Stainless steel is an iron-based alloy that always contains chromium (at least about 10.5% by mass), plus other elements like carbon, nickel, and often molybdenum in smaller amounts.

What stainless steel is made of

At its core, stainless steel is mostly iron , with a carefully controlled mix of alloying elements that give it corrosion resistance and strength.

Typical elements in stainless steel:

  • Iron (Fe): Base metal, usually the “balance” of the composition.
  • Chromium (Cr): 10.5–30%; creates a thin, self-healing oxide film that makes the steel “stainless.”
  • Carbon (C): Usually low (around 0.08% or less in many common grades); controls hardness and strength.
  • Nickel (Ni): Commonly 8–10.5% in popular grades like 304; improves corrosion resistance and toughness, especially in austenitic grades.
  • Molybdenum (Mo): Added (e.g., in grade 316) to improve resistance to pitting and crevice corrosion, especially in chloride environments.
  • Manganese (Mn), Silicon (Si): Help deoxidize the steel and adjust strength and workability.
  • Nitrogen (N): Enhances strength and corrosion resistance, especially in some high-performance grades.
  • Phosphorus (P) and Sulfur (S): Kept very low; sulfur can be slightly increased in “free-machining” grades to improve machinability.

Example: Common austenitic stainless steels

These are the “everyday” stainless steels used in kitchenware, architecture, and many industrial applications.

Because you asked for tables as HTML, here’s an approximate composition table for two very common grades:

[3][7] [3] [7][3] [3] [7][3] [7][3] [3][7] [10][3] [10][3] [10][3] [10][3] [10][3] [10][3] [10][3]
Grade Carbon (C) Chromium (Cr) Nickel (Ni) Molybdenum (Mo) Manganese (Mn) Silicon (Si) Others / Notes
304 stainless steel ≤ 0.08% 17.5–19.5% 8.0–10.5% ≈ 0% (no required Mo) ≤ 2.0% ≤ 1.0% Small amounts of P, S, N; Fe is balance.
316 stainless steel ≤ 0.08% (typical spec range)16–18% (typical spec range)10–14% (typical spec range)2–3% (key for chloride resistance)≤ 2.0% (typical)≤ 1.0% (typical)Small amounts of P, S, N; Fe is balance.
In simple terms: _stainless_ steel is mostly iron, but it only gains its rust-resisting character once you add enough chromium (and often nickel and other elements) in the right proportions.

Information gathered from public forums or data available on the internet and portrayed here.