1.2343 hot work die steel is a high-performance German standard hot work tool steel, corresponding to the ASTM H11 steel grade in international standards. It belongs to the chromium-molybdenum-vanadium alloy system and is widely recognized for its excellent thermal stability, toughness, and wear resistance, making it a preferred material in industries where molds endure repeated high-temperature cycling and mechanical loads. Below is a detailed overview:
Chemical Composition
The typical chemical composition of 1.2343 hot work die steel is as follows:
Carbon (C): 0.32–0.42% (provides the basis for hardness and strength through heat treatment)
Chromium (Cr): 4.80–5.50% (enhances oxidation resistance, heat resistance, and hardenability)
Molybdenum (Mo): 1.00–1.50% (improves high-temperature strength, toughness, and thermal fatigue resistance)
Vanadium (V): 0.40–0.50% (refines grain structure, increases wear resistance, and stabilizes carbides at high temperatures)
Silicon (Si): 0.80–1.20% (aids in deoxidation, enhances heat resistance, and improves toughness)
Manganese (Mn): 0.20–0.50% (boosts hardenability and reduces brittleness)
Phosphorus (P): ≤0.030% (minimized to prevent embrittlement)
Sulfur (S): ≤0.030% (controlled to avoid reduced toughness and machinability issues)
Key Properties
1.2343 steel exhibits a balanced combination of properties tailored for hot work applications, ensuring reliability under extreme conditions:
Excellent Thermal Fatigue Resistance
Resists cracking caused by repeated heating (up to ~600°C) and cooling cycles, a critical feature for extending mold service life in high-temperature operations.
High Toughness and Ductility
Maintains good toughness even after heat treatment, reducing the risk of brittle fracture during heavy-duty processes like forging or die casting.
Superior Wear Resistance
Withstands abrasion and deformation under high-temperature friction, making it suitable for prolonged contact with hot workpieces or molten metals.
Good Hardenability and Heat Treatment Stability
Achieves uniform hardness across thick sections with minimal distortion during heat treatment, ensuring dimensional precision in complex molds.
Oxidation Resistance
Forms a protective oxide layer at elevated temperatures, reducing scaling and degradation when exposed to air or industrial atmospheres.
Physical Properties
Density: ~7.85 g/cm³
Thermal Expansion Coefficient: ~11.0×10⁻⁶/K (at 20–500°C)
Thermal Conductivity: ~35 W/(m·K) (at room temperature)
Melting Point: ~1450–1500°C
Mechanical Properties (After Heat Treatment)
Hardness: Typically 42–48 HRC (adjustable via tempering to balance wear resistance and toughness).
Tensile Strength (Rm): ~1200–1500 MPa
Yield Strength (Rp0.2): ~1000–1300 MPa
Elongation (A): ~10–15%
Impact Toughness (Charpy V-notch): ≥20 J/cm² (at room temperature, depending on heat treatment parameters).
Heat Treatment Process
Proper heat treatment is essential to unlock 1.2343’s optimal performance. The process typically includes:
Annealing
Purpose: Soften the steel for machining, relieve internal stress, and improve machinability.
Process: Heat to 830–860°C, hold for 2–4 hours, then furnace cool slowly (≤50°C/hour) to below 500°C before air cooling.
Result: Hardness ≤235 HBW, ensuring ease of machining.
Quenching
Purpose: Harden the steel by transforming austenite to martensite.
Preheating: Two stages—first at 650–750°C, then at 850–900°C (to avoid thermal shock and ensure uniform heating).
Austenitizing: Heat to 1000–1050°C, hold for 30–60 minutes (based on section thickness) to dissolve carbides evenly.
Cooling: Quench in oil or compressed air (oil for deeper hardness penetration; air for minimal distortion in large parts).
Tempering
Purpose: Relieve quenching stress, reduce brittleness, and optimize the balance between hardness and toughness.
Process: Temper at 500–650°C, hold for 2–4 hours per 25mm thickness, then air cool. Double tempering is recommended to eliminate retained austenite.
Result: Hardness adjusted to 42–48 HRC with enhanced thermal stability and toughness.
Application Fields
1.2343 hot work die steel is widely used in high-temperature manufacturing due to its versatile performance:
Die Casting Molds: Ideal for aluminum, magnesium, and zinc die casting (e.g., automotive engine parts, electronic enclosures, and household appliance components).
Hot Forging Dies: Suitable for forging steel, aluminum, and brass alloys (e.g., crankshafts, gears, and structural metal parts).
Extrusion Dies: Used for extrusion of non-ferrous metals like aluminum and copper (e.g., profiles, pipes, and heat sinks).
Hot Stamping Tools: Applied in hot stamping processes for high-strength steel components in automotive manufacturing (e.g., safety structural parts).
Industrial Furnace Components: Employed in parts requiring heat resistance, such as furnace fixtures and hot work holders.
1.2343 steel’s reliability and adaptability make it a staple in hot work applications, valued for its ability to maintain performance under the demanding conditions of high-temperature manufacturing.
