A.I.S.I.-S.A.E. Tool Steel (Hl3) Type

Composite Forgings Ltd. THERMONEAL is a tough hot work steel suitable for tools requiring a higher degree of toughness at moderately elevated temperatures than is obtainable in the Tungsten types of hot work steel. It is an outstanding die casting steel particularly for Lead, Zinc, Aluminum, Magnesium and low temperature Brass. It is also economical to use for long run Zinc dies and inserts.

GENERAL CHARACTERISTICS

The Vanadium content of THERMONEAL increases its resistance to wash caused by the erosive actions of molten die casting alloy, increases its resistance to heat checking and imparts superior properties at elevated temperatures. This alloy also has excellent impact strength to resist cleavage cracking. It is easy to machine, is air hardening and non-deforming and can be water cooled in service if desired.

THERMONEAL also has excellent size change characteristics. It will normally grow slightly when heat treated. Since it is an air hardening steel, it combines the advantages of both heat treatment and resistance to deformation during hardening. Thus it can be used for complicated and intricate sections with little danger of excessive distortion during heat treatment. Our special annealing process after forging enhances the properties of THERMONEAL.

ANNEALING

Heat to 1625°F, hold at temperature until heated through and cool slowly in furnace.

For Cycle Annealing, heat to 1625°F, hold for two (2) hours minimum, cool to 1400°F. I hold four (4) to six (6) hours. It is very important that actual temperature of the steel be maintained for the stated times, consequently furnace temperatures may be maintained for longer times depending on size, otherwise unsatisfactory results may be obtained. The steel then may be cooled in air if desired. THERMONEAL should always be annealed after forging and slow cooling, and before hardening.

HARDENING

In order to prevent any possibility of decarburization on finished tools during hardening, it is desirable to use an atmospheric controlled furnace. When this is not available, pack hardening is recommended. Wrap tools in paper and pack in container with an inert material such as six to eight mesh spent pitch coke. Preheat thoroughly at 1400/1500°F

then heat to 1850/1870°F. and hold until heated through. Cool in air below 150°F or to a temperature at which tools may be held in the bare hands before tempering. Soaking at temperature aids in maintaining hardness at high temperature.

TEMPERING

If hardened at 1850/1870°F, temper immediately, holding at tempering temperature two (2) hours per inch of greatest thickness up to and including two (2) inches increasing one (1) hour for each one (1) inch increase over two (2) inches. Air cool to room temperature. Double tempering is recommended, hold at temperature one half of the required single temper time and air cool to room temperature. Reheat to the same temperature, hold same period of time and air cool to room temperature.

SURFACE PROTECTION

Surface protection of finished tools may be provided by one of the following methods:

1. Diffused Nickel-Cadmium Plating for corrosion and oxidation resistance up to I000°F.
2. Hot Dip Aluminizing for oxidation resistance up to 1700°F.
3. Silicon paint for oxidation resistance up to I000°F.
4. Nitriding for wear resistance.

It is recommended that nitriding not be used on thin or intricate sections as the nitriding treatment will embrittle these sections and cause premature failure.

NITRIDING

Where a high wear resistant surface is needed to retard washing and soldering, gas nitriding is employed. This heat treatment is used after all grinding and polishing has been done.

Dies and inserts should be given a gas nitriding treatment for 10 to 12 hours at 950°F. This treatment should result in a case of approximately .004 to .005 inch.

Other products such as sleeves, plungers, etc., may be treated for 40 to 50 hours at 950°F. with a resulting case of approximately .012 to .015 inch.

RECOMMENDED APPLICATIONS

Extrusion Rams
Extrusion Liners
Mandrels
Punches for Aluminum-Brass
Piercers Magnesium and Cupro-Nickel
Upsetting Dies
Mechanical Forging Press Dies
Insert Dies
Die Casting Dies (Lead, Zinc, Aluminum, Magnesium and low temperature Brass)
Aircraft Structural Applications.