O7
OtherO7
Oil-hardening cold-work tool steel. (ASTM A681; equiv ASTM A681 / DIN 1.2510 / JIS SKS3). Nominal values—confirm mill certificate.
Chemical Composition (%)
| C | 1.1 |
|---|---|
| MN | 0.5 |
| CR | 0.4 |
| W | 1.3 |
| SI | 0.1 |
| P | 0.03 |
| S | 0.03 |
Mechanical Properties
Hardness(annealed):≤217 HB;Hardness(hardened):60-64 HRC
Chinese Standard
ASTM A681 O7
Equivalent Standards
ASTM A681
Equivalent Grades
DIN 1.2510 / JIS SKS3
Applications
油淬冷作模具钢。,"Bar
Available Forms
Block"
Uses
Tool and die steel for cutting, forming, punching and molding tools. Tungsten/molybdenum (≈1.65%/0%) give hot hardness and red-hardness for high-speed and hot-work tools. High chromium (≈0.55%) provides wear resistance and secondary hardening. Applied to blanks, punches, extrusion dies, shear blades, plastic-mold and cold-work tooling.
Heat Treatment
Powder/HSS: preheat 800–850 °C, austenitize 1180–1230 °C (salt or vacuum), quench, triple temper 540–570 °C to ≈64–66 HRC.
Precautions
Risk of quench cracking and distortion — use graded preheating, controlled cooling and multiple tempers. Avoid overheating the austenitizing temperature. Machine in the soft annealed condition; allow for dimensional change after heat treatment. Grind with coolant to prevent rehardening cracks.
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