S45VN heat treat: austenitize, quench & temper chart
S45VN is a stainless knife steel. Here is the full heat-treat schedule — austenitizing temperature, quench, cryo and a tempering-temperature chart mapping each temper to final HRC — with every number cited to the source, not guessed.
The S45VN heat-treat schedule
Austenitize: 1950–2000°F (2000°F recommended), hold 20 min once to temperature. A controlled oven or kiln beats forge colour for hitting this window repeatably.
Quench: Plate quench. Never use Water, Brine, Parks 50, Duratherm 48, Parks AAA, Canola oil. Plate quench between 1″ aluminum plates.
Cryo (recommended): LN₂ best; dry ice second; household freezer as last resort. Straight from the quench into cryo, then temper.
Temper: 2 passes of 2 h at 400°F for the recommended edge (~61–62 HRC). Temper twice for 2 hours. 2000°F austenitize (vs datasheet 1950°F) improves both hardness and toughness.
S45VN tempering-temperature chart
Two-hour temper (×2), HRC after cryo where used. Pick the tempering temperature for the hardness your knife needs:
| Tempering temperature | Resulting hardness |
|---|---|
| 300°F (149°C) | 63–64 HRC |
| 350°F (177°C) | 62–63 HRC |
| 400°F (204°C) | 61–62 HRC |
Target hardness for S45VN by knife type
| Use | Recommended HRC |
|---|---|
| Kitchen | 62–63 HRC |
| EDC | 61–62 HRC |
| Hunter | 61–62 HRC |
| Hard-use chopper | 60–61 HRC |
Most common mistake
Datasheet 1950°F is conservative — 2000°F is the tested optimum. Do not skip cryo on 60+ HRC targets.
FAQ
What temperature do you austenitize S45VN?
1950–2000°F, with 2000°F recommended, held 20 min once the steel is fully up to temperature.
What is the best quench for S45VN?
Plate quench. Never Water, Brine, Parks 50, Duratherm 48, Parks AAA, Canola oil. Plate quench between 1″ aluminum plates.
What HRC does S45VN reach?
61–64 HRC across the usable tempering range; about 62–63 HRC for a kitchen knife. Temper at 400°F for ~61–62 HRC.
How do you temper S45VN?
2 passes of 2 h at 400°F for the recommended edge. See the chart above to pick a different tempering temperature for a harder or tougher blade.
Can you forge S45VN?
S45VN is best heat-treated in a controlled oven or kiln rather than forged by colour — its austenitizing window and quench are too tight to hit reliably by eye.
What you need to heat-treat S45VN
Repeatable hardness comes from controlling temperature and quench speed — eyeballing colour is how blades end up soft or cracked.
- A heat-treat oven or kiln holds the 2000°F austenitizing temperature — the single biggest factor in repeatable hardness.
- Air-hardening steel plate-quenches between aluminium quench plates — no oil bath needed.
- Verify the result with a Rockwell hardness tester or hardness files — don't trust the schedule blind.
- Wrap in stainless tool-wrap foil to stop decarb and scale at high austenitizing temperatures.
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Sources
Heat-treat schedules are the cited published values for S45VN; every furnace, quench and blade geometry varies, so verify against your own hardness testing. Getting steel to non-magnetic is not the same as reaching austenitizing temperature — use a controlled oven or kiln for repeatable results.