A-7 Modified
Chemical
Analysis: |
|
|
Tempering Temp.
º(F) |
Hardness Rc |
|
Carbon
|
2.55/2.70
|
|
As-quenched |
67.0 |
| Manganese |
55/.75 |
|
300 |
66.0 |
| Phosphorus |
.030
Max. |
|
400 |
62.5 |
| Sulfur |
.030
Max. |
|
500 |
62.0 |
| Silicon |
.25/.45 |
|
600 |
61.5 |
| Chromium |
7.75/8.50 |
|
700 |
61.0 |
| Vanadium |
4.25/4.75 |
|
800 |
60.5 |
| Tungsten |
.35 Max. |
|
900 |
58.0 |
| Molybdenum |
1.05/1.30 |
|
1000 |
57.5 |
| Cobalt |
------- |
|
1100 |
52.5 |
|
|
|
1200 |
45.0 |
Uses:
Brick mold liners, sand slinger liners, machine ways.
Forging/Rolling:
Preheat to 1500° F
and soak thoroughly. Then raise to 1900°
F - 2000° F. Do not forge or roll below 1800° F, cool slowly from the forging or rolling temperature.
Do not normalize.
Annealing:
Heat slowly to 1500° F
- 1550° F, and hold for uniformity, furnace cool at
a rate of 20° F per hour to 1000°
F, then air cool. Expect Brinell hardness 235 - 262.
Hardening:
Preheat to 1550° F
- 1600° F, soak until uniformly heated, and either
transfer or raise furnace temperature to 1700°
F - 1800° F, and hold 2 hour per inch of greatest thickness.
Cool in still air.
Tempering:
Temper immediately after quenching, before part has
cooled to below 150° F. Parts should be held a minimum of
2 hours per inch of greatest thickness. Double tempering is recommended.
For maximum wear resistance temper at 300°
F. The above tempering table may be used as a guide.
However, since 1/2" dia. specimens were used for this test, it
may be found that heavier sections are several points lower.
© Copyright 1999 Diamond Metals Corporation.
All Rights Reserved.
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