Wondering which type of nut to use? Here’s what you need to know about stainless steel vs. galvanized vs. zinc plated nuts.
Nuts are fasteners that are manufactured in a variety of materials including the likes of steel, titanium, plastic, and more. In addition to this, there are different grades to choose from. Some of these fasteners are also available in various coatings or plating, which is meant to enhance the corrosion resistance of the product and reduce costs.
Choosing the right fastener material is important as it will determine how strong or brittle the product is. The material of the fastener also dictates its resistance to corrosion as well as its aesthetic appeal. If you need to replace your existing fasteners, it is best to replace them with the same fastener material, unless the material itself is causing corrosion or not coping in the environment that it is in.
When comparing stainless steel vs. zinc plated vs. galvanized nuts, it’s important to realize that stainless steel itself is a material and galvanizing and zinc plating are forms of coating.
What Are Stainless Steel, Galvanized, and Zinc Plated Nuts?
Before we compare them, let’s have a look at how each type of nut is made and what makes it unique.
Stainless Steel Nuts
Stainless steel is the most durable option when it comes to different types of nuts. These nuts not only offer enhanced corrosion resistance, but the integrity of this resistance won’t be affected even if the product is scratched. The only tricky part of opting for stainless steel nuts is that they must be installed by a professional with exceptional care to avoid galling (seizing).
Common Types of Stainless Steel:
- 304 stainless steel – General-purpose, corrosion-resistant, and commonly used in construction.
- 316 stainless steel – More resistant to salt water, ideal for marine and aerospace applications.
- Duplex stainless steel – Combination of austenitic and ferritic properties, offering high strength and corrosion resistance for high-stress environments.
Best for: Marine applications, industrial use, and environments exposed to salt water or chemicals.
Zinc Plated Nuts
Steel fasteners that are electroplated with zinc (zinc plated) to improve corrosion resistance are also a good choice. While zinc plated bolts and nuts are considered resistant to corrosion and have a number of suitable applications outdoors and within the industrial sphere, zinc plated nuts are not suitable for use in marine environments or in environments where humidity is higher than average.
The main benefit of zinc plated bolts and nuts is that they are much cheaper than stainless steel nuts. They will often provide an acceptable level of strength and corrosion resistance for most non-specialty applications, making them a worthwhile consideration to keep in mind.
Best for: Indoor applications, light-duty industrial use, and furniture assembly.
Galvanized Nuts
Many people are surprised to discover that galvanized nuts are also coated in a layer of zinc. The difference is that when nuts are hot-dip galvanized, the metal is coated in a much thicker layer which, in turn, makes the product even more corrosion resistant than regular zinc plated nuts. While these present the most durable material, they are not compatible with bolts manufactured from other materials as galvanized steel vs. stainless steel nuts have slightly different dimensions to other types of fasteners.
Galvanized and stainless steel fasteners are not always compatible, as mixing them can lead to galvanic corrosion. Additionally, the weld quality of galvanized steel must be carefully managed, as the zinc coating can create fume hazards when heated.
Best for: Outdoor structures, roofing, fencing, and general construction where moisture is present.
Stainless Steel vs. Galvanized vs. Zinc Plated Nuts: Key Differences
Galvanized vs. Stainless Steel
When comparing stainless steel vs galvanized steel, the key differences come down to corrosion resistance, strength, and cost. While both materials are designed to withstand rust, they achieve it in different ways.
Corrosion Resistance
Stainless steel is naturally resistant to corrosion because it is made from an alloy that contains chromium, which forms a passive layer of chromium oxide that prevents rust from forming. Even if the surface is scratched, this layer regenerates, keeping the metal protected.
Galvanized steel, on the other hand, is regular steel that has been coated with a thick layer of zinc through hot-dip galvanization. This zinc layer acts as a barrier, protecting the steel from moisture and rust. However, if the coating wears off or gets scratched, the exposed steel underneath will begin to corrode.
Best for corrosion resistance: Stainless steel (especially for marine or chemical environments).
Strength and Durability
Stainless steel is stronger and more durable than galvanized steel. It has a higher tensile strength, meaning it can withstand greater force before breaking. This makes it ideal for structural applications, high-pressure environments, and heavy-duty fasteners.
Galvanized steel is strong but not as strong as stainless steel. Its zinc coating does not add any strength—it only provides corrosion protection. Over time, the coating can wear off, reducing the durability of the material.
Best for strength: Stainless steel.
Corrosion Resistance
Galvanized steel is more affordable than stainless steel. If you need good corrosion protection at a lower cost, galvanized nuts and bolts are a great option for outdoor use, roofing, fencing, and general construction.
