Steel is the material that modern manufacturing heavily relies on to make countless items across industries. Like its vast usability, several types of steel are available in the market with distinct alloying compositions and properties. Stainless steel is one of the favorable alloys due to corrosion resistance, thermal performance, strength, and aesthetic appeal, but it is costlier than others.
Often, manufacturers use surface-treated ordinary steels to achieve these qualities at a competitive rate. However, it is essential to understand the anodized steel vs stainless steel so you don’t select the wrong material for your project.
This article will present a comparative overview of stainless steel and anodized steel.
What is the Anodized Steel?
Anodized steel
Anodized metal or anodizing process is typically associated with aluminum and its alloys. A thin natural oxide layer is made on aluminum alloys with an electrochemical process, which provides better wear resistance and excellent corrosion protection. However, steel anodizing does not involve only an electrochemical process; instead, acidic baths of secondary metals (like zinc or aluminum) are used to create a hard coat anodizing layer. Sometimes, the plating metals are used as anode to create a plating surface.
“The steel anodization is not similar to the aluminum; either hot acidic baths or electrochemical deposition of secondary metal creates the hard-protective layer on steel surface: Like Blak oxide coating can provide the same level of protection as anodized aluminum.”
Anodized steel parts
Custom anodizing of steel with zinc or aluminum is typically suitable for low-carbon and medium-carbon alloy grades like SAE 1018, SAE 1020, SAE 1045, AISI 4130, and AISI 4140. It is better to process with CNC operations first and anodize the end parts later when it comes to machining.
What is Stainless Steel?
Stainless steel is an alloy of iron and chromium with other additional alloying elements in tiny amounts, molybdenum, nickel, carbon, and nitrogen. Often, it is known as a chromium alloy due to the high percentage of chromium in its composition.
The typical composition of stainless steel is as follows;
| Element | % |
| Iron (Fe) | Balance (majority) |
| Chromium (Cr) | 10.5–30% |
| Nickel (Ni) | 0–35% |
| Carbon (C) | 0–1.2% |
| Manganese (Mn) | 0–2% |
| Molybdenum (Mo) | 0–7% |
| Silicon (Si) | 0–1% |
| Nitrogen (N) | 0–0.25% |
Each of these individual alloying elements contributes to the final properties of stainless steel. Chromium content enhances corrosion resistance, hardness, and thermal strength. Nickel makes it ductile and carbon increases toughness. Consequently, manganese acts as a deoxidizer and improves tensile strength.
Stainless steel part
In a comparison of anodized steel vs stainless steel, stainless is resistant as anodized against corrosion and even there is no issue of coating wearing off. The next section involves a head-to-head comparison between these two types of engineering steels.
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Anodized Steel vs Stainless Steel: Physical & Mechanical Properties
Which material to choose for any manufacturing part or product heavily depends on whether the particular material has sufficient mechanical and physical characteristics required for intended applications. So, let’s look at the differences in physical & mechanical properties of anodized and stainless steel one by one;
Weight and Strength
Stainless steel is lighter than anodized mild or low-can steel, offering better mechanical strength and strength-to-weight ratio.
Corrosion Resistance
If we compare anodized steel vs stainless steel’s corrosion resistance Both anodized ordinary steel alloy and stainless alloy provide resistance against corrosion, even in harsh environmental conditions. However, stainless steel can maintain the resistance capability over time, whereas the anodized hard coat can be worn over longer spans.
Stainless steel corrosion
The steel parts treated with a custom anodizing finish are susceptible to galvanic corrosion when in contact with certain metals, whereas stainless steel forms a passive oxide layer of chromium on the surface that self-repairs in case of degradation.
Surface Hardness
Although anodizing steel provides higher surface hardness, whether it is higher than stainless or not depends on which type of alloy steel you have anodized. Additionally, the anodizing thickness also influences the surface hardness.
Aesthetic Quality
Anodized steel colors
One of the main advantages of anodization is that it allows dyeing with desired colors due to its porous nature, the pores absorb the dye and the subsequent sealing process makes the color stable and long-lasting. You can also apply secondary painting on steel parts if they are anodized with coating or other metals.
Thermal Conductivity
Stainless steel has higher thermal conductivity, approximately 15W/K/m. So, it can be used in heat transfer-related applications like cookware radiators, heat exchangers, etc.
Anodized Steel vs Stainless Steel: Uses and Application Scope
Instead of making parts and products from anodized steel sheets, manufacturers produce parts and anodize them with suitable materials. In performance-sensitive applications, stainless steel might be the more favorable choice.
