A3
Alloy SteelA3
(IS 6240). Nominal values—confirm mill certificate.
Chemical Composition (%)
| C | 1.2 |
|---|---|
| CR | 4.75 |
| MO | 0.9 |
| V | 0.8 |
| MN | 0.3 |
| P | 0.03 |
| S | 0.03 |
Mechanical Properties
Hardness(annealed):≤248 HB;Hardness(hardened):58-63 HRC
Equivalent Grades
IS 6240 A3
Available Forms
Bar,Plate
Uses
Tool and die steel for cutting, forming, punching and molding tools. Tungsten/molybdenum (≈0%/1.15%) give hot hardness and red-hardness for high-speed and hot-work tools. High chromium (≈5%) provides wear resistance and secondary hardening. Applied to blanks, punches, extrusion dies, shear blades, plastic-mold and cold-work tooling.
Heat Treatment
Hot-work: preheat 800 °C, austenitize 1020–1080 °C, quench, temper 540–620 °C (multiple) for hot hardness and thermal fatigue resistance.
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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