A7 Modified Tool Steel

Chemical Analysis:
Carbon 2.55/2.70
Manganese .55/.75
Phosphorus .030 Max.
Sulfur .030 Max.
Silicon .25/.45
Chromium 7.75/8.50
Vanadium 4.25/4.75
Tungsten .35 Max.
Molybdenum 1.05/1.30
Cobalt -------
Tempering Temp. º(F): Hardness Rc
As-Quenched 67.0
300 66.0
400 62.5
500 62.0
600 61.5
700 61.0
800 60.5
900 58.0
1000 57.5
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.