SAE 4140 Alloy Steel – High-Strength Oil Hardening Steel

SAE 4140 Alloy Steel is a versatile low-alloy steel known for its excellent combination of strength, toughness, wear resistance, and fatigue strength. This grade is oil-hardening and features a good balance between performance and machinability. It is widely used in critical engineering applications across multiple industries due to its dependable mechanical properties. At TK Steels, we supply high-quality SAE 4140 steel in the as-rolled condition, ensuring optimal formability and strength, ready for further processing or direct use.

Key Features

High tensile and yield strength
Excellent toughness and fatigue resistance
Good wear resistance under harsh working conditions
Moderate corrosion resistance
Good machinability and hardenability
Oil hardening capability

Typical Applications

Thanks to its mechanical properties, SAE 4140 Alloy Steel is widely used in industries such as:

Aerospace – Gears, shafts, spindles, and structural components
Automotive – Drive shafts, axle shafts, steering knuckles
Oil & Gas – Forged components, drill collars, tool joints
Agriculture – Heavy-duty machinery parts and attachments
Defense & Industrial – Fixtures, jigs, high-stress components

Chemical Composition (%)

Element	Range
Carbon (C)	0.38 – 0.43
Manganese (Mn)	0.75 – 1.00
Silicon (Si)	0.15 – 0.35
Phosphorus (P)	≤ 0.035 (Max)
Sulfur (S)	≤ 0.035 (Max)
Chromium (Cr)	0.90 – 1.10
Molybdenum (Mo)	0.15 – 0.25

Hardness

Brinell Hardness (BHN): 280 – 310 (as-rolled condition)

This hardness level offers an excellent combination of durability and machinability, making SAE 4140 suitable for both precision parts and wear-resistant components.

Equivalent Grades

Standard	Grade
AISI/SAE	4140
EN	EN19
DIN	42CrMo4
BS	709M40
IS	40Cr4Mo3

These equivalents ensure global availability and easy cross-referencing for international buyers and engineers.

Mechanical Properties (Typical)

(Values vary with heat treatment)

Tensile Strength	655–1080 MPa
Yield Strength	415–835 MPa
Elongation	20–25%
Impact Toughness	High, especially after quenching and tempering

Why Choose SAE 4140 from TK Steels?

Consistent Quality: Sourced and processed under strict quality control
Technical Expertise: Support for selecting the right grade for your needs
Custom Sizing: Cut-to-length and custom processing available
Quick Delivery: Fast dispatch across India and worldwide

Industries We Serve

Aerospace & Aviation
Automotive & Transportation
Oil & Gas Exploration
Heavy Machinery
Agriculture Equipment
Industrial Manufacturing

Request a Quote

Looking for reliable SAE 4140 Alloy Steel suppliers? Contact TK Steels today for pricing, availability, and custom requirements.