T8 Tool&Mould Steel
Chemical composition
| C | Si | Mn | P | S | Cr | Mo | Ni | Cu | V |
| 0.75-0.85 | 0.2-0.4 | 0.2-0.4 | 0.03 | 0.03 | 3.75-4.5 | 0.4-1 | 0.3 | 0.25 | 1.80-2.40 |
Equivalent Grades of Steel
| USA | Germany | Japan | France | England | China | Sweden | Inter |
| UNS | DIN | JIS | NF | BS | GB | SS | ISO |
| T72301 | C80W2 (1.1625) | SK85 SK75 | C80E2U | 060A78 060A81 | T8
| 1778 | TC80 |
Mechanical properties of Steel
- Tensile strength：1158 MPa
- Elongation: 15%
- Modulus of elasticity: 190-210 GPa
- Poisson’s ratio: 0.27-0.3
Application
- Drills
- Planer tools
- Cutoff tools
- Roll-turning tools
- Lathe tools
Heat Treatment Conditions
- Critical point temperature: Ac1=730℃, Ar1=700℃, Ms=240℃
- Normalizing specification: normalizing temperature 800-820℃, hardness 241-302HBW
- Ordinary annealing specifications: 740-750℃×2-4h, cooling rate <30℃/h, slow cooling to 500-600℃ with the furnace, air cooling.
- Isothermal spheroidizing annealing specifications: 740-750℃×2-4h, cooled to 650-680℃×4-6h, furnace cooled to 500-600℃, air cooling, hardness ≤187HBW. 750-770℃×1-2h, cooled to 680-700℃×2-3h, furnace cooled to 500-600℃, air-cooled, hardness 163-187HBW, pearlite structure grade 1-5.
- Quenching + high temperature tempering spheroidization specifications: quenching temperature (800±10)℃, holding for 0.5h, water cooling, tempering temperature (700±10)℃, holding for 2h, furnace cooling to 550℃, air cooling, hardness 196-229HBW
- Quenching and tempering specifications: quenching temperature 770-790℃, water cooling or oil cooling, hardness ≥62HRC, tempering temperature 170-190℃.
