18/8 Stainless Steel Properties, Yield Strength, Composition, Density, Tensile Strength, Hardness

18/8 stainless steel refers to the chemical composition of stainless steel containing 18% chromium (Cr) and 8% nickel (Ni). Standard 18-8 stainless steel includes SS 304, 304L, 304N, 304LN, 304H, non-standard 18-8 grade includes AISI 301, 302, 301L, 301LN, 302B, etc. 18/8 steel is the most widely used material, has excellent corrosion resistance in mild environments, and has good weldability and mechanical properties.

Datasheet & Specification

The tables below list the datasheet and specification including chemical composition and properties. For full datasheet and specification, please view AISI 304, 304L, 301, and 302.

Chemical Composition

18-8 stainless steel composition is given in table below.

		Chemical Composition, %
ASTM	AISI (UNS)	C, ≤	Si, ≤	Mn, ≤	P, ≤	S, ≤	Cr	Ni	N, ≤	Product
ASTM A240/A240M	304 (UNS S30400)	0.07	0.75	2.00	0.045	0.030	17.5-19.5	8.0-10.5	0.10	Plate, Sheet, and Strip
ASTM A276A/276M		0.08	1.00	2.00	0.045	0.030	18.0-20.0	8.0-11.0	–	Bars and Shapes

18/8 Stainless Steel Properties

The following table shows 18/8 stainless steel properties including mechanical properties and physical properties.

Mechanical Properties

The tables below list 18-8 stainless steel mechanical properties including yield strength, tensile strength, elongation and hardness, etc.

		Mechanical Properties
ASTM Type	AISI (UNS)	Tensile Strength, (MPa), ≥	Yield Strength, ≥ (MPa) at 0.2% Offset	Elongation in 50 mm (%, ≥)	Reduction of Area, %, ≥	Brinell Hardness, (HBW) ≤	Rockwell Hardness, (HRBW) ≤	Product	Condition
ASTM A240/A240M	304 (UNS S30400)	515	205	40	–	201	92	Plate, Sheet, and Strip	–
ASTM A276A/276M		515	205	40	50	–	–	Bars and Shapes	Hot finished
		620	310	30	40	–	–		Cold finished, Dia ≤ 12.7mm
		515	205	30	40	–	–		Cold finished, Dia. > 12.7mm

Physical Properties

18-8 stainless steel properties – physical properties including density, melting point, magnetic, specific heat capacity, electrical resistivity, modulus of elasticity (elastic modulus), thermal diffusivity, thermal conductivity and coefficient of thermal expansion.
Notes:

• 10^-6·K^-1 = 10^-6/K
• 1 Ω·mm²/m = 1 μΩ·m
• 1 g/cm3 = 1 kg/dm3 = 1000 kg/m3
• 1 GPa = 1 kN/mm2
• 1 MPa = 1 N/mm2

Type 304 Physical Properties
Density, g/cm3 (lb/in3)	7.93 (0.286)
Melting point, °C (°F)	1400-1450 (2550-2650)
Specific heat capacity, J/kg·K (Btu/lb ·°F)	500 (0.12) at 20 °C (68 °F)
Electrical resistivity, μΩ·m	0.72 at 20 °C (68 °F)
Conductivity, %, IACS	2.5
Magnetic permeability	1.02 (Approximate)
Elastic modulus (Modulus of Elasticity), GPa (106 psi)	193 (28)
Thermal diffusivity, mm2/s (in2/s)	3.84 (0.006)
Thermal conductivity, W/m·K (Btu/ft·h·°F)	16.2 (9.4) at 100 °C (212 °F)
	21.5 (12.4) at 500 °C (932 °F)
Coefficient of thermal expansion (CTE), 10-6/K (μin./in·°F)	17.2 (9.6) at 0-100 °C (32-212 °F)
	17.8 (9.9) at 0-315 °C (32-600 °F)
	18.4 (10.2) at 0-538 °C (32-1000 °F)

Applications

18/8 stainless steel is widely used in petroleum & chemical industry, metallurgical machinery, aerospace industry, food processing equipment, instruments, household appliances and hardware manufacturing industries.

18/8 steel is made into a great many intermediate products such as steel sheet & plate, steel tube & pipe, steel bar & flat, rod & wire, etc.

Final products such as all kinds of kitchenware, tableware, medical device, machinery and parts, wire mesh, filter, architectural and decorative metal products, etc.