Sep 26 2012
Topics Covered
IntroductionChemical CompositionPhysical PropertiesMechanical PropertiesThermal PropertiesOther Designations
Introduction
Alloy steels are of many types where each steel type comprises compositions that exceed the limitations of Si, Va, Cr, Ni, Mo, Mn, B and C allocated for carbon steels. Alloy steels have elements such as chromium, cobalt, nickel, etc.
Alloy steels are capable of using unique melting and deoxidization processes for specific kind of applications. When compared with to carbon steels, the alloy steels seem to be a lot more responsive to mechanical and heat treatments.
The following datasheet provides an overview of AISI 4720 alloy steel.
Chemical Composition
The chemical composition of AISI 4720 alloy steel is outlined in the following table.
Element |
Content (%) |
Iron, Fe |
96.705-97.78 |
Nickel, Ni |
0.900-1.20 |
Manganese, Mn |
0.500-0.700 |
Chromium, Cr |
0.350-0.550 |
Carbon, C |
0.170-0.220 |
Silicon, Si |
0.150-0.300 |
Molybdenum, Mo |
0.150-0.250 |
Sulfur, S |
≤ 0.0400 |
Phosphorous, P |
≤ 0.0350 |
Physical Properties
The following table shows the physical properties of AISI 4720 alloy steel.
Properties |
Metric |
Imperial |
Density |
7.85 g/cm3 |
0.284 lb/in³ |
Mechanical Properties
The mechanical properties of AISI 4720 alloy steel are displayed in the following table.
Properties |
Metric |
Imperial |
Bulk modulus (typical for steel) |
140 GPa |
20300 ksi |
Shear modulus (typical for steel) |
80.0 GPa |
11600 ksi |
Elastic modulus |
190-210 GPa |
27557-30458 ksi |
Poisson's ratio |
0.27-0.30 |
0.27-0.30 |
Hardness, Brinell |
187-229 |
187-229 |
Hardness, Knoop (converted from Brinell hardness) |
230 |
230 |
Hardness, Rockwell B (converted from Brinell hardness) |
94 |
94 |
Hardness, Rockwell C (converted from Brinell hardness, value below normal HRC range, for comparison purposes only) |
15 |
15 |
Hardness, Vickers (converted from Brinell hardness) |
218 |
218 |
Machinability (hot rolled and cold drawn, based on 100 machinability for AISI 1212 steel) |
65 |
65 |
Thermal Properties
The thermal properties of AISI 4720 alloy steel are given in the following table.
Properties |
Metric |
Imperial |
Thermal conductivity (typical steel) |
44.5 W/mK |
309 BTU in/hr.ft².°F |
Other Designations
Equivalent materials to AISI 4720 alloy steel are:
- ASTM A322
- ASTM A331
- ASTM A519
- ASTM A535
- ASTM A711
- SAE J404
- SAE J412
- SAE J770