5. Class Vocabulary
Code- A collection of laws or standards that outline practices for a
particular application. Welding code ensure safe welding practices and high
quality welded products.
Specification- A detailed description of particulars, specification is often
used interchangeably with the term code when referring to welding codes,
Essential Variables- Are variables that have a significant affect on the
mechanical properties of a joint. They must not be changed except within
the limits specified by this code. e.g. Material thickness range, Material
Group etc.
Non-Essential Variables -Are variables that have no significant affect on
mechanical properties. They can be changed without re qualification of the
PQR.
Supplementary Variables- Are variables that have an affect on the impact
properties of a joint. They are classed as Non-Essential if impact testing is
not required
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6. Class Vocabulary
Weld backing- A strip of metal located on the side opposite of the weld that
provides a surface for depositing the first layer of metal to prevent molten
metal from escaping through the joint. Weld backing is used for complete
penetration weld.
PWHT- Post-weld heat treatment is most generally used for stress
relief. The purpose of stress relieving is to remove any internal or residual
stresses that may be present from the welding operation. Stress relief after
welding may be necessary in order to reduce the risk of brittle fracture, to
avoid subsequent distortion on machining, or to eradicate the risk of stress
corrosion.
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7. Weld Bead
The first type of weld is called a weld bead (referred to
simply as a bead). A weld bead is a weld deposit produced
by a single pass with one of the welding processes.
A weld bead may be either narrow or wide, depending on the
amount of transverse oscillation (side-to-side move-ment)
used by the welder.
When there is a great deal of oscillation, the bead is wide;
when there is little or no oscillation, the bead is narrow. A
weld bead made with-out much weaving motion is often
referred to as a stringer bead. On the other hand, a weld
bead made with side-to-side oscillation is called a weave
bead.
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