What You Need to Know About Stainless Steel

Key Takeaways

Stainless steel is a high-strength, corrosion-resistant metal. Its many grades, differentiated by microstructure and alloying elements, make it adaptable to a wide range of applications, each with its own optimal grade. It is classified as a difficult-to-machine material, and machining costs for a given geometry tend to be higher than for materials like aluminum alloys.

Characteristics of Stainless Steel

Stainless steel is an alloy steel made by adding chromium and nickel to iron. Its defining characteristic is corrosion resistance. When iron contains 10.5% or more chromium, a strong passive oxide layer forms on the surface that protects the underlying material from corrosion. This layer is extremely thin, just a few nanometers, but even when damaged by external factors, it self-repairs as the chromium reacts with oxygen in the air.

Stainless steel grades are classified by their microstructure and the type and amount of alloying elements added. The wide variety of available grades makes it possible to find an optimal material across a broad range of applications.

• Excellent corrosion resistance

• High strength

• Low electrical and thermal conductivity

• Susceptible to work hardening

• Susceptible to hydrogen embrittlement

• Difficult to machine

Types of Stainless Steel

The crystal structure and properties of stainless steel vary depending on the alloying element ratios and heat treatment temperatures used during production. The wide range of available grades makes stainless steel suitable for everything from precision components and structural materials to everyday products.

• Martensitic stainless steel (SUS403, SUS410, SUS416, SUS420, SUS440)

• Ferritic stainless steel (SUS430, SUS444)

• Austenitic stainless steel (SUS303, SUS304, SUS310S, SUS316)

• Austenitic-ferritic stainless steel (SUS329J1, SUS329J3L)

• Precipitation hardening stainless steel (SUS630, SUS631, SUS660)

Material Selection Notes

Stainless steel is notably susceptible to hydrogen embrittlement, where hydrogen penetrates the material and causes a significant loss of strength. Ferritic grades tend to be particularly prone to this. Stainless steel is also classified as a difficult-to-machine material: its low thermal conductivity accelerates tool wear, and work hardening can occur during cutting. As a result, machining costs run higher than for easier-to-machine materials like aluminum alloys and brass.

• Susceptible to hydrogen embrittlement

• Difficult to machine

Step Up Your Project with Yumoto Electric

Yumoto Electric delivers high-quality components fast, worldwide. We provide precision machining for a wide range of metals using milling, turning, and specialized metal processing. We have experience with over 200 materials including aluminum alloys, stainless steel, molybdenum, and titanium. 

If you’re unsure about material selection or machining methods, we offer complimentary consultations to help optimize your design and production. For any questions, please feel free to contact us.