Understanding Stainless Steel
Composition of Stainless Steel
Metals are rarely used in their pure form. Alloying elements are added to change their properties.
Steel
Iron (Fe) + Carbon (C)
All steels are alloys of iron (Fe) and carbon (C) with the addition of other alloying elements.
Fun Fact: There are 4 main types of steel (Carbon Steels, Alloy Steels, Stainless Steels, and Tool Steels) each with multiple unique combination of alloying elements.
Stainless Steel
Iron (Fe) + ≤1.2% Carbon (C) + ≥10.5% Chromium (Cr)
Stainless steels are iron(Fe) based with maximum amount of carbon (C) added and a minimum amount of chromium added.
Fun Fact: There are over 150 different stainless steels with unique alloying element combinations.
304 Stainless Steel
Iron (Fe) + ≤0.08% Carbon (C) + ≥18% Chromium (Cr) + ≥8% Nickel (Ni)
Grade 304 stainless steel is considered the best and most common stainless steel in the world and gets its’ unique properties due to its’ notable concentrations of chromium (Cr) and nickel (Ni).
304 Stainless Steel
304 Stainless Steel: Contains mostly Iron (Fe) with at least 18% Chromium (Cr) and at most 0.08% Carbon (C) + other alloying elements such as Nickel (Ni).
Grade 304 stainless steel is defined as a Chromium-Nickel austenitic alloy that used to be referred to as “18/8 stainless steel” with a minimum of 18% Chromium and 8% Nickel.
The exact element by weight percentage composition of 304 stainless steel is as follows:
Iron (Fe): 67%-71%
Chromium (Cr): 18%-20%
Nickel (Ni): 8%-12%
Manganese (Mn): ≤ 2%
Silicon (Si): ≤ 0.75%
Nitrogen (N): ≤ 0.10%
Carbon (C): ≤ 0.08%
Phosphorus (P): ≤ 0.045%
Sulfur (S): ≤ 0.03%
General Properties of Stainless Steel
Easy-to-Clean
Stainless steel items are easy to clean using common cleaning products such as soaps and detergents.
Durable
Compared to other materials, stainless steel has strong mechanical properties.
Anti-Corrosive
With a minimum of chromium content stainless steel is continuously protected by a passive layer of chromium oxide.
Recyclable
Stainless steel is a “green material” in that it is infinitely recyclable. Its longevity fulfils requirements of sustainable use.
Fire Resistant
Stainless steel has the best fire resistance of all metallic materials having a critical temperature above 800°C.
Aesthetic
Stainless steel has a smooth shiny surface and modern look that can be embossed, tinted, or painted for unique styles.
Mechanical Properties
Comprehensive Strength: 210 MPa
Proof Stress: 210 Min MPa
Tensile Strength: 520-720 MPa
Elongation: 45 Min%
Physical Properties
Density: 8,000 Kg/m³
Melting Point: 1450°C
Thermal Expansion: 17.2 x 10−⁶/K
Modulus of Elasticity: 193 GPa
Thermal Conductivity: 16.2W/m.K
Electrical Resistivity: 0.072 x 10−⁶ Ω .m
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