Heat Treated Parts.

Welded engine blocks must be leak tested before placing them back

in operation. Leak testing procedures are specified in TM 9-237.

(3) Heat Treated Parts.

(a) The functions performed by certain parts in automotive

equipment require heat treatment during their manufacture.

Welding of these parts should not be attempted unless the repair

shop is equipped with suitable heat treating equipment for

handling these parts after welding.

(b) In some cases, alloy steels, or specially treated parts,

may be repaired by using a heat affected zone that is weaker than

the original heat treated part. In general, where it is possible

to heat treat the parts after welding, they should be annealed

prior to welding them.

properties as the base metal should be used, and the parts heat

treated after welding.

(c) In cases where the part to be welded is in a heat treated

condition, a stainless steel filler rod and the transition bead

welding method may be used as described below:

1 Deposit a layer of stainless steel (25 percent chromium, 20

percent nickel, or modified 18 percent chromium, 8 percent nickel

stainless steel rod) on the surfaces of the broken edges.

2 Weld the prepared edges with mild steel or high strength

filler metal.

Use 11 to 14 percent manganese or high strength

filler metal on the stainless steel layer instead of mild steel

where hardness and toughness are required. The weld then may be

covered with a layer of hard surfacing metal.

(d) These methods are useful in the field, but should be used

under emergency conditions only.

(4) Wheel Vehicle Components.

(a) Frames. The repair of frames by welding is not authorized.

Crossmembers and horns for the frame may be straightened,

repaired, and reinforced.

A commonly used method of repairing

and strengthening a broken or weakened crossmember or horn is

performed by using reinforcing plates as

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