WELDING DRAWINGS

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WELDING DRAWINGS
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Definition

• A welding drawing is a detailed multiview drawing
  showing all the parts welded together.

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• The graphic representation of welded parts is
  shown by welding symbols. The weldment is not
  shown, but the joint lines are shown.
• The welding symbols give all the information
  necessary for the welder to fasten the parts
  together using one the welding techniques.

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Welded joints
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Weld Symbols

• Each type of weld is characterized by a basic
  symbol derived from its section shape.
• Supplementary symbols are usually used to
  specify the contour of the weld, whether the
  welding is performed in the field or in the shop,
  or if it is applied all around the welded part.

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The weld symbol consists of eight parts which are
as follow

• Reference line
• Leader line
• Basic weld symbol (location/depth of weld)
• Finish symbol
• Weld symbol (type of weld)
• Dimensions
• Supplementary symbols
• Tail and specification

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Supplementary weld symbols
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The weld symbol is attached to the horizontal
portion of the leader line, called the reference
line, see figure below. The text height is 3
mm. The arrow points to the area to be welded.
The tail is used when a specification is made to
the weld symbol.
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Supplementary weld symbols

• A weld symbol is centered and placed below the
  reference line if the weld is on the same side as
  the arrow.
• A weld symbol is centered and placed above the
  reference line if the weld is on the opposite
  side as the arrow.
• A weld symbol is centered and placed above and
  below the reference line if the weld is to be on
  both sides of the joint.
• A weld symbol is placed at the intersection of
  the leader and the reference lines if the weld is
  to be all-around the joint.
• When the welding process is to take place in the
  field or on the site of assembly, a special
  symbol in the form of a flag is used.
• The melt-through symbol is used when there is to
  be 100 penetration of the weld from one side all
  the way through the joint.

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• The backer or spacer material symbol is used when
  small extra piece is to be added between the
  parts to be welded.
• Contours symbols are used to represent welds that
  are machined. Horizontal lines for flush
  contours, arcs for convex or concave contours.
  Methods of finishing are represented by the
  following letter designations, placed above or
  below the contour symbol G- grinding,
  C-chipping, M-machining, R-rolling, and
  H-hammering.
• If a joint is to be prepared prior to welding,
  such as machined, then the leader line is bent.