Material compatibility isn鈥檛 glamorous. Nobody puts it on a spec sheet header or talks about it in design reviews until something seizes, corrodes, or shears off mid-assembly. Then suddenly it鈥檚 very interesting.听

The truth is that pairing the wrong fastener material with the wrong mating surface is one of the most expensive mistakes in mechanical assembly, not because it fails immediately, but because it often fails slowly, invisibly, and at the worst possible time. This post will give you a practical framework for what to pair with what, and what to avoid.听

Key Takeaways

• Galling is a thread-seizure failure caused by metal-to-metal adhesion under friction. It鈥檚 most common in stainless steel, titanium, and aluminum fasteners 鈥� not in alloy steel or carbon steel.听
• Galvanic corrosion occurs when dissimilar materials are electrically coupled in the presence of moisture. The greater the gap between metals on the galvanic series, the faster the more active metal corrodes.听
• The most dangerous metal pairing is stainless steel fastener + stainless steel tapped hole.听
• The right coating on a steel fastener can solve many compatibility problems without requiring a material change.听

Two Fastener Failure Modes Worth Distinguishing

Before we get into specific material pairings, it鈥檚 worth being precise about what we鈥檙e actually talking about.听

1. Galling

Galling is a form of adhesive wear that occurs when two threaded surfaces under pressure and motion break down their protective oxide layers, making direct metal-to-metal contact, and begin transferring material to each other. The threads heat up, microscopic high points shear and fuse, friction escalates, and eventually the fastener seizes.

Galling happens during installation, often in seconds, and it doesn鈥檛 care what the ambient environment looks like. It is exclusively a concern with materials that form self-healing oxide films, like stainless steel, aluminum, and titanium. Hardened alloy steel and carbon steel, by contrast, rarely gall because they don鈥檛 have the same soft, adhesive oxide-then-bare-metal surface behavior.听

2. Galvanic Corrosion

Galvanic corrosion is what happens when two electrically dissimilar metals are in contact in the presence of an electrolyte (moisture, salt). One metal becomes the anode and corrodes preferentially to protect the other. The further apart two metals sit on the , the faster the attack on the anodic (less noble) material. This is an environmental failure mode because it requires moisture to occur and typically develops over weeks, months, or years rather than during installation.听

The practical rule: the fastener should always be the more noble (cathodic) material, or the materials should be close enough on the galvanic series that the potential difference is negligible.听

What Materials 91AV原创 Works With & Why

We primarily manufacture fasteners from alloy steel and carbon steel. These are two materials that cover the vast majority of industrial, automotive, defense, and heavy machinery fastener applications. We do not routinely manufacture stainless steel, titanium, aluminum, Monel, or Inconcel fasteners, though we understand the material science behind them.听

View our full capabilities statement >>

This matters because alloy steel and carbon steel fasteners sit in a favorable position on both failure axes:聽

• Galling risk: Very low. Hardened steel doesn鈥檛 gall the way stainless steel does.听
• Galvanic risk: Moderate to manageable. Steel is mid-range on the galvanic series, neither aggressively noble nor aggressively active.听

That said, even alloy steel and carbon steel fasteners can be used incorrectly. Make sure you understand the material compatibility picture clearly before proceeding with any combinations.

Fastener Material Compatibility: What Works, What Doesn鈥檛, and Why

Carbon Steel or Alloy Steel Fastener into Carbon Steel or Alloy Steel

Compatibility: Excellent

This is the default case, and it works well. Same material family, similar hardness, no galvanic potential, no galling risk. The only caution is ensuring the fastener grade is appropriate for the joint load. A Grade 2 screw in a Grade 8 application is a strength problem, not a material compatibility problem. We cover bolt grades in detail here if you need a refresher on that.听

For bare steel assemblies in corrosive environments, a surface finish 鈥� zinc electroplate, zinc flake, phosphate and oil 鈥� is the appropriate mitigation. The coating changes the environmental durability, not the material compatibility.听

