≤100℃. Poor corrosion resistance in sulfuric acid and hydrochloric acid ； It is particularly sensitive to crevice corrosion caused by chlorinated media such as cooling water. 2. The corrosion resistance and applications of 304L stainless steel are basically the same as those of 304 stainless steel. Due to its lower carbon content (≤0.03%), it offers better corrosion resistance (especially against intergranular corrosion, including in the weld area) and weldability, making it suitable for semi-welded or fully welded PHEs.
Special care must be taken when using 304 and 304L stainless steels in chlorinated aqueous solutions, as both are prone to crevice corrosion. 304L has a lower carbon content, which gives it greater resistance to intergranular corrosion after welding; therefore it is suitable for use in heat exchangers and other devices that require welding. In short, if the chloride ion concentration in the water is not high and the temperature is not high (such as at room temperature), it can be used with caution ； If the chloride ion concentration is high or the temperature is high, it is better to choose a more chlorine-resistant material such as 316L. .