M2

Drill Bits – Used for drilling metal, wood, and plastic due to excellent edge retention and heat resistance. End Mills – Ideal for high-speed machining and milling operations in CNC and manual machines. Taps and Dies – Perfect for threading tools, offering long tool life and clean threads. Saw Blades – Used in power saws for cutting metals and hard materials. Reamers – Employed in precision hole-finishing applications where accuracy is crucial. Broaches – Applied in internal and surface broaching tools for forming complex shapes. Punches and Forming Tools – Suitable for cold forming and blanking of hard materials. Lathe Cutting Tools – Used in turning operations where consistent performance and durability are needed. Knives and Blades – Utilized in industrial and commercial knives for heavy-duty cutting. Woodworking Tools – Reliable in router bits, chisels, and planer blades requiring long-lasting sharpness.

We are a leading supplier, stockist, and dealer of M2 High-Speed Steel (HSS), catering to the needs of tool manufacturers, industrial fabricators, and engineering companies across India and abroad.

Annealed Condition: Brinell Hardness: ~220–280 HB Supplied soft for easier machining and tool shaping before heat treatment. Hardened and Tempered Condition: Rockwell Hardness (HRC): 62–66 HRC Achieved after proper hardening (austenitizing around 1210–1240 °C) and triple tempering at 540–560 °C. Red Hardness: Maintains hardness at elevated temperatures (up to ~600 °C) without losing cutting performance.

1. Preheating Purpose: Prevent thermal shock and ensure uniform heating. Steps: First preheat: 450–500 °C Second preheat: 820–870 °C Optional third preheat (for large tools): 1050–1150 °C Heating Rate: Slow, to avoid cracking. 2. Austenitizing (Hardening Heat) Temperature: 1190–1230 °C (typical: 1210–1220 °C) Holding Time: 2–5 minutes after the tool reaches temperature (longer for large parts). Atmosphere: Vacuum, protective gas, or salt bath to avoid decarburization. 3. Quenching Medium: Salt bath at ~550 °C, followed by air cooling. Alternative: High-pressure gas quenching in vacuum furnaces. Target Hardness after quench: 64–66 HRC. Cooling must be controlled to minimize distortion and cracking.

Preheating Why: Prevent cracking and reduce thermal shock. Steps: First preheat: 450–500 °C Second preheat: 820–870 °C (Optional for large tools) Third preheat: 1050–1150 °C 2. Austenitizing (Hardening Heat) Temperature Range: 1190–1230 °C Common choice: 1210–1220 °C Soaking Time: 2–5 minutes at temperature (longer for thick tools). Atmosphere: Vacuum furnace (best for surface quality) Protective gas Molten salt bath 3. Quenching Purpose: Rapid cooling to form martensite. Methods: Salt Bath Quench: First quench to ~550 °C salt bath, then air cool. Vacuum Furnace Quench: High-pressure gas (4–6 bar nitrogen). Oil Quench: Rare, only for small tools, due to cracking risk. Cooling Rate: Moderate — too fast may crack, too slow may retain austenite. Hardness After Quench: 64–66 HRC (before tempering).

1. Preparation Clean the surface: Remove oil, rust, coatings, and cracks should be ground out. Preheat Required: 250–300 °C minimum, often up to 400–500 °C for large tools. Preheat prevents cracking by reducing thermal shock and hardness gradient. 2. Welding Process Options TIG Welding (GTAW): Most common for tool repair. MMA (Stick) Welding: Can be used with special tool steel electrodes. Laser or Electron Beam Welding: Best for precision, low distortion. Powder Metallurgy Cladding / PTA Welding: For rebuilding cutting edges. 3. Filler Material Special tool steel filler rods matching HSS chemistry (often M2-compatible). For TIG: M2 HSS rods, or cobalt-based alloys (e.g. Stellite) when toughness is more important. In some repairs, high-speed steel powder welding rods are used. 4. Welding Technique Use short weld beads to limit heat buildup. Maintain interpass temperature around 250–350 °C. Peen lightly between passes to reduce stress. Keep the part in preheated condition throughout welding. 5. Post-Weld Heat Treatment (PWHT) Slow cooling: Wrap in insulating blanket or furnace cool to avoid cracking. Full re-heat treatment recommended if tool performance is critical: Re-austenitize: 1210–1220 °C Quench in salt bath or vacuum Triple temper at 550 °C For less critical repairs: Temper at 540–560 °C without full hardening. 6. Expected Hardness Weld metal and HAZ after full heat treatment: ~62–64 HRC Without proper PWHT, hardness and wear resistance drop significantly.

1.General Machinability Rating: Relative Machinability: ~40–50% (based on 1.0% carbon tool steel = 100%) Condition Matters: Annealed M2 (~230 HB / 22–24 HRC): Machinable Hardened M2 (62–66 HRC): Very difficult to machine — usually ground, EDM’d, or wire-cut 2. Recommended Condition for Machining Always machine in annealed state (softened), before hardening. After heat treatment, finishing is usually done by: Grinding Electrical Discharge Machining (EDM) Wire EDM (WEDM) 3. Cutting Tool Recommendations Tool Material: Carbide tools (best choice for productivity) Cobalt-based HSS (M42, T15) for drills and taps Ceramic or CBN (Cubic Boron Nitride) for hardened M2 Cutting Speeds: Very slow compared to plain steels. Carbide tools: 15–25 m/min HSS tools: 6–10 m/min Feed & Depth: Light to moderate cuts; heavy cuts increase tool wear quickly. 4. Coolant & Lubrication: Abundant coolant is mandatory to: Reduce heat Minimize tool wear Prevent work hardening Use water-soluble cutting fluid with EP (Extreme Pressure) additives. 5. Challenges in Machining M2: High tool wear due to hard carbides (vanadium, tungsten, molybdenum carbides). Work hardening tendency if cut improperly. Poor thermal conductivity, meaning heat concentrates at the cutting edge. BUE (Built-Up Edge) may form if speed and lubrication aren’t optimized. 6. Tips for Better Machinability: Always use the annealed condition before hardening. Prefer carbide tooling for milling, turning, and drilling. Keep cutting edges sharp. Apply rigid setups to prevent chatter. Use multiple roughing passes instead of one heavy cut. Finish with grinding or EDM after hardening.