Description
42CrMo4 Grade Introduction:
42CrMo4, also known as SAE-AISI 4140, is a low-alloy steel known for its high strength and hardness. It is commonly used in the manufacture of round bars for machinery and OEM auto components. These round bars are produced from prime quality billets and blooms, ensuring superior quality. 42CrMo4 is a medium carbon steel with chromium and molybdenum as key alloying elements, offering excellent toughness, wear resistance, and resistance to high stress. The steel is typically supplied in a hardened and tempered condition (T condition) for enhanced machinability and durability.
42CrMo4 Grade Application:
42CrMo4 alloy steel is extensively used in engineering applications, including:
- Machinery components
- Automobile parts
- Mining equipment
- Engine gearwheels and driving gears
- High-pressure components like pins and connecting rods
- Powertrain applications
- Cold-formed fasteners
- Shafts, gears, and drill collars in oil exploration
42CrMo4 Equivalent Grades:
The following are equivalent grades for 42CrMo4 steel:
- AISI 4140
- SAE 4140
- DIN 1.7225
42CrMo4 Chemical Composition:
| Element | Content (%) |
|---|---|
| Carbon (C) | 0.38-0.45 |
| Silicon (Si) | Max 0.40 |
| Manganese (Mn) | 0.60-0.90 |
| Phosphorus (P) | Max 0.035 |
| Sulfur (S) | Max 0.035 |
| Chromium (Cr) | 0.90-1.20 |
| Molybdenum (Mo) | 0.15-0.30 |
42CrMo4 Mechanical Properties:
| Size (Ø mm) | Yield Stress (Rp0.2, N/mm²) | Ultimate Tensile Strength (Rm, N/mm²) | Elongation (A5, %) | Hardness (HB) | Toughness (KV, Joule, min.) |
|---|---|---|---|---|---|
| <40 | 750 | 1000-1200 | 11 | 295-355 | 35 at 20°C |
| 40-95 | 650 | 900-1100 | 12 | 265-325 | 35 at 20°C |
| >95 | 550 | 800-950 | 13 | 235-295 | 35 at 20°C |
42CrMo4 Hardness:
The hardness of 42CrMo4 alloy steel typically ranges between 295-355 HB.
42CrMo4 Heat Treatment:
42CrMo4 alloy steel responds well to heat treatment processes, particularly quenching and tempering, which optimize its strength and toughness. After oil quenching, hardness is achieved up to 60 mm diameter bar size. However, for larger sizes, the steel may not fully convert to martensite.
42CrMo4 Hardening:
To harden 42CrMo4:
- First quench at 880°C, followed by adequate soaking and quenching in oil or water.
- Second quenching at 780-820°C, followed by quenching in oil or water.
42CrMo4 Tempering:
Tempering should be done by heating the steel to 205-649°C, followed by cooling in water or oil. The standard delivery hardness is 18-22 HRC.
42CrMo4 Physical Properties:
| Property | Value | Unit |
|---|---|---|
| Thermal expansion | 10 e-6/K | |
| Thermal conductivity | 25 W/m·K | |
| Specific heat | 460 J/kg·K | |
| Melting temperature | 1450°C | |
| Density | 7700 kg/m³ | |
| Resistivity | 0.55 Ohm·mm²/m |
42CrMo4 Thermal Properties:
- Thermal conductivity: 0.42 kW/(cm·K)
42CrMo4 Forging Properties:
42CrMo4 can be forged at temperatures ranging between 926 to 1205°C.
42CrMo4 Stress Relieving:
The stress-relieving process is done between 450-650°C.
42CrMo4 Normalizing:
42CrMo4 is normalized by heating to 840-880°C.
42CrMo4 Annealing:
The annealing process involves:
- Heating slowly to 800-850°C.
- Cooling gradually in the furnace to 480°C.
- Final cooling in the air.
42CrMo4 Density:
The density of 42CrMo4 steel is 7.85 kg/m³.
42CrMo4 Machinability:
42CrMo4 alloy steel exhibits good machinability when annealed, making it easier to machine and shape.
42CrMo4 Welding:
While 42CrMo4 can be welded, it is typically recommended to preheat before welding to avoid cracking. Proper post-weld heat treatment is also required to restore mechanical properties.
Supply Cities:
Mumbai Ahmedabad, Amaravathi, Ambattur, Bangalore, Belgaum, Chennai, Chittoor, Coimbatore, Dindigul, Mysore, Nellore, Hyderabad, Kochi, Mangalore, Tirupur, Tuticorin, Madurai, Andhra Pradesh, Karnataka, Puducherry, Kerala, Tamil Nadu, Telangana, Visakhapatnam, Kochi, Kerala, Hubli-Dharwad, Karnataka, Ghaziabad Kolkata.
