Annealing Method

: The Working Of Steel

Forgings which are too hard to machine are put

in pots with a little charcoal to cause a reducing atmosphere and

to prevent scale. The covers are then luted on and the pots placed

in the furnace. Carbon steel from 15 to 25 points is annealed at

1,600 deg.F. Nickel steel of the same carbon and containing in addition

3-1/2 per cent nickel is annealed at 1,450 deg.F. When the pots are

heated through, they are rolled to th
yard and allowed to cool.

This method of annealing gives the best hardness for quick machining.

The requirements in the machine operations are very rigid and, in

spite of great care and probably the finest equipment of special

machines in the world, a small percentage of the product fails

to pass inspection during or at the completion of the machine

operations. These pieces, however, are not a loss, for they play

an important part in the hardening process, indicating as they do

the exact depth of penetration of the carburizing material and

the condition of both case and core.