Painting for stainless steel pipes above 120 degrees?
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According to the painting requirements in SH/T 3022, stainless steel exposed to temperatures between -20 and 120 degrees requires a primer, an intermediate coat, and a topcoat. What about stainless steel pipes exposed to temperatures above 120 degrees? Is painting necessary? Including insulated and uninsulated pipes, I would appreciate any advice from fellow sailors. Thank you.
Appendix C of SH/T 3022-2011, \"Common Anti-corrosion Coating Systems,\" provides anti-corrosion coating solutions for stainless steel equipment and pipelines in the range of -20–120°C in two scenarios: (1) anti-corrosion coating in highly corrosive environments [such as oxide and chlor-alkali environments], and (2) anti-corrosion protection for insulation equipment and pipelines [only applicable when chloride ions in the insulation materials are at elevated levels]. In my opinion, stainless steel equipment and pipelines above 120°C should also be painted for corrosion protection under the aforementioned conditions.
SH/T 3022 specifies corrosion protection in highly corrosive environments, particularly in environments with chloride ions and in chlor-alkali environments. Specifically, for stainless steel pipes at 120 degrees, there are two issues to consider: first, those with insulation should be coated with two layers of heat-resistant primer. The reason is that the insulation materials we usually choose contain chloride ions, and the absence of a barrier layer can cause pitting corrosion on stainless steel. Second, those without insulation can be used in the atmosphere without the need for corrosion protection.
It is sufficient to use the nuclear-grade composite silicate product provided by Chongqing Yahan Insulation Materials Co., Ltd.; no painting is required. This type is used for insulation in nuclear power stainless steel applications. For inquiries, contact QQ2293022071