A7
OtherA7
Air-hardening cold-work tool steel. (ASTM A681; equiv ASTM A681 / DIN 1.2363 / JIS SKD12). Nominal values—confirm mill certificate.
Chemical Composition (%)
| C | 2.2 |
|---|---|
| CR | 5 |
| MO | 1 |
| V | 3.5 |
| W | 0.5 |
| MN | 0.5 |
| P | 0.03 |
| S | 0.03 |
Mechanical Properties
Hardness(annealed):≤269 HB;Hardness(hardened):62-66 HRC
Chinese Standard
ASTM A681 A7
Equivalent Standards
ASTM A681
Equivalent Grades
DIN 1.2363 / JIS SKD12
Applications
空淬冷作模具钢。,"Bar
Available Forms
Block"
Uses
Tool and die steel for cutting, forming, punching and molding tools. Tungsten/molybdenum (≈1%/1.25%) give hot hardness and red-hardness for high-speed and hot-work tools. High chromium (≈5.375%) 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.
Comments 0