ASTM SAE AISI 1018 Carbon Steel Chemical Composition, Mechanical Properties

SAE AISI 1018 Steel

SAE AISI 1018 steel is one of the commonly used low carbon steels. It is usually used as carburized steel. Since most of the 1018 carbon steel is produced by cold drawing, this cold rolled steel is called C1018 (1018 cold rolled steel). AISI C1018 steel (1018 CRS) has good weldability, surface hardening quality, higher mechanical properties and better machinability. Cold drawing increases tensile strength, yield strength, torsional strength, surface hardness and wear resistance, but reduces ductility.

ASTM AISI SAE 1018 hot rolled steel is also known as 1018 HR, and has good toughness, strength, ductility, formability, weldability and workability.

AISI SAE 1018 Steel Properties

Below is material AISI 1018 carbon steel properties and specifications including chemical composition, physical and mechanical properties such as density, thermal expansion coefficient, thermal conductivity, tensile, yield strength and hardness, etc.

AISI SAE 1018 Chemical Composition

ASTM AISI SAE 1018 chemical composition is presented in the following table.

AISI SAE 1018 Chemical Composition (%)
Steel Grade (UNS) C Mn P (≤) S (≤)
1018 (UNS G10180) 0.15-0.20 0.60-0.90 0.040 0.050

AISI SAE 1018 Mechanical Properties

Modulus of elasticity (Young’s modulus): 186 GPa (27×106 psi)

The following tables give AISI SAE 1018 steel mechanical properties of cold-drawn carbon steel rounds, squares, and hexagons.

Steel (UNS) Tensile strength (Mpa) Yield strength (Mpa) Elongation in 50 mm, % Reduction in area, % Hardness (HB) Processing, condition or treatment Sample Diameter (mm)
AISI 1018 (G10180) 483 413 18 40 143 Cold drawn 16-22
440 370 15 40 125 Cold drawn 20-32
414 345 15 35 120 Cold drawn 32-51
400 220 25 50 115 Hot rolled (steel bar) 20-32

Physical Properties

Notes: 10-6/K = 10-6.K-1 = (µm/m)/°C

AISI SAE 1018 mild steel coefficients of linear thermal expansion
Value (10-6/K) Temperature (°C) Treatment
or condition
12.0 0-100 Annealed
13.5 0-400
14.5 0-600
Material 1018 thermal conductivity
Value (W/m·K) Temperature (°C) Treatment or condition
51.9 0 Annealed
50.8 100
48.9 200
Specific Heat of AISI SAE1018 Carbon Steel
Value (J/Kg·K) Temperature (°C) Treatment or condition
486 50-100 Annealed
519 150-200
599 350-400
Electrical Resistivity of AISI SAE 1018 Carbon Steel
Value (μΩ·m) Temperature (°C) Treatment or condition
0.16 0 Annealed
0.22 100
0.29 200

SAE 1018 Steel Heat Treatment

The following table shows AISI SAE ASTM 1018 steel heat treat including annealing, carburizing, carbonitriding, and rockwell hardness.

Full Annealing for Small Steel Forgings

AISI 1018 Heat Treatment
Heat Treat Temperature (℃) Hardness Cooling/Agent Section thickness
Annealing (full annealing of small steel forgings) 855-900 110-150 HB Furnace cooling (28 °C/h (50 °F/h) 75 mm

Heat treatment to 855-900 °C (1575-1650 °F), slow cooling from 855 °C (1575 °F) at a rate of 28 °C (58 °F)/hour to 705 °C (1300 °F), section thickness is less than 75 mm (3 in.)

Typical Heat Treatment for SAE 1018 Case Hardening

  • Carbon temperature: 900-925 °C (1650-1700 °F), cooling method: water or caustic;
  • Reheat temperature: 790 °C (1450 °F), cooling method: water or 3% sodium hydroxide;
  • Carbonitriding temperature: 790-900 °C (1450-1650 °F), cooling method: oil;
  • Temper temperature: 120-205 °C (250-400 °F), for stress relief and improving resistance to cracking (not mandatory).

Carburizing Treatment

Liquid carburizing in noncyanide baths
Grade Temperature (°C) Weight (kg) Case depth (mm) Time (h) Quench Hardness (HRC) Typical applications
1018 925 0.5-2.0 0.38 0.5-1.0 Brine 50-60 Production tools


Production cycles for carbonitriding
Grade Case depth (mm) Furnace temperature (°C) Time in furnace Quench Applications
1018 0.40-0.50 870 2 h Oil at 150 °C (300 °F); tempered at 150 °C (300 °F); for 1 h. Sliding spur gear, 67 mm outside diameter
Oil at 150 °C (300 °F); tempered at 260 °C (500 °F) for 1 h. Spur pinion shaft, 41mm outside diameter


The recommended preheat and interpass temperatures for 1018 welding:

For thickness ≤50mm (2 in.), the recommended preheat and interpass temperature is above -12 °C.

For thickness (t) 50< t ≤100, the recommended preheat and interpass temperature is 38 °C (for low hydrogen); and 121 °C (for other than low hydrogen).

Postweld heat treatment is optional, temperature is 590-675 °C (1100-1250 °F).


AISI SAE ASTM 1018 steel has many semifinished and final products such as round bar, flat bar, steel tubing and pipes, etc.

1018 carbon steel is versatile and is commonly used in a variety of carburized parts such as gears, pinions, ratchets, worms, pins, chain pins, pins, machine parts, tools and mold components.

Equivalent Material

ASTM AISI SAE 1018 carbon steel equivalent material to European EN (Germany DIN EN, British BSI, French NF…), Chinese GB and Japanese JIS standard.

1018 Steel Equivalent Material
US Germany China Japan ISO
Standard AISI (UNS) Standard Grade Standard Grade (Steel Number) Standard Grade Standard Grade Standard Grade
1018 (G10180) AMS 5069D

Related Material: AISI 1020, AISI 1045, AISI 1095

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