Stainless steel is more expensive, but it offers better long-term durability, which means lower maintenance costs over time. If you’re working on a project exposed to salt water, chemicals, or extreme temperatures, stainless steel is the better investment.
Best for budget-conscious projects: Galvanized steel.
- Choose stainless steel for marine, aerospace, and high-stress applications.
- Choose galvanized steel for construction, fencing, and general outdoor use.
Galvanized vs. Zinc Plated
The main difference between galvanized steel and zinc plated steel is how the zinc coating is applied and how much protection it provides.
Coating Thickness and Durability
Galvanized nuts and bolts are coated through hot-dip galvanization, where they are dipped into molten zinc to create a thick protective layer. This layer is significantly thicker than the coating on zinc plated nuts, making galvanized fasteners much more resistant to rust and corrosion.
Zinc plated nuts are made using an electroplating process, which applies a thin layer of zinc to the steel. While this does provide some corrosion resistance, it is far less durable than the coating on galvanized nuts.
Best for long-term durability: Galvanized steel.
Corrosion Resistance
Because galvanized steel has a thicker zinc layer, it lasts much longer in outdoor environments compared to zinc plated steel. If exposed to rain, humidity, or salt water, zinc plated fasteners will corrode much faster than galvanized fasteners.
Best for corrosion resistance: Galvanized steel.
Cost and Application
Zinc plated nuts and bolts are cheaper than galvanized ones, making them a good option for indoor applications where corrosion is not a major concern. They are commonly used in furniture, appliances, and general hardware.
Galvanized fasteners, while more expensive, are better suited for construction, outdoor structures, and automotive applications where durability is required.
- Choose galvanized steel for outdoor construction and high-moisture environments.
- Choose zinc plated steel for indoor projects or areas with minimal moisture exposure.
Zinc Plated Steel vs. Stainless Steel
When deciding between stainless steel vs. zinc plated steel, the biggest differences are in corrosion resistance, longevity, and cost.
Corrosion Resistance
Stainless steel is naturally resistant to rust because it contains chromium, which forms a passive layer of chromium oxide that protects the metal from moisture and oxidation. This makes it ideal for marine environments, food processing, and chemical exposure.
Zinc plated steel, on the other hand, relies on a thin layer of zinc to provide corrosion protection. However, if this layer is scratched or worn off, the steel underneath will start to rust quickly. This makes zinc plated fasteners unsuitable for outdoor or high-moisture environments.
Best for corrosion resistance: Stainless steel.
Strength and Durability
Stainless steel is significantly stronger and more durable than zinc plated steel. It has a higher tensile strength, meaning it can handle greater stress and weight without breaking. This makes stainless steel fasteners ideal for heavy-duty applications, including construction, aerospace, and marine use.
Zinc plated steel is generally not as strong and is better suited for light-duty applications.
Best for strength: Stainless steel.
Cost and Application
Zinc plated nuts and bolts are cheaper than stainless steel and are a good option for indoor projects, furniture assembly, and light industrial applications.
Stainless steel fasteners are more expensive, but they offer better long-term value because they don’t need frequent replacement due to corrosion.
- Choose stainless steel for marine, chemical, and outdoor applications.
- Choose zinc plated steel for budget-friendly indoor projects.
Final Considerations: Stainless Steel, Galvanized, or Zinc Plated?
- For maximum corrosion resistance and long-term durability: Stainless steel is the best choice.
- For a cost-effective solution that can withstand outdoor environments: Galvanized steel is a solid option.
- For budget-friendly indoor applications with minimal moisture exposure: Zinc plated steel will work fine.
The bottom line is that you cannot go wrong with stainless steel nuts. This is because they do not need to be coated in order to provide strength, durability, and corrosion resistance. They are inherently all of those things. As for coated and zinc plated nuts, the coatings can begin to erode over time, ultimately affecting their overall strength and longevity. At the end of the day, it is a matter of both budget and preference. As long as you ensure that you choose a reputable nuts and bolts supplier, you should not have to worry about any issues along the way.
Marsh Fasteners
At Marsh Fasteners we stock a wide variety of stainless steel and nickel brass nuts including the likes of Acorn Cap Nuts, All Metal Nuts, Barrel Nuts, Coupling Nuts, Finish Hexagon Nuts, KEP “K” Nuts, Machine Screw Nuts, Metric Nuts, Nylon Insert Lock Nuts, Serrated Flange Nuts, Thin Nuts, and Wing Nuts. These are available in various grades of stainless steel and nickel brass.
For more information and advice on choosing between stainless steel vs. galvanized vs. zinc plated nuts, contact us via email or telephone at Marsh Fasteners today.
