Stainless Steel vs Galvanized Steel: Some Key Differences

Are you done looking for screws? You’ve likely seen that some of them are made of 100% stainless steel, while others are made of galvanized steel. Because of this, it’s hard to recognize the difference between them. Keeping in view everything, the two of them look and function similarly. So, what’s the contrast between stainless steel and galvanized steel?

These two kinds of screw materials are sold by every home-improvement retailer on the planet. There’s no simple response to this inquiry that which is best since the two kinds of steel have their pros and cons. All things considered, stainless steel and galvanized steel have the equivalent common objective of ensuring against rust and corrosion and they accomplish this objective astoundingly well. Before selecting one for a utility, first, we have to do a deep analysis of both these materials. Their quality, strength, and pricing, hence everything matters.

 

Stainless Steel

The term stainless steel is utilized to portray steel that has been blended in with at least 10% chromium. The expansion of chromium as a composite assist with securing against rust.

304 Grade Stainless Steel
316 Grade Stainless Steel

Properties
Stainless steel is shinier and progressively refined looking. While stainless steel isn’t invulnerable to rust, it positively has a more significant level of opposition than 100% steel. This is the reason stainless steel is frequently utilized in open-air conditions where there’s a lot of dampness. The chromium attempts to secure the metal against rust.

Composition
Stainless steel alloys are composed primarily of iron, with varying amounts of carbon, chromium, and other elements such as nickel, molybdenum, and titanium. The composition of these alloys can be adjusted to provide specific properties such as corrosion resistance, strength, and ductility. Threading and cold forming cause stainless bolts to become slightly magnetic, some fasteners will be more magnetic than others depending on size and how quick the cold forming process is. The detailed composition of stainless steel types is listed below;

Grades
(by ASTM standard)
Content by weight
Chrome Nickel Carbon (max) Molybdenum (max)
18-8 Stainless Steel 18% 8% 0.08% 0%
305 Stainless Steel 17%-19% 8%-10% 0.12% 0%
316 Stainless Steel 16%-18% 10%-14% 0.08% 2%
410 Stainless Steel 11.5%-13.5% 0% 0.15% 0%

 

Galvanized, Plated

Galvanized steel, then again, is a sort of steel that has been covered in a layer of zinc. Much like its partner, galvanized steel is additionally made to secure against rust. The zinc goes about as an obstruction of assurance between airborne dampness and the steel, shielding it from rust.

Zinc Plated Steel

 

Hot Deep Galvanized Steel

 

Yellow Zinc Plated Heat Hardened Steel

Properties
Galvanization is a procedure that plates steel in a way that shields it from rusting or eroding. This makes galvanized steel incredible for indoor and outside use. It additionally implies that you can support the galvanized tie or metal piece in a way that reaches another metal or material and do so by utilizing a different fastener or screw. It has different coatings;

Composition

Galvanized steel comprises of plunging a completed steel item into a hot shower of zinc. In this procedure, a bond happens, mixing the zinc to the outside of the steel. The zinc plate bonding develops until the external layer is fully composed of zinc. The external layer of this new steel item is harder than the steel to which it is attached to. The steel currently has a defensive layer of plating shielding it from rust. It has different coatings;

Material Coating Thickness Temperature Range Expected
Durability
Suitability
US Metric US Metric
Zinc Plated Up to 1 mil Up to 25 μm -148°F – 392°F -100°C – 200°C 15+ years Indoor

&

Outdoor

Hot Dipped 1.7 – 3.4 mils 43-58 μm -148°F – 392°F -100°C – 200°C 45-80 years Indoor

&

Outdoor

Electroplated 0.2 mil 5 μm -148°F – 392°F -100°C – 200°C 10+ years Indoor

&

Outdoor

*mil – a unit length in the US system equal to a thousandth inch or 0.001 inches.
*μm – a unit of length in the Metric system equal to one millionth (10-6) of a meter.

Comparison

Strength Analysis

Both galvanized and stainless screws are the absolute best materials for strength and quality. They are particularly valid for metal fixation, that’s why they are commonly known as self-tapping metal screws. Nonetheless, there are some measures you will need to observe while selecting between the two.