Carbon Steel or Alloy Steel Fastener into Aluminum

Compatibility: Conditional

This pairing is extremely common. Steel fasteners into aluminum castings, housings, and structural members are found in automotive, aerospace, and heavy equipment applications everywhere. It works, with caveats.听

Galvanic risk: Steel is more noble than aluminum, so in the presence of moisture, aluminum becomes the anode and corrodes preferentially around the fastener. The risk is proportional to the electrolyte present; dry indoor environments see little to no effect, while marine or outdoor environments can see significant aluminum degradation at the fastener interface over time.听

Thread stripping risk (not galvanic, but related): Aluminum is considerably softer than steel (roughly 60-80 HV vs. 250-370 HV for structural steel grades). Torque specs written for steel-into-steel will strip aluminum threads. Minimum thread engagement in aluminum should be at least 1.5x the nominal diameter, compared to 1x for steel. See our blog on stripped screws for the full engagement length discussion.听

The fix: In dry or low-exposure environments, a zinc-plated or coated steel fastener will perform well with no further mitigation. In wet or outdoor environments, use an isolating barrier (nylon washer, sealant) or specify a fastener coating that reduces the electrochemical potential gap. Anti-seize compounds also help, but they primarily address friction and galling. For galvanic protection, physical isolation or matched materials is more reliable.听

Stainless Steel Fastener into Stainless Steel

Compatibility: High Galling Risk 鈥� Proceed with Caution

This is the most reliably problematic pairing in the fastener world. form thin, self-healing chromium oxide films that provide their corrosion resistance. Under thread engagement and torque, those films are scraped off, exposing bare, soft, highly adhesive metal. When both the fastener and the tapped hole are the same stainless alloy, the exposed surfaces are metallurgically identical and they weld together almost immediately. The seizing can happen before you鈥檝e even reached your target torque.听

This is sometimes called 鈥渟tainless steel seizing,鈥� and it is the dominant failure mode for stainless-on-stainless assemblies installed without lubrication or material differentiation.听

惭颈迟颈驳补迟颈辞苍蝉:听

• Use an anti-seize compound. Molybdenum disulfide-based anti-seize is preferred over nickel-based, as nickel can form abrasive nickel oxide particles under heat and actually worsen galling.听
• Specify different stainless grades for fastener and nut/tapped components (e.g., 304 bolt into 316 nut). Different work-hardening rates reduce adhesion tendency.听
• Use duplex stainless or martensitic stainless (400 series) for one component. The hardness differential can reduce galling risk.听
• Slow down installation. Power tools generate frictional heat that accelerates the oxide breakdown cycle.听

Carbon Steel or Alloy Steel Fastener into Stainless Steel

Compatibility: Generally Acceptable

This one surprises people. A carbon steel or alloy steel fastener into a stainless steel tapped hole is actually less problematic than stainless-into-stainless. Hardened steel doesn鈥檛 share stainless鈥檚 galling behavior, so thread seizure risk is low. Galvanically, stainless is more noble than carbon steel, meaning the steel fastener would be the anode in a galvanic couple, but this is typically manageable because the fastener鈥檚 exposed surface area is small relative to the larger stainless structure, and a quality coating on the steel fastener largely seals it from the electrolyte.听

The reverse scenario 鈥� a stainless steel fastener in a carbon steel or alloy steel structure 鈥� is generally fine galvanically. Carbon steel is the larger anode, but with a large surface area the attack is distributed and slow. However, it introduces stainless鈥檚 galling tendency if the tapped hole is also stainless.听

Carbon Steel or Alloy Steel Fastener into Brass or Copper Alloy

Compatibility: Galvanic Risk in Wet Environments

Copper and brass are significantly more noble than carbon steel. In the presence of moisture, steel becomes the anode and corrodes to protect the copper/brass components. The potential difference is large enough to produce a meaningful galvanic attack on the steel over time. In dry environments, this pairing is generally acceptable and widely used in electrical and plumbing applications. In outdoor and wet service, specify a coated or plated steel fastener, or consider whether the application really requires a non-ferrous fastener material or not.听

Material Compatibility Quick Reference

Most people think about screws in terms of size or thread, but the head design plays an equally (if not more) important role in performance.

