Metal Fabrication Resources by Blackstone Advanced Technologies

Blackstone Advanced Technologies Blog
Dec 10, 2018 4:11:00 PM

Easy Guide to Welding Symbols

One of the most common mix-ups between engineers and their manufacturing vendors is with welding symbols. Providing your manufacturer the proper design notations can be the difference between a great product and a distorted, ugly mess.


Here’s your guide to making things easy for your vendor to understand. And if you’ve specified an aluminum weld and want help picking the ideal grade, check this out.


Welding Symbols Guide

Here are the common welding symbols we particularly receive a lot from customers:

  • Fillet -- Joining two pieces of metal, whether they are perpendicular or at an angle. Also commonly referred to as tee joints (perpendicular) or lap joints (overlap, welded at the edges)
  • Square-groove -- A butt welding joint with two pieces flat and parallel to each other.

  • Spot welding -- Contacting metal surfaces joined by the heat obtained from resistance to electric current.

This graphic illustrates the most common welding symbols:

welding symbols (Photo courtesy Structural Engineering Professional)


Where to put your symbols

Typical elements of weld symbols include:

  • Arrows (required)
  • Reference lines (required)
  • Basic weld symbols
  • Supplementary symbols
  • Dimensions and other data
  • Tails
  • Finish symbols
  • Other specifications

welding symbols

(Photo courtesy Structural Engineering Professional)


Consequences of Getting It Wrong

If you expect a certain part to be welded a certain way and you mark your drawing incorrectly, prepare to be disappointed. This is how you end up with a fillet weld instead of a bevel weld -- and back at square one.


Your manufacturer is forming your part based on your specs -- don’t leave the interpretation up to the vendor.


Talk to Your Manufacturer

Like many relationships in life, the best way to avoid mix-ups is to communicate with your vendor. The sooner in the process this begins, the better.


Many manufacturers are willing to help you in the early design phase of your project. How does this specifically relate to welding symbols? Your partner can:

  • Ask you about confusing notations instead of moving forward with a “best guess”
  • Identify overwelding and other potential design flaws
  • Collaborate with you on how to best notate your drawings for future efficiency

When a weld symbol appears to be incorrect, dedicated manufacturing partners will start a dialogue between you and their engineers or sales teams, depending on the issue. Sometimes it’s OK to ask for help!

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(Editor's Note: This blog was originally published in September 2017 and was recently updated.)