Comparing Alloy Steel and Stainless Steel
All the key differences between these two manufacturing metals
Alloy steel and stainless steel are not the same thing, but stainless steel is a type of alloy steel. “Alloy steel” is a term that covers any steel that has at least one more element added to it to give it extra perks, like more strength or durability and change its overall properties. We’ve written up a whole guide on alloy steel if you’d like to know more about it. Basic steel, without any alloying elements, usually consists of iron and some carbon. Aside from these, you might find some chromium, which is added to make it corrosion-resistant, but stainless steel has at least 10.5% chromium.
Stainless steel is extremely popular among Xometry customers, but there are many different grades of it, all with different strengths (and maybe also some weaknesses). Keep reading for more on the different types of alloys and stainless steel and how stainless steel fares compared to the other types of alloys.
Types of Alloy Steel
Alloy steels are available in various broad categories. We break these down in the table below.
| Type | Description |
|---|---|
Type Low-alloy | Description Only a small amount of additional elements are added to this type of steel to enhance some of its properties, like strength, hardness, or toughness. These could be chromium, nickel, and/or manganese. It’s used when the strength-to-weight ratio is important, like for construction and mining equipment. |
Type High-alloy | Description These have larger amounts of alloying elements to greatly improve the steel’s performance. These include chromium, vanadium, and nickel, which are particularly helpful in ramping up the steel’s hardness and strength. |
Type Tool | Description Tool steels are used for making tools, and will usually have many other elements added to make them extra hard and wear-resistant, even at high temperatures. |
Type Maraging | Description These types of steel are impressively strong and tough. They’re often used in circumstances that require serious strength like aerospace and the military. |
Types of Alloy Steel
The below image shows some pipes made from alloy steel:
| Type | Description |
|---|---|
Type Austenitic | Description This category usually contains a minimum of 16% chromium and 6% nickel (the basic grade 304 is 18% chromium and 8% nickel). Because this type of steel won’t easily corrode, rust, or stain when in contact with water, many Xometry customers use it in chemical plants and food processing equipment. |
Type Ferritic | Description Ferritic stainless steel usually contains between 11% and 27% chromium, and little to no nickel. They’re not the best when it comes to corrosion resistance, especially when compared to austenitic stainless steels, but they exhibit better mechanical properties at elevated temperatures. |
Type Martensitic | Description This type of stainless steel typically contains between 14% and 18% chromium and between 0.2% and 1.2% carbon, which is considered moderate. Like carbon steel, it can be hardened and tempered. |
Type Duplex | Description These have 18–28% chromium, and 3.5–5.5% nickel. They’re more corrosion-resistant than austenitic grades, and less likely to become brittle than martensitic grades. |
Types of Stainless Steel
Here’s what duplex stainless steel looks like:
| Alloy Steel | Alloy Steel | Stainless Steel | Stainless Steel |
|---|---|---|---|
Alloy Steel Physical Properties | Alloy Steel Chemical Properties | Stainless Steel Physical Properties | Stainless Steel Chemical Properties |
Alloy Steel High strength-to-weight ratio | Alloy Steel High levels of chromium, molybdenum, and/or other alloying elements | Stainless Steel Corrosion- and stain-resistant | Stainless Steel Composed of iron, chromium, and carbon, with some varieties including silicon, manganese, and nickel, among others |
Alloy Steel Good corrosion resistance | Alloy Steel Higher alloying element levels can allow the metals to be heat treated to many different hardnesses | Stainless Steel Very durable | Stainless Steel Resistant to bases, acids, and organic compounds |
Alloy Steel Strong and durable | Stainless Steel Electrically conductive | Stainless Steel - | |
Alloy Steel Wear-resistant | Alloy Steel Stainless steel is not magnetic | Stainless Steel Easy to clean/ maintain | Stainless Steel - |
Alloy Steel Stays hard at high temperatures | Alloy Steel It’s highly resistant to heat | Stainless Steel Not magnetic | Stainless Steel - |
Alloy Steel - | Alloy Steel - | Stainless Steel Highly heat-resistant | Stainless Steel - |
Alloy Steel vs. Stainless Steel Physical and Chemical Properties
Now let’s have a look at how each steel type compares in relation to thermal conductivity, tensile strength, and applications:
| Property | Alloy Steel | Stainless Steel |
|---|---|---|
Property Thermal Conductivity | Alloy Steel Around 45 W/(mK) | Stainless Steel 15 W/(mK) |
Property Tensile Strength | Alloy Steel Up to 960 Mpa (more durable than stainless steel) | Stainless Steel Around 621 Mpa |
Property Application | Alloy Steel Mainly construction and manufacturing | Stainless Steel Food and beverage, medical |
Alloy Steel vs. Stainless Steel Thermal Conductivity, Tensile Strength, and Applications
How Xometry Can Help
Xometry provides a wide range of manufacturing capabilities and other value-added services for all your prototyping and production needs. If you need any information or services for alloy steel, stainless steel, or any other metal, feel free to reach out to one of our representatives, or get a quick no-obligation quote.
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