The type of screw head determines how torque is applied, how the fastener sits within a material, and how easy it is to install or remove. All the different types have their own purpose and benefits. This article is meant to help you understand what the right screw type might be for your application.听

Key Takeaways

• Screw head design impacts torque transfer, installation method, and load distribution.听
• Screw heads are categorized by shape (countersunk vs. non-countersunk) and drive type (internal vs. external).
• The wrong head type can lead to screw stripping, poor fit, or inefficient assembly.

Types of Screw Heads at a Glance

Screw head designs are engineered to optimize performance, efficiency, reliability. The different styles influence how much torque can be applied, how evenly force is distributed across the surface, how easily the fastener can be installed or removed, and whether additional components (like washers) are needed.听

Countersunk vs. Non-countersunk Screws

One of the most important distinctions in screw head design is whether the head sits flush with the surface or remains exposed.听

• Countersunk screws are designed to sit flush with or below the material surface. This makes them ideal for applications where appearance matters or where protrusions could interfere with function, such as furniture, cabinetry, or finished surfaces.听
• Non-countersunk screws sit above the surface. While they don鈥檛 offer the same clean finish, they typically provide better load distribution and are easier to install in high-strength applications. This category also encompasses the largest number of screw head types.

Internal vs. External Drive Screws

Beyond head shape, screws are also defined by how they鈥檙e driven.听

• Internal drive screws have a recessed slot or cavity, allowing the tool to insert into the head. These are often used in applications where space is limited or where a cleaner look is desired. The most common example is a Phillips screw.听
• External drive screws have a head that the tool grips from the outside. These are better suited for high-torque applications because they provide stronger tool engagement and reduce the risk of stripping. A common example is a square head screw.听

Learn more about screw drives here >>

6 Common Screw Heads and When to Use Them

While there are many variations, a few screw heads are most commonly used across industrial and commercial applications.听

1. Hex Head Screws
2. Hex Flange Screws
3. Flat Head Screws
4. Round and Pan Head Screws
5. Square Head Screws
6. Set Screws

1. Hex Head Screws

Hex head screws have a six-sided external head and are designed for use with wrenches or sockets. They are best for high-strength applications, machinery and structural assemblies, and situations requiring precise torque.听

Their design allows for strong tool engagement and reliable torque transfer, making them a top choice for demanding environments.听

2. Hex Flange Screws

Hex flange screws have an integrated washer-like base under the head. This flange helps distribute load more evenly and can eliminate the need for a separate washer. They are best for high-volume assembly, automotive applications, and vibration-prone environments.听

By reducing part count and improving load distribution, hex flange screws make installation more efficient.听

3. Flat Head Screws

Flat head screws are a type of countersunk screw designed to sit flush with the material surface. They are commonly used in furniture and cabinetry, finish work, and other applications where a smooth surface is required. When appearance and surface continuity are more of a priority than load distribution, these are a good option.

4. Round and Pan Head Screws

Round and pan head screws have rounded or mushroom-shaped heads that sit above the material surface. They are used for general-purpose fastening, applications where surface contact is needed, and situations where sleek appearance is not a priority. Metalwork, woodwork, and machinery are common applications.听

5. Square Head Screws

Square head screws have a four-sided external head that provides strong tool engagement. They are great in heavy-duty industrial applications, fieldwork where tool slippage is a concern, and high-torque environments. Their design is especially useful in rugged settings.