Stainless steel screws are made out of a few components, with chromium being the most noteworthy of the added substances and nickel a nearby second. The greatest and most significant point is that the whole of the clasp is stainless. It isn’t only a covering. Its quality and rust insurance are all through. That represents its higher rigidity rating. Companies did pressure tests on latches to mention that, what sort of crazy burden-bearing limit these stainless steel machine screws have. Stainless steel has a tensile PSI quality of 100,000 to 150,000. Hot Dipped galvanized screw has a rigidity of 62,000 PSI since they are grade 2 fasteners.

 

 

Material Tensile Strength Yield Strength
PSI MPa PSI MPa
Stainless Steel 100000-150000 689-1034 30000-40000 206-275
Galvanized Steel 38000-62000 262-427 21000-31000 144-213

Rusty Nature

The process of galvanization involves the application of a molten zinc coating onto a core of plain steel. While it is rare, the core of the screw may be exposed due to wear and tear over time.

In contrast, stainless steel screws are protected by their inherent chromium composition, which enables the formation of a passivation layer that provides excellent resistance to rust and corrosion. However, if the availability of oxygen is limited, such as in the presence of water, stainless steel screws may still corrode. Although such scenarios are relatively rare, it is essential to consider the potential risk of rusting in any application involving water and stainless steel screws.

Conclusion

Both have their distinct properties acquainted with their utility. Galvanized steel screw is cheaper than stainless steel screw but stainless steel screw is much more durable due to their anti-rust chromium property. This isn’t generally an immediate challenge. Galvanized screws have that solid, dull, mechanical look, while stainless steel is shinier and more refined looking. Thus, galvanized wins with regards to its cheap price, stainless steel with regards to quality, and rust insurance.

References

Related Categories

Fasteners In Salt Water Environments: What You Need To Know

Fasteners In Salt Water Environments

One of the biggest complaints we hear about are fasteners rusting prematurely. The first question we are likely to ask is “Are you within 20 miles of a salt water environment?”

Surprisingly, an overwhelming amount of customers say yes. It is commonly understood that metal rusts and that it rusts worse in corrosive environments. It is not commonly understood that those environments spread beyond what the eye can see, however, this should be one of the bigger factors taken into consideration when buying fasteners.

Stainless steel is a prime example of this. Almost anyone you talk to can tell you stainless steel is corrosion resistant, but did you know that grade 410 stainless steel is less corrosion resistant because it is heat-treated to be harder? or that grade 304 stainless is not suited for highly corrosive environments?

In fasteners, the material and sometimes even the grade matter when it comes to choosing the right fastener for your installations. There are several materials that do extremely well in salt-water environments, some that kind of work and some that are almost guaranteed to fail.

 

SHOP STAINLESS STEEL     SHOP ALUMINUM

SHOP SILICON BRONZE     SHOP HOT DIP GALVANIZED 

 

What You Should Use

fasteners for salt water: aluminum, silicon bronze, 316 stainless steel

There are generally a few materials that work extremely well in salt-water environments. Depending on your needs you should aim to choose from the following:

  • Grade 316 Stainless Steel
  • Aluminum
  • Silicon Bronze

These materials (or specific grades) are ideal for salt-water environments because they can resist the corrosive effects that salt-water very well.

Another option to try is HDG (Hot Dip Galvanized) fasteners. HDG is a form of zinc coating that will protect the fastener from harm and is usually a cheaper option but is not a perfect solution.

HDG fasteners can handle well in certain salt-water environments but results can vary depending on if they are submerged, water temperature and air temperature. Due to these factors, we do not recommend it as it will likely not perform as well as the materials listed above.



Pro Tip

Although 316 stainless steel and aluminum are both listed as good materials to use in corrosion resistant environments, you also do not want to mix the two. If you do, the process of galvanic corrosion is more than likely to occur, resulting in a significantly shortened lifespan for your fasteners.

To see the fasteners we carry in these selections check out our marine grade and aluminum fasteners pages.

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Black Oxide Coating: What Is Black Oxide?

 

SHOP BLACK OXIDE FASTENERS

 

Black Oxide Coating: What Is Black Oxide?black oxide treated lock washers

Black Oxide, sometimes called blackening, is the act of converting the top layer of a ferrous material with a chemical treatment. Treating fasteners with a black oxide coating not only adds a nice clean black look but can also add a mild layer of corrosion and abrasion resistance. To achieve the maximum in corrosion resistance, black oxide can either be waxed or oiled to add an extra layer of protection. The wax coating may dull the color of the treatment but provides the best resistance. The black oxide treatment is also referred to as gun bluing.

