Brazing

TM 750-245-4

8-11. Resistance Welding

c. Hammer Welding. A process in which heat is

This is a welding process in which a weld is made by

obtained from a forge or furnace and hammer blows are

heat obtained front resistance of the work to the flow of

used to apply pressure.

an electric current in a circuit of which the work is a part

and by the application of pressure.

8-9. Brazing

a. Resistance-Spot Welding. The size and shape

A group of welding processes in which the filler metal is

of the individually formed welds are limited primarily by

a nonferrous metal or alloy with a melting point above

the size and contour of the electrodes. The electrodes

800 degrees Fahrenheit, but lower than that of the

apply pressure.

metals to be joined. The filler metal is distributed

b. Resistance-Seam Welding.

This weld is a

between the closely fitted surfaces of the joint by

series of overlapping spot welds made progressively

capillary attraction.

along a joint by rotating the circular electrodes. The

a. Torch Brazing. A process in which a gas flame

electrodes apply pressure.

produces the necessary heat.

c. Projection Welding. These welds are localized

b. Twin-Carbon-Arc Brazing. A process in which

at predetermined points by the design of the parts to be

an arc is maintained between two carbon electrodes to

welded. The localization is usually accomplished by

produce the necessary heat.

projections, embossments, or intersections.

The

c. Furnace Brazing. A process in which a furnace

electrodes apply pressure.

produces the necessary heat.

d. Flash Welding.

This weld is made

d. Induction Brazing. A process in which heat is

simultaneously over the entire area of abutting surfaces

obtained from resistance of the work to the flow of

by the application of pressure after the heating is

induced electric current.

substantially completed. Flashing is accomplished by

e. Dip Brazing.

A process in which heat is

expulsion of metal from the joint.

obtained in a molten chemical or metal bath. The bath

e. Upset Welding.

This weld is made

provides the filler metal.

simultaneously over the entire area of abutting surfaces

f. Resistance Brazing. A process in which heat is

or progressively along a joint. Pressure is applied

obtained from resistance to the flow of electric current in

before heating is started and is maintained Throughout

a circuit of which the work is a part.

the heating period.

g. Block Brazing. A process in which heat is

f. Percussion Welding.

This weld is made

obtained from heated blocks applied to the part to be

simultaneously over the entire area of abutting surfaces

joined.

by the heat obtained from an arc. The arc is produced

h. Flow Brazing. A process in which heat is

by a rapid discharge of electrical energy.

It is

obtained from molten nonferrous filler metal poured

extinguished by pressure percussively applied during

over the joint until the brazing temperature is attained.

the discharge.

8-10. Flow Welding

8-12. Induction Welding

This is a welding process in which molten-filler metal is

A welding process in which a weld is made by the heat

poured over the surfaces to be welded until the welding

obtained from resistance of the work to the flow of

temperature has been attained, and the required filler

induced electric current, with or without the application

metal has been added. The filler metal is not distributed

of pressure.

to the joint by capillary attraction.

Section III. WELD INSPECTION

8-13. General

b. Destructive. Destructive inspection of repaired

Welds must be examined to detect any condition or

items is not recommended, because so will destroy the

defect that may impair the reliability of the welded joint.

item. The inspector may have samples made for

Examination of the welds may be accomplished by three

destructive inspection. These samples should simulate

methods; nondestructive (visual), destructive, and

the type metal and process of the item it represents.

metallurgical.

c. Metallurgical. Metallurgical inspection is not

a. Nondestructive. This inspection is visual and

used by the QC inspector but is included for

requires that the inspector have a thorough knowledge

informational purposes. At some time, the information

of what he is inspecting.

presented may be required.

8-4