DEFINITIONS AND TERMS (cont) - TM-750-245-40098

TM 750-245-4

RESISTANCE WELDING: A group of welding processes

or gouge as a result of a sharp instrument striking or

in which fusion is produced by heat obtained from

scraping the skin surface.

resistance of the work to the flow of electric current in a

circuit of which the work is a part and by the application

SEAL WELD: A weld used primarily to obtain tightness

or pressure.

and to prevent leakage.

REVERSE POLARITY: The arrangement of direct

SEAM WELDING: Welding a lengthwise seam in sheet

current arc welding leads in which the work is the

metal either by abutting or overlapping joints.

negative pole and the electrode is the positive pole of

the welding arc.

SELECTIVE BLOCK SEQUENCE: A block sequence in

which successive blocks are completed in a certain

ROOT: See root of joint and root of weld.

order selected to create a predetermined stress pattern.

ROOT CRACK: A crack in the weld or base metal which

SERIES WELDING: A resistance welding process in

occurs at the root of a weld.

which two or more welds are made simultaneously by a

single welding transformer with the total current passing

ROOT EDGE: The edge of a part to be welded which is

through each weld.

adjacent to the root.

SHEET SEPARATION: In spot, seam, and projection

ROOT FACE: The prepared edge of a member to be

welding, the gap surrounding the weld between fraying

joined by a groove weld which is not beveled or

surfaces, after the joint has been welded.

grooved.

SHIELDED WELDING: An arc welding process in which

ROOT OF JOINT: That position of a joint to be welded

protection from the atmosphere is obtained from a flux,

where the members approach closest to each other. In

decomposition of the electrode covering, or an inert gas.

cross section, the root of a joint may be a point, a line,

or an area.

SHOULDER: See root face.

ROOT OF WELD: The points, as shown in cross

SHRINKAGE STRESS: See residual stress.

section, at which the bottom of the weld intersects the

base metal surfaces.

SINGLE-IMPLUSE WELDING: The making of spot

projection and upset welds by a single impulse of

ROOT OPENING: The separation between

the

current. When alternating current is used, an impulse

members to be joined at the root of the joint.

may consist of a fraction of a cycle or a number of

cycles.

ROOT PENETRATION: The depth a groove weld

extends into the root of a joint measured on the

SIZE OF WELD: a. Groove weld The joint penetration

centerline of the root cross section.

(depth of chamfering plus the root penetration when

specified).

ROSEN JOINT: A pocket of rosen in a soldered

b. Equal leg fillet welds The leg length of the

connection.

This occurs when insufficient heat is

largest right triangle which can be inscribed within the

applied to perform the soldering operation.

fillet weld cross section.

c. Unequal leg fillet welds The leg length of the

largest right triangle which can be inscribed within the

fillet weld cross section.

SAPONIFICATION NUMBER: The milligrams of

d. Flange weld The weld metal thickness

potassium hydroxide required to saponify (form soap)

measured at the root of the weld.

one gram (of oil).

SKIP SEQUENCE: See wandering sequence.

SATURATION: In a magnetic material, the condition

that exists when all magnetic domains are perfectly

SLAG INCLUSION: Non-metallic solid material

aligned with the externally applied magnetic field. The

entrapped in the weld metal or between the weld metal

magnetic induction has reached its maximum possible

and the base metal.

value.

SLOT WELD: A weld made in an elongated hole in one

SCARF: The chamfered surface of a joint.

member of a lap or tee joint joining that member to that

portion of the surface of the other member which is

SCARFING: A process for removing defects and checks

exposed through the hole. The hole may be open at

which develop in the rolling of steel billets by the use of

one end and may be partially or incompletely filled with

a low velocity oxygen deseaming torch.

weld metal. (A fillet welded slot should not be construed

as conforming to this definition.) SLUGGING: Adding a

SCRATCH OR GOUGE: Surface skin damage in which

separate piece of pieces of material in a joint before or

the metal has been displaced to the sides of the scratch

during welding with a resultant welded joint that does

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