When fasteners are dipped into the black oxide bath materials (warm and hot processes) the harsh chemical components convert the top layer into magnetite. Black Oxide Stainless Steel Nuts Bolts and Washers are the most common form of black oxide fastener available. Prized both for the corrosion resistance of stainless steel with the added benefits of the black oxide treatment.

Materials That Can Get The Black Oxide Treatment

blackening finishing cup washers

  • Stainless Steel
  • Copper
  • Copper Based Alloys
  • Zinc
  • Powdered Metals
  • Silver Solder

The Black Oxide Processes

Blackening can be achieved in a number of different ways. There are three main ways to do this. If you are interested in the specifics of each type check out this article from Wikipedia.

Hot Bath

The process of treating the fasteners in different chemicals in order to convert the surface material into magnetite. The process is completed by dipping the fasteners into different tanks and occasionally placed in water. Once the process of dipping is completed the top layer of the fastener is porous and a layer of oil is applied. The oil seeps into the material adding that extra corrosion resistance to rust. This process creates a black oxide bath that complies with MIL-DTL-13924, AMS 2485, ASTM D769 and ISO 11408 standards.

Cold Coating

The cold process applies a compound (copper selenium) onto the fasteners at room temperature. This process is more convenient for working in house as it does not require many chemicals at heated temperatures to apply. Once applied it is considered weaker than the other forms of oxidization until a layer of oil or wax is applied to the surface.

Mid-Temperature Bath

Like the hot bath treatment method but does not produce the same toxic fumes of the hot bath and the surface is converted to magnetite at a much lower temperature. This method can also meet the same military standards that the hot bath version produces.

Benefits Of Black Oxide Fastenersblack stainless steel socket set screws

  • Does not significantly change the dimensions of the fasteners as hot dip galvanizing does.
  • A cheaper alternative to other methods of corrosion resistance such as electroplating.
  • An appealing look when a bright shine is not desired.
  • The process can normally be done in large quantities which makes it faster and cheaper for smaller sizes.
  • Reduces the risk of galling by adding an oil finish
  • Decorative finish
  • Adds a layer of mild corrosion and abrasion resistance
  • Paint sticks well to the black coating if painting is required



Will Black Oxide Bolts Rust

Black Oxide adds a mild layer of corrosion and abrasion resistance to fasteners. Like any material, black oxide treated fasteners can rust in the right environments. It will depend on if the fastener is damaged or marred, the type of metal with the black oxide treatment and environmental conditions.

Disadvantages Of Black Oxide

Black oxide is not nearly as corrosion resistant as some of the other options available to improve corrosion resistance.

The black oxide finish can be easily rubbed off. To prevent this, put some painters tape over the tip of your bit to create a tighter fit and prevent scratching in the event of a slip out of the drive.

The Black residue from the fasteners may come off of them so for certain applications it is recommended that they are wiped down before use. This extra step can be labor-some if many fasteners are needed.

Black oxide fasteners are largely used in the automotive industry due to their sleek black look. This look can deteriorate very quickly though in hot environments. Often, after a black oxide coat is applied to a fastener, they are placed in an oil bath for an extra layer of protection. The oil residue that stays on the fasteners will begin to turn brown when in high heat environments. So many users find they bolts look like they rust prematurely. It is not recommended to place black oxide bolts on or near engines.

SHOP BLACK OXIDE FASTENERS

 

Custom Coating For Fasteners

black stainless nylon insert lock nuts

Our company offers custom black oxide orders VIA phone orders. Can’t Find what you need in black oxide? Give us a call at 866-573-445 for pricing and availability!

Custom Fasteners and Hardware

 

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5 Stainless Steel Facts You Need To Know Before Buying Fasteners

5 Stainless Steel Facts About Fasteners You Should Know

Stainless steel fastener

Stainless steel is a highly used metal and prized for its corrosion resistance. Did you know that stainless steel actually can corrode? It’s not even that hard to make it happen. Before you buy your fasteners here are five stainless steel facts you need to know before buying fasteners.

