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Comparing Alloy Steel and Stainless Steel

picture of Kat de Naoum
Written by
Megan Conniff - Xometry Contributor
Updated by
 2 min read
Published December 23, 2022
Updated September 13, 2024

All the key differences between these two manufacturing metals

Stainless steel metal profiles and tubes. Image Credit: Shutterstock.com/Maxx-Studio

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.

TypeDescription
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:

Alloy pipes
Alloy pipes

Types of Stainless Steel

Stainless steel is actually available in thousands of different grades, but we can pretty much group them into four categories:

TypeDescription
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:

Duplex steel
Duplex steel

Alloy vs. Stainless Steel

Below you’ll find a side-by-side comparison of alloy and stainless steel’s physical and chemical properties.

Alloy SteelAlloy SteelStainless SteelStainless 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:

PropertyAlloy SteelStainless 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.

Disclaimer

The content appearing on this webpage is for informational purposes only. Xometry makes no representation or warranty of any kind, be it expressed or implied, as to the accuracy, completeness, or validity of the information. Any performance parameters, geometric tolerances, specific design features, quality and types of materials, or processes should not be inferred to represent what will be delivered by third-party suppliers or manufacturers through Xometry’s network. Buyers seeking quotes for parts are responsible for defining the specific requirements for those parts. Please refer to our terms and conditions for more information.

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Kat de Naoum
Kat de Naoum is a writer, author, editor, and content specialist from the UK with 20+ years of writing experience. Kat has experience writing for a variety of manufacturing and technical organizations and loves the world of engineering. Alongside writing, Kat was a paralegal for almost 10 years, seven of which were in ship finance. She has written for many publications, both print and online. Kat has a BA in English literature and philosophy, and an MA in creative writing from Kingston University.

Read more articles by Kat de Naoum

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