4140 Alloy Steel

4140 Alloy Steel

4140 Alloy Steel For Demanding Engineering

TSI Metals supplies AISI 4140 Alloy Steel for engineering and industrial applications requiring a strong combination of strength, toughness, wear resistance and hardenability.

4140 is a chromium-molybdenum alloy steel commonly considered for components exposed to demanding mechanical loads and repeated service conditions. It is used across engineering, automotive, machinery and industrial applications where reliable mechanical performance is essential.

Key Properties

  • High Strength
  • Good Toughness
  • Good Hardenability
  • Wear Resistance
  • High Tensile Strength
  • Good Machinability
  • Suitable for Heat Treatment
  • Good Fatigue Performance
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Technical Specifications

Parameter 4140 Alloy Steel
Material Type Chromium-Molybdenum Alloy Steel
Grade AISI 4140
Application Engineering & Industrial Components
Key Characteristics Strength, Toughness & Hardenability
Available Forms As per TSI stock & requirement
Supply Condition As-Rolled / Annealed / Heat Treated
Heat Treatment Hardening & Tempering
Cutting Bandsaw Cutting Available

Chemical Composition

Element Typical Composition
Carbon (C) 0.38–0.43%
Chromium (Cr) 0.80–1.10%
Manganese (Mn) 0.75–1.00%
Silicon (Si) 0.15–0.30%
Molybdenum (Mo) 0.15–0.25%
Sulphur (S) 0.040% Max
Phosphorus (P) 0.035% Max
Iron (Fe) Balance

Applications

4140 is widely used for mechanical and engineering components where strength and toughness are important.

Shafts & Axles
Suitable for shafts and axles exposed to mechanical loads, torque and repeated operating conditions.

Gears & Gear Components
Used for gears and related transmission components requiring strength and wear resistance.

Crankshafts
Suitable for crankshafts and other components subjected to repeated mechanical loads.

Spindles & Couplings
Used for spindles, couplings, and rotating components requiring dependable mechanical performance.

Bolts & Fastener
Suitable for high-strength bolts and other engineering components where increased mechanical strength is required.

Machinery Components
Used across heavy machinery and general engineering applications where toughness and strength are important.

 

Heat Treatment

4140 can be processed through different heat-treatment routes depending on the required mechanical properties and application.

Hardening — Heating followed by controlled quenching can be used to develop higher hardness and strength.

Tempering — Helps balance hardness, toughness, and mechanical performance according to application requirements.

Normalizing — Used to develop a suitable material structure before subsequent processing or heat treatment.

Annealing — Used to improve machinability and provide a softer condition for manufacturing.

Heat-treatment parameters should be selected according to section size, application, and applicable specification.

The supplied reference describes hardening, normalizing, annealing, and tempering processes for 4140 Alloy Steel.

Available Forms

  • Round Bars — Suitable for shafts, pins and machined components.
  • Blocks — Suitable for heavy engineering and machining requirements.
  • As-Rolled — Standard supply condition where applicable.
  • Annealed — Suitable for machining requirements.
  • Hardened & Tempered — Available for applications requiring specific mechanical properties.
  • Full Length — Supplied in available dimensions.
  • Cut-to-Size — Cut according to required dimensions.

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