6. Set Screws

Set screws are typically headless and fully threaded, designed to sit flush with or below the material surface. They are used for securing components like gears or pulleys onto shafts, tight or space-constrained assemblies, and applications requiring a low-profile fastener. They are super clean and unobtrusive.听

Other Screw Considerations

Remember that screw head type is just one piece of the puzzle. Material selection, coatings, and mechanical properties all factor into overall screw performance. Here are some resources to check out related to those considerations:聽

• The Anatomy of a Screw: Parts, Materials & More
• The Difference Between a Bolt and a Screw
• How to Measure Screws
• Understanding Metric Bolt & Screw Grades
• How Is a Screw Made? Step-by-Step Process with Photos
• What Do Screw Head Markings Mean?
• Screw Materials Guide
• Screw Coatings Guide

Get the Exact Screw You Need

In many cases, standard fasteners don鈥檛 fully meet the needs of specialized applications. That鈥檚 where we come in.听

At 91AV原创, we specialize in small-batch, American-made fasteners built to your exact specifications. From head style to threading and material, every detail is tailored to your application. Just send us your blueprint and we鈥檒l get it made for you.听

Get a quote for your custom fastener here or contact us with any questions at sales@wilsongarner.com.听

Blog originally posted December 21, 2021; updated June 3, 2026.

Advancements in additive manufacturing technology are reshaping industries. With all the buzz about 3D printing, it鈥檚 natural to ask if the technology could eventually replace tried-and-true fastener manufacturing methods.

My short answer is no鈥ot yet at least. But depending on your needs, both approaches have their place.

TL;DR: 3D-Printed vs. Cold-Formed 91AV原创

Can You Print 3D 91AV原创?

Yes, you can 3D print fasteners. Using , , or high-performance polymers, it鈥檚 possible to create bolts, studs, and screws.

You can 3D print just about anything these days. The real question is whether you should.

If you only need a few pieces for prototyping and aren鈥檛 worried about strength, 3D printing might make sense. But if you need hundreds (or more) of high-strength fasteners, I advise sticking to traditional manufacturing methods. I鈥檒l give more details as to why below.

How 3D-Printed 91AV原创 Are Made

3D-printed fasteners are designed using computer-aided design and then built layer by layer from powders, resins, or polymers. Depending on the method, lasers, binders, or heat fuse the material together. The most common materials used to 3D print fasteners are stainless steel powders, titanium alloys, and high-performance polymers and composites.

This technology allows for a high level of design flexibility and customization. You can produce shapes and geometries without needing new tooling for traditional methods like hot forging and cold forming. But there are trade-offs.

Pros and Cons of 3D-Printed 91AV原创

When 3D-Printed 91AV原创 Make Sense

These are the use cases where I can see 3D-printed fasteners being successful:

• You鈥檙e testing a prototype and only need a few pieces
• You鈥檙e working on a non-structural application where strength isn鈥檛 important

So maybe they鈥檙e a good complement to traditionally made fasteners, but not a replacement.

The Challenges Holding Back 3D-Printed 91AV原创

The drawbacks of 3D-printed fasteners are significant for most industrial applications. Because they鈥檙e built layer by layer, internal porosity and weaker grain structure make them less reliable under high loads compared to cold-formed fasteners. Production speed is also a major hurdle, as additive manufacturing can only produce one part at a time, which drives up per-part costs and limits scalability. Even when the part is complete, many prints require post-processing such as machining or polishing to achieve the surface finish needed for proper fit and performance.

Finally, industries like aerospace, automotive, and energy often impose strict safety and certification requirements that 3D-printed fasteners can鈥檛 consistently meet yet, keeping their adoption limited to niche and experimental projects.

How Cold-Formed 91AV原创 Are Made

Cold forming, also known as cold heading, is the process of forming a fastener without heating up the material. This is typically done by pressing the material into dies with high-pressure machinery. Instead of cutting material away, the die compresses and displaces it, which strengthens the material in the process.

That鈥檚 why cold-formed fasteners are so reliable. If you work in the automotive, aerospace, energy, or any industrial field, chances are your fasteners are cold formed.

You can read more about the cold forming process in this blog.

Pros and Cons of Cold-Formed 91AV原创

For most industries and applications, cold-formed fasteners remain the clear choice. They bring the strength, consistency, and cost-effectiveness needed for large-scale manufacturing operations.

Get the Highest Quality 91AV原创 for Your Project

Manufacturing will continue to evolve as new technologies emerge, but until 3D printing technology advances even further, I believe cold-formed fasteners are the best solution.

