welding representation

Welding RepresentationChapter 22

*Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart 2009 Pearson Education, Upper Saddle River, NJ 07458.All Rights Reserved.

ObjectivesDescribe the various welding processesDraw the common welding symbolsDimension 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 weldDescribe the use of welding symbols in CAD drawings


Welding ProcessesThe principal methods of welding are:Gas weldingArc weldingResistance welding


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


Weldment Drawing


Welding SymbolsThe items that can be specified in a welding symbol are:Type of weldProcessDepth of bevel, size or strength for some weld typesGroove weld sizeFinishing designatorContour


Welding SymbolsCont.Groove angleRoot openingLength of weldNumber and pitch of weldsWhether the weld is to be field weldedAll around indicatorWhich side of the material is to be welded


Basic Welds and Symbols


Types of Welded JointsThere are five basic types of welded joints:Butt jointCorner jointT-jointLap jointEdge joint


Types of Welded Joints


Types of WeldsThere are four types of arc and gas welds:Back or backing weldFillet weldPlug or slot weldGroove weld


Types of WeldsThe four basic resistance welds are:Spot weldProjection weldSeam weldFlash or upset weld


Welding SymbolsThe basic element of the symbol is the bent arrowThe arrow points to the joint where the weld is to be madeAttached to the reference line, or shank, is the symbol for the desired weld


Welding Symbols


Complete Welding Symbol


Fillet WeldsThe usual fillet weld has equal legs


Groove Welds


Back or Backing Welds


Surface WeldsThe surface weld symbol indicates a surface to be built up


Plug and Slot Welds


Spot Welds


Seam Welds


Projection Welds


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


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


Welding TemplatesWelding templates can simplify drawing welding symbols by handThey have all the forms needed for drawing the arrow, weld symbols, and supplementary symbols


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

welding representation

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