O1 Precision Ground steel, machined steel. This steel is very used by craftsmen, especially in the United States. It presents a good alloy that greatly enhances the qualities that offer simple carbon steels, while remaining in many aspects, such as the ability to work with him and the possibility of correcting errors in heat treatment.
Its main features:
- Medium-high hardness.
- Good edge retention.
- High toughness.
- Up to 65 HRC.
- High machinability.
Chemical composition (%): C: 0.95, Si: 0.25, Mn: 1.10, Cr: 0.55, W: 0.55, V: 0.10
This steel is recommended both for beginners as professionals, the degree of difficulty of work is medium-low.
Supplied annealed (soft), to facilitate the work.
- Forging : 850 to 1050 ° C. Very slow cooling in furnace or insulation materials (sand, salt, mica).
- Normalizing : 650 ° C. To eliminate the structural tensions caused by forging or roughing. Preferred time, 1 hour.
- Hardening ( oil) : 780 to 820 ° C. Warmup at 700 ° C, stabilized temperature, thermal jump to temple, reached temperature, maintain at least 1 minute per millimeter . Cooling in oil to 210 - 250 ° C to reduce thermal shock, keep cool for 15 to 20 minutes. 63-65 HRC hardness.
- Tempering : Slow heating to the tempering temperature (see temperature chart). Reached the temperature keep 10 minutes per mm, the minimum recommended time is 1 hour . Another possibility, is reduce the tempering temperature and increase the time.
Recommended carry out annealing and tempering in conservative atmosphere, by its high de-carburized, see tempered blade. This is the recommended thermal treatment, there are others. Temperatures, times or form of realization of it, depending on your needs you can vary or experience in such process.