Annealing Alloy Steel

: The Working Of Steel

The term alloy steel, from the steel maker's point of view, refers

largely to nickel and chromium steel or a combination of both. These

steels are manufactured very largely by the open-hearth process,

although chromium steels are also a crucible product. It is next

to impossible to give proper directions for the proper annealing

of alloy steel unless the composition is known to the operator.

Nickel steels
may be annealed at lower temperatures than carbon

steels, depending upon their alloy content. For instance, if a

pearlitic carbon steel may be annealed at 1,450 deg.C., the same analysis

containing 2-1/2 per cent nickel may be annealed at 1,360 deg.C. and

a 5 per cent nickel steel at 1,270 deg..

In order that high chromium steels may be readily machined, they

must be heated at or slightly above the critical for a very long

time, and cooled through the critical at an extremely slow rate.

For a steel containing 0.9 to 1.1 per cent carbon, under 0.50 per

cent manganese, and about 1.0 per cent chromium, Bullens recommends

the following anneal:

1. Heat to 1,700 or 1,750 deg.F.

2. Air cool to about 800 deg.F.

3. Soak at 1,425 to 1,450 deg.F.

4. Cool slowly in furnace.