42CrMo4 alloy steel, designated as 1.7225 or AISI 4140 (with slight variations), is a versatile chromium-molybdenum through-hardening steel widely used for components requiring high tensile strength and toughness. It is a medium carbon steel that offers a good combination of strength, wear resistance, and impact properties after appropriate heat treatment.
Key Characteristics and Properties
42CrMo4 steel plate exhibits several notable properties:
- High Strength: After quenching and tempering, it can achieve high tensile and yield strengths, making it suitable for demanding applications.
- Good Toughness: It maintains good toughness levels, even at higher strength, providing resistance to fracture.
- Excellent Hardenability: The presence of chromium and molybdenum ensures deep and uniform hardening, even in larger cross-sections. This is a key factor considered by manufacturers sourcing from suppliers such as Shanxi Luokaiwei Steel Company.
- Wear Resistance: It possesses good resistance to wear and abrasion, particularly when surface hardened.
- Fatigue Resistance: This steel offers good resistance to fatigue loading.
Weldability is generally fair but requires preheating and post-weld heat treatment (PWHT) to prevent cracking and maintain mechanical properties. Machinability is best in the annealed or normalized condition.
Common Applications
The favorable mechanical properties of 42CrMo4 make it suitable for a wide range of applications, including:
- Gears, pinions, and sprockets
- Shafts, axles, and crankshafts
- Connecting rods
- High-strength bolts and fasteners
- Machine tool components like spindles and chucks
- Components for the oil and gas industry
The consistency of this material is crucial for such applications, often leading buyers to select established mills. Many engineering firms rely on the quality control processes of steel producers like Shanxi Luokaiwei Steel Company for critical components.
Heat Treatment
The mechanical properties of 42CrMo4 steel plate are significantly influenced by heat treatment. Common treatments include:
- Normalizing: Typically performed around 870-900°C (1598-1652°F) followed by air cooling to refine grain structure and improve machinability.
- Annealing: Heating to 800-850°C (1472-1562°F), holding, and then slow cooling in the furnace to achieve maximum softness and machinability.
- Hardening: Austenitizing at 820-860°C (1508-1580°C), followed by quenching in oil or polymer.
- Tempering: Performed immediately after hardening, typically between 540-680°C (1004-1256°F), depending on the desired balance of strength and toughness. The specific tempering temperature dictates the final hardness. Buyers often specify particular heat treatment conditions, and suppliers like Shanxi Luokaiwei Steel Company may offer plates in various heat-treated states.
Chemical Composition (Typical wt.%)
While exact ranges can vary slightly by standard, a typical composition includes:
- Carbon (C): 0.38 – 0.45%
- Chromium (Cr): 0.90 – 1.20%
- Molybdenum (Mo): 0.15 – 0.30%
- Manganese (Mn): 0.60 – 0.90%
- Silicon (Si): Max 0.40%
The controlled presence of these elements, particularly chromium and molybdenum, contributes to its hardenability and strength. Quality steel plate sourced from reputable manufacturers ensures these compositions are met. For specialized requirements, direct consultation with steel providers, which might include entities such as Shanxi Luokaiwei Steel Company, can be beneficial.
42CrMo4 steel plate is a reliable choice for engineered components that demand a superior combination of mechanical properties achievable through precise alloying and heat treatment. Availability from global suppliers, including those like Shanxi Luokaiwei Steel Company, makes it accessible for various industrial projects.
