Skip to Content

Properties of Stainless Steel Alloys

There are more than 60 grades of stainless steel and over 150 grades of stainless steel finishes. Stainless steel alloy can be milled into; coils, sheets, plates, bars, wire & tubing.

Stainless Steel Grades

  • 100 Stainless Steel Series
    • 101 Stainless Steel is austenitic chromium-nickel-manganese alloys, hardenable through cold working
    • 102 Stainless Steel is austenitic chromium-nickel-manganese alloys, general purpose stainless steel
  • 200 Stainless Steel Series
    • 201 Stainless Steel is austenitic chromium-nickel-manganese alloys, hardenable through cold working
    • 202 Stainless Steel is austenitic chromium-nickel-manganese alloys , general purpose stainless steel
  • 300 Stainless Steel Series
    • 301 Stainless Steel is austenitic chromium-nickel alloys, highly ductile for formed products, hardens rapidly, good weld ability, and better wear resistance and fatigue strength than 304.
    • 302 Stainless Steel is austenitic chromium-nickel alloys and the same corrosion resistance as 304, with higher strength due to the addition of carbon. o 303 Stainless Steel is austenitic chromium-nickel alloys, free machining version of 304 via addition of sulfur and phosphorus. Also referred to as "A1" in accordance with ISO 3506.[9]
    • 304 Stainless Steel is austenitic chromium-nickel alloys, the most common grade; the classic 18/8 stainless steel. Also referred to as "A2" in accordance with ISO 3506.[9]
      304L Stainless Steel is austenitic chromium-nickel alloys, the same as 304 grade but less carbon to increase weld ability and slightly weaker than 304.
      304LN Stainless Steel is austenitic chromium-nickel alloys, same as 304L, but also nitrogen is added to obtain a much higher yield and tensile strength than 304L.
    • 308 Stainless Steel is austenitic chromium-nickel alloys, used as the filler metal when welding 304 o 309 Stainless Steel is austenitic chromium-nickel alloys, better temperature resistance than 304, also sometimes used as filler metal when welding dissimilar steels, along with inconel.
    • 316 Stainless Steel is austenitic chromium-nickel alloys, the second most common grade (after 304); the addition of molybdenum prevents specific forms of corrosion. It is 316 used in the manufacture and handling of food and pharmaceutical products where it is often required in order to minimize metallic contamination. It is referred to as "A4" in accordance with ISO 3506.[9] o 321 Stainless Steel is austenitic chromium-nickel alloys, similar to 304 but lower risk of weld decay due to addition of titanium.
  • 400 Stainless Steel Series
    • 405 Stainless Steel is ferritic and martensitic chromium made for welding applications
    • 408 Stainless Steel is ferritic and martensitic chromium alloys, heat-resistant; poor corrosion resistance; 11% chromium, 8% nickel.
    • 409 Stainless Steel is ferritic and martensitic chromium alloys, the cheapest type (ferritic iron/chromium only).
    • 410 Stainless Steel is ferritic and martensitic chromium alloys, wear-resistant, but less corrosion-resistant.
    • 416 Stainless Steel is ferritic and martensitic chromium alloys, easy to machine due to additional sulfur
    • 420 Stainless Steel is ferritic and martensitic chromium alloys cutlery grade with excellent polishability.
    • 430 Stainless Steel is ferritic and martensitic chromium alloys, decorative, with good formability, but with reduced temperature and corrosion resistance.
    • 440 Stainless Steel is ferritic and martensitic chromium alloys, a higher grade of cutlery steel, with more carbon in it,
    • 446 Stainless Steel is ferritic and martensitic chromium alloys for elevated temperature service
  • 500 Stainless Steel —heat-resisting chromium alloys
  • 600 Stainless Steel Series
    • 601 through 604 Stainless Steel is martensitic low-alloy steels.
    • 610 through 613 Stainless Steel is martensitic secondary hardening steels.
    • 614 through 619 Stainless Steel is martensitic chromium steels.
    • 630 through 635 Stainless Steel is semiaustenitic and martensitic precipitation-hardening stainless steels. Type 630 is most common PH stainless, better known as 17-4; 17% chromium, 4% nickel.
    • 650 through 653 Stainless Steel is austenitic steels strengthened by hot/cold work.
    • 660 through 665 Stainless Steels are austenitic superalloys; all grades except alloy 661 are strengthened by second-phase precipitation.

Stainless Steel Finishes

With over 150 grades of stainless steel finishes, the categories are basically standard and special.

“Standard” stainless steel finishes are categorized as either “Mill” or “Polished”. “Mill” finishes can be dull to mirror-like and are the least expensive of the finish options. “Polished” finishes can produce a mirror-like appearance. Surface finish designations like #4, #8 refer to the grit of the polishing media used to create the finish. "Mirror" finishes are sometimes called "super #8 or #10.

“Special” stainless steel finishes can include swirls, circles, embossing, coloring and other types of aesthetic requirements. A "Bright Annealed" finish is a highly reflective finish that is retained by final annealing in a controlled atmosphere furnace that does not affect the surface condition.

Aerodyne Alloys Note: The information on this page is provided strictly and specifically for information purposes only.