An autoclave uses pressurized steam to clean instruments and other objects inside its chamber. It’s a standard treatment for sterilizing medical and dental tools — the high-pressure and high-temperature environment kills microbes, pathogens, and other contaminants. While this effectively cleans tools, autoclaving weakens stainless steel’s properties over time. Fortunately, there are some steel grades that stand up better than others.
In this post:
- How autoclaving affects steel
- Typical applications where autoclave-resistant steel is necessary
- Characteristics of steels resistant to autoclaving
- The best grades for autoclaving
How Autoclaving Affects Steel
Autoclaving a steel medical or dental tool just once for a few minutes has minimal effect on the metal. Repeated autoclaving is more brutal. It subjects instruments to steam and high temperatures over and over again, which eventually causes:
- Discoloration, particularly in narrow grooves or small crevices (corrosion)
- Dulling of blade edges
- Bending of thin parts (dimensional changes)
- Softening of the metal (a decrease in hardness)
Stainless steel is essential for autoclaved tools because of its corrosion-resistance properties. However, some grades are better than others. High-performance steels that withstand the rigors of repeated autoclaving help instruments last much longer.
Typical Applications for Autoclave Stainless Steel
Medical and dental tools are the most likely instruments to require autoclaving.
This can include:
- Scalpels
- Knives
- Screwdrivers
- Drill tips
- Other surgical instruments
Characteristics of Resilient Autoclave Stainless Steels
Ideally, a medical or dental tool will come out of an autoclave with the same physical properties it had when it went in. High-performance steels maintain hardness, corrosion resistance, and blade sharpness (even after autoclaving) thanks to specific characteristics, such as:
- Proper chemical composition: Adjusting an alloy’s chemical composition using chromium, molybdenum, and nitrogen helps increase and maintain corrosion resistance, even after repeated rounds in an autoclave.
- A fine microstructure: The finer a steel’s microstructure, the better a tool’s edge retention and dimensional stability. A microstructure of fine carbides also increases wear resistance and makes a metal’s surface easy to polish for a bright, shiny finish.
Autoclave-resistant Stainless Steel Grades
High-performance stainless steel grades well-suited to autoclaving applications include XD15NWⓇ (frequently known as X15TNⓇ and 420 MOD in the medical industry) and XD16NⓇ.
XD15NWⓇ
XD15NWⓇ (X40CrMoVN16-2) has the exact same chemical composition as the familiar medical tool steel X15TNⓇ or 420 MOD. (It’s also sometimes used in aerospace manufacturing as an alternative to Cronidur 30Ⓡ.) It is a high-performance stainless steel with chromium and molybdenum that increase corrosion resistance. XD15NWⓇ has a fine microstructure, helping it keep dimensional stability even after many rounds of autoclaving. The same fine microstructure means its surface can be polished to a high shine.
Get details from the manufacturer about XD15NWⓇ in the official Aubert & Duval brochure.
XD16NⓇ
XD16NⓇ (X105CrMo17) is an air-melt version of XD15NWⓇ, displaying similar corrosion-resistance and hardness properties while typically coming in at a lower price point.
Get details from the manufacturer about XD16NⓇ in the official Aubert & Duval brochure.
Need to Autoclave Stainless Steel?
At Sullivan Steel, we stock specialty metals for critical applications, including essential medical equipment. If you’re seeking a superior, autoclave-resistant stainless steel, we are the U.S.’s exclusive distributor of XD15NWⓇ and XD16NⓇ. Our steel experts can walk you through the details of each grade and help you choose the best option for your application.
Contact Sullivan to discuss your project, or request a quote.