1. Stainless Steel Is A Soft Metal (Sort Of)

Stainless steel is considered a soft metal meaning it is not great for many high load applications that require intense strength. However, certain grades are hardened to create a stronger version. It may effect the corrosion resistance of the fastener however. A classic example of this is Grade 410 Stainless Steel.

2. Stainless Steel Can Still Corrode

Stainless steel is prized for its corrosion resistance. Beyond that many don’t know anything about it. Stainless steel comes in many different grades, 304, 305 and 316 are just a few examples and each come with their own benefits. If you are within 20 miles of the beach for example, you need to make sure you use 316 stainless steel.

3. Stainless Steel Is Not Non-Magnetic

It is important to know that stainless steel is not fully non-magnetic. In situations where the non-magnetic quality of a material is critical, stainless steel is not a recommended choice.

4. Stainless Steel Has An Invisible Self Repairing Outer Layer

Stainless metals form an invisible oxide coating that protects it from external factors. This is the main reason stainless steel is so resistant to corrosion. As long as the material is in an oxygen rich environment, even if the metal is damaged removing the oxide layer, it will reform and protect the metal again.

5. Stainless Steel Reacts Negatively With Aluminum

Stainless Steel and Aluminum are two separate kinds of metal. One is positively charged (anode) and one is negatively charged (cathode). As these metals are connected and an electrolyte is introduced, such as saltwater, a transfer of electrons occurs which will ruin the integrity of the materials resulting in galvanic corrosion. To avoid these situations either use some sort of in-between like a rubber material or simply do not use them together (recommended).

Working With Stainless Steel

Ultimately stainless steel can be a bit more complicated than you thought. Stainless steel fasteners are still an excellent choice for many situations. Just take these 5 things into consideration when buying your fasteners to help you choose the appropriate material and grade.



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What Screws Should You Use For Building A Deck?


Building A Deck This Summer?

Deck Screws For Building a Deck

Having a deck in your home is a luxury many people enjoy having. Being able to sit outside and enjoy the weather or view with family and friends is an excellent way to spend nice days, especially with summer right around the corner.

If you decide to take the journey of building a deck yourself, you are going to have many questions along the way. One of the most essential points to consider is “Which screws should I use for this deck?”. We’ve heard this question before, and there are quite a few things to take into consideration.

1. What Material Should I Use?

Of all the available materials to use for your deck, the most common is stainless steel. Stainless steel deck screws offer an excellent solution due to their increased corrosion resistance. However, stainless steel can still corrode in certain situations so make sure you have the correct grade for your environment.



2. Do You Want To See The Screw Heads?

One of the biggest concerns when making your deck is choosing the correct screw head. Deck screws are usually only found in flat head varieties so they can sit flush with the wood once installed. The question remains, do you want to see the head?

If your answer is yes, then a standard stainless steel flat head deck screw will suffice. If your answer is no, then you have a few options for hiding the screw heads.

  • Painted Head Deck Screws – These stainless steel screws are stainless steel with painted heads to match common wood colors. They are the easiest way to hide a deck screw because they are camouflaged in plain sight. Just install them as you would any other deck screw.
  • Hardwood Plug Kits – These kits come with little wood corks that you can use to cover the screws. They require more work to install properly but usually leave a great result. First a countersunk hole must be made to sink the screws lower into the wood. Then an adhesive is applied to the plug and placed in the hole over the screw head. One downfall to this method is that removing them is difficult. You can also get a drill bit that can cut these plugs for you instead of buying a kit: Hardwood Plug Cutter Bit.
  • Ipe Clips – A third and quickly becoming a very popular option are Ipe Clips. Ipe Clips are installed between the boards of a deck hiding the screws entirely. Mostly used with Ipe wood, these clips can also be used with regular wood to help create an evenly spaced deck.

What Drive Style Should I Use?

Usually, there are three types of drive to consider here. Phillips, Square or Star drive. Although all three are decent choices, we recommend using the star drive for installations. The star drive has the least chance of slippage and cam out during installation making it the ideal choice when working with finished products where slipping out of the drive could damage the surface you are working on. In fact, on many decks built today you are more likely to see star drive screws being used.

Building a deck can be a daunting task but with the proper screws you are now one step closer to enjoying your yard and the weather this year.



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