4Cr5MoSiV1 Hot Work Tool Steel

At Aobo Steel, we work extensively with 4Cr5MoSiV1 hot work tool steel, also known internationally as H13 (AISI) or SKD61 (JIS). With over 20 years of specialization in tool steel forging, we have a thorough understanding of this material’s capabilities and applications. This chromium-molybdenum hot work tool steel is a reliable choice for demanding applications, offering a strong balance of toughness and performance at high temperatures.

1.  4Cr5MoSiV1 Tool Steel Chemical Composition

Understanding the composition is key to understanding performance. The typical chemical breakdown (by weight%) for 4Cr5MoSiV1 is:

• Uhlík (C): 0.32% – 0.45%
• Křemík (Si): 0.80% – 1.20%
• Mangan (Mn): 0.20% – 0.50%
• Chrom (Cr): 4.75% – 5.50%
• Molybden (Mo): 1.10% – 1.75%
• Vanad (V): 0.80% – 1.20%
• Fosfor (P):≤ 0,030%
• Síra (S):≤ 0,030%

These elements work together:

• Chromium: Boosts hardness and resistance to wear.
• Molybdenum: Critical for strength and creep resistance at high temperatures.
• Vanadium: Enhances wear resistance and refines the grain structure for improved toughness.
• Silicon & Manganese: Aid in deoxidation and contribute to hardenability and strength.

2. Key Properties and Performance Characteristics

Based on our experience, 4Cr5MoSiV1 offers several advantages:

• Air Hardening: This simplifies heat treatment and reduces the risk of distortion compared to oil-hardening steels.
• High-Temperature Strength: It maintains hardness and strength effectively at elevated working temperatures.
• Good Toughness & Thermal Fatigue Resistance: Essential for tools undergoing repeated heating and cooling cycles.
• Odolnost proti opotřebení: Offers durability in contact-heavy applications.
• Scale Resistance: Reduced tendency to form scale during air quenching.

It’s essential to manage hardness correctly; excessive hardness can sometimes lead to fatigue issues, particularly in applications such as aluminum die casting. We generally advise a maximum service temperature of around 600°C.

3. Nástrojová ocel 4Cr5MoSiV1 Heat Treatment Guidelines

Proper heat treatment is crucial for achieving the desired properties. Aobo Steel has extensive experience controlling these processes.

3.1 Žíhání

• Proces: Heat to 860-890°C, hold for 3-4 hours, furnace cool to 500°C, then air cool.
• Target Hardness: ≤ 229 HBW.

3.2 Hardening

• Austenitizace: Heat to 1020-1080°C.
• Kalení: Oil or air cool.
• Resultant Hardness: Typically 56-58 HRC.
• Grain Size: ASTM 8-11 (depending on quench temperature).

3.3 Tempering

• Proces: Usually tempered between 560-580°C, air cooled. Double tempering is common, with the second temper being slightly cooler.
• Typical Hardness: 47-49 HRC.
• Poznámka: Specific applications (e.g., large forging dies, die casting molds) may require adjusted temperatures and hardness targets (e.g., 37-41 HRC or 42-47 HRC). Stress relieving at ~200°C after machining is also an option.

3.4 Surface Treatments

• Nitriding: Gas nitriding can be applied after hardening and tempering (e.g., base 32-38 HRC or 46-50 HRC) to significantly increase surface hardness and wear resistance, which is particularly common in aluminum extrusion dies.

4. Nástrojová ocel 4Cr5MoSiV1 Běžné aplikace

Thanks to its versatility, 4Cr5MoSiV1 is used across many industries:

• Die Casting: Dies for aluminum and copper alloys, with a primary application.
• Hot Extrusion: Dies for aluminum, copper, and sometimes steel.
• Kování: Fabricating hammer and press forging dies, punches, and core pins.
• Plastic Molding: Injection molds for polymers like polycarbonate and polyamide.
• Konstrukční komponenty: Mid-temperature (400-500°C) parts in aerospace applications.

5. Material Quality and Supply

The consistency and purity of 4Cr5MoSiV1 directly impact tool life and performance. Factors like precise chemical control, low phosphorus and sulfur levels, and minimal inclusions are critical. At Aobo Steel, we leverage our network of over 40 stable suppliers and our extensive forging expertise to ensure the highest quality materials. Processes like Electroslag Remelting (ESR) can be utilized to produce cleaner, more homogeneous steel for demanding applications that require superior polishability or fatigue resistance.

6. Machining Considerations

Machining 4Cr5MoSiV1, particularly after hardening, requires the use of appropriate tooling and techniques. We generally recommend performing rough machining operations before heat treatment to simplify the process.

If you have specific requirements for your 4Cr5MoSiV1 application, contact us at Aobo Steel. With our deep knowledge of tool steel, we can provide the right material and technical support.