DEFINITIONS AND TERMS (cont) - TM-750-245-40100

TM 750-245-4

machine, the distance from the centerline of the

the axis of the weld is approximately vertical. In pipe

electrodes or platens to the nearest point of interference

welding, the pipe is in a vertical position and the welding

for flatwork or sheets. In a seam-welding machine with

is done in a horizontal position.

a universal head, the throat depth is measured with the

machine arranged for transverse welding.

VIBRATION BENDS: A turn or bend made into an

electrical lead to prevent vibrations from a harness or

THROAT OF FILLET WELD: a. Theoretical - The

cable being transmitted to electronic components.

distance from the beginning of the root of the joint

perpendicular to the hypotenuse of the largest right

VISCOSITY: The distinguishing characteristic which

triangle that can be inscribed within the filletweld cross

denotes the body or relative fluidity of a lubricating oil.

section.

The heavier the oil, the higher its viscosity.

b. Actual The shortest distance from the root of a

VISCOSITY INDEX: The viscosity of a petroleum oil

fillet weld to its face.

changes with temperature. The rate of change is

indicated by its viscosity index.

TOE CRACK: A crack in the base metal occurring at the

toe of the weld.

WANDERING BLOCK SEQUENCE: A block sequence

TOE OF THE WELD: The junction between the face of

in which successive blocks are completed at random

the weld and the base metal.

after several starting blocks have been completed.

TORCH: See cutting torch or welding torch.

WANDERING SEQUENCE: A longitudinal sequence in

which the weld bead increments are deposited at

TORCH BRAZING: A brazing process in which fusion is

random.

produced by heating with a gas flame and by using a

nonferrous filler metal having a melting point above 800

WEAVE BEAD: A type of weld bead made with

degrees F, but below that of the base metal. The filler

transverse oscillation.

metal is distributed in the joint by capillary attraction.

WEAVING: A technique of depositing weld metal in

TORQUE: A force that tends to set a body into rotation.

which the electrode is oscillated.

It is usually

accomplished in a semicircular motion of the arc

TRANSVERSE SEAM WELDING: The making of a

terminal to the right and left of the direction of

seam weld in a direction essentially at right angles to the

deposition. Weaving serves to increase the width of the

throat depth of a seam welding machine.

deposit, decreases overlap, and assists in slag

formation.

WELD: A localized fusion of metals produced by heating

UNDERBEAD CRACK-: A crack in the heat affected

to suitable temperatures. The application of pressure

zone not extending to the surface of the base metal.

and / or the use of filler metal may or may not be used.

The filler metal has a melting point approximately the

UNDERCUTTING: An undesirable crater at the edge of

same or below that of the base metals, but always

the weld caused by poor weaving technique or

above 800 degrees F.

excessive welding speed.

WELD BEAD: A weld deposit resulting from a pass.

UPSET: A localized increase in volume in the region of

a weld, resulting from the application of pressure.

WELD GAGE: A device designed for checking the

shape and size of welds.

UPSET WELDING: A resistance welding process in

which fusion is produced simultaneously over the entire

WELD METAL: That portion of a weld that has been

area of abutting surfaces, or progressively along a joint,

melted during welding.

by the heat obtained from resistance to the flow of

electric current through the area of contact of those

WELD SYMBOL: A picture used to indicate the desired

surfaces. Pressure is applied before heating is started

type of weld.

and is maintained throughout the heating period.

WELDING SYMBOL: The assembled symbol consists of

UPSETTING FORCE: The force exerted at the welding

the following eight elements, or such of these as are

surfaces in flash or upset welding.

necessary: reference line; arrow; basic weld symbols;

dimension and other data; supplementary symbols;

finish symbols; tail; specification, process, or other

VERTICAL POSITION: The position of welding in which

references.

B-14