nd varying conditions. These have already
been referred to on pages 39 to 41 in connection with the different
steels used in automobile practice. These treatments are designated
by letter and correspond with the designations in the table.

HEAT TREATMENTS

_Heat Treatment A_

After forging or machining:
1. Carbonize at a temperature between 1,600 deg.F. and 1,750 deg.F.
(1,650-1,700 deg.F. desired.)
2. Cool slowly or quench.
3. Reheat to 1,450-1,500 deg.F. and quench.

_Heat Treatment B_

After forging or machining:
1. Carbonize between 1,600 deg.F. and 1,750 deg.F. (1,650-1,700 deg.F.
Desired.)
2. Cool slowly in the carbonizing mixture.
3. Reheat to 1,550-1,625 deg.F.
4. Quench.
5. Reheat to 1,400-1,450 deg.F.
6. Quench.
7. Draw in hot oil at 300 to 450 deg.F., depending upon the degree of
hardness desired.

_Heat Treatment D_

After forging or machining:
1. Heat to 1,500-1,600 deg.F.
2. Quench.
3. Reheat to 1,450-1,500 deg.F.
4. Quench.
5. Reheat to 600-1,200 deg.F. and cool slowly.

_Heat Treatment E_

After forging or machining:
1. Heat to 1,500-1,550 deg.F.
2. Cool slowly.
3. Reheat to 1,450-1,500 deg.F.
4. Quench.
5. Reheat to 600-1,200 deg.F. and cool slowly.

_Heat Treatment F_

After shaping or coiling:
1. Heat to 1,425-1,475 deg.F.
2. Quench in oil.
3. Reheat to 400-900 deg.F., in accordance with temper desired and cool
slowly.

_Heat Treatment G_

After forging or machining:
1. Carbonize at a temperature between 1,600 deg.F. and 1,750 deg.F.
(1,650-1,700 deg.F. desired).
2. Cool slowly in the carbonizing mixture.
3. Reheat to 1,500-1,550 deg.F.
4. Quench.
5. Reheat to 1,300-1,400 deg.F.
6. Quench.
7. Reheat to 250-500 deg.F. (in accordance with the necessities of the case)
and cool slowly.

_Heat Treatment H_

After forging or machining:
1. Heat to 1,500-1,600 deg.F.
2. Quench.
3. Reheat to 600-1,200 deg.F. and cool slowly.

_Heat Treatment K_

After forging or machining:
1. Heat to 1,500-1,550 deg.F.
2. Quench.
3. Reheat to 1,300-1,400 deg.F.
4. Quench.
5. Reheat to 600-1,200 deg.F. and cool slowly.

_Heat Treatment L_

After forging or machining:
1. Carbonize between 1,600 deg.F. and 1,750 deg.F. (1,650-1,700 deg.F. desired).
2. Cool slowly in the carbonizing mixture.
3. Reheat to 1,400-1,500 deg.F.
4. Quench.
5. Reheat to 1,300-1,400 deg.F.