Grade Overview

M2 Tool Steel — HS 6-5-2

M2 is a widely used high-speed steel grade, valued for its balanced alloy composition that provides superior toughness and excellent cutting-edge retention. As a general-purpose molybdenum-type high-speed steel, M2 offers an optimal blend of wear resistance, red hardness, and toughness. Compared to T1, M2 provides up to 50% higher bending strength, toughness, and thermal plasticity.

This grade is ideal for metal-cutting tools such as twist drills, milling cutters, thread dies and broaches, reamers, countersinks, circular saws, and shaping tools. It also performs exceptionally well for cold-forming tools, extrusion dies, precision cutting tools, high-wear plastic molds, and woodworking tools.

Chemical Composition

M2 Chemical Composition (%)

C	Si	Mn	P	S	Cr	Mo	V
0.78 - 0.88	0.20 - 0.45	0.15 - 0.40	0.03 max	0.03 max	3.75 - 4.50	4.50 - 5.50	1.75 - 2.20

Properties

Mechanical & Physical Properties

Mechanical Properties

Tensile Strength	1000–1400 MPa
Yield Strength	3250 MPa
Abrasion (as-hardened; ASTM G65)	25.8 mm³
Impact Toughness	67 J/cm²
Hardness	262 HRC
Modulus of Elasticity	207 GPa

Thermal Conductivity

Temperature	W/(m·K)
20°C	32.8
350°C	23.5
700°C	25.5

Heat Treatment

Heat Treatment & Processes

Proper heat treatment ensures M2 achieves optimal hardness and cutting performance.

Process	Temperature	Cooling	Result
Soft Annealing	770–860°C	Furnace	Max 269 HB
Stress-Relief Annealing	630–650°C	Furnace	—
Hardening	1190–1230°C	Salt Bath ≥550°C, Oil, or Air	64–66 HRC

Hardening Detail

1st Preheat	2nd & 3rd Preheat	Hardening °C	Quenching	Tempering °C	Hardness After Tempering
~400°C (Air Furnace)	850 / 1050	1190–1230	Salt Bath ≥550°C, Oil, or Air	Twice at 530–560	64–66 HRC

Hardening Process

Preheat in two stages at 450–500°C and 850–900°C, then heat to 1200–1250°C for final hardening. Avoid prolonged exposure at peak temperature. Quench in hot oil or brine and cool in air.

Tempering

Temper immediately after quenching. Typical range: 530–560°C. Hold for two hours, then air cool. Dual tempering is required; triple tempering is recommended for large or EDM-machined sections.

Forging & Annealing

Forging: Preheat gradually to 850–900°C, then increase to 1050–1150°C. Cool slowly after forging. Annealing: Heat at slow rate to 829–843°C, hold for two hours per inch of thickness, cool slowly. Nitriding: Performed at 500–600°C for 20–100 hours in nitrogen-rich ammonia gas chamber.