Although galvanized and stainless steel look the same, they are different in terms of composition, weight, strength and application. It is important to tell them apart so as to know which one to go for if you have a task that needs steel, since each type of steel is suitable for a particular use.
Galvanized steel: has been coated by a layer of zinc in order to protect it from corroding.
Stainless steel: has been mixed with at least ten percent chromium while in a molten state.
|Galvanized Steel||Stainless Steel|
|Manufactured by dipping steel in molten zinc.||Manufactured by mixing molten steel with 10% molten chromium.|
|Covered by a thin layer of zinc oxide to protect from rusting||Mixed with chromium to protect from rusting|
To tell the difference, let’s take a closer look at how these two types of steel are made, their common applications, durability, longevity, as well as cost.
- The manufacture of stainless steel involves a mixture of at least ten percent chromium and regular carbon steel in molten state. It is then left to cool and harden, after which, the steel is acid treated to remove any impurities present on its surface. It is then subjected to passivation to give it a protective layer.
Galvanized steel, on the other hand, is manufactured by coating regular carbon steel with zinc to protect it from rusting. This can be done by either electro-galvanizing or hot-dipping.
Hot-dipping occurs when steel is immersed in a hot liquid of zinc. As it cools, the zinc coating and the steel adhere together forming galvanized steel. Electro-galvanizing is also another method of manufacturing galvanized steel. This is done by immersing steel in an electrolyte solution.
- Although both of these categories of steel are suitable for most applications, their make-up often dictates their specific uses. For instance, galvanized steel has only a layer of zinc coating which eventually wears off. By contrast, stainless steel is made up of chromium throughout meaning that that its protective layer is always in place. This also makes stainless steel the stronger of the two. For instance, because of its strength, stainless steel is used in the construction of skyscrapers and homes. Major pipelines are made of stainless steel, as well as important hand tools and saw blades. Its makeup also makes it the best to work with in marine environments, as it is more resistant to salt.
- Galvanized steel is covered by a rust-protective layer that is barely a millimeter thick. This means that whenever it is scratched, rusting immediately starts to occur around the scratched area. Unlike galvanized steel, stainless steel does not rust even when scratched since its protection is actually an integral part of it. This is why stainless steel is common in utensils such as knifes that are sharpened from time to time.
- Stainless steel is far more expensive than galvanized steel, which is ideal for projects that require a lot of steel materials if they do not move or collide against each other or if the project requires thick components, such as in the construction of buildings. Due to its low cost, galvanized steel is mostly used in making nuts, bolts, nails, and many home appliances.