Welding Representation

Objectives Describe the various welding processes Draw the common welding symbols Dimension a welding drawing using standard ANSI welding notations

Objectives (cont.) Identify and draw a fillet weld, groove weld, back weld, spot weld, seam weld, projection weld, and flash weld Describe the use of welding symbols in CAD drawings

Welding Processes The principal methods of welding are: Gas welding Arc welding Resistance welding

Standard Symbols Welding drawings are a special type of assembly drawing as weldments are composed of a number of separate pieces fastened together as a unit Joints are all shown as they would appear before welding

Weldment Drawing

Welding Symbols The items that can be specified in a welding symbol are: Type of weld Process Depth of bevel, size or strength for some weld types Groove weld size Finishing designator Contour

Welding Symbols Cont. Groove angle Root opening Length of weld Number and pitch of welds Whether the weld is to be field welded All around indicator Which side of the material is to be welded

Basic Welds and Symbols

Types of Welded Joints There are five basic types of welded joints: Butt joint Corner joint T-joint Lap joint Edge joint

Types of Welded Joints

Types of Welds There are four types of arc and gas welds: Back or backing weld Fillet weld Plug or slot weld Groove weld

Types of Welds The four basic resistance welds are: Spot weld Projection weld Seam weld Flash or upset weld

Welding Symbols The basic element of the symbol is the “bent” arrow The arrow points to the joint where the weld is to be made Attached to the reference line, or shank, is the symbol for the desired weld

Welding Symbols

Complete Welding Symbol

Fillet Welds The usual fillet weld has equal legs

Groove Welds

Back or Backing Welds

Surface Welds The surface weld symbol indicates a surface to be built up

Plug and Slot Welds

Spot Welds

Seam Welds

Projection Welds

Flash and Upset Welds Flash and upset weld symbols have no arrow-side or other-side significance

Welding Applications Welding is often cheaper when only one or a few identical parts are required Welding is also suitable for large structures that are difficult or impossible to fabricate entirely in a shop

Welding Templates Welding templates can simplify drawing welding symbols by hand They have all the forms needed for drawing the arrow, weld symbols, and supplementary symbols

Computer Graphics Welding symbol libraries available in CAD and allow for rapid application of accurate, uniform symbols that are in compliance with standards