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AISI 4140 is made by placing iron, carbon, and other alloying elements into an electric furnace or oxygen furnace. The major alloying elements added to AISI 4140 are: Chromium Manganese Molybdenum Once the iron, carbon, and other alloying elements have been mixed together in liquid form, it is allowed to cool. The steel may then be annealed; possibly several times.
After the annealing is complete, the steel is heated to a molten phase again so that it can be poured into the desired form and can either be hot worked or cold worked through rollers or other tools to reach the desired thickness. Of course, there are other special operations that can be added to this to reduce mill scale or improve mechanical properties.
Chemical Composition
The following table shows the chemical composition of AISI 4140 alloy steel.
|
Element |
Content (%) |
|
Chromium, Cr |
0.80 – 1.10 |
|
Manganese, Mn |
0.75 – 1.0 |
|
Carbon, C |
0.380 – 0.430 |
|
Silicon, Si |
0.15 – 0.30 |
|
Molybdenum, Mo |
0.15 – 0.25 |
|
Sulfur, S |
0.040 |
|
Phosphorous, P |
0.035 |
|
Iron, Fe |
Balance |
Physical Properties
The physical properties of AISI 4140 alloy steel are highlighted in the following table.
|
Properties |
Metric |
Imperial |
|
Density |
7.85 g/cm3 |
0.284 lb/in³ |
|
Melting point |
1416°C |
2580°F |
Mechanical Properties
The following table outlines the mechanical properties of AISI 4140 alloy steel.
|
Properties |
Metric |
Imperial |
|
Tensile strength |
655 MPa |
95000 psi |
|
Yield strength |
415 MPa |
60200 psi |
|
Bulk modulus (typical for steel) |
140 GPa |
20300 ksi |
|
Shear modulus (typical for steel) |
80 GPa |
11600 ksi |
|
Elastic modulus |
190-210 GPa |
27557-30458 ksi |
|
Poisson’s ratio |
0.27-0.30 |
0.27-0.30 |
|
Elongation at break (in 50 mm) |
25.70% |
25.70% |
|
Hardness, Brinell |
197 |
197 |
|
Hardness, Knoop (converted from Brinell hardness) |
219 |
219 |
|
Hardness, Rockwell B (converted from Brinell hardness) |
92 |
92 |
|
Hardness, Rockwell C (converted from Brinell hardness. Value below normal HRC range, for comparison purposes only) |
13 |
13 |
|
Hardness, Vickers (converted from Brinell hardness) |
207 |
207 |
|
Machinability (based on AISI 1212 as 100 machinability) |
65 |
65 |
Thermal Properties
The thermal properties of AISI 4140 alloy steel are given in the following table.
|
Properties |
Metric |
Imperial |
|
Thermal expansion coefficient ( 0-100°C/32-212°F) |
12.2 µm/m°C |
6.78 µin/in°F |
|
Thermal conductivity (100°C) |
42.6 W/mK |
296 BTU in/hr.ft².°F |
Other Designations
Other designations equivalent to AISI 4140 alloy steel are listed in the following table.
|
AMS 6349 |
ASTM A193 (B7, B7M) |
ASTM A506 (4140) |
ASTM A752 (4140) |
|
AMS 6381 |
ASTM A194 (7, 7M) |
ASTM A513 |
ASTM A829 |
|
AMS 6382 |
ASTM A29 (4140) |
ASTM A513 (4140) |
SAE J1397 (4140) |
|
AMS 6390 |
ASTM A320 (L7, L7M, L7D) |
ASTM A519 (4140) |
SAE J404 (4140) |
|
AMS 6395 |
ASTM A322 (4140) |
ASTM A646 (4140) |
SAE J412 (4140) |
|
AMS 6529 |
ASTM A331 (4140) |
ASTM A711 |
|
Smelting Option
1 EAF: Electric Arc Furnace
2 EAF+LF+VD: Refined-smelting and vacuum degassing
Forming Option
1 Hot rolling process
2 Hot Forging: Electro-hydraulic; High-speed-hydraulic; Oil-hydraulic; Precision-forging
Heat-treatment Option
1 +A: Annealed (full/soft/spheroidizing)
2 +N: Normalized
3 +NT: Normalized and tempered
4 +QT: Quenched and tempered (water/oil)
Suface Option
1 Black Surface
2 Grounded: Bright but rough ; Not precision
3 Machining for plate: Bright and precision; Little turning scar
4 Peeled/Turned: Bright and precision; Little turning scar
5 Polished: Very Bright and precision size; Not turning scar
Other Services
1 Cutting: Small pieces
2 CNC Machine: Produce as your drawing
3 Package: Bare/Nylon/Canvas/Wooden
4 Payment:T/T, L/C, O/A(request credit)
5 Transport:FOB/CFR/CIF/DDU/DDP (train/ship/Air)
