Differences between galvanized steel and stainless steel?

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Clients often want to know which is better between galvanized steel and stainless steel? Which one is more expensive? Which one is better against environmental elements? The simple fact is that not any type of steel is always a better choice in all situations. These are some basic knowledge about the differences between galvanized steel and stainless steel that you can refer to make the optimal choice.

What is galvanized steel?

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Galvanized steel is steel that has been coated with a layer of zinc to prevent the underlying steel from rusting. This layer is usually quite thin, usually measured in thousandths of an inch or micron. To make galvanized steel, a layer of zinc is usually added after smelting and refining. Sometimes it is even done after manufacturing process such as bending or welding.

Applications of galvanized steel

Galvanized steel is used for applications where corrosion is not desired but a bit corrosion may be allowed and aesthetics is not a concern. Applications of galvanized steel including:

  • Ventilation duct system
  • Components of automobiles
  • Several types of latches
  • Structural beams
  • Metal cabinet
  • balcony
  • Traffic signs
  • Power poles
  • Protective mask

What is stainless steel?

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Stainless steel is made by adding Chromium, Carbon, Silicon and Manganese… to molten steel. It is very durable and resistant to rust from exposure to water, even salt water and extreme conditions…

There are 4 types of stainless steel, engineers and architects need to update their differences to optimize the application in use.

  • Austenitic stainless steel is a popular product and used for industrial purposes, machine shops…
  • Ferritic stainless steel is a cheaper product used in applications that are easy to replace such as automobile exhausts…
  • Martensitic stainless steel is hard to corrode and used for machining hard surfaces.
  • Duplex stainless steel combines the molecular structures of austenitic and ferritic stainless steels and very difficult for machining.

Please see more:

Applications of stainless steel

Stainless steel is commonly used in areas including:

  • Aerospace engine components
  • Kitchen tools
  • Several types of latches
  • Interior furniture
  • Fences, railings, doors
  • Building materials
  • Building ships, boats
  • Transportation
  • Medical equipment
  • Water treatment equipment
  • Industry – chemistry
  • Energy industry

Differences between galvanized steel and stainless steel

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Galvanized steel vs stainless steel which one is stronger?

When compared at the same thickness and appearance, stainless steel is always sturdier than galvanized steel. An effective way to compare this is to look at the tensile strength of each material. Tensile strength is the breaking resistance of a material under tension. The exact number will vary according to the alloy used.

Galvanized steel vs stainless steel which one is heavier?

In most cases, stainless and galvanized steel will have very similar weights. Specific differences will vary depending on the stainless steel alloy and the thickness of the zinc coating on the galvanized steel product. Stainless steel contains more alloys or a thicker zinc coating will result in more weight. This is unavoidable.

How ductile are galvanized steel and stainless steel?

Galvanized steel has the same malleability as the basic steels. This means that in most cases it will be more ductile than similarly shaped stainless steel.

If you must use stainless steel and want it to have more ductility but unsure how to choose the perfect stainless steel, considering austenitic grades. These contain higher amount of nickel, making them easier to shape for larger objects like sinks, basins and tanks, etc.

How well galvanized steel and stainless steel conduct heat?

Both stainless and galvanized steel conduct heat in a similarly way. However, in the case of galvanized steel, you must keep in mind the melting point of zinc. Although molten zinc is not toxic, heating galvanized steel past its melting point can create a risk of burns or fire as the zinc coating liquefies and separates from the underlying steel.

At the structural level, both stainless & galvanized steels must provide excellent heat resistance for usage in high temperature areas.

Can galvanized steel and stainless steel be welded?

Both stainless and galvanized steel are weldable. However, both have their own considerations.

Welding stainless steel can degrade the passivation layer and create brittleness. This may result in reduced corrosion resistance or affect the structural integrity of the stainless steel parts. Rust remover method can help reduce the effects of welding and heat exposure in most stainless steel applications.

For welding galvanized steel, you must adequately ventilate the fumes when welding galvanized steel because zinc oxide fumes can be harmful when inhaled. If welding near stainless steel, you must also make sure that the molten zinc produced is kept away from the stainless steel parts. Failure to do so may result in brittleness of any stainless steel material. For these reasons, welding steel requirement should be performed prior to galvanizing whenever possible.

Are galvanized steel and stainless steel magnetic?

Magnetism will completely depend on the type of used steel. For galvanized steel, if the zinc coated steel is magnetic, the zinc coating should not interfere with the magnetic reaction.

If you want to choose magnetic stainless steel, then austenitic steel is the most magnetic one. Other alloys will exhibit different degrees of magnetism based on their iron content.

Should we use galvanized steel or stainless steel in household appliances?

Stainless and galvanized steel both provide safe usage in most food service conditions. Galvanized steel is one of the extremely popular choices for building kitchenware racks. It also provides a stand-alone look for serving on dining tables and other decorative elements.

However, you must be very careful to avoid highly acidic foods to be served with galvanized steel kitchenware as they can degrade the zinc coating surprisingly fast with frequent contact.

Stainless steel is less reactive so if you are looking for a versatile option, then stainless steel is your best option.

Because galvanized steel is also not as smooth as stainless steel and will become coarser over time. This means that galvanized steel cleaning requirements will increase over time with changes in surface texture.

Is galvanized steel or stainless steel commonly used in medical equipment?

In most cases, stainless steel will be preferred over galvanized steel in medical conditions. Medical uses, such as devices, instruments or even implants, require long-lasting performance and easy-to-clean surfaces. Whether you are talking about scalpels or surgery room surfaces, you can see that stainless steel is used almost everywhere.

The rough surface of galvanized steel and the possibility of the zinc coating being scratched or chipped make it less safe for medical use and potentially more difficult to clean.

Is galvanized steel more expensive than stainless steel?

Despite the price difference, the key element depends on the chemical composition, needs and intended use, etc. stainless steel price always costs more than galvanized steel. The price of galvanized steel is almost same as untreated structural steel. Therefore, OSS Dai Duong recommends that you should determine your needs first in order to choose the most suitable product.

Thank you for your interest in the article of OSS Dai Duong: “Differences between galvanized and stainless steel?”

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                                                                                    Editorial Board: O S S Dai Duong

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