Tool Steel H21

Principal Design Features

This alloy is one of the Hot Work, tungsten containing tool steels. The tungsten content is beneficial for hot strength at red heat, although toughness is somewhat reduced.

Applications

Used for hot working dies and tooling such as die casting, extrusion and hot forming of parts.

Machinability

The tungsten content makes H21 somewhat difficult to machine. As compared to the W group of water hardening low alloy steels rated at 100& for machinability the H21 would rate 55%

Forming

The alloy may be formed by conventional means.

Welding

This alloy may be welded. Consult the supplier for details.

Heat Treatment

Preheat to 1500 F and then heat rapidly to 2150 F. Hold at 2150 F for 2 to 5 minutes and then air cool (quench) or oil quench.

Forging

Forge at 2100 f down to 1700 F. Do not forge below 1650 F.

Hot Working

See “Forging”.

Cold Working

H21 may be cold worked by conventional methods.

Annealing

Anneal at 1625 F and slow furnace cool at less than 40 F per hour.

Aging

Not applicable to this alloy.

Tempering

Tempering is done at 1100 F to 1250 F for Rockwell C hardness of 54 to 36. A double temper treatment should be done at the temperature selected and the parts should be held at temperature for 1 hour.