Whats better Stainless Steel or Galvanized Steel Screws?

The two types of steel have specific properties that make each one useful for particular purposes. Let’s look at some differences between stainless steel vs galvanized steel, and each of their many applications.

Each type of steel is formed differently. First, steelmakers heat coal until it’s basically carbon or coke, and then leave it to cool. To make steel, the iron ore is heated and melted to remove impurities, with coke then added to provide greater strength. Most steel is made with either blast furnaces or electric arc furnaces. The former mainly use raw materials – generally iron ore, coke, and limestone – whereas the latter mainly uses scrap steel.

Making galvanized steel involves coating it with a thin layer of zinc, in a process called hot-dip galvanizing. It involves immersing steel into molten zinc to create a multi-layered coating of zinc and iron alloy that helps the metal resist corrosion. Welders working with galvanized steel require protection against its fumes, as zinc’s boiling point is below that of the steel, and welding causes zinc to vaporize.

Stainless steel involves a more complex process, with chromium, silicon, nickel, carbon, nitrogen, and manganese added to molten steel. It’s then cast into semi-finished forms before being heated again and reformed into sheets, bars, wires, plates, and strips. Most types of stainless steel also go through annealing, a controlled treatment where the steel is heated and cooled to soften the metal and relieve internal stresses. When it comes to welding, welders need to take more care when heating and cooling stainless steel, matching filler materials with those being welded.

Generally, the more complex the alloy, the greater the strength. While galvanized steel is more supple and easier to work, stainless steel resists corrosion better and is stronger.

The zinc that coats galvanized steel protects it from rust by keeping the steel from coming into contact with oxygen, which causes corrosion. This keeps nails, bolts, nuts, and screws from degrading when exposed to the weather. Even when this zinc coating receives minor scratches, it still resists corrosion due to the fact the surrounding zinc is more reactive than steel, preventing rust from forming.

It’s even water-resistant, though tends to corrode faster than stainless steel when exposed to seawater. The combination of salt, moisture, and oxygen causes metals to corrode, with saltwater causing corrosion five times quicker and seawater accelerating it to 10 times, as it also contains bacteria that consume the iron. The temperature of seawater also affects its degradation, with tropical seawater causing galvanized steel to corrode even more quickly than seawater at lower temperatures.

Elements in stainless steel – especially chromium – allow it to resist corrosion much better. The chromium combines with oxygen in the environment to create a passive layer of chromium oxide, which helps prevents iron oxide from forming. Grades of stainless steel with higher amounts of chromium better resist rusting and, like galvanized steel, scratches can still resist corrosion around affected areas.

The zinc layer surrounding galvanized steel tends to be less effective against corrosion, especially when exposed to seawater, which is why stainless steel is used for sea-going vessels and other environments in which metal is exposed to saltwater. Additionally, many people consider stainless steel the more attractive option. Considering its shiny, silvery color compared to the dullish gray of galvanized steel, stainless steel offers a better aesthetic look.

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