ASTM SAE AISI 1018 Carbon Steel Chemical Composition, Mechanical Properties

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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 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.

Datasheet & Specification

Below is material AISI 1018 carbon steel datasheet including chemical composition, density, thermal expansion coefficient, thermal conductivity, yield strength, 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 GradeCMnP (≤)S (≤)
1018 (UNS G10180)0.15-0.200.60-0.900.0400.050

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 treatmentSample Diameter (mm)
AISI 1018 (G10180)4834131840143Cold drawn16-22
4403701540125Cold drawn20-32
4143451535120Cold drawn32-51
4002202550115Hot rolled (steel bar)20-32

AISI SAE 1018 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
Material 1018 thermal conductivity
Value (W/m·K)Temperature (°C)Treatment or condition
Specific Heat of AISI SAE1018 Carbon Steel
Value (J/Kg·K)Temperature (°C)Treatment or condition
Electrical Resistivity of AISI SAE 1018 Carbon Steel
Value (μΩ·m)Temperature (°C)Treatment or condition

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 Steel Heat Treatment
Heat TreatTemperature (℃)HardnessCooling/AgentSection thickness
Annealing (full annealing of small steel forgings)855-900110-150 HBFurnace 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
GradeTemperature (°C)Weight (kg)Case depth (mm)Time (h)QuenchHardness (HRC)Typical applications
10189250.5-2.00.380.5-1.0Brine50-60Production tools


Production cycles for carbonitriding
GradeCase depth (mm)Furnace temperature (°C)Time in furnaceQuenchApplications
10180.40-0.508702 hOil 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).

Equivalent Grade

ASTM AISI SAE1018 carbon steel equivalent to European EN (Germany DIN EN, British BSI, French NF…), Chinese GB and Japanese JIS standard.

AISI 1018 equivalent
StandardGrade (UNS)StandardGradeStandardGrade (Steel Number)StandardGradeStandardGradeStandardGrade
1018 (G10180)AMS5069D

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