Custom anodized steel part
Anodized steel parts are used in marine, medical equipment, and industrial components. The increased corrosion & wear protection and resistance against saltwater or mild chemicals make it perfect for these applications.
- Ship hulls and dock components
- Surgical tool handles
- Cookwares
- Mounting brackets for solar panels
- Conveyor rollers
- Industrial machinery hardware
On the other hand, stainless steel has more diverse applications, various grades are processed with CNC machining, metal forming, casting, and other techniques. Moreover, stainless steel machining is one of the common methods to produce designed stainless steel components.
Stainless steel applications
Stainless steel is popular for producing architectural items, automotive parts, food-processing systems, chemical processing components, and many more.
- Kitchen and cookware
- Exhaust manifolds for vehicles
- Surgical scalpels
- Storage tanks and pipes for the chemical industry
- Bathroom fixtures
- Fastening screws and bolts
- Handrails on stairs
- Heat exchangers
Anodized Steel vs Stainless Steel: Common Alloy Grades
First, there are no specific grades or alloy series of anodized steel. Different alloys with zinc or other metals are anodized ( low carbon, high carbon, tool steel grade). Basically, anodized steels are the same ordinary steel grades in which surfaces are treated with anodizing. So, the grade depends on the type of underlying steel part.
Steel grades like 1018,1045, 4140, D2, 430, and A36 can be anodized with suitable metal to achieve desired surface properties, both functional and aesthetic.
On the other hand, the common stainless steel machining grades are 303, 304, 316, 410, 416, 420, 430, 440C, 17-4PH, 15-5PH, etc.
Is Steel Anodizing Similar to Powder Coating?
No! They are completely different surface finishing techniques for steels. Powder coating uses a dry powder coat on steel surfaces. Cleared parts are dipped in an electrostatically charged powder bed, which causes the bonding of powder with steel surface molecules. After this, thermal curing stabilizes the bonded powder molecules on the surface, forming a protective coating of powder material.
Powder coated steel parts
Common powder materials for steel coating include Epoxy, Polyester, Acrylic, Nylon, Zinc, Silicone, Fluoropolymer, and Thermoplastic resins.
Consequently, the powder coat layer resists corrosion, wear, and impact. Additionally, powder with custom colors can be applied to achieve the desired aesthetic.
The table below outlines Anodizing vs Powder coating differences in brief;
| Aspect | Anodizing | Powder Coating |
| Process | Acidic bath coating or electroplating | Powder sprayed, then cured with heat |
| Durability | Highly wear and corrosion-resistant | Durable but can chip or scratch |
| Appearance | Matte or satin, metallic finish | Wide color options, non-metallic |
| Thickness | 1-5 microns | 40-100 microns |
| Cost | Higher due to complex process | More cost-effective |
| Conductivity | Maintains conductivity | Non-conductive |
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Anodize your Parts at ProleanTech for High-quality Finishing
Are you looking to anodize your metal parts like aluminum and steel? At ProleanTech, our anodizing service can cater to the finishing needs for performance and appearance. We can coat parts with thin and hard-coat anodizing, maintaining a roughness level as low as 3.2μm. Furthermore, you can choose anodized color options like Clear, black, grey, red, blue, and gold.
Our comprehensive manufacturing facilities can also machine all types of steel alloys, including stainless. This means you send us the design, and we will cover everything from machining to surface finishes.
Our experience of more than a decade in manufacturing and surface treatment can be useful in bringing your design into functional prototypes of end products.
Conclusion
Steel anodizing is not the same as aluminum anodizing; secondary metal baths are used in steel anodizing as the natural iron-oxide layer is not resistant to rust and wear. Although it improves surface hardness and corrosion resistance, the durability does not match that of stainless steel. The applications critical for high precision and durability still require stainless steel grades, whereas those applications where the tackling of corrosion and surface degradation are the main issues can replace ordinary steel parts with anodized ones.
FAQs
Can I anodize steel alloys?
Traditional anodizing, such as aluminum (developing its oxide layer on the surface), is not feasible with steel alloys. However, you can anodize with alternative techniques like an acidic bath or coating a superior metal oxide layer.
Which one is better in Anodized steel vs stainless steel?
Anodized steel and stainless steel serve different purposes and offer distinct benefits, so which one is better for your parts depends on specific requirements. Stainless steel is suitable for applications requiring excellent corrosion, scratches, and stain resistance over a long time, whereas anodized offers corrosion resistance but not strength, lightweight, and durability as stainless.
Are anodized steel parts as durable as stainless?
No! The protective coating of hard-anodizing tends to wear over time, leading to surface degradation.
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