Characteristics of GB 4Cr5MoSiV Hot Working Die Steel

Characteristics of GB 4Cr5MoSiV Hot Working Die Steel
1. Excellent Thermal Strength and High-Temperature Stability
Composition Design: Contains 0.32%-0.45% carbon, 4.75%-5.50% chromium, 1.10%-1.75% molybdenum, and 0.80%-1.20% vanadium. The addition of chromium and molybdenum significantly enhances hardenability and resistance to temper softening, while vanadium refines grain structure, improving toughness and wear resistance.
Performance: Maintains high hardness and creep resistance at 600°C, with thermal strength far exceeding first-generation die steels (e.g., 5CrNiMo, 3Cr2W8V). Suitable for high-temperature die casting, hot extrusion, and other demanding applications.
2. High Toughness and Thermal Fatigue Resistance
Intermediate-Temperature Toughness: Exhibits superior toughness compared to similar steels in the 500-600°C range, effectively resisting thermal fatigue crack propagation.
Anti-Adhesion and Erosion Resistance: Forms a dense oxide film on the surface, reducing adhesion of molten metal. Particularly well-suited for aluminum alloy die-casting molds, with outstanding resistance to erosion by molten aluminum.
Data Support: Maintains high impact energy, with transverse impact absorption reaching up to 21.5 J (under specialized heat treatment), a 78% improvement over conventional processes.
3. Superior Hardenability and Dimensional Stability
Air Quenching Process: Air quenching at lower austenitizing temperatures (e.g., 1000-1010°C) minimizes heat treatment distortion and reduces scaling, making it ideal for precision mold manufacturing.
Hardenability: Fully hardens through air cooling in bars up to 100 mm in diameter, with pronounced secondary hardening effects and excellent temper resistance.
Dimensional Control: High-temperature tempering after wire electrical discharge machining (EDM) eliminates over 97% of residual stress, ensuring mold accuracy and reducing post-processing correction costs.
4. Good Wear Resistance and Surface Properties
Hardness Range: Achieves a hardness of 52-56 HRC after quenching, adjustable to 40-48 HRC after tempering to meet varying operational requirements.
Surface Hardening: Nitriding treatment further enhances surface hardness, wear resistance, and corrosion resistance, making it suitable for high-load, high-wear environments.
Comparative Advantage: Outperforms similar steels like SKD61 in wear resistance, particularly under high-temperature gradients.
5. Excellent Machinability and Weldability
Cutting Performance: With a hardness of ≤235HB after annealing, it is easy to machine and supports complex processes such as deep drawing and bending.
Weld Repair: Requires preheating and post-heating temperatures 50°C lower than those for SKD11 steel, simplifying repair welding and reducing the risk of brittleness in the heat-affected zone.
Surface Quality: Although polished surfaces exhibit a darker luster, corrosion resistance is superior to conventional cold work die steels, delaying rust formation and lowering maintenance costs.