1084 heat treat: austenitize, quench & temper chart
1084 is a simple carbon 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 1084 heat-treat schedule
Austenitize: 1450–1480°F (1475°F recommended), hold 5–15 min once to temperature. A controlled oven or kiln beats forge colour for hitting this window repeatably.
Quench: Parks 50. Also acceptable: Duratherm 48, Parks AAA. Never use Water, Brine. Parks 50 is the NJSB-recommended quench. A slower oil may reduce as-quenched hardness. Water cracks plain carbon — do not use.
Temper: 2 passes of 2 h at 400°F for the recommended edge (~60–61 HRC). Temper twice for 2 hours. Do not exceed 650°F unless intentionally annealing.
1084 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) | 65 HRC |
| 350°F (177°C) | 63–64 HRC |
| 400°F (204°C) | 60–61 HRC |
| 450°F (232°C) | 57–58 HRC |
| 500°F (260°C) | 55–56 HRC |
| 550°F (288°C) | 53–54 HRC |
| 600°F (316°C) | 52–53 HRC |
| 650°F (343°C) | 50 HRC |
Target hardness for 1084 by knife type
| Use | Recommended HRC |
|---|---|
| Kitchen | 60–61 HRC |
| EDC | 60–61 HRC |
| Hunter | 57–58 HRC |
| Hard-use chopper | 55–56 HRC |
Forging 1084
Forge-friendly: 1084 reaches non-magnetic at ~1385°F (per Knife Steel Nerds). Forge HT consistency drops vs. furnace, but the cited schedule still applies.
Most common mistake
Normalize three cycles (1650°F → 1500°F → 1350°F, 10–15 min each, air cool) before hardening — undersoaking the third cycle is more common than oversoaking.
FAQ
What temperature do you austenitize 1084?
1450–1480°F, with 1475°F recommended, held 5–15 min once the steel is fully up to temperature.
What is the best quench for 1084?
Parks 50. Duratherm 48, Parks AAA also work. Never Water, Brine. Parks 50 is the NJSB-recommended quench. A slower oil may reduce as-quenched hardness. Water cracks plain carbon — do not use.
What HRC does 1084 reach?
50–65 HRC across the usable tempering range; about 60–61 HRC for a kitchen knife. Temper at 400°F for ~60–61 HRC.
How do you temper 1084?
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 1084?
Forge-friendly: 1084 reaches non-magnetic at ~1385°F (per Knife Steel Nerds). Forge HT consistency drops vs. furnace, but the cited schedule still applies.
What you need to heat-treat 1084
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 1475°F austenitizing temperature — the single biggest factor in repeatable hardness.
- Quench in Parks 50 for the cited as-quenched hardness.
- Verify the result with a Rockwell hardness tester or hardness files — don't trust the schedule blind.
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Sources
Heat-treat schedules are the cited published values for 1084; 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.