The Packing Department

: The Working Of Steel

In Fig. 56 is shown the packing pots where

the work is packed. These are of malleable cast iron, with an internal

vertical flange around the hole A. This fits in a bell on the

end of the cast-iron pipe B, which is luted in position with

fireclay before the packing begins. At C is shown a pot ready

for packing. The crown gears average 10 to 12 in. in diameter and

weigh about 11 lb. each. When placed in the pots, they su

the central tube, which allows the heat to circulate. Each pot

contains five gears. Two complete scrap gears are in each furnace

(i.e., gears which fail to pass machining inspection), and at

the top of front pot are two or more short segments of scrap gear,

used as test pieces to gage depth of case.

After filling to the top with compound, the lid D is luted on.

Ten pots are then placed in a furnace. It will be noted that the

pots to the right are numbered 1, 2, 3, 4, indicating the position

they are to occupy in the furnace.

The cast-iron ball shown at E is small enough to drop through

the pipe B, but will not pass through the hole A in the bottom

of the pot. It is used as a valve to plug the bottom of the pot

to prevent the carburizing compound from dropping through when

removing the carburized gears to the quenching bath.

Without detracting from the high quality of the work, the metallurgist

in this plant has succeeded in cutting out one entire operation

and reducing the time in the hardening room by about 24 hr.

Formerly, the work was carburized at about 1,700 deg.F. for 9 hr. The

pots were then run out into the yard and allowed to cool slowly.

When cool, the work was taken out of the pots, reheated and quenched

at 1,600 deg.F. to refine the core. It was again reheated to 1,425 deg.F.

and quenched to refine the case. Finally, it was drawn to the proper