S1 Tool Steel

S1 tool steel suppliers and stockholders. S1 is an alloy shock resisting tool steel supplied in round bar with delivery to the whole of the UK. S1 is suited for both hot and cold work applications. The tungsten content of this tool steel grade confers fatigue resistance, the chromium content gives depth of hardness and resistance to abrasion. S1 tool steel is suitable for cold work tools subject to heavy shock and uneven loading; for example, press tools used for punching heavy gauge material, shear blades, nut blanking tools, perforating and piercing punches. This steel is also used with great success for chisels and punches required for heavy work on hard and tough materials. S1 tool steel is resistant to heat checking. It is suitable for hot work applications where high fatigue strength in combination with medium hot hardness is desirable. Tools made from this tool steel may be water cooled in service with little risk of cracking.

We welcome export enquiries for tool steel. Please contact our sales office and consult our shipping policy for further details.

Related Specifications

AISI ASTM A681 DIN 17350 BS EN ISO 4957

Alternative tool steel grades we supply

O1 | D2 | D3 | O2 | D6 | A2 | H13 | P20 | P20S | 420 | 1.2083 | 2767 | M2 | M42 | 1.1730

Form of Supply

West Yorkshire Steel are stockholders and suppliers of round bar. Diameters in S1 can be sawn to your required lengths as one offs or multiple cut pieces. Ground tool steel bar can be supplied, providing a quality precision finished bar to your required tolerances.

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  • Diameter

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Typical hot work applications for S1 tool steel include mandrel bars for drawing steel tubes. Medium temperature applications include swaging, forming and gripper dies, also punching, piercing and trimming dies. Other applications include shear blades working at medium temperature including flying shear blades.

Carbon 0.50% Chromium 1.00%
Silicon 0.70% Tungsten 2.00%
Manganese 0.40% Vanadium 0.20%

Heat carefully to 1000-1050°C and forge with light rapid blows. Reheat when temperature falls below 900°C if further work remains to be done. After forging, cool slowly, preferably in a furnace.

Heat the S1 tool steel component slowly and uniformly to 800-810°C. Soak thoroughly for two to three hours and cool slowly in the furnace to room temperature.

For applications where distortion must be at a minimum or where the machining operations have been severe, we recommend stress relieving just before the tools are finish machined in order to relieve machining strains. Heat slowly to 700°C and allow to cool in the air.

Pre heat at 650°C followed by rapid increase of temperature to the hardening temperature of 900-950°C. Quench in oil.

Heat slowly to the required tempering temperature, soak thoroughly for two hours per 25mm section and allow to cool in still air. For hot work applications, a minimum tempering temperature of 550°C should be used.

Temperature [°C] 150 200 250 350 400
Hardness [HRc] 58-56 56-54 55-53 53-51 52-49

Typical physical properties at room temperature.

Modulus of elasticity 10³N/mm² :  210

Density kg/dm³ :  8.00

Thermal Conductivity W/(m.K) :  25.0

Electric resistivity Ohm.mm²/m :  0.30

Specific heat capacity J/(kg.K) :  460


Mean coefficient of thermal expansion (at varying temperatures)

Temperature 20-100°C 20-200°C 20-300°C 20-400°C 20-500°C
10-6 m/(m.K) 11.0 12.5 13.0 13.5 14.0

Heat treatment temperatures, including rate of heating, cooling and soaking times will vary due to factors such as the shape and size of each S1 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 S1 tool steel.

S1 tool steel is supplied in accordance with our ISO 9001:2015 registration.