Sep 27 2012
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Introduction
Alloy steels contain a broad range of steels whose compositions exceed the limitations of C, Mo, Cr, Va, Mn, Ni, Si, and B associated with carbon steels. These steels are more responsive to mechanical and heat treatments than carbon steels.
The following datasheet provides further details about AISI 8740 alloy steel.
Chemical Composition
The following table shows the chemical composition of AISI 8740 alloy steel.
|
Element |
Content (%) |
|
Iron, Fe |
96.595-97.72 |
|
Manganese, Mn |
0.750-1.00 |
|
Nickel, Ni |
0.400-0.700 |
|
Chromium, Cr |
0.400-0.600 |
|
Carbon, C |
0.380-0.430 |
|
Molybdenum, Mo |
0.200-0.300 |
|
Silicon, Si |
0.150-0.300 |
|
Sulfur, S |
0.0400 |
|
Phosphorous, P |
0.0350 |
Physical Properties
The physical properties of AISI 8740 alloy steel are outlined in the following table.
|
Properties |
Metric |
Imperial |
|
Density |
7.85 g/cm3 |
0.284 lb/in³ |
Mechanical Properties
The mechanical properties of annealed AISI 8740 alloy steel are outlined in the table below.
|
Properties |
Metric |
Imperial |
|
Tensile strength |
695 MPa |
101000 psi |
|
Yield strength |
415 MPa |
60200 psi |
|
Elastic modulus |
190-210 GPa |
27557-30458 ksi |
|
Bulk modulus (typical for steel) |
140 GPa |
20300 ksi |
|
Shear modulus (typical for steel) |
80 GPa |
11600 ksi |
|
Poisson’s ratio |
0.27-0.30 |
0.27-0.30 |
|
Elongation at break (50mm) |
22.20% |
22.20% |
|
Izod Impact |
41 J |
30.2 ft.lb |
|
Hardness, Brinell |
201 |
201 |
|
Hardness, Knoop (converted from Brinell hardness) |
223 |
223 |
|
Hardness, Rockwell B (converted from Brinell hardness) |
93 |
93 |
|
Hardness, Rockwell B (converted from Brinell hardness, value below normal HRC range, for comparison only) |
13 |
13 |
|
Hardness, Vickers (converted from Brinell hardness) |
211 |
211 |
|
Machinability (hot rolled and cold drawn, based on 100 machinability for AISI 1212 steel) |
65 |
65 |
Thermal Properties
The thermal properties of AISI 8740 alloy steel are highlighted below.
|
Properties |
Metric |
Imperial |
|
Thermal conductivity |
46.6 W/mK |
323 BTU in/hr.ft².°F |
Other Designations
Equivalent materials to AISI 8740 alloy steel are outlined in the table below.
|
DIN 1.6546 |
UNI 40 NiCrMo 2 KB |
B.S. Type 7 |
AMS 6322 |
AMS 6322F |
AMS 6323 |
|
AMS 6323D |
AMS 6325 |
AMS 6325D |
AMS 6327D |
AMS 6358 |
AMS 6358B |
|
ASTM A322 |
ASTM A331 |
ASTM A505 |
ASTM A519 |
SAE J770 |
SAE J412 |
|
AMS 6327 |
MIL SPEC MIL-S-6049 |
AMS 7496 |
ASTM A29 |
ASTM A752 |
MIL S-6049 |
|
SAE J1397 |
ASTM A320 (L7C, L73) |
SAE J404 |
|
|
|