As a production engineer and executive, a knowledge of “location of elements of a welding symbols” is necessary for indicating or interpreting. This will now be discussed in more details in the following paragraphs. Any of the following standards could be used depending upon the situation and case of use.

1. AWS-A24: Symbols for welding and non-destructive testing.

2. BS : 499 (Part II): Symbols for welding.

3. ISO : 2553: Symbolic representation on drawings.

4. IS : 813 (1961): Scheme of symbols for welding.

Basic symbols used in ISO and AWS are identical.

In the AWS system a complete welding symbol consists of the following elements:

1. Reference line (always shown horizontally)

2. Arrow

3. Basic weld symbol

4. Dimentions and other data

5. Supplemental symbols

6. Finish symbols

7. Tail

8. Specification process or other references.

These elements have specified locations with respect to each other on or around the reference line as shown in Fig. 8.1.



Length of weld

Field weld symbol

Pitch (center-to-center spacing) of welds

Number of spot or projection welds

Arrow connecting ref­erence line to arrow side member of joint

Specification, process or other reference

Basic weld symbol or detail reference

Finish symbol Contour symbol

Root opening; depth of filling for plug and slot welds

Effective throat

Depth of preparation size or strength for certain welds

(Tail omitted when reference is not used)


Elements in this area remain as shown when tail and arrow are reversed

Groove angle; included angle of countersink for plug welds

Weld-all-around symbol Reference line

Fig. 8.1 Standard location of elements on the welding symbol

There are two prevailing systems of placing the symbol with respect to the reference line. In USA and UK, the symbol is placed below the reference line for welds on the arrow side. ISO has accomodated both and designate them as A and E (for European system). The designer must be aware of these two systems and take care that his drawing is not misinterpreted.

Size of fillet Depth of

in inches preparation in inches


[/ 2 to 4

Field weld Length and pitch

points to tail in inches

Fig. 8.2 Size location, field weld length, and pitch






Fig. 8.4 Straight line always on left

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