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Stress relieving
After rough machining the
tool should be heated through to 650°C (1200°F), holding time 2
hours. Cool slowly to 550°C (930°F), then freely in air.
Hardening
Pre-heating temperature:
600-850°C (1110-1480°F)
Austenitizing temperature:
980-1080°C (1800-1980°F). Normally 1020°C (1870°F)
Holding time: 20-30
minutes
Holding time = time at
temperature after the tool is fully heated through.
Quenching:
- Circulating air or
atmosphere
- Air blast
- Vacuum
- Mar-tempering bath at
200-550°C (390-1020°F) for 1 to 100 minutes, then cool in air
- Oil
Tempering
After rough machining the
tool should be heated through to 650°C (1200°F), holding time 2
hours. Cool slowly to 550°C (930°F).
Nitriding
Nitriding gives a hard case
which is very resistant to wear and erosion. In diecasting dies, nitrided
cavities are less subject to welding-on. The nitrided layer is brittle and may
crack or spall when exposed to mechanical or thermal shock. The risk increases
with case thickness. Before nitriding, the tool should be hardened, and
tempered at approx. 50°C (90°F) above the nitriding
temperature.
Nitriding in ammonia has as
525°C (975°F) gives a surface hardness of 1000-1250 HV.
EDRO #5™ H13 can be
nitrided in the soft annealed condition. The hardness and depth of case will,
however, be somewhat reduced.
Tufftriding
The Tufftride Process is
done in a special salt bath at 570°C (1060°F). Holding time: normally
2 hours. It gives a surface hardness of approx. 950-1000 HV.
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