Sep 18 2012
Topics Covered
IntroductionChemical CompositionPhysical PropertiesMechanical PropertiesOther Designations
Introduction
Air-hardening, medium alloy, cold work steels comprise several types that include A2, A3, A4, A6, A7, A8, A9, and A10. These steels also known as group A steels contain sufficient amounts of manganese, molybdenum and chromium. The presence of manganese, molybdenum and chromium in these steels provide full hardness in sections comprising thickness of at least 100 mm (4 in.) in diameter when air cooled.
Group A steels have a carbon content ranging from 0.5 to 2% and are provided with air hardening characteristics that permit minimum distortion and cracking on quenching.
The data below will provide an overview of A3 air-hardening, medium-alloy, cold-work tool steels.
Chemical Composition
The chemical composition of A3 tool steels is predominantly Iron (Fe) with the following elements outlined in the table also present:
Element |
Content (%) |
C |
1.20-1.30 |
Mn |
0.40-0.60 |
Si |
0.50 |
Cr |
4.75-5.50 |
Ni |
0.30 |
Mo |
0.90-1.40 |
V |
0.80-1.40 |
Cu |
0.25 |
P |
0.03 |
S |
0.03 |
Physical Properties
The following table shows the physical properties of A3 tool steels.
Properties |
Metric |
Imperial |
Density |
7.86 g/cm3 |
0.284 lb/in3 |
Mechanical Properties
The mechanical properties of A3 tool steels are displayed in the following table.
Properties |
Metric |
Imperial |
Machinability (based on carbon tool steel) |
65% |
65% |
Shear modulus (typical for steels) |
80.0 GPa |
11600 ksi |
Poisson's ratio |
0.27-0.30 |
0.27-0.30 |
Elastic modulus |
190-210 GPa |
27557-30457 ksi |
Other Designations
Equivalent materials to A3 tool steels are:
- ASTM A681
- FED QQ-T-570
- UNS T30103