What are the principles for considering the corrosion margin of the main components of a heat exchanger?
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According to GB/T 151: ① Corrosion allowance shall be considered on both sides of the tube sheet, floating head flanges, floating head covers, and hook rings; ② Corrosion allowance shall be considered on the inner surfaces of flat covers, convex heads, tube boxes, and cylinders; ③ When partition grooves are made in the tube sheet and flat covers, the metal protruding above the bottom surface of the groove can be used as the corrosion allowance, but if the corrosion allowance is greater than the depth of the groove, the difference between the two values shall be added; ④ Corrosion allowance shall be considered on the inner diameter surfaces of pressure vessel flanges and pipe flanges; ⑤ No corrosion allowance is considered for heat exchange tubes (the thickness required for strength can be used for C2); ⑥ Non-compressive elements such as tie rods and spacers generally do not require a corrosion allowance. For carbon steel and low-alloy steel, C2 ≥ 1 mm; for stainless steel, when the corrosivity of the medium is very low, C2 = 0.
After ensuring safety, considering it from an economic perspective
GB/T 151-2014 4.4.5 – Take a look at it and you’ll know what needs to be considered.
By comparing with the standards, the source can be found.
Minimum allowance requirements apply, along with consideration of corrosion rate. Generally, for ordinary media with five special requirements, taking the minimum allowance is sufficient