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400 Series Stainless Steel

Properties & Characteristics of Stainless Steel Grades 410-440C

400 series stainless steel is a stainless steel alloy similar to 300 stainless steel. The main difference between these alloys and their associated grades is their chemical makeup and components.

The lack of nickel content in 400 stainless steel is a notable difference from 300 stainless steel. This can make 400 SS more prone to corrosion - although stainless steel is already more protected against corrosion than other metals. Additionally, 400 SS contains a higher carbon content than 300 SS. The carbon adds to its durability and strengthens the alloy.

Our skilled machinists have experience forming mission-critical components from multiple grades of 400 series stainless steel. Our 400 series stainless steel selection allows us to create durable, high-precision parts for various industries.

Learn more about our 400 series stainless steel casting alloys below, or contact Aero Metals for more information.

400 Series Stainless Steel Differences By Grade

400 SS includes both ferritic and martensitic steels. The specific alloy ideal for your application depends on the required corrosion resistance, formability, wear, strength, temperature resistance, cost, and additional factors. We have broken down our 400 series stainless steels by grade below.


410 (CA15) Stainless Steel | UNS S41000

410 SS is the general-purpose alloy for 400 stainless steel. It has a strong corrosion resistance when exposed to low concentrations of acids or atmospheric corrosion. It is hardened yet machinable, making it applicable to many industries or projects.

410 Stainless Steel Applications

410 SS is commonly utilized for items such as cutlery, bolts and fasteners, medical instruments, and nozzles.


416 (IC 416) Stainless Steel | UNS S41600

416 SS is martensitic and has the highest machinability of any stainless steel. It has low frictional properties, which help reduce galling and seizing during machining. It is both hardenable and corrosion-resistant.

416 Stainless Steel Applications

416 SS is found in fasteners, pumps and valves, gears, motors, and machine components.


420 (CA40) Stainless Steel | UNS S42000

420 SS is a martensitic grade of stainless steel similar to 410 SS. It contains a higher level of carbon, giving it more strength. Corrosion resistance is low, but 420 SS is desired for its high hardening levels.

420 Stainless Steel Applications

Typical applications of 420 SS include hand tools, cutlery, shear blades, and surgical instruments.


431 (IC 431) Stainless Steel | UNS S43100

431 SS is martensitic with corrosion-resistant solid properties. It is tough, with high torque strength and tensile properties. When heat treated, 431 SS can increase in strength levels.

431 Stainless Steel Applications

431 SS is commonly used for bolt and shaft applications, especially in aerospace industries and other trades requiring high-yield strength.


440A (IC 440A) Stainless Steel | UNS S44002

440A SS is martensitic with high machinability. It contains less carbon than 440C SS, making it less corrosion-resistant. However, it has high levels of hardness and is resistant to wear.

440A Stainless Steel Applications

440A SS is suitable for cutting tools like knife blades, kitchen cutlery, and medical or dental instruments.


440C (IC 440C) Stainless Steel | UNS S44004

440C SS is martensitic with high corrosion resistance. It contains more carbon than 440A SS but with less machinability. It has the highest hardness of any stainless steel alloy and is wear-resistant.

440C Stainless Steel Applications

The hardness of 440C SS makes it suitable for ball bearings and bearing races, as well as cutlery and knives.


400 Series Stainless Steel Applications

Aero Metals works with several metal alloys in our stainless steel casting process. Based on your performance and application requirements, our expert metallurgists can help you choose the best alloy for your stainless steel investment casting needs. Frequent industries served include:

Contact Us Today to Learn More About Steel Investment Casting Alloys

Aero Metals is dedicated to delivering reliable investment cast parts from high-quality metals that provide outstanding benefits. With top-tier metal casting quality, testing, and inspection standards, Aero Metals is a trusted source for premium-grade precision investment casting services for various industries.