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Features and Uses of H11 Hot Work Tool Steel
A 5% chromium hot work die steel with a lower vanadium content than the H13
type tool steel. It is air hardening with excellent non-deforming properties,
and is well suited to resist cracking or heat checking when water cooled in
service.
Typical applications of H11 include extrusion dies, pressure pads, extrusion
liners, blanking and bending tools, forgings punches and dies, hot brass
pressing dies, hot heading tools, pressure die casting dies and inserts for
aluminium alloys, die-holders, hot shearing and hot cropping blades.
This material is suitable for nitriding after heat treatment.
Available Forms
Working and Heat Treatment
Forging
Pre-heat to 790/820°C, raise the temperature rapidly to 1120/1160°C and
ensure the material is thoroughly soaked before commencing forging. Do not allow
the material to fall below 950°C, re-heat as often as required to complete the
forging. After completing the forging allow the material to cool in the furnace,
finished forging should be fully annealed.
Annealing
Soak thoroughly at 850/860°C, cool slowly in the furnace (20°C/hour max) .
Brinell hardness of 235 should result.
Stress Relieving
Heat uniformly to 650°C. Allow to equalise, remove from the furnace and
allow to cool in still air to room temperature.
Hardening
Preheat slowly to about 650/760°C then raise the temperature to 1000/1020°C
and soak for 30 min. To minimise decarburisation and scaling in heat treatment
parts should be hardened in an atmosphere controlled furnace or packed in a
neutral packing mixture (e.g. cast iron chips), if pack hardening ensure that
the parts are thoroughly soaked for the recommended time. Air cool from
the hardening temperature and ensure that the parts are tempered as soon as they
are hand warm.
Tempering
Temper in the range 560/600°C and soak for 1 hour per 25 mm of
section. Allow to cool to room temperature. Double tempering is recommended.
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