Heat-treating A2 with stainless tool wrap
Air-hardening tool steel — tough, dimensionally stable, scale-prone without foil.
Recommended SSTW grade
Grade 321 stainless foil
A2 austenitizes at or below ~2000°F, so 321 stainless foil is the right everyday choice — full scale and decarb protection at a lower cost per roll.
Shop 321 tool wrap rollsA2 heat-treat reference
- Austenitizing temp
- 1725–1775°F
- Soak at temp
- 20–45 min
- Quench
- Air / plate
- Temper
- 375–500°F, 2× 2 hr
- Typical uses
- Hard-use field knives, tooling
- Also known as
- 1.2363
General knifemaking guidance — always follow the steel manufacturer's published data sheet for your exact stock.
Why wrap A2 in stainless foil
At 1775°F the bare surface of A2 oxidizes and loses carbon (decarburization), leaving a soft, scaled skin you have to grind back past. Sealing the blade in SSTW 321 stainless tool wrap keeps oxygen off the steel through the soak and quench, so it comes out of the kiln bright with full hardness right to the edge — less post-heat-treat grinding, no decarb surprises.
A2 foil FAQ
Do I need stainless foil to heat treat A2?
Wrapping A2 in stainless tool wrap before the kiln prevents surface scale and decarburization, so the blade comes out clean with the carbon at the edge intact. It is strongly recommended for A2, especially for air- and plate-quenched work where the blade sits at temperature.
Which SSTW grade should I use for A2 — 309 or 321?
A2 austenitizes at or below ~2000°F, so 321 stainless foil is the right everyday choice — full scale and decarb protection at a lower cost per roll.
What temperature is A2 heat treated at?
A2 is commonly austenitized around 1725–1775°F with a 20–45 min soak, then air / plate and tempered (375–500°F, 2× 2 hr). Always confirm against the steel mill's published data sheet for your exact stock — these figures are general knifemaking guidance.
Ready to heat treat A2 clean?
SSTW Grade 321 stainless tool wrap, sold by the roll and shipped from the USA.
Shop tool wrap rolls