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AISI 4140

AISI 4140

Premium AISI 4140 Alloy Steel from MetalZenith

AISI 4140 is a versatile chromium-molybdenum alloy steel renowned for its exceptional strength, toughness, and hardenability. This medium-carbon steel offers superior mechanical properties through heat treatment, making it ideal for demanding applications requiring high strength and wear resistance.

MetalZenith's Advanced Manufacturing Excellence

At MetalZenith, we leverage state-of-the-art electric arc furnaces and vacuum degassing technology to produce AISI 4140 with exceptional purity and consistency. Our advanced rolling and forging capabilities ensure optimal grain structure and mechanical properties throughout the material cross-section.

Key Applications & Industries

  • Automotive components: crankshafts, connecting rods, axles, and gears
  • Oil and gas industry: drill collars, tool joints, and pressure vessel components
  • Aerospace applications: landing gear components and structural elements
  • Heavy machinery: hydraulic cylinders, pump shafts, and industrial tooling
  • Mining equipment: wear-resistant components and structural parts

Quality Assurance & Certifications

MetalZenith maintains ISO 9001:2015, AS9100D, and API Q1 certifications, ensuring consistent quality and traceability. Our comprehensive testing includes chemical analysis, mechanical testing, ultrasonic inspection, and metallographic examination. Each shipment includes detailed mill test certificates and material traceability documentation.

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20 Years Experience | 1000+ Brand Partners | Full Customization

We have 20 years of industry experience, have partnered with over 1,000 brands, and support any customization needs.

Technical Specifications

Product Overview

Metallurgical Characteristics

AISI 4140 is a low-alloy steel with chromium and molybdenum as primary alloying elements. The chromium content enhances hardenability and provides moderate corrosion resistance, while molybdenum improves high-temperature strength and reduces temper brittleness. The medium carbon content (0.38-0.43%) provides an excellent balance between strength and toughness.

Heat Treatment Process

MetalZenith's heat treatment process begins with normalizing at 870-900°C, followed by cooling in still air. For hardening, the steel is austenitized at 845-870°C and quenched in oil or water. Tempering is performed at 540-650°C depending on desired hardness levels. Our computer-controlled furnaces ensure uniform heating and precise temperature control throughout the process.

Manufacturing Process Excellence

Our production process utilizes electric arc furnaces with secondary refining through ladle metallurgy and vacuum degassing. This ensures low inclusion content and excellent cleanliness. Hot rolling is performed using state-of-the-art rolling mills with precise dimensional control. Cold finishing operations include turning, grinding, and centerless grinding to achieve superior surface finish and dimensional accuracy.

Quality Standards & Testing

MetalZenith adheres to stringent quality standards including ASTM A29, A108, A322, and international equivalents EN 10083 and JIS G4105. Our quality control process includes chemical analysis using optical emission spectroscopy, mechanical testing per ASTM E8, hardness testing, ultrasonic inspection for internal soundness, and metallographic examination. Each batch undergoes comprehensive testing with full traceability documentation.

Machinability & Weldability

AISI 4140 exhibits good machinability in the annealed condition with a machinability rating of approximately 65% relative to AISI 1212. Preheating to 200-300°C and post-weld stress relief at 600-650°C are recommended for welding operations. MetalZenith provides detailed welding procedures and technical support for critical applications.

🧪 Chemical Composition

ElementComposition (%)
Carbon (C)0.38 - 0.43
Manganese (Mn)0.75 - 1.00
Silicon (Si)0.15 - 0.35
Phosphorus (P)≤ 0.035
Sulfur (S)≤ 0.040
Chromium (Cr)0.80 - 1.10
Molybdenum (Mo)0.15 - 0.25
Nickel (Ni)≤ 0.30
Copper (Cu)≤ 0.35
Aluminum (Al)0.020 - 0.035

