1.3343 high-speed steel (HSS) is a premium German standard high-speed tool steel, belonging to the tungsten-molybdenum-vanadium alloy system. It is renowned for its exceptional hot hardness, wear resistance, and red hardness (ability to retain hardness at elevated temperatures), making it a top choice for cutting tools that operate at high speeds and temperatures. Below is a detailed overview:
Chemical Composition
The typical chemical composition of 1.3343 high-speed steel is as follows:
Carbon (C): 0.75–0.85% (forms hard carbides with alloying elements, enhancing wear resistance and hardness)
Tungsten (W): 5.50–6.75% (improves red hardness and high-temperature strength, a key element for high-speed cutting)
Molybdenum (Mo): 4.50–5.50% (works synergistically with tungsten to boost hot hardness and toughness)
Chromium (Cr): 3.80–4.50% (enhances hardenability, oxidation resistance, and edge retention)
Vanadium (V): 1.70–2.10% (forms hard vanadium carbides, improving wear resistance and grain refinement)
Cobalt (Co): 4.50–5.50% (increases red hardness and high-temperature strength, critical for heavy-duty cutting)
Silicon (Si): ≤0.45% (aids in deoxidation and improves mechanical properties)
Manganese (Mn): ≤0.40% (enhances hardenability)
Key Properties
1.3343 high-speed steel is engineered to excel in high-performance cutting applications, with properties optimized for extreme conditions:
Excellent Red Hardness
Maintains hardness and cutting performance at elevated temperatures (up to ~600–650°C), allowing for high-speed machining without significant softening. This is crucial for continuous cutting operations where frictional heat is intense.
Superior Wear Resistance
The formation of hard carbides (tungsten, vanadium, and chromium carbides) provides exceptional resistance to abrasion and edge wear, extending tool life even when cutting hard or abrasive materials (e.g., alloy steels, cast irons).
High Toughness
Compared to some other high-speed steels, 1.3343 offers a better balance of toughness and hardness, reducing the risk of chipping or breakage during interrupted cutting or heavy-duty operations.
Good Hardenability
Achieves uniform hardness across thick sections, ensuring consistent performance in large or complex tool geometries.
Machinability in Annealed State
In its annealed form, it can be machined (milled, ground, or shaped) with relative ease before final heat treatment, allowing for precise tool manufacturing.
Physical Properties
Density: ~8.2–8.4 g/cm³
Melting Point: ~1300–1390°C
Thermal Expansion Coefficient: ~10.5×10⁻⁶/K (at 20–500°C)
Thermal Conductivity: ~25 W/(m·K) (at room temperature)
Mechanical Properties (After Heat Treatment)
Hardness: 63–66 HRC (after quenching and tempering, ensuring high wear resistance)
Tensile Strength (Rm): ~2000–2400 MPa
Compressive Strength: ~3500–4000 MPa
Impact Toughness (Charpy V-notch): ~10–15 J/cm² (at room temperature, considering its high hardness)
Heat Treatment Process
Heat treatment is critical to unlock 1.3343’s full potential as a high-speed cutting tool:
Annealing
Purpose: Soften the steel for machining and reduce internal stress.
Process: Heat to 850–880°C, hold for 2–4 hours, then furnace cool slowly (≤10°C/hour) to 600°C before air cooling.
Result: Hardness ≤255 HBW, improving machinability.
Quenching
Purpose: Harden the steel by forming martensite and dissolving carbides for optimal hot hardness.
Preheating: Two stages—first at 600–650°C, then at 850–900°C (to avoid thermal shock and ensure uniform heating).
Austenitizing: Heat to 1180–1220°C, hold for 10–20 minutes (depending on section size) to dissolve carbides evenly.
Cooling: Quench in oil or air (high-pressure gas quenching is common for complex tools to minimize distortion).
Tempering
Purpose: Relieve quenching stress, enhance toughness, and precipitate fine carbides to maximize red hardness.
Process: Temper at 540–580°C, hold for 1–2 hours per cycle, and repeat 2–3 times (triple tempering is standard). Air cool after each cycle.
Result: Hardness of 63–66 HRC with optimal balance of wear resistance and high-temperature performance.
Application Fields
1.3343 high-speed steel is widely used in the manufacturing of high-performance cutting tools for demanding machining operations:
Metal Cutting Tools: Ideal for drills, end mills, reamers, taps, and broaches used in high-speed machining of alloy steels, stainless steels, and cast irons.
Heavy-Duty Cutting Tools: Suitable for tools used in roughing operations, interrupted cutting, and machining of hard materials (up to 30–35 HRC), where toughness and wear resistance are critical.
Cold Work Tools: Used for punches, dies, and shear blades in cold forming applications, leveraging its high hardness and wear resistance.
Woodworking Tools: Applied in high-speed woodworking cutters, where heat resistance prevents edge softening during continuous operation.
Comparison with Other High-Speed Steels
Feature 1.3343 High-Speed Steel T1 (W18Cr4V) High-Speed Steel M2 (W6Mo5Cr4V2) High-Speed Steel
Alloy Focus Tungsten-molybdenum-cobalt Tungsten-dominated Tungsten-molybdenum
Red Hardness Excellent (with cobalt) Good Very Good
Toughness Good Lower Better than T1
Wear Resistance Very High High High
Best For Heavy-duty, high-temperature cutting General high-speed cutting Balanced performance, cost-effective
1.3343 high-speed steel’s exceptional combination of red hardness, wear resistance, and toughness makes it a premium choice for high-performance cutting tools, ensuring reliability and long service life in the most demanding machining applications.