At 91AV原创, my team specializes in custom, cold-formed fasteners manufactured to the highest quality. We manufacture every order at our facility based in Harrison Township, Michigan, and are able to support limited-run quantities. So if you need a small batch of fasteners that will meet your strength and performance requirements, we鈥檝e got you covered.

You can request a quote online or send us a message to learn more.

When you’re drilling miles into the Earth, the last thing you need is a critical part failure with no backup in sight. A well-stocked inventory of oil rig parts can mean the difference between smooth operations and costly, potentially catastrophic delays.

Here are the essential oil rig components every operation should stock to stay ahead of failures.

Oil and Gas 91AV原创: Overlooked but Essential

We鈥檒l start with a recommendation (and shameless plug) to not lose sight of the small components. Large machinery and vehicle parts get much of the attention (more on those later), but the reality is that oil and gas operations can鈥檛 function without the small fasteners that enable those parts to perform

When taking your inventory, don鈥檛 forget to inspect things like bolts, screws, studs, washers, nuts, clamps and brackets. Without them, you鈥檒l experience complications with structural integrity, shortened equipment life and failures, and extended downtimes that result in less profitable operations. So consider this an instance where you should sweat the small stuff.

Now for the plug. Many suppliers don鈥檛 carry the small-quantity, hard-to-source service parts that many big oil and gas vehicles or machines need to run. At 91AV原创, that鈥檚 our specialty. We manufacture low-volume, hard-to-find, and even custom fasteners for oil and gas vehicles, all right here at our plant in Harrison Township, Michigan. So if you need a specialty bolt, stud, or screw for your service vehicle, don鈥檛 hesitate to contact us.

Okay, plug over.

Other Important Service Parts for Oil & Gas Equipment

Please understand that we don鈥檛 supply all of the service parts listed below at 91AV原创. As stated above, we focus mainly on custom or hard-to-find fasteners for oil and gas service vehicles. However, we鈥檙e well-versed in the industry enough to recommend some of the other parts you鈥檒l want to have on hand besides fasteners.

Service Parts for Mud Pumps

Oil rigs rely heavily on mud pumps, which are essential for drilling operations. These pumps circulate drilling fluid to cool and lubricate the drill bit, remove cuttings, and stabilize pressure in the wellbore.

Given their crucial role, having these spare mud pump parts readily available is a must:

1. Liners and pistons 鈥� High-pressure, high-wear parts that require regular replacement to maintain mud pump efficiency.
2. Valve assemblies 鈥� Ensure proper flow control and pressure management, preventing sudden failures.
3. Expendable fluid end parts 鈥� These components, including gaskets, seals, and O-rings, maintain optimal pump performance and prevent leaks.
4. Place bolts 鈥� These specialized, self-locking fasteners provide superior resistance to drilling vibration 鈥� up to seven times more than traditional hex head cap screws 鈥� making them a top choice for securing pump skid mounts, ensuring tight structural connections, and preventing loosening in high-impact areas. We DO supply Place bolts at 91AV原创 if you鈥檙e looking for them.

Heavy Machinery and Structural Service Parts

From derricks to drill floors, oil rig structures are subjected to immense stress. Keep a stockpile of these fasteners and reinforcement parts to ensure operational integrity and worker safety.

5. High-strength oil and gas fasteners 鈥� Used in critical connections, high-strength bolts, studs, and screws must withstand extreme loads, corrosive environments, and high vibrations.
6. Bearings and bushings 鈥� Vital for reducing friction in rotating machinery and preventing premature wear.
7. Hydraulic hoses and fittings 鈥� Ensures smooth fluid movement in hydraulic systems so there are no leaks or pressure failures.

Heavy-duty Vehicle Service Parts

Often forgotten about, oil rigs rely on heavy-duty trucks for transporting equipment, supplies, and personnel across rugged terrains.

