9 Basic Steps to Read Welding Symbols

The ability to read and understand weld symbols is very important yet the vast majority of welders have hard time with these symbols.   A very small percentage of companies require that welder candidates know how to read symbols.   With the shortage of welders in today’s market imposing this prerequisite would not be feasible.  What companies need to do is to have training for their welders.  The problem is that in many cases manufacturers don’t have someone on staff that can do this.  This is usually the case in small to medium size companies.  However, if you are in need of this kind of training you can rely on outside help.  Vendors, mainly industrial distributors and welding manufacturer’s reps, should have this knowledge.  At least highly qualified ones do.  They typically can offer this type of training at either a reduced fee or at no cost.

The 9 steps below represent a very basic introduction to weld symbol reading. This is just barely skimming the surface of welds symbols training.  If you have a questions please let us know by replying to the post.

Weld Symbols Basics

  1. Every weld symbol must consist of an arrow and a reference line.

1 arrow ref line

  1. The arrow may point up or down

2

  1. The arrow does not necessarily need to point to the side of the joint that needs to be welded.   Sometimes space constraints in the drawing will not allow for the arrow to fit on one side, so the information placed on the reference line will be an indication of whether the weld goes on the arrow side or the opposite side.

3

  1. The type of weld joint is indicated by a specific symbol.  The American Welding Society has a very nice chart detailing these symbols.  Below is a section of it.

4

Going forward we will stay with Fillet welds since the following information is displayed differently depending on the type of weld joint.

  1. Information such as size, length and other special considerations will be displayed next to the weld symbol.  Location of this information matters.  Below we see an example of a fillet weld symbol.

5

Fillet weld symbols will ALWAYS have the vertical line of the symbol on the left.

 

  1. The length of the fillet weld, if it is not the entire length of the join, is displayed to right side of the symbol.

6

  1. Intermittent welds are called out using Length and Pitch.  As noted above the number to the right of the diagonal line of the fillet symbol is the length (in the US this will be in inches unless otherwise noted).  The pitch is displayed to the right of the length and it indicates the distance between centers.

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  1. VERY IMPORTANT: if you ever see a flag at the intersection of the reference line and the arrow do NOT make that weld if you are in a shop.  This circle denotes a field weld.

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The circle notation means the weld has to go all the way around.

  1. Several of the diagrams above show the configuration of the base material (graphical representation of the joint by showing how the two pieces come together).  This is almost never the case on an actual drawing, and thus it is why it is important to know the different welds symbols shown on the AWS Symbols Chart.  A drawing will more than likely look something like this:

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This was a very basic introduction to weld symbols.   Training programs that we have gone thru or put on for customers range between 4 and 16 hours.  Programs are typically tailored to the customer’s need and thus vary widely in length.

Want to learn about welding symbols for groove welds? Check out “9 Basic Steps to Reading Welding Symbols for Groove Welds.”

Source: AWS A2.4:2007 – Standard Symbols for Welding, Brazing, and Nondestructive Examination
 

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5 thoughts on “9 Basic Steps to Read Welding Symbols

  1. hi thanks i have quastion which would you like to choose as electrod for low alloy steel for useing pressure vessel materiyal selection?? where is the selection guide in asme???iwill de happy if answer to me