Terms Used With Welding Symbols

Reference Line: Is always drawn as a horizontal line.

Arrow: May be drawn from either end of the reference line. It always touches the line that represents the welded joint.

Tail: Used only when necessary. Used to give information on specifications.

Weld Symbol: Indicates the type of weld to be made.

Arrow Side: The side of the metal which the arrow touches.

Other Side: The opposite surface from the arrow.

Root Opening: The space between the pieces at the bottom or root of the joint.

Groove Angle: This is the included angle or total angle of a groove weld.

Contour Symbol: This is the shape or contour of the finished weld. Shown as a straight or curved line.

Finish Symbols: Indicates the method of finishing. C: Chipping  G: Grinding  M: Machining  R: Rolling  H: Hammering

Depth of Bevel, Size or Strength: The "S" position on the welding symbol indicates the depth of bevel or the depth of preparation for a groove type joint.

Groove Weld Size: Given in parentheses in the "E" position on the welding symbol indicates the depth to which the weld penetrates into the base metal.

Length of Weld: On intermittent welds, the length dimension is used to indicate the length of each weld.

Pitch of the Weld: This indicates the distance from the center of one weld segment to the center of the next.

Backing Weld Symbol: A backing weld may be used to obtain 100% penetration when welding is possible on both sides.

Melt-Through Symbols: The melt-through symbol is used on welds that are welded from one side only and require 100% penetration.

Weld-All-Around Symbol: This indicates that the same type of weld joint is used on all edges of a box or cylindrical part.

Field Weld Symbol: Used when the weld is to be made away from the shop.

Multiple Reference Lines: Used when a sequence of operations is to be done. The reference line nearest the arrow indicates the first operation. The last operation to be performed is on the reference line furthest from the arrow.