Popular Steel Corporation

M42 HIGH SPEED STEEL .Chemical composition
The chemical composition of M42 molybdenum high speed tool steel is outlined in the following table.
ElementsMinMaxCarbon, C0.700.85Manganese, Mn-.--0.40Silicon, Si-.--0.40Molybdenum, Mo----Chromium,Cr3.804.50W17.0019.00V0.801.20Co4.505.50Physical Properties
The table below shows the physical properties of M42 molybdenum high speed tool steel.
PropertiesMetricImperialDensity7.81 g/cm30.282 lb/in3Mechanical Properties PropertiesMetricImperialHardness, Rockwell C (oil quenched from 1204°C, 5 minutes)64.364.3Hardness, Rockwell C (oil quenched from 1177°C, 5 minutes)65.565.5Hardness, Rockwell C(oil quenched from 1163°C)65.865.8Izod impact unnotched (oil quenched at 1191°C; 510°C temper temperature)13.6 J10.0 ft- lbIzod impact unnotched (oil quenched at 1191°C; 622°C temper temperature)24.4 J25.8Machinability (1% carbon steel)35.0 - 40.0%35.0 - 40.0%Poisson's ratio0.27-0.300.27-0.30Elastic modulus190-210 GPa27557-30458 ksiOther Designations

Equivalent materials to M42 molybdenum high speed tool steel are:

• AFNOR 07-05-04-04-02

• DIN 1.3246

• ASTM A600

• FED QQ-T-590

• UNS T11342

• DIN 1.3247

Machinability
M42 tool steel can be drilled, turned, threaded, broached, milled and tapped when it is in its annealed condition and rated at 45% of 1% carbon steel.
Forging
M42 molybdenum high speed tool steel is preheated to 871°C (1599°F) in a slow manner and then soaked. This is followed by rapid heating to 1093°C (1999°F) and slow cooling. Temperatures below 982°C (1799°F) are not suitable for the forging process.
Tempering
M42 tool steel is tempered for three times at 538-593°C (1000-1099°F) and then cooled completely between cycles to obtain good results. Tempering is performed in vacuum furnaces or in salt baths.
Annealing
M42 tool steel is heated at 871°C (1599°F) and then cooled slowly in a furnace.
Hardening
M42 tool steel is preheated to 871°C (1599°F), soaked and finally heated to 1204°C (2199°F)
Quenching
A salt media is used for quenching M42 tool steel at 538°C (1000°F) and then the steel is air cooled.
Heat Treatment
Heat treatment temperatures, including rate of heating, cooling and soaking times will vary due to factors such as the shape and size of each M42 steel component. Other considerations during the heat treatment process include the type of furnace, quenching medium and work piece transfer facilities. Please consult your heat treatment provider for full guidance on heat treatment of high speed steels
Stress Relieving
If tools produced from M42 high speed steel are heavily machined or ground it is recommended to stress relieve after machining and prior to hardening to minimise the possibility of distortion. To stress relieve heat the component to 600-650°C and soak well (approximately two hours) Cool slowly in the furnace. The M42 tools can be finish machined before heat treatment.

M35) 5% Cobalt tool bits are designed for heavy duty machining alloy steels and tough materials, such as castings and forgings. They have high heat and abrasion resistant properties and are best used when making heavy cuts, at high speeds and feeds, or where high heat is a factor.

The mechanical properties of M35 molybdenum high speed tool steels are tabulated below.

The following table shows the thermal properties of M35 molybdenum high speed tool steels.

Used in conditions where the demand for hot hardness is important. It is also a good quality wear resistant grade for cold work applications. Commonly used for cutting tools including broaches, milling cutters, reamers, end mills and saw blades.Twist drills, taps, knives, and hobs.