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400 Series Stainless

The 400 series group of stainless steels has an 11 percent chromium and 1-percent manganese increase, above the 300 series group. The 400 series is susceptible to rust and corrosion under some conditions. Heat-treating will harden the 400 series. The 400 series of stainless steels have higher carbon content, giving it a martensitic crystalline structure. This provides high strength and high wear resistance. Martensitic stainless steels aren’t as corrosion resistant as the austenitic types.

Penn Stainless stocks the following products in 400 Series stainless steel:

Stainless Steel 400 Series Products

Stainless Steel Plate

Plate Mill Plate, Coil Plate More Information 

Stainless Steel Sheet

2B/2D Finish, Polished Sheet, Perforated Sheet, Flat & Expanded  More Information

Stainless Steel Bar

Round Bar – Square Bar – Hex Bar – Rolled Flat – Sheared & Edged  More Information

Stainless Steel Structural

Some structural items may be available in 400 series stainless. Contact a sales associate for details.  More Information

Stainless Steel Tubular

Some tubular items may be available in 400 series stainless steels. Please contact a sales associate for details.  More Information

Please contact us directly with technical questions.

The 400 series includes both ferritic and martensitic steels.

Ferritic steels: non-hardening steels,  ideal for conditions in elevated temperatures. Typical applications for ferritic stainless steels include petrochemical, automotive exhaust systems, heat exchanges, furnaces, appliances and food equipment to name a few.

Martensitic steels: able to be hardened, ideal for a wide variety of common uses. Martensitic stainless steels are used extensively in cutlery, sport knives and multi-purpose tools.


The table below shows common types of 400 series steel:

400 Series Applications

Type 405

 a ferritic steel, used especially for welding applications

Type 408

heat-resistant; poor corrosion resistance; 11% chromium, 8% nickel.

Type 409

cheapest type; used for automobile exhausts; ferritic (iron/chromium only).

Type 410

 martensitic (high-strength iron/chromium). Wear-resistant, but less corrosion-resistant.

Type 416

easy to machine due to additional sulfur

Type 420

Cutlery Grade martensitic; Excellent polishability.

 Type 430

 decorative steel, used for automotive trim; ferritic. Good formability, but with reduced temperature and corrosion resistance.

 Type 440

 a higher grade of cutlery steel, with more carbon in it, which allows for much better edge retention when the steel is heat-treated properly.

 Type 446

 For elevated temperature service





Advantages and Characteristics of 400 Series Stainless Steel

Ferritic, or nonhardenable stainless steels, are classified in the 400 series. This series is known for:

  •  superior corrosion resistance
  • resistance to scaling at elevated temperatures
  • inherent strength greater than carbon steels
  • provide an advantage in many applications where thinner materials and reduced weight are necessary
  • nonhardenable by heat treating
  • always magnetic

Martensitic, or hardenable stainless steels, are classified in the 400 series. This series is known for:

  • higher levels of carbon than ferritics
  • ability to be heat treated to a wide range of hardness and strength levels
  • excellent corrosion resistance
  •  easily machined
  • good ductility

Call us at 1-800-222-6144 for more information