4CrW2Si Tool Steel Properties

4CrW2Si tool steel is an alloy tool steel featuring Chromium (Cr), Tungsten (W), and Silicon (Si) as its principal alloying elements. This grade is known for its performance in specific tooling applications requiring a balance of strength, hardness, and toughness, particularly under impact conditions.

1. 4CrW2Si tool steel Chemical Composition (GB/T 1299—2000)

The typical chemical composition for 4CrW2Si steel is:

• Carbon (C): 0.35% – 0.45%
• Silicon (Si): 0.80% – 1.10%
• Manganese (Mn):≤ 0.40%
• Chromium (Cr): 1.00% – 1.30%
• Tungsten (W): 00% – 2.50%
• Phosphorus (P): ≤ 0.030%
• Sulfur (S): ≤ 0.030%
• Copper (Cu): ≤ 0.25% (Typical limit)
• Nickel (Ni): ≤ 0.25% (Typical limit)

2. 4CrW2Si tool steel Properties

2.1 Strengths

• Good strength and hardness, particularly at elevated temperatures.
• Achieves high toughness after appropriate tempering.
• Offers adequate hardenability and high-temperature strength.
• Relatively low sensitivity to decarburization, deformation, and cracking during heat treatment compared to other tool steels.
• While the base carbon content gives moderate initial hardness, carburizing followed by quenching significantly enhances surface hardness while maintaining core toughness, leading to excellent overall mechanical properties for demanding roles.

2.2 Considerations

• This steel grade is susceptible to decarburization; careful atmosphere control during heat treatment is necessary.
• Managing quenching distortion can require specific attention.
• Certain tool steels alloyed with molybdenum (Mo) or nickel (Ni) have lower abrasive wear resistance and impact toughness.

3. 4CrW2Si tool steel Applications

4CrW2Si is suitable for tools and dies operating under high impact loads. Common applications include:

• Pneumatic (wind-powered) tools
• Composite blanking and trimming dies
• Punching dies
• Cold-cutting shears
• Medium-stress hot forging dies
• Die-casting molds (for applications not exceeding moderate temperatures)
• Shear blades for cold metal
• Scrapers for thread rolling dies
• Die blocks for cold blanking and trimming
• Ejector pins and punches
• Woodworking tools
• Smaller hot work dies

After carburizing and quenching, it can also be used for:

• Heavy-duty cold stamping dies
• Large and medium-sized heavy-duty cold heading punches
• Precision pressing dies

4. 4CrW2Si tool steel Heat Treatment Guidelines

4.1 Annealing / Pre-treatment

• Standard Annealing: Heat to 800-820°C, hold 3-5 hours. Furnace cool to below 550°C, then air cool. Target hardness: 229-285 HBW (Structure: Granular pearlite + small carbides).
• High-Temperature Tempering (for improved machinability): Heat to 710-740°C, hold 3-6 hours. Furnace cool or air cool.

4.2 Hardening (Quenching)

• Quench Temperature: 860-900°C
• Quench Medium: Oil (typically 20-40°C)
• Expected Hardness (As-Quenched): ≥53 HRC

4.3 Tempering

• Temper immediately after quenching to achieve the desired final properties and relieve stress.
• For High Hardness (Stress Relief/Stabilization): Temper at 200-250°C (Oil or molten salt). Air cool. Expected hardness: 53-58 HRC.
• For Increased Toughness (Lower Hardness): Temper at 430-470°C (Air furnace, salt bath, or molten alkali) and air cool. Expected hardness: 45-50 HRC.
• (Note: Hardness decreases as tempering temperature increases. Example: After 880°C oil quench, 2 hr temper at 100°C ≈ 54 HRC; 2 hr temper at 600°C ≈ 32 HRC.

5. 4CrW2Si tool steel Forging Recommendations

5.1 Heating Temperature:

• Ingots: 1180-1200°C
• Billets: 1150-1170°C

5.2 Initial Forging Temperature:

• Ingots: 1150-1180°C
• Billets: 1120-1150°C

5.3 Finishing Forging Temperature: ≥850°C

5.4 Post-Forging Cooling: Slow cooling is recommended.