QuenchFast oil (Parks 50) as default; water/brine only for hamon / differential hardening (advanced — high crack risk)
Temper2× 2 h · cool to room temp between cycles
Reliable hardness59–65 HRC
Shallow-hardening — prized for hamon / differential hardening. Short soak.
Temper → hardness chart
Approximate HRC after a double-temper at each temperature (from the sources below). Set your target and pick the matching temper.
Temper °F
Temper °C
Hardness
300°F
149°C
65 HRC
350°F
177°C
63 HRC
400°F
204°C
61 HRC
450°F
232°C
58 HRC
Composition (typical, wt%)
Element
%
C
1%
Cr
0.15%
V
0.2%
Mn
0.25%
Si
0.25%
AISI W2 typical (NJSB heats run ~0.96–1.07 C)
HeatTreatBench — the recipes in your shop, offline
Get the full W2 recipe plus 25 more steels offline — set your target HRC and the app gives you the exact temper, with a forge timer and a per-blade log. Works in the shop with no signal.