708M40 Alloy Steel

708M40 708M40T steel suppliers and stockholders. 708M40 is a high tensile steel supplied in round bar with delivery to the whole of the UK. 708M40 is a similar grade to 709M40 but with a variation in the molybdenum content. As a high quality alloy steel specification 708M40 is usually supplied heat treated to ‘T’ condition. This grade offers good ductility and shock resisting properties combined with resistance to wear. With these characteristics it is a popular high tensile engineering steel with a tensile of 850°-1000N/mm². At low temperatures it has reasonably good impact properties. It is also suitable for a variety of elevated temperature applications. For maximum wear and abrasion resistance the steel can be nitrided to give a shallow depth wear resistant case. Flame or induction hardening of 708M40T can give a case hardness of 50HRc or higher.

West Yorkshire Steel are suppliers of bright drawn bar and hot rolled black bar as full bars or cut pieces.

We welcome export enquiries for alloy steel. Contact our sales office and consult our shipping policy for further details.

Alternative grades we supply

605M36T | 709M40T | 817M40T | 826M40W | 835M30 | 535A99 | 655M13 | 722M24 | 905M39

Form of Supply

West Yorkshire Steel are stockholders and suppliers of round bar. Diameters can be sawn to your required lengths as one offs or multiple cut pieces. 708M40T centreless ground steel bar can be supplied, providing a high tensile steel precision ground bar to tight tolerances.

Click here to contact our experienced sales team who will assist you with your 708M40T enquiry.

  • Diameter

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708M40T is now widely used in areas such as the motor, oil and gas industries. Suitable for components such as shafts, gears, spindles, bolts, studs and a wide variety of applications where a good quality high tensile steel grade is required.

Carbon 0.36-0.44% Chromium 0.90-1.20%
Manganese 0.70-1.00% Molybdenum 0.15-0.25%
Silicon 0.10-0.35% Sulphur 0.040% max
Phosphorous 0.035% max

Preheat the steel carefully, then raise temperature to 850-1200°C for forging. Do not forge below 850°C. After forging this alloy steel, cool slowly in still air.

Heat the steel slowly to 680-700°C. Cool in air.

This grade is commonly supplied ready heat treated. If further heat treatment is required annealed 708M40 should be heated slowly to 860-890°C and after adequate soaking at this temperature quench in oil. Temper as soon as tools reach room temperature.

Heat the component carefully to a suitable temperature selected by reference to a tempering chart or table, soak at the temperature for two hours per 25mm of ruling section, then allow to cool in air. Tempering between 250-375°C is not advised as tempering within this range will seriously reduce the impact value.

Condition Tensile
S 775-925 585 14 16 223-277
T 850-1000 650 13 35 248-302
U 925-1075 755 12 42 269-331

(*subject to ruling section)

Heat treatment temperatures, including rate of heating, cooling and soaking times will vary due to factors such as the shape and size of each 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 708M40 alloy steel.

708M40T alloy steel is available with BS EN 10204 3.1 mill certificate, please request when placing any orders.

708M40T is supplied in accordance with our ISO 9001:2015 registration.