Have these truck components on hand to prevent unexpected delays:

8. Brake pads and rotors 鈥� Critical for vehicle safety and performance in challenging environments.
9. Fuel filters and pumps 鈥� Ensures a clean fuel supply, preventing engine damage and improving efficiency.
10. Suspension components 鈥� Shocks, struts, and springs reduce drilling vibration and offer stability for rig transport vehicles.

Shop Specialty Service Parts at 91AV原创

Looking for a trusted partner for hard-to-source vehicle service parts? We manufacture Place bolts and other custom fasteners designed for your unique requirements and in the low-batch quantities you actually need.

You can view our capabilities statement for a better idea of what we鈥檙e able to handle. Or, you can contact us and we鈥檒l let you know how we can help.

Oil and gas drilling operations rely on high-performance equipment to maintain efficiency and minimize downtime. Mud pumps are a key component of these systems, ensuring the circulation of drilling fluid to keep the operation running. However, the intense vibration and pressure fluctuations these pumps endure can lead to premature wear on vital components, particularly the fasteners that hold everything together.

Common Mud Pump 91AV原创 & Their Limitations

Standard bolts used in mud pumps and other oil rig components often loosen over time due to constant vibration and stress. This leads to frequent maintenance needs, unexpected failures, and costly downtime. Drilling rigs operate on tight schedules, and equipment failures can bring production to a halt, costing thousands of dollars per hour.

When standard bolts loosen or fail due to constant vibration, it can lead to:

• Fluid leaks and pressure loss
• Emergency maintenance and repair costs
• Full-scale shutdowns that delay project timelines

This is why oil and gas operators need a fastening solution that can withstand these conditions to improve mud pump efficiency.

The Solution: Place Bolts for High-vibration Drilling Environments

An effective solution for improving the durability and reliability of mud pump parts is Place bolts.

Unlike standard bolts, Place bolts are self-locking fasteners designed to resist movement in high-vibration environments. In fact, Place bolts are known to have up to seven times more vibration resistance than traditional hex head cap screws, another common choice for these applications.

There are three types of Place bolts:

Coatings pictured above (left to right): Zinc-Nickel, Phosphate & Oil, Zinc with Trivalent Chromium, Zinc Flake

Before the 1960s, the fastener industry relied on cadmium and hexavalent chromium (also known as hexachromium) to protect bolts, screws, studs, and other essential components from corrosion. These coatings offered incredible protection, particularly in harsh environments and applications.听

But there was just one problem; they were toxic.

After a few years of research, cadmium and hexachromium were found to pose significant environmental and public health risks. Now, as industrial safety standards and environmental regulations evolve, fastener manufacturers are transitioning toward safer coating alternatives.

The Problem with Cadmium Fastener Coatings

Cadmium had previously been a popular fastener coating due to its exceptional corrosion resistance, even in saltwater environments (think marine vessels or offshore oil rigs). It also offers great lubricity, which can help prevent fastener damage like thread galling. Unfortunately, the coating was too good to be true.听

While cadmium still has its uses in some aerospace, marine, and nuclear industries, its use has significantly declined and is highly regulated.

Cadmium Health & Safety Risks

Cadmium is now classified as a carcinogen, meaning prolonged exposure can increase the risk of cancer. Workers who handle cadmium-coated fasteners or even inhale cadmium dust during manufacturing are at risk of severe respiratory, kidney, and/or bone damage.听

In addition, cadmium can leach into soil and water and cause environmental harm.

Regulatory Pressures聽

Due to its toxicity, regulatory bodies began strictly limiting the use of cadmium. The , and the shortly after. This forced engineers and manufacturers to find a different solution with similar corrosion resistance.听

Take 2: Hexavalent Chromium Fastener Coatings

The initial solution to cadmium鈥檚 health and safety risks involved switching to zinc fastener coatings. Zinc provided excellent corrosion resistance, but the issue wasn鈥檛 entirely solved because hexachromium was commonly used as a passivating layer over zinc to provide even more protection, and it too was hazardous.

