O1 Tool Steel
Generic / House Brand
☀ UV Stable
Overview
Oil-hardening carbon-chromium tool steel with excellent dimensional stability during heat treatment. Hardened to 62-65 HRC for cutting tools, dies, and precision gauges. Must be purchased in annealed state for machining, then hardened by heat treater or oven quench.
Properties
Difficulty
advanced
Flexibility
rigid
Layer Adhesion
excellent
Enclosure
no
Heated Bed
no
Dry Storage
no
Pros
- Hardens to 62-65 HRC after heat treatment
- Excellent dimensional stability during oil quench vs water quench
- Good machinability in annealed state
- Affordable entry-level tool steel
- Superior wear resistance after hardening
- Can hold razor-sharp edge
Cons
- Rusts rapidly without coating
- Low resistance to thermal shock — slow heat/cool cycles required
- Must be annealed before machining, hardened after
- Requires accurate heat treatment (1475°F/802°C, oil quench)
- Cannot be welded after hardening
- Ground rather than machined after hardening
Best For
- Cold work dies and punches|Knife and blade making|Precision gauges and fixtures|Forming tools|Cutting tools|Wood chisels and plane blades
Avoid For
- Corrosive environments|Hot work (use H13 instead)|Applications requiring weld repair|Large parts with complex geometry (distortion risk)|High-speed cutting (use M2 HSS)
Storage
Store oiled. Purchase annealed for machining. After heat treatment, grind to final dimensions — dimensional tolerance changes during hardening. Apply anti-rust oil immediately after each step.
Brands
McMaster-CarrOnline MetalsAdmiral SteelPrecision Ground StockNiagara Specialty Metals