HSS M42 sheets

M42 high speed steel is a cobalt molybdenum tools steel, the addition of 8% cobalt means that M42 delivers superior red-hardness when compared to M2. The composition of M42 makes for a good balance of toughness and hardness and can be found widely used for all types of cutting tools, often used for machining materials and super alloys that are difficult to machine. M42 high speed steel has a heat-treated hardness in the range 68 to 70 HRC. 

Applications:

M42 is a high-speed steel for conditions that demand excellent hot hardness. M42 is suitable for cutting tools such as, twist drills, 

broaches, taps, milling cutters, saws, reamers, bandsaw blades and cold work tools. See our tool steel application chart

If the higher red-hardness of M42 if not required for your application then consider M2 high speed steel.       

Quick Detail:M42  sheets

COMPOSITION

RELATIVE PROPERTIES

PHYSICAL PROPERTIES

·  Density: 0.282 lb/in3 (7806 kg/m3)

· Specific Gravity: 7.81

· Modulus of Elasticity: 30 x 106 psi (207 GPa)

· Machinability: 35-40% of a 1% carbon steel

HEAT TREATING INSTRUCTIONS： HARDENING       

Preheating:Heat at a rate not exceeding 400°F per hour (222°C per hour) to 1500-1600°F (816-871°C), and equalize.

Austenitizing (High Heat):Heat rapidly from the preheat.

Furnace: 2150-2175°F (1177-1191°C)

Salt: 2125-2150°F (1163-1177°C)

To maximize toughness, use the lowest temperature.

To maximize hot hardness, use the highest temperature.

Quenching:Pressurized gas, warm oil, or salt. For pressurized gas, a rapid quench rate to below 1000°F

(538°C) is critical to obtain the desired properties. 

For oil, quench until black, about 900°F (482°C), then cool in still air to 150 -125°F (66-51°C).

For salt maintained at 1000-1100°F (538-593°C), equalize, then cool in still air to 150 -125°F (66-51°C).

Tempering:Temper immediately after quenching. Typical tempering range is 950-1050°F (510-566°C). Hold at temperature for 2 hours, then air cool to ambient temperature. Triple tempering is required.

ANNEALING

Annealing must be performed after hot working and before re-hardening.

Heat at a rate not exceeding 400°F per hour (222°C per hour) to 1500-1575°F (843-857°C), and hold for 1 hour per inch (25.4 mm) of thickness, 

minimum of 2 hours. Then cool slowly with the furnace at a rate not exceeding 50°F per hour (28°C per hour) to 1000°F (538°C). 

Continue cooling to ambient temperature in the furnace or in air. The resultant hardness should be 269 HBW or lower.

Forging M42

Pre-heat slowly to 650 - 760°C and soak. Increase more quickly to the forging temperature of 1010 - 1150°C and equalize prior to forging. 

If the temperature drops below 980°C re-heating will be required. Cool the M42 very slowly after forging.

(data sheet & typical analysis available on request).