Outdoor bolt issues in coastal environments
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Regarding the issue of outdoor bolts in coastal environments, some recommend yellow chromium plating, others suggest blackening, and still others propose Teflon plating – which one should be chosen? What is the difference between yellow chromium plating and yellow zinc plating?
Electroplating is not recommended; instead, inorganic anti-corrosion coatings (which are rich in zinc and have good weather resistance due to their integrated base layer) should be used for protection, or zinc-rich anti-corrosion paint combined with a weather-resistant topcoat can be employed. The reason electroplating is not recommended and zinc-rich coatings are preferred is that, whether through electroplating or coating, tooth occlusion will damage these protections, resulting in a potential difference. Utilizing the cathodic protection function of zinc-rich sacrificial anodes, along with the self-healing property resulting from the oxidation of zinc powder in zinc-rich coatings, will **extend the anti-corrosion lifespan**.
Fasteners, using inorganic zinc-rich coating? ~~~Fasteners, using a sacrificial anode? ~Personally, I recommend hot-dip galvanizing~~~
I’m referring to the anti-corrosion reinforcement after it’s installed
304 will do, right? Why is it so complicated?
Generally speaking, fasteners that have been installed are not coated with any types of paint anymore~~~ Of course, this does not apply to those used underwater~~~
Cadmium plating is recommended; this “cadmium” is different from the “chromium” you mentioned. The chromium plating you mention is generally used for decorative purposes. As for galvanized zinc, its salt spray tests last for 24 hours, 36 hours, and 72 hours. Of course, it can also be treated with Teflon. Carbon steel and alloy steel products require an undercoat treatment before spraying... The specific requirements depend on your needs for corrosion protection. PS: I can do these on my end. It shouldn’t be considered advertising, right?
The bolts used for equipment and pipelines on offshore platforms are generally galvanized plus Teflon-coated