Tool Steel Manufacturers & Suppliers

O1 oil-hardening tool steel is the lowest-alloy and lowest-cost option — it machines freely in the annealed state, responds predictably to simple oil quench hardening to 60-62 HRC, but shows moderate distortion on complex geometries. A2 air-hardening steel uses a slower, less severe air-cooling quench that dramatically reduces warpage and cracking risk on intricate die shapes, making ±0.001" dimensional control through hardening achievable on complex punches. D2 high-carbon, high-chromium cold-work steel pushes wear resistance to the maximum: 1.5% carbon and 12% chromium form massive chromium carbides that resist abrasive wear in high-volume blanking of abrasive materials. The trade-off is D2's relatively brittle nature — it chips rather than bending when overloaded, unsuitable for impact or shock applications.

H13 hot-work tool steel's combination of hot hardness, thermal fatigue resistance, and toughness is uniquely suited to the die-casting cycle. At operating temperatures of 800-1100°F, H13 maintains hardness around 40-44 HRC, whereas cold-work steels like D2 would temper to unusable softness. Its 5% chromium, 1.5% molybdenum, and 1% vanadium chemistry creates a stable tempered martensite structure resistant to heat checking — the network of surface cracks caused by repeated thermal cycling from the molten aluminum injection. Proper H13 die construction requires vacuum-melted ESR (electroslag remelted) grade for low sulfide inclusion content, and the dies are operated at 400-500°F preheat to reduce thermal shock from first-shot injection.

S7 shock-resisting steel is formulated specifically for impact applications — its 0.50% carbon and 3.25% chromium chemistry produces a relatively tough matrix (Charpy impact values of 10-20 ft-lbs at working hardness of 55-58 HRC) that A2 at 58-60 HRC cannot match. Applications include cold chisels, pneumatic tooling, heavy stamping punches where the dominant failure mode is chipping or cracking from impact loads rather than abrasive wear. A2's higher carbon and more complex carbide structure give it better wear life but lower toughness — the wrong trade-off when the punch must survive thousands of high-impact strokes without fracturing. S7 also tolerates interrupted cuts better in machining, since its lower alloy content reduces the microstructural sensitivity that makes D2 and A2 prone to grinding cracks.