Pre heat the M35 high speed steel slowly and uniformly to
450-500°C and equalise. Then increase more quickly to the forging
temperature of 950-1100°C and equalise prior to forging. Do not allow
the forging temperature to drop below 950°C, if this occurs re heating
will be necessary. Always cool the steel very slowly after forging.
M35 is supplied in the annealed and machineable
condition. Re annealing will only be necessary if the steel has been hot
worked, forged, or hardened by the toolmaker. Heat the M35 high speed steel
to 850°C at a rate of no more than 220°C per hour. Always hold at
temperature for one hour per 25mm of thickness (with two hours being
minimum). Furnace cool slowly. The M35 annealed hardness achieved should be
260 Brinell or lower.
Stress Relieving :
If tools produced from M35 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 600-700°C and soak well (approx
2 hours) Cool slowly in the furnace. The tools can be finish machined before
For best results harden in a vacuum or controlled
furnace, or in a properly rectified salt bath. Pre heat thoroughly in two
steps to 450-500°C, then to 820-870°C, transfer to the high
temperature salt bath or furnace. The exact hardening temperature to use for
M35 will depend on the type of work being treated, but in general components
should be hardened from the range of 1050-1250°C.
M35 high speed steel components can be tempered between
510-620°C. Triple tempering is recommended with a minimum of two hours
at temperature per cycle. The component should be cooled in still air to
room temperature between tempering treatments.
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 M35 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.
Final Grinding :
Select the correct grade of wheel in consultation
with the grinding wheel supplier. Ensure the grinding wheel is in good
condition by means of a suitable dressing tool. Wet grinding is a preferable
option using a copious supply of coolant. If dry grinding is resorted to
then use a very soft wheel.