M35

Drilling Tools – twist drills, step drills, and center drills for stainless steel, titanium, and high-strength alloys Milling Tools – end mills, slot mills, and form cutters requiring high wear resistance Tapping & Threading Tools – machine taps, hand taps, dies, and thread mills Broaching Tools – keyway broaches, spline broaches, and surface broaches for hard alloys Cutting Tools for Hard-to-Machine Materials – stainless steels, inconel, nickel-based alloys, and titanium alloys Sawing Tools – bandsaw blades and circular saws for alloy steels and nonferrous metals Reaming Tools – precision reamers for finishing holes in tough or hardened materials Precision Machining – cutting tools requiring long service life, heat resistance, and dimensional accuracy

M35 High Speed Steel is widely supplied by both domestic and international dealers who specialize in tool steels and high-performance cutting materials. These dealers ensure the availability of M35 in various forms and sizes, tailored to different industrial needs.

Annealed Condition: ~ 255 HB (approx. 25–27 HRC) Soft enough for machining before hardening Hardened & Tempered Condition: 64 – 66 HRC (typical range) Achieved after proper heat treatment (austenitizing, quenching, tempering) Hot Hardness (Red Hardness): Maintains cutting edge hardness up to 600–650 °C Superior to M2 due to 5% cobalt addition

Annealing: Heat to 850 – 900 °C Hold for 1 – 2 hours Cool slowly in the furnace (≤10 °C per hour) down to 600 °C, then air cool Hardness after annealing: ~255 HB (25–27 HRC): Stress Relieving Heat to 600 – 700 °C Hold for 1 hour Furnace cool to prevent cracking or distortion Hardening (Austenitizing & Quenching): Preheat in two stages: 450 – 500 °C then 850 – 900 °C Heat to 1180 – 1230 °C (austenitizing temperature) Hold uniformly, then quench in salt bath, oil, or high-pressure gas Hardness after hardening: ~66 HRC (before tempering) Tempering: Temper immediately after quenching to reduce brittleness Typical tempering range: 540 – 560 °C Triple tempering recommended (2 hours each time) for stability Final hardness after tempering: 64 – 66 HRC

Preheating: Stage 1: Heat to 450 – 500 °C Stage 2: Heat to 850 – 900 °C Purpose: to reduce thermal shock and ensure uniform heating Austenitizing: Heat to 1180 – 1230 °C (exact temperature depends on section size and furnace type) Hold at temperature until fully and uniformly heated Goal: dissolve alloying elements (W, Mo, V, Cr, Co) into austenite Quenching: Quench in salt bath, oil, or high-pressure gas For smaller tools, salt bath is preferred; for larger sections, oil or air blast quenching is used Result: forms a hard martensitic structure Hardness after Quenching: ~66 HRC (before tempering) Tempering Requirement: Immediate tempering is essential to relieve stresses and prevent cracking Usually performed 3 times at 540 – 560 °C, holding for 2 hours each

Preheating: Heat component to 300 – 500 °C before welding to reduce thermal shock. Welding Process: TIG (GTAW) or MMA (Shielded Metal Arc Welding) with matching high-speed steel electrodes. Use low heat input and short weld runs. Post-Weld Heat Treatment: Immediately temper at 540 – 560 °C to relieve stresses. In some cases, re-hardening and tempering may be required for restoring full properties. Filler Material: Use electrodes/rods compatible with high-speed steels (e.g., M2/M35-based fillers).

General Machinability: M35 has poor machinability compared to conventional tool steels due to its high hardness and cobalt content. Its machinability rating is about 40–50% of W1 (water-hardening tool steel). Requires specialized cutting tools and reduced cutting speeds. Condition for Machining: Best machined in the annealed condition (~255 HB / 25–27 HRC). In hardened condition (~64–66 HRC), machining is almost impossible; grinding is required. Recommended Cutting Methods: Carbide or ceramic cutting tools for machining in annealed state. Coolant is essential to reduce tool wear and overheating. Use rigid setups to avoid chatter and tool breakage. Grinding: After hardening, grinding is the preferred method for finishing. Requires suitable grinding wheels (aluminum oxide or CBN). Avoid overheating to prevent surface cracking.