4Cr5W2VSi Hot Work Tool Steel Technical Overview

4Cr5W2VSi Tool Steel is an air-hardening, hot-work tool steel. This means it’s designed specifically for tooling that operates under high temperatures and stress. You might also see it referred to as a w(Cr)5% type hot work die steel. It’s a solid choice for many factory tooling needs.

1.  4Cr5W2VSi Tool Steel Chemical Composition

A typical chemical composition (weight%) for this grade is:

• C: 0.32-0.42%
• Mn: ≤0.40%
• Cr: 4.50-5.50%
• W: 1.60-2.40%
• V: 0.60-1.00%
• P: ≤0.030%
• S: ≤0.030%

These elements combine to deliver the performance characteristics mentioned earlier.

2. 4Cr5W2VSi Tool Steel Characteristics

This grade offers a good balance of essential properties for hot work applications:

• High Hardness & Thermal Strength: Especially effective at medium operating temperatures, helping tools maintain their shape.
• Good Toughness: Resists cracking and fracturing under impact, common in forging or pressing.
• Good Wear Resistance: This contributes to longer tool life by reducing material loss due to friction.
• Good Thermal Fatigue Performance: Withstands the stress of repeated heating and cooling cycles typical in hot work processes.

3.  4Cr5W2VSi Tool Steel Equivalents

To ensure clarity across different standards, 4Cr5W2VSi Tool Steel is equivalent to several international designations:

• JIS: SKD62
• AISI: H12
• DIN: X37CrMoW5-1 (Material No. 1.2606)
• BS: BH12
• NF: Z35CWDV5
• UNS: T20812
• Böhler: W320
• KS: TD62

Knowing these equivalents helps in accurate material selection, which is something we always emphasize at Aobo Steel.

4.  4Cr5W2VSi Tool Steel Heat Treatment Procedures

Proper heat treatment is essential for achieving optimal performance from 4Cr5W2VSi Tool Steel.

4.1 Forging

• Start Temperature: 1100-1150°C
• End Temperature: 850-900°C
• Cooling: Slow cooling after forging (e.g., in sand or a cooling pit).

4.2 Annealing / Stress Relieving

• Post-Forging Anneal: Heat to 860-880°C, hold 3-4 hours, furnace cool to <500°C, then air cool. Target hardness: ≤229 HBW.
• Isothermal Spheroidizing Anneal: Heat to 860°C (hold for 2-4 hours), then isothermally hold at 750°C (4-6 hours). Furnace cooled to <550°C, followed by air cooling. Target hardness: ≤229 HBW.
• Stress Relieving: Heat to 750-780°C, hold 2-4 hours, furnace or air cool.

4.3 Hardening and Tempering

• Quenching: Heat to 1030-1080°C. Cool in oil (20-40°C) or air. Expected hardness: 53-58 HRC. (Note: Higher quench temps can increase hardness but may result in coarser grain size.)
• Tempering: Temper between 550 °C and 650°C (air cool). A double temper is often recommended, with the second temper being 10-20°C lower than the first. Tempering around 560-580°C typically yields 47-49 HRC. The chosen temperature affects the final balance of hardness and toughness.

5. Typical Applications

Thanks to its properties, 4Cr5W2VSi Tool Steel is widely used for:

• Hot extrusion dies and mandrels, especially for aluminum and zinc.
• Forging dies (hammer and press dies).
• Punches (e.g., for high-speed hammer forging).
• Die-casting molds, especially for zinc alloys.
• Shear blades for hot-rolled materials.
• Certain types of plastic molds.

6. Surface Treatments for Enhanced Performance

The performance of 4Cr5W2VSi Tool Steel can be further improved with surface treatments like:

• Nitriding: Enhances wear and corrosion resistance, making it particularly useful for die-casting molds.
• Chromium-Vanadium Co-deposition + Ion Nitriding: Significantly enhances wear and oxidation resistance, making it beneficial for applications such as aluminum extrusion dies.

Working with Aobo Steel

At Aobo Steel, we have extensive experience supplying 4Cr5W2VSi Tool Steel and other tool steels. With over 20 years of experience in forging and a network of reliable suppliers, we can provide high-quality materials and practical advice tailored to your specific needs. If you have questions about using 4Cr5W2VSi for your specific applications, please don’t hesitate to contact us at sales@aobosteel.com. We focus on providing solutions.