Aisi 4140 Chrome Alloy Steel Hex Bar

Aisi 4140 Alloy Steel Hex Bar

4140/4142 Alloy Steel Hex Bar is commonly used in heavy-duty industrial applications. Also known as Chrome-Molybdenum Steel, it is a widely used cold rolled steel. 4140/4142 is known for its strength, resistance to fracture, wear and impact in high stress applications. Alloy Steel Hex Bar is available in standard sizes and custom lengths.

AISI 4140 Hexagonal Bar: Comprehensive Property Table

(Per ASTM A108 / JIS G4105 Standards)

Property	Annealed	Quenched & Tempered (QT)	Key Significance
Chemical Composition (%)	C: 0.38-0.43<br>Cr: 0.80-1.10<br>Mo: 0.15-0.25<br>Mn: 0.75-1.00	-	Hardenability backbone
Tensile Strength (MPa)	655 - 850	950 - 1200	Heavy-duty fastener & shaft capability
Yield Strength (MPa)	≥ 415	≥ 750	Anti-deformation for impact loads
Hardness (HB)	197 - 241	280 - 350	Wear resistance for drive interfaces
Corner Radius (Min.)	0.15 × S (S = Across Flats)	-	Prevents stress concentration
Impact Toughness (J)	45 - 55	30 - 40	Shock absorption in tool holders
Machinability Rating	75%(vs. 1215 steel)	-	Excellent chip control
Weight (kg/m)	0.0068 × S²<br>(e.g., 30mm bar ≈ 6.12 kg/m)		Logistic cost calculation

Specifications of AISI 4140 Alloy Steel Hex Bar

Grade	Cr %	Mo %	C %	Mn %	P % (max)	S % (max)	Si %
4140	0.80-1.10	0.15-0.25	0.38-0.43	0.75-1.00	0.035	0.04	0.15-0.35

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)	0.257	0.257
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. )	13	13
Hardness, Vickers (converted from Brinell hardness)	207	207
Machinability (based on AISI 1212 as 100 machinabilities)	65	65

Applications of AISI 4140 Alloy Steel Hex Bar

Typical uses for 4140 include:

Gears:

Utilized in the fabrication of gears for machinery and automotive systems, where 4140 steel's high strength and wear resistance contribute to the durability and efficient operation of the gears.

Crankshafts:

Found in the manufacturing of crankshafts for engines, particularly in the automotive and aerospace industries, taking advantage of 4140 steel's robust properties for reliable and high-performance engine operation.

Suspension Systems:

Applied in the production of components for suspension systems in vehicles, providing the necessary strength and toughness to withstand dynamic loads and ensure stability.

Bulldozer Blades:

Used for constructing bulldozer blades due to its excellent combination of hardness and toughness, making the blades resistant to wear and impact during heavy-duty earthmoving applications.

Oil and Gas Equipment:

Employed in the manufacturing of components for oil and gas exploration and extraction equipment, where the steel's strength and resistance to harsh environmental conditions are crucial for reliable performance.

AISI 4140 Hexagonal Bar: Market Standard Sizes

(Per ASTM A108 / EN 10060 Standards)

Across Flats (mm)	Length (m)	Tolerance	Surface Finish	Primary Applications
6 - 20	3 - 5	h9 (±0.03mm)	Cold-Drawn, Ground	Precision Shafts, Valve Spindles
21 - 36	3 - 6	h10 (±0.05mm)	Peeled/Turned	Hydraulic Fittings, Gear Blanks
38 - 65	4 - 8	h11 (±0.1mm)	Hot-Rolled	Fastener Dies, Tool Holders
68 - 100	4 - 12	h12 (±0.2mm)	As-Forged	Heavy Machinery Keys, Drive Sockets

GNEE Group Aisi 4140 chrome Alloy Steel Bar Factory Environment

GNEE Group Aisi 4140 Alloy Hex Bar Packaging

GNEE Group Aisi 4140 chrome Hex Bar Testing

Is 4140 alloy steel corrosion resistant?
Although 4140 steel contains chromium to improve corrosion resistance, it is not highly resistant to corrosion. Appropriate coatings or protective measures are recommended for use in corrosive environments.
What is the difference between 4140 and 4340 alloy steels?
4140 steel has a lower carbon content than 4340 steel, making it easier to machine. However, 4340 steel has higher strength and toughness, especially in larger sections, and is often used in heavy-duty applications.
Can 4140 alloy steel be welded?
Yes, 4140 steel can be welded using the proper welding techniques and precautions. However, post-weld heat treatment may be required to restore its properties, especially in the heat-affected zone.
What is the maximum hardness that 4140 steel can achieve through heat treatment?
Depending on the specific heat treatment process, 4140 steel can reach a hardness of up to approximately 58-60 HRC.
Is 4140 alloy steel round bar available in a variety of sizes and shapes?
Yes, 4140 Alloy Steel Round Bar is available in a variety of sizes and can also be made into a variety of shapes including square bars and flat bars to suit a variety of applications.

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