M-42 High Speed Tool Steel


M-42 is a molybdenum-chromium-vanadium-tungsten high speed steel alloy with an additional 8% cobalt. It is widely used in metal manufacturing because of its superior red-hardness as compared to more conventional high speed steels, allowing for shorter cycle times in production environments due to higher cutting speeds or from the increase in time between tool changes. M-42 is also less prone to chipping when used for interrupted cuts and cost less when compared to the same tool made of carbide.

Analysis:

C CO CR MN MO NI P S SI V W
1.05 - 1.157.75 - 8.753.50 - 4.250.15 - 0.409.00 - 10.00 0.15 - 0.650.95 - 1.351.15 - 1.85

Size Availability:

Flats • Hollowbar • Metric • Non-Standard • Rounds • Squares • Standard

Applications:

BroachesCold Extrusion PunchesCounter Bores
End MillsForm CuttersKeyway Cutters
Planer ToolsReamersRoll Turning Tools
Shaving ToolsTapsTwist Drills

Designations:

AISI M42 High Speed Steel-US
AFNOR 07-05-04-04-02-France
DIN 1.3246-Germany
ASTM A600-US
FED QQ-T-590-US
UNS T11342-US

TreatmentTemperature RangeCooling/QuenchingNotes
Forging1975-2025° FSlow.Cool slowly in dry sand or in other insulating media.
Annealing1550-1625° FCool slowly at a rate of 35° F per hour to 1000° F.For best results, insulating media is desirable. Hold at temperature for 2 hours.
Stress Relieving1100-1300° FCool slowlyStress relieve after rough machining
Preheating1500-1550° FPreheat time in furnace is ¾ Hr. per inch of thickness. Heating up to temperature as slow as possible.
Hardening2175-2200° F (furnace) 2150-2175° F (salt bath)Quench in air or warm oil. To minimize quenching strains, quench in salt at 1000° FFor maximum wear resistance, harden at 2200° F. For maximum toughness and high hardness, harden at 2150° F.
Tempering(See Chart)Double temper when using tempering temperature above 1000° F. Triple temper when using tempering temperatures below 1000° F. Recommended temperature is 950-1075° F
Data is typical and should not be construed as actual values for any category.
Applications and technical information require engineers and tool designers to exercise independent judgement.