AISI 1018 Carbon Steel (UNS G10180)

Topics Covered

Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Fabrication and Heat Treatment
     Machinability
     Forming
     Welding
     Heat Treatment
     Forging
     Hot Working
     Cold Working
     Annealing
Applications

Introduction

There are many different categories of steel, and carbon steels are one such category that contains 0.12 to 2% carbon in them. The steel gains hardness and strength with heat treatment when the carbon percentage content increases; however its ductility is reduced.

AISI 1018 carbon steel is a free machining grade that is the most commonly available grade around the world. Although its mechanical properties are not very unique, it still can be easily formed, machined, welded and fabricated.

The following sections will discuss in detail about AISI 1018 carbon steel.

Chemical Composition

The chemical composition of AISI 1018 carbon steel is outlined in the following table.

Element Content (%)
Manganese, Mn 0.60-0.90
Carbon, C 0.15-0.20
Sulfur, S 0.05 (max)
Phosphorous, P 0.04 (max)
Iron, Fe Balance

Physical Properties

The physical properties of AISI 1018 carbon steel are tabulated below.

Properties Metric Imperial
Density 7.87 g/cm3 0.284 lb/in3

Mechanical Properties

The following table shows mechanical properties of cold drawn AISI 1018 carbon steel.

Properties Metric Imperial
Tensile strength 440 MPa 63800 psi
Yield strength 370 MPa 53700 psi
Modulus of elasticity 205 GPa 29700 ksi
Shear modulus (typical for steel) 80 GPa 11600 ksi
Poisson’s ratio 0.29 0.29
Elongation at break (in 50 mm) 15% 15%
Hardness, Brinell 126 126
Hardness, Knoop (converted from Brinell hardness) 145 145
Hardness, Rockwell B (converted from Brinell hardness) 71 71
Hardness, Vickers (converted from Brinell hardness) 131 131
Machinability (based on AISI 1212 steel. as 100 machinability) 70 70

Thermal Properties

The thermal properties of AISI 1018 carbon steel are given in the following table.

Properties Metric Imperial
Thermal conductivity 51.9 W/mK 360 BTU in/hr.ft2.°F

Other Designations

Other designations that are equivalent to AISI 1018 carbon steel include the following.

AMS 5069 ASTM A29 ASTM A512 ASTM A611 (D-1) ASTM A635
AMS 5069A ASTM A510 ASTM A794 ASTM A519 ASTM A544
ASTM A108 ASTM A513 ASTM A830 ASTM A545 ASTM A548
ASTM A549 ASTM A659 SAE J412 SAE J1397 MIL S-11310 (CS 1018)
ASTM A576 SAE J403 SAE J414 MIL J-1397 MIL J-403
MIL J-412









Fabrication and Heat Treatment

Machinability

AISI 1018 carbon steel is rated at 62% of AISI 1112 carbon steel. Machining provides this alloy with a fine finish, with continuous and hard chips. It is possible to machine this alloy in all conditions.

Forming

It is easy to form AISI 1018 carbon steel in the annealed condition.

Welding

AISI 1018 carbon steel can be welded using most of the conventional methods such as gas, oxyacetylene, resistance, and submerged melt welding.

Heat Treatment

AISI 1018 carbon steel can be case hardened to Rc 42, but only in thin sections. In case of thicker sections of over 4 in., Rc 28-30 can be obtained.

Forging

Forging of AISI 1018 carbon steel can take place in the range of 996-1260°C (1825-2300°F).

Hot Working

AISI 1018 carbon steel can be easily hot worked.

Cold Working

Cold working AISI 1018 carbon steel will affect the hardness and mechanical properties. Intermediate annealing has to be performed to overcome the alloy’s tendency to work harden.

Annealing

Complete annealing of this alloy can be achieved by soaking at 899°C (1650°F) followed by furnace cooling. Process annealing can be done at 649°C (1200°F).

Applications

AISI 1018 carbon steel is commonly used in high volume screw machine parts applications. The other applications of this alloy are as follows:

  • Shafts
  • Spindles
  • Pins
  • Rods
  • Sprocket assemblies.

Date Added: Jun 7, 2013 | Updated: Jun 17, 2013
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