Heating Of Manganese Steel

: FURNACES
: The Working Of Steel

Another form of heat-treating furnace

is that which is used for the heating of manganese and other alloy

steels, which after having been brought to the proper heat are drawn

from the furnace into an immediate quenching tank. With manganese

steel in particular, the parts are so fragile and easily damaged

while hot that it is frequent practice to have a sloping platform

immediately in front of the furnace door down which the castings

may slide into a tank below the floor level. Such a furnace with

a quenching tank in front of its door is shown in Fig. 108.



These tanks are covered with plates while charging the furnace

and the cold castings are placed in a moderately cool furnace.

Since some of these steels must not be charged into a furnace where

the heat is extreme but should be brought up to their final heat

gradually, there is little discomfort during the charging process.

When quenching, however, from a temperature of 1,800 deg. to 1,900 deg.,

it is extremely unpleasant in front of the doors. The swinging

shield is here adapted to give protection for this work. As will

be noted it is hung a sufficient distance in front of the doors,

that it may not interfere with the castings as they come from the

furnace, and slide down into the tank.



To facilitate the work, and avoid the necessity of working with

the bars outside the edges of the shield, the slot-like hole is

cut in the center of the shield, and through this the bars or rakes

for dragging out the castings are easily inserted and manipulated.

The advantage of such a swinging shield is that it may be readily

moved from side to side, or forward and back as occasion requires.