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D-7 Air Hardening Tool Steel
D-7 is a high carbon high chromium die steel with added carbon and vanadium for abrasion resisting qualities. Useful for applications involving extreme abrasive wear.
Analysis:
| C | CO | CR | MN | MO | NI | P | S | SI | V | W |
|---|
| 2.15 - 2.50 | 11.50 - 13.50 | 0.10 - 0.60 | 0.70 - 1.20 | 0.10 - 0.60 | 3.80 - 4.40 |
Size Availability:
Flats • Hollowbar • Metric • Non-Standard • Rounds • Squares • StandardApplications:
| Burnishing Tools | Can Dies | Ceramic Dies |
| Coining Dies | Draw Dies | Extrusion Dies |
| Forming Rolls | Lamination Dies | Lathe Centers |
| Paper Knives | Punches | Slitters |
Designations:
ASTM A681 - USFED QQ-T-570 - US
SAE J437 - US
SAE J438 - US
UNS T30407 - US
AISI D7 Tool Steel - US
| Treatment | Temperature Range | Cooling/Quenching | Notes |
|---|---|---|---|
| Forging | 2050-2100° F | Slow. | Cool slowly in dry sand or in other insulating media. |
| Annealing | 1600-1650° F | Cool slowly at a rate of 25° F per hour to 1000° F. | Protect against surface decarburization using controlled atmosphere or by pack-annealing. |
| Stress Relieving | 1150-1300° F | Cool slowly. | Stress relieve after rough machining |
| Preheating | 1400-1500° F | Preheat time in furnace is ¾ Hr. per inch of thickness. Heating up to temperature as slow as possible. | |
| Hardening | 1900-2000° F | In air. | Allow to cool to 125-150° F before tempering. Soak time is 15 minutes per inch of thickness. Minimum of 30 minutes. |
| Tempering | (See Chart) | Complete equalization of temperature throughout the tool is essential for good results. Double temper. Recommended temperature is 400-1000° F. Temper 1 hour per inch of thickness, 2 hours minimum. |