⚙️ Mechanical Properties

PropertyAnnealed ConditionQuenched & Tempered
Tensile Strength655 MPa (95 ksi)1020 MPa (148 ksi)
Yield Strength (0.2% offset)415 MPa (60 ksi)880 MPa (128 ksi)
Elongation in 50mm25.7%17.7%
Reduction of Area56.9%53.3%
Hardness (Brinell)197 HB302 HB
Hardness (Rockwell C)-28-32 HRC
Impact Energy (Charpy V-notch)54 J (40 ft-lb)54 J (40 ft-lb)
Fatigue Limit (10&sup7; cycles)310 MPa500 MPa
Modulus of Elasticity205 GPa205 GPa

🔬 Physical Properties

PropertyValueTemperature Range
Density7.85 g/cm³Room Temperature
Melting Point1416°C-
Thermal Conductivity42.6 W/m·K20°C
Thermal Expansion Coefficient12.2×10-6/K20-100°C
Specific Heat Capacity475 J/kg·K20°C
Electrical Resistivity0.27 µΩ·m20°C
Magnetic PermeabilityFerromagneticRoom Temperature
Curie Temperature770°C-
Poisson's Ratio0.27-0.30Room Temperature

📏 Product Specifications

SpecificationAvailable OptionsStandards
Product FormsRound bars, flat bars, plates, sheets, forgings, tubesASTM A29, A108, A322
Round Bar Diameter6mm - 500mm (0.25' - 20')ASTM A29/A29M
Flat Bar DimensionsThickness: 3-100mm, Width: 10-300mmASTM A108
Plate Thickness6mm - 200mm (0.25' - 8')ASTM A29, A322
LengthUp to 12 meters (custom lengths available)Customer specification
Surface FinishHot rolled, cold drawn, turned, ground, polishedASTM standards
ConditionAnnealed, normalized, quenched & temperedCustomer specification
Tolerance±0.1mm to ±0.5mm depending on sizeASTM A29, ISO h11
International Equivalents42CrMo4 (EN), SCM440 (JIS), 41Cr4 (DIN)EN 10083, JIS G4105

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Our Advantages in Processing AISI 4140

Manufacturing Advantage 1

Advanced Vacuum Degassing Technology

MetalZenith employs cutting-edge vacuum degassing and ladle refining processes to achieve ultra-low inclusion content and superior cleanliness in AISI 4140 production, resulting in enhanced fatigue resistance and improved mechanical properties.

Comprehensive Heat Treatment Capabilities

Our state-of-the-art heat treatment facilities feature computer-controlled furnaces with precise temperature uniformity, enabling optimal quenching and tempering cycles that maximize the hardenability and toughness characteristics of AISI 4140.

Manufacturing Advantage 2
Manufacturing Advantage 3

Global Supply Chain & Custom Solutions

MetalZenith offers flexible supply solutions with strategically located warehouses worldwide, providing rapid delivery and custom processing services including machining, heat treatment, and surface finishing to meet specific customer requirements.

YOUR TRUSTED STEEL

MANUFACTURING PARTNER

20
Years Experience
Leading Steel Manufacturing & Distribution
1000+
Brand Partners
Trusted by Global Industry Leaders
Full
Customization
Tailored Solutions for Every Project
50M+
Tons Delivered
High-Quality Steel Products Worldwide
95%
Client Retention
Long-term Partnership Success
ISO 9001
Certified Quality
International Standards Compliance
20
Years Experience
Leading Steel Manufacturing & Distribution
1000+
Brand Partners
Trusted by Global Industry Leaders
Full
Customization
Tailored Solutions for Every Project
50M+
Tons Delivered
High-Quality Steel Products Worldwide
95%
Client Retention
Long-term Partnership Success
ISO 9001
Certified Quality
International Standards Compliance
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Industries We Serve

Professional steel solutions across major industries

Construction

High-rise Buildings • Infrastructure • Commercial Real Estate

Oil & Gas

Pipeline Systems • Storage Equipment • Refinery Facilities

Manufacturing

Precision Machinery • Industrial Equipment • Automation Systems

Automotive

Body Structure • Chassis Components • Engine Parts

Shipbuilding

Hull Structure • Marine Engineering • Port Equipment

Energy & Power

Power Generation • Transmission Towers • Renewable Energy

Aerospace

Aircraft Materials • Precision Components • Special Alloys

Railway

Track Systems • Vehicle Manufacturing • Infrastructure

Qualifications & Certifications

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