Stainless steel is a powerhouse material that offers an impressive strength-to-weight ratio, corrosion resistance, and lasting durability. These qualities make it a go-to choice for a wide range of applications, from medical instruments to aeroplane components.
While stainless steel is incredibly versatile, it’s not a one-size-fits-all solution. Each type is designed with specific uses in mind, and choosing the right one can make a big difference in your project’s success.
Two popular types, austenitic and martensitic stainless steel, are often compared when it comes to strength and durability. But which one is actually stronger?
The MG Metals team have spent years working with every type of stainless steel, so we know the ins and outs of each. Below, we’ll break down the unique properties of austenitic and martensitic stainless steel to help you find the best fit for your needs.
What is Austenitic Stainless Steel?
Austenitic stainless steel is one of the most popular types around. Thanks to high levels of chromium (16-26%) and nickel (8-22%), it’s non-magnetic and highly resistant to rust and staining. This makes it ideal for everything from kitchenware to chemical processing equipment.
Example grades:
- 204
- 316
- 310
- 321
Strength and Properties
Austenitic stainless steels are generally more ductile than martensitic grades, meaning they can undergo significant deformation without breaking. This flexibility makes them ideal for applications requiring resilience and malleability. However, austenitic stainless steels are typically not as hard as martensitic stainless steels, which offer greater shear strength.
Its key properties include:
- High corrosion resistance
- Excellent ductility and formability
- Non-magnetic (in most cases)
- Moderate strength but high toughness
What is Martensitic Stainless Steel?
Martensitic stainless steel isn’t as common as austenitic, but it’s a go-to choice when high strength and hardness are essential. It has more carbon and lower levels of chromium (11-18%) and nickel (0-1%). This type of stainless steel is magnetic and can be heat-treated to adjust its hardness, making it perfect for applications where durability is the top priority.
Example grades:
- 410
- 420
- 440C
- 17-4PH
Strength and Properties
Martensitic stainless steels are naturally harder, stronger, and more brittle than austenitic steels, but this strength does come with a trade-off: martensitic steels aren’t as corrosion-resistant as austenitic types, so they can be more prone to rust in certain conditions. They’re also harder to form.
Because of this balance, they’re commonly used in products like cutlery, surgical instruments, and blades, where durability and sharpness are more important than resisting corrosion or flexibility.
Its key properties include:
- High strength and hardness
- Magnetic properties
- Lower corrosion resistance compared to austenitic grades
- Heat-treatable to enhance hardness
Which One is Stronger?
There isn’t a simple answer to this, because “strength” in metals can mean different things depending on the context. When discussing metal strength, we need to distinguish between two key properties:
- Tensile Strength: This is the maximum stress a material can handle while being stretched or pulled before it breaks.
- Hardness: This refers to a material’s ability to resist deformation, especially permanent indentation.
Martensitic stainless steel is typically harder and has higher tensile strength than austenitic stainless steel, particularly after heat treatment. However, this extra strength also makes it more brittle, so it’s not the best choice for situations that require a lot of flexibility.
Austenitic stainless steel, on the other hand, might not be as hard as martensitic steel, but it offers excellent ductility and toughness. This makes it a better option for applications where flexibility and impact resistance are important.
So, whether martensitic or austenitic stainless steel is the “stronger” choice really depends on the specific needs of the application.
Which Type of Stainless Steel Should You Choose for Your Project?
Both types have their strengths, so the best choice really depends on what your project needs:
- If you need high corrosion resistance and flexibility, austenitic stainless steel is probably your best bet.
- If you’re looking for hardness and strength – especially for high-stress situations or applications that need cutting and abrasion resistance – martensitic stainless steel might be the way to go.
High-Quality Stainless Steel, Delivered Direct to You
At MG Metals, we offer a wide range of high-quality custom-cut metal components, including both austenitic and martensitic stainless steels. Whether you’re looking for the flexibility of austenitic steel or the strength of martensitic, we’ve got exactly what you need.
Even better, with our range of finishing and processing services, your metal will be ready to use the moment it arrives at your site.
Ready to get started? Get a free quote online or give us a call on 01794 521070, and let us help bring your project to life!