Cromdane Steel, Inc. distributes quality AISI 4140 alloy steel
forged bar and forgings. Our inventory is controlled within our API
Q1 and ISO 9001:2015 certified Quality Management Systems
requirements and is available for immediate saw, cut and delivery.
We meet stringent customer specifications with short lead times and
quick turnarounds.
AISI/SAE 4140 alloy steel is a chrome molybdenum series low alloy
steel. AISI 4140 has high strength, hardenability, good toughness,
small deformation during quenching, high creep strength and
long-lasting strength at temperature. AISI 4140 alloy steel bar has
a higher carbon content than AISI 4130 therefor it has greater
strength and heat treatment capabilities.
4140 alloy steel forged bar has many uses in the aerospace, oil and
gas and automotive industries. It is commonly used in downhole
tools.
AISI – SAE 4140 Alloy Steel Composition
4140 steel contains both chromium (Cr) and molybdenum (Mo). The
amount of these elements in the alloy varies depending on the grade
of 4140 steel being used. For example, Grade AISI 4140 contains
0.38-0.43% Cr and 0.15-0.25% Mo while Grade AISI 4150 contains
0.47-0.53% Cr and 0.20-0.30% Mo. The addition of other elements,
such as manganese, can also alter the composition of 4140 steel
depending on the grade being used.
| 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 |
AISI – SAE 4140 Alloy Steel Chemical Properties
SAE 4140 steel is a chromium-molybdenum alloy beloved by many
metalworkers because of its versatility and malleability. Due to
its impressive chemical properties, it has been used in
applications ranging from shipbuilding to the manufacture of tools.
4140 Steel has excellent strength, toughness, and hardenability
values, especially when tempering and quenching are employed for
further processing. Additionally, it is highly corrosion-resistant
and has a large amount of wear resistance as well. This makes it
ideal for uses like shafts, gears, bolts, and other parts subject
to mechanical stress. As a result of all these qualities, 4140
Steel remains one of the most popular materials for metalworking
today – and it doesn’t look like that popularity will be waning
anytime soon!
AISI – SAE 4140 Alloy Steel Physical Properties
The chemical and physical properties vary depending on the grade
being used; however, some common characteristics are high strength
(up to 1600MPa), high wear resistance (due to its high abrasion
resistance), good ductility and toughness (due to its low carbon
content), high fatigue strength (due to its quenching process),
good creep strength (at elevated temperatures), good corrosion
resistance (due to its chromium content) and good weldability (due
to its low carbon content).
| Properties | Metric | Imperial |
|---|
| Density | 7.85 g/cm3 | 0.284 lb/in³ |
| Melting point | 1416°C | 2580°F |
AISI – SAE 4140 Alloy Steel Mechanical Properties
| 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 |
AISI – SAE 4140 Alloy Steel Thermal Properties
| 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 |
AISI – SAE 4140 Alloy Steel Equivalent
| 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 | |
AISI – SAE 4140 Alloy Steel Uses
Due to its versatility, 4140 steel has many uses across various
industries, including automotive components such as gears shafts,
axles, pistons, and valves ; construction materials such as bolts,
nuts, screws; tools such as chisels, punches, taps etc.; sporting
goods such as golf clubs; agricultural equipment such as plows; oil
rigs etc.
