SAE AISI 1018 steel
SAE AISI 1018 steel is one of the commonly used low carbon steels. It is generally used as carburized steel. Since most 1018 carbon steel is produced by cold drawing, this cold-rolled steel is called C1018 (1018 cold-rolled steel). AISI C1018 (1018 CRS) steel 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.
Properties of AISI SAE 1018 steel
Below are the properties and specifications of AISI 1018 carbon steel, including chemical composition, physical and mechanical properties such as density, coefficient of thermal expansion, thermal conductivity, tensile strength, yield strength and hardness, etc.
AISI SAE 1018 Chemical Composition
The ASTM AISI SAE 1018 chemical composition is presented in the following table.
| AISI SAE 1018 Chemical Composition (%) | ||||
| Steel Grade (UNS) | W | 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 (27×10 6 psi)
The following tables provide the mechanical properties of AISI SAE 1018 cold drawn carbon steel, rounds, squares and hexagons.
| Steel (UNS) | Tensile strength (Mpa) | Yield strength (Mpa) | Elongation by 50 mm, % | Area reduction, % | Hardness (HB) | Processing, condition or treatment | Sample diameter (mm) |
| AISI 1018 (G10180) | 483 | 413 | 18 | 40 | 143 | Cold drawing | 16-22 |
| 440 | 370 | 15 | 40 | 125 | Cold drawing | 20-32 | |
| 414 | 345 | 15 | 35 | 120 | Cold drawing | 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 Linear Thermal Expansion Coefficients | ||
| Value (10 -6 /K) | Temperature (°C) | Treatment or condition |
| 12.0 | 0-100 | Annealed |
| 13.5 | 0-400 | |
| 14.5 | 0-600 | |
| Thermal conductivity of material 1018 | ||
| 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 Carbon Steel AISI SAE 1018 | ||
| 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 the heat treatment of AISI SAE ASTM 1018 steel, including annealing, carburizing, carbonitriding and rockwell hardness.
Full annealing for small steel forgings
| AISI 1018 heat treatment | ||||
| Heat treatment | Temperature (℃) | Toughness | Cooling/Agent | Section thickness |
| Annealing (complete annealing of small steel forgings) | 855-900 | 110-150 HB | Oven cooling (28 °C/h (50 °F/h) | 75mm |
Heat treatment at 855-900°C (1575-1650°F), slow cooling to 855°C (1575°F) at a rate of 28°C (58°F)/hour at 705°C (1300°F) , section thickness is less than 75 mm (3 in.)
Typical heat treatment for case hardening SAE 1018
- Carbon temperature: 900-925°C (1650-1700°F), cooling method: water or caustic;
- Reheating temperature: 790°C (1450°F), cooling method: water or 3% sodium hydroxide;
- Carbonitriding temperature: 790-900°C (1450-1650°F), cooling method: oil;
- Quenching temperature: 120-205 °C (250-400 °F), to relieve stress and improve resistance to cracking (not mandatory).
Carburization Treatment
| Liquid carburizing in cyanide-free baths | |||||||
| Note | Temperature (°C) | Weight (kg) | Box depth (mm) | Time (h) | To switch off | Hardness (HRC) | Typical applications |
| 1018 | 925 | 0.5-2.0 | 0.38 | 0.5-1.0 | Brine | 50-60 | Production Tools |
Carbonitridation
| Production cycles for carbonitriding | |||||
| Note | Box depth (mm) | Oven temperature (°C) | Time in the furnace | To switch off | Forms |
| 1018 | 0.40-0.50 | 870 | 2 hours | Oil at 150°C (300°F); tempered to 150°C (300°F); for 1h. | Sliding spur gear, 67 mm outer diameter |
| Oil at 150°C (300°F); tempered at 260 °C (500 °F) for 1 h. | Spur pinion shaft, 41 mm outer diameter | ||||
Welding
The recommended preheat and interpass temperatures for 1018 welding:
For thicknesses ≤50 mm (2 in.), the recommended preheat and interpass temperature is greater than -12 °C.
For thickness
