Jun 19 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Applications
Introduction
The alloying elements in all types of alloy steels tend to form carbides or compounds, rather than being uniformly mixed with carbon and iron. Silicon, nickel and aluminum are some of the elements that form compounds in the steel. Tungsten and vanadium also form carbides to increase the stability and hardness of the finished product.
AISI 4640 alloy steels are characterized by high toughness, strength and corrosion resistance. The following section will discuss in detail about AISI 4640 alloy steel.
Chemical Composition
The chemical composition AISI 4640 alloy steels is outlined in the following table.
Element |
Content (%) |
Nickel, Ni |
1.65-2 |
Manganese, Mn |
≤0.6-0.8 |
Carbon, C |
≤0.38-0.43 |
Silicon, Si |
≤0.2-0.35 |
Molybdenum, Mo |
0.2-0.3 |
Phosphorus, P |
≤0.04 |
Sulfur, S |
≤0.04 |
Physical Properties
The following table shows the physical properties of AISI 4640 alloy steels.
Properties |
Metric |
Imperial |
Density |
7.75 g/cm3 |
0.280 lb/in3 |
Mechanical Properties
The mechanical properties of AISI 4640 alloy steels are displayed in the following table.
Properties |
Metric |
Imperial |
Tensile strength |
1276 MPa |
185100 psi |
Yield strength |
1103 MPa |
160000 psi |
Modulus of elasticity |
201-209 GPa |
29200-30300 ksi |
Bulk modulus |
160-170 GPa |
23200-24700 ksi |
Shear modulus |
81-82 GPa |
11700-11900 ksi |
Poisson’s ratio |
0.27-030 |
0.27-030 |
Elongation at break |
14% |
14% |
Hardness, Brinell |
390 |
390 |
Thermal Properties
The thermal properties of AISI 4640 alloy steels are given in the following table
Properties |
Metric |
Imperial |
Thermal expansion co-efficient (@0-100°C/32-212°F) |
10 µm/m°C |
5.5 µin/in°F |
Thermal conductivity |
25 W/mK |
173 BTU.in/hrft².°F |
Applications
The following are the applications of AISI 4640 alloy steels:
-
Aircraft engine mounts
-
Welded tubing applications