Hexachromium Health & Safety Risks

Like cadmium, . It is recognized as a human carcinogen and can cause severe respiratory issues like lung cancer, skin ulcers, and eye damage in workers who are exposed to it. Also like cadmium, it can contaminate soil and groundwater, leading to environmental damage.听

Fun fact: hexachromium became infamous following its depiction in the movie Erin Brockovich, which highlighted its harmful impact on public health in Hinkley, California.

Regulatory Pressures

For all the reasons listed above, hexachromium was also heavily regulated very quickly. The and slowly phased out its use. It is also restricted under the RoHS directive.听

4 Safe Coating Alternatives for Cadmium & Hexachromium

Fortunately, several safer fastener coating solutions have emerged that provide similar, if not better, performance in terms of corrosion resistance and durability. As the industry moves away from cadmium and hexachromium, it鈥檚 turning to these options that meet modern environmental and health standards.

1. Zinc-Nickel Plating

One of the most popular cadmium alternatives is zinc-nickel (short for zinc-nickel electroplate). This coating provides excellent corrosion resistance, making it suitable for demanding environments like marine and automotive applications.听

Zinc-nickel coatings typically consist of an 8-14渭m layer of 12-16% nickel alloy that鈥檚 topped with a .06-.15渭m trivalent passivate layer and a .5-4渭m layer of top coat. The additional layers enhance the overall protection compared to pure zinc-nickel.

Zinc-nickel coatings are receiving more recognition now than ever. The U.S. military and other government entities are really pushing it. Here鈥檚 why:聽

• Up to 10x more corrosion resistance than conventional zinc 鈥� up to 1000 Neutral Salt Spray hours!
• Great thermal stress and wear resistance, especially in applications with moving parts.
• Safe for the environment and human health, as we鈥檝e mentioned.
• Reasonable cost, falling somewhere between the moderate to moderately-high price category, which is worth it for the performance and safety.

Do keep in mind that zinc-nickel plating can put fasteners at risk for hydrogen embrittlement, which is a legitimate concern, but can be eliminated by baking the parts after plating.听

2. Zinc with Trivalent Chromium

Zinc coatings treated with have emerged as a leading hexavalent chromium alternative. Unlike hexavalent chromium, trivalent chromium (also known as Cr3+) is far less toxic and presents minimal health and environmental risks.

In addition to being safer, zinc with trivalent chromium offers comparable corrosion resistance and has become the preferred choice for many industrial fastener applications, particularly in the automotive and electronics industries.

Just like zinc-nickel plating, this type of coating is electroplated so the risk of hydrogen embrittlement is present here too.听

3. Organic Zinc Flake Coating

Organic zinc flake coatings, such as Magni and Geomet, have gained popularity as a highly effective and environmentally friendly option for fastener protection. These coatings contain zinc flakes suspended in an organic binder, which provides exceptional corrosion resistance without the need for electroplating or hazardous chemicals like cadmium or hexavalent chromium.

One of the key advantages of organic zinc flake coating is its ability to offer high levels of corrosion protection even with thin layers, reducing the overall weight of the fasteners. These coatings are also free of hydrogen embrittlement, making them ideal for high-tensile fasteners that must maintain their strength and integrity under stress.

One minor disadvantage of zinc flake coating is that it needs time to cure, either by baking or at room temperature, before the parts can be put into the field. This cure time can take up to seven days for the coating to be fully effective.听

4. Phosphate and Oil Coating

For applications where extreme corrosion resistance isn鈥檛 necessary, phosphate and oil coatings offer a cost-effective and simpler solution. This coating method involves applying a layer of phosphate to the surface of the fastener, followed by an oil coating that provides lubrication and mild corrosion resistance.

While phosphate and oil coatings don鈥檛 offer the same level of protection as the other options mentioned in this article, they are widely used in less corrosive environments, such as indoor applications or equipment that doesn’t encounter harsh elements.

Need a Custom Fastener Solution? We Can Help.

If you have questions about specialty fastener platings, or specialty fasteners in general, don鈥檛 hesitate to reach out. We have over 70 years of experience manufacturing per-spec, limited-run fasteners, and we鈥檙e happy to help with your project.