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817M40 - 1.5% Nickel-Chromium-Molybdenum Through Hardening Steel

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817M40 grade steel is a general purpose steel used for a wide range of engineering parts.

It is capable of being heat treated to produce a wide range of tensile strengths combined with good ductility and resistance to shock.

It has good hardenability, enabling it to be used for medium tensile strengths in fairly large sections, and possesses good resistance to wear. At low temperatures good impact values can also be obtained.

Bars are often supplied in the hardened and tempered condition with a tensile strength range of 850-1000 N/mm². The material is readily machinable so that the components can be put into service without the cost of further treatment.

Bars can also be supplied in the softened state which require hardening and tempering, but give increased machinability.

Nickel-chromium-molybdenum steels benefit from a combination of alloying elements. Nickel imparts toughness; chromium depth of hardness; molybdenum inhibits temper brittleness and each element tends to reduce grain size.

Size Range

32mm - 860mm Dia

Typical applications of 817M40 grade steel

  • Shafts
  • Connection rod bolts
  • Push rods
  • Studs
  • Pinion sleeves
  • Mandrel bars for tube manufacturing
  • Breech mechanism parts
  • High-duty engine connecting rods
  • High temperature bolts in oil refining and steam installations
  • Various parts of machine tools, such as spindle gears, power transmission gears and slide cams

817M40 steel is still often referred to as EN24 steel - its equivalent grade under the previous BS 970: 1955 standard.

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