WELDING REPRESENTATION CHAPTER 22 WELDING REPRESENTATION

IMPORTANCE OF THE DRAWING Welding is used very extensively and for large variety of purposes. It is essential to show accurate method of welding on working drawing. To provide complete weld information on the drawing, a system of welding symbols was developed by ANSI.

Welding Processes • Arc welding (SMAW, Shielded Metal Arc Welding, GMAW Gas Metal Arc Welding, plus others…) • Resistance welding (RSW, Resistance Spot Welding, and others…) Gas welding (OFW, Oxy Fuel Welding) RSW OFW GMAW An automobile frame is welded on a robotic automobile assembly line. (Courtesy of Vladimir Pcholkin/Stone/Getty images.)

Joints

25.4 TYPES OF WELD Four basic types of Arc and Gas weld. Back or backing Fillet Plug or spot Groove

Basic Welds and Symbols

UNDERSTANDING A WELDING SYMBOL A welding symbol added to the drawing has many different features that specify each detail of the weld. The items that can be specified are: • Type of weld • Process • Depth of bevel, size, or strength for some weld types • Groove weld size • Finishing designator • Contour • Groove angle • Root opening • Length of weld • Number and pitch (center to center spacing) of welds • Whether the weld is to be field welded (done on site) • All-around indicator • Which side of the material is to be welded

Welding Symbols

Fillet Welds The usual fillet weld has equal legs

Fillet Weld Length and Pitch TWO inch length of weld, with a FIVE inch pitch (center-to-center). The .25 represents the weld leg length. THREE inch length of weld, with a TEN inch pitch (center-to-center). The .25 represents the weld leg length.

Surface Contour and Fillet Welds Fillet weld with a Convex Finish by Machining Fillet weld with a Flush Finish Fillet weld with a Flush Finish by Grinding Fillet weld with a Flush Finish by Chipping Fillet weld with a Flush Finish by Machining KEY: C= chipping G = grinding M = machining R = rolling H = hammering

The Welding Symbol Tail Reference to a specification, process, or other supplementary information is indicated by any desired symbol in the tail of the arrow. Otherwise, a general note may be placed in the tail. If no reference is indicated in the symbol, the tail may be omitted. UNLESS OTHERWISE INDICATED, MAKE ALL WELDS PER SPECIFICATION NO.XXX Resistance Spot Weld and an Electron Beam Weld are called out in the Tail of the Welding Symbols.

Welds extending completely around a joint are indicated by an open circle around the elbow of the arrow.

FIELD WELD

Complete Welding Symbol

J-GROOVE WELD

Groove Welds

BACK OR BACKING WELDS A back or backing symbol opposite the groove weld symbol indicates bead-type welds used as back or backing welds on single-groove welds. Back or Backing Weld Symbols

PLUG AND SLOT WELDS The same symbol is used for plug welds and slot welds. If it is in the arrow-side member, place the weld symbol below the reference line If it is in the other-side member, place the weld symbol above the line A plug weld is understood to fill the depth of the hole unless its depth is indicated inside the weld symbol

SURFACE WELD Show the deposit of the weld at left side of the symbol SURFACE WELD Show the deposit of the weld at left side of the symbol. Since used for build up the surfaces not for joint, no arrow or other side, symbol always below.

25.11 SPOT WELD

SPOT WELDS The size of a spot weld is its diameter. If you need to indicate the minimum acceptable shear strength in pounds per spot, instead of the size of the weld, place this value at the left of the weld symbol. The pitch would be placed to the right of the weld symbol if needed . .

25.12 SEAM WELDING

SEAM WELDS The seam weld symbol, with the welding process indicated in the tail, The size of the seam weld is its width. Show this value at the left of the weld symbol, on either side of the reference line. If you need to indicate the minimum acceptable shear strength in pounds per linear inch, instead of the size of the weld, place this value at the left of the weld symbol, and show the length of a seam weld at the right of the weld symbol