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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
| Element | Composition (%) |
|---|---|
| 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
| Property | Annealed Condition | Quenched & Tempered |
|---|---|---|
| Tensile Strength | 655 MPa (95 ksi) | 1020 MPa (148 ksi) |
| Yield Strength (0.2% offset) | 415 MPa (60 ksi) | 880 MPa (128 ksi) |
| Elongation in 50mm | 25.7% | 17.7% |
| Reduction of Area | 56.9% | 53.3% |
| Hardness (Brinell) | 197 HB | 302 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 MPa | 500 MPa |
| Modulus of Elasticity | 205 GPa | 205 GPa |
🔬 Physical Properties
| Property | Value | Temperature Range |
|---|---|---|
| Density | 7.85 g/cm³ | Room Temperature |
| Melting Point | 1416°C | - |
| Thermal Conductivity | 42.6 W/m·K | 20°C |
| Thermal Expansion Coefficient | 12.2×10-6/K | 20-100°C |
| Specific Heat Capacity | 475 J/kg·K | 20°C |
| Electrical Resistivity | 0.27 µΩ·m | 20°C |
| Magnetic Permeability | Ferromagnetic | Room Temperature |
| Curie Temperature | 770°C | - |
| Poisson's Ratio | 0.27-0.30 | Room Temperature |
📏 Product Specifications
| Specification | Available Options | Standards |
|---|---|---|
| Product Forms | Round bars, flat bars, plates, sheets, forgings, tubes | ASTM A29, A108, A322 |
| Round Bar Diameter | 6mm - 500mm (0.25' - 20') | ASTM A29/A29M |
| Flat Bar Dimensions | Thickness: 3-100mm, Width: 10-300mm | ASTM A108 |
| Plate Thickness | 6mm - 200mm (0.25' - 8') | ASTM A29, A322 |
| Length | Up to 12 meters (custom lengths available) | Customer specification |
| Surface Finish | Hot rolled, cold drawn, turned, ground, polished | ASTM standards |
| Condition | Annealed, normalized, quenched & tempered | Customer specification |
| Tolerance | ±0.1mm to ±0.5mm depending on size | ASTM A29, ISO h11 |
| International Equivalents | 42CrMo4 (EN), SCM440 (JIS), 41Cr4 (DIN) | EN 10083, JIS G4105 |
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Our Advantages in Processing AISI 4140
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.
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.
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