AWS Blueprint Reading & Symbols 2 — Questions and Answers

Question 1: What does the reference line in a welding symbol represent?

The weld length
The baseline from which all weld information is communicated (Correct answer)
The heat-affected zone boundary
The joint root opening

Correct answer: The baseline from which all weld information is communicated

The reference line is the horizontal line in a welding symbol from which all weld specifications — type, size, length, finish — are communicated above, below, or at the tail.

Per AWS A2.4, the reference line is the foundation of a welding symbol. Information placed below the line applies to the arrow side of the joint; information above applies to the other side. The tail at the right end carries references to specifications, processes, or other notes. Without understanding the reference line orientation, a welder cannot correctly interpret side-specific instructions.

Question 2: A circle at the intersection of the arrow and reference line on a welding symbol means:

Weld all around (Correct answer)
Field weld
Flush contour required
Inspect after welding

Correct answer: Weld all around

A circle at the junction of the arrow and reference line is the 'weld all around' symbol, instructing the welder to weld the entire perimeter of the joint.

AWS A2.4 defines the 'weld all around' symbol as a small circle placed where the arrow meets the reference line. It tells the welder that the weld is continuous around all sides of the piece, commonly used for pipe-to-plate connections or tube-to-base plate welds. A flag at the same location would indicate a field weld instead.

Question 3: On a welding symbol, the number to the LEFT of the weld symbol indicates:

Weld depth
Number of welds required
Length of the weld (Correct answer)
Pitch (center-to-center spacing)

Correct answer: Length of the weld

Per AWS A2.4, the length of the weld is shown to the right of the weld symbol, while pitch (spacing) is shown after a dash to the right. The number to the left indicates weld size.

In AWS A2.4 standard, the weld size (or effective throat for groove welds) appears to the LEFT of the weld symbol. Weld length appears to the RIGHT. For intermittent welds, length and pitch appear as 'length-pitch' to the right. Misreading left vs. right can lead to undersized welds or wrong spacing, causing joint failure.

Question 4: Which groove weld symbol resembles a capital letter 'V'?

Bevel groove
V-groove (Correct answer)
J-groove
U-groove

Correct answer: V-groove

The V-groove weld symbol is drawn as a 'V' shape between two parallel lines, representing both sides of the joint beveled to form a V shape.

AWS A2.4 uses pictographic weld symbols that reflect the cross-section of the weld groove. A V-groove symbol looks like a 'V', indicating both members are beveled to meet at a point. A bevel symbol has only one slanted line (one side beveled). A U-groove uses curved lines, and a J-groove uses one curved plus one straight line. Recognizing these shapes instantly communicates joint preparation requirements.

Question 5: A flag on the welding symbol indicates:

Weld is safety critical
Weld must be performed in the field (on-site) (Correct answer)
Weld requires radiographic inspection
Welder must be AWS certified

Correct answer: Weld must be performed in the field (on-site)

A flag (pennant shape) at the junction of the arrow and reference line indicates a field weld — the weld is to be made at the installation or erection site, not in the shop.

The field weld flag per AWS A2.4 is a filled triangular pennant attached where the arrow meets the reference line. It distinguishes shop welds (fabricated in controlled conditions) from field welds (made on-site during erection or installation). Field welds may require different procedures, inspection access, and weather protection to ensure quality.

Question 6: In a welding symbol, contour symbols (flush, convex, concave) are placed:

To the left of the weld symbol
Above or below the reference line at the end (Correct answer)
At the tail of the reference line
On the arrow itself

Correct answer: Above or below the reference line at the end

Contour symbols are placed directly above (other side) or below (arrow side) the reference line, adjacent to the weld symbol, to indicate the desired weld face shape.

AWS A2.4 specifies that contour symbols — a straight line for flush, a convex arc for convex, and a concave arc for concave — are placed on the same side of the reference line as the weld symbol they modify. A finish symbol letter (G for grind, M for machine, C for chip) may accompany the contour symbol to specify how the final surface should be achieved.

AWS Blueprint Reading & Symbols 2

What does the reference line in a welding symbol represent?