1. WELDING REPRESENTATION
CHAPTER 22
WELDING REPRESENTATION

2. 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.

3. 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.)

5. Joints

6. 25.4 TYPES OF WELD Four basic types of Arc and Gas weld.
Back or backing
Fillet
Plug or spot
Groove

7. Basic Welds and Symbols

8. 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

9. Welding Symbols

10. Fillet Welds
The usual fillet weld has equal legs

11. 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.

12. 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

13. 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.

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

15. FIELD WELD

16. Complete Welding Symbol

17. J-GROOVE WELD

18. Groove Welds

19. 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

20. 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

21. 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.

22. 25.11 SPOT WELD

23. 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 . .

24. 25.12 SEAM WELDING

25. 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