Welding Symbols – Important identifiers worth knowing

Last Updated on Jan 18, 2022

Do you have some scrap metals you wish to join to make something useful out of it instead of throwing it away? Learning to weld is useful. It could help you save up some more money instead of hiring someone to do it. One of the most crucial things in learning something is the ability to interpret the symbols used in it.

Just like in math, welding also has its own set of symbols the manufacturers used to tell us how a certain material should be welt. Without it, we would be unable to know what kind and where a piece should be welt.

Elements Of a Welding Symbol

In order for it to classify as a welding symbol, it should contain the main parts, which are the reference line, arrow, tail, and any following elements:

  • Basic weld symbols
  • Supplementary symbols
  • Dimensions and other data
  • Finish symbols
  • Specification
  • Process

Parts of the welding symbol

These weld symbols indicate the processes to follow to join materials like metals. For us to know how to read and understand these symbols, we should first be knowledgeable about their structure. In that way, we can clearly understand how it works. The welding symbol has three parts: the arrow, reference line, and tail.

The first thing to notice in a welding sign is a line referred to as the reference line. It is referred to as the anchor since all of the welding symbols and directions for how to make the weld can be found here. It is the most important portion of the sign since it contains all of the information required to perform effective welding.

In locating the joint where the welding should be done, look for the arrow, as it connects the reference line to the spot you are looking for.

In most situations, it is made up of two sides in the joint where the arrow is directed. Know that there are two spots where you may weld in such a case. The finest illustration is when the two steel plates you’re working on are connected together in the shape of a T. This demonstrates that the welding might be done on any side.

What helps us determine the two sides of a joint is the weld symbols, and by the usage of arrow and space above and below the anchor or what we call the reference line. There are two sides of the joint. The arrow side which the arrow is pointing to and the other side. The rule written below the line is applied to the arrow side, and the one above it is applied to the other side no matter where the arrow is directed to.

The flag indicates that the weld could be made outside of a shop, and the absence of it tells us that it should be made inside. The open circle that is shown in the same illustration above is used to determine if the weld should be done all around the joint. The tail of the symbol is a designated place for some additional information on the weld.

Designation of Welding Processes by Letters

We all know that it is not applicable in every situation that the symbols could stand alone to convey a whole list of instructions. That is where the letters come in. These help us to be informed about the more specific welding processes. A picture is attached below, and as you can see, there is a designated abbreviation for every welding process.

But this does not only apply in the welding processes alone. Letters are also used to specify the cutting process, as shown in the picture below.

Supplementary Symbols

These symbols show us the appearance of the weld, the raw material used in preparing the joint, and if the welding could be performed outside of a shop. Below is a chart showing the different symbols and their meanings.

Spot, seam, and stud weld symbols

Spot weld symbol is a small circle that can be placed above, below, or along the reference line. This helps us to identify the location of the weld. If the circle is above, it indicates that the weld should be on the other side. If the circle is below, then it means the weld should be on the arrow side. A circle along the reference line tells us that there is no side significance.

Stud welds are usually done inside shops as there is a designated tool used for it. The symbol of stud welds is seen as a small circle just like the spot weld but with an x mark inside it.

The seam weld symbol is almost the same as the spot welds’ except it has parallel lines across it.

Finish Symbols

These are used to identify the method of how a contour should be made. These are made up of letters such as:

  • U meaning unspecified
  • G meaning grinding
  • M meaning machining
  • C meaning chipping
  • R meaning rolling
  • H meaning hammering
  • P meaning planishing


This refers to the indication of whether or not it is significant to place something on the weld joint supporting the melted metal.

Types of welds and their symbols

Each type of weld has its corresponding symbol located near the reference line. This helps us to determine which type of weld should be done.

Plug and slot welds

This metal joining method is used to unite overlapping components. The arrow in this sign does not point to the joint but rather to the exterior surface of one of the members of the joint. Just like the previous one, there are two sides. The one to which the arrow points is referred to as the arrow side member, and the other one is referred to as the other side member.

Groove welds

This form of welding is typically applied to create an edge-to-edge junction, although it may also be used to create joints between flat and rounded metals. Groove welds are classified into numerous categories. Square groove welds, v-groove welds, bevel groove welds, u-groove welds, j-groove welds, flare-v groove welds, flare bevel groove welds, and j-groove welds are all examples.


  • Square groove welds are used to show either a fit or a slight separation of the edges. The measurement is shown by the weld symbol. The sign resembles two horizontal parallel lines.
  • The edges of a component are gently chopped off to generate a sloping edge to form a groove in V-groove welding. The dimensions are usually close to the weld sign.
  • Bevel groove welds are a hybrid of the v-groove and the square groove, with one edge shaved off to produce a slope and the other one is squared.
  • U-groove welds are seen as the concave type of welds.
  • J-groove welds, like bevels, are a mixture. It is the combination of u-groove and square as one of the edges is cut in a concave manner while the other one is squared.
  • Flare-V groove welds are used to join two round edges.
  • Flare bevel groove welds are used to join a round edge and a squared one.

Fillet welds

This sort of weld that is used to bind two pieces of metal together is the least expensive form of welded junction since it just requires one piece of metal to be welded perpendicularly to it. Furthermore, this sort of weld does not adhere to a certain minimum metal thickness. The symbol is seen as the triangular cross-section.

Weld Location

  1. Arrow side

The arrow side is the side of the joint where the arrow is pointed to.

  1. Other side

This is the side that the arrow is not pointed to. It is the opposite side of the arrow side.

  1. Both sides

This is shown by putting the symbols on both sides of the reference line.

  1. No side significance

As the name suggests, the weld symbol, resistance spot, flash, and even the resistance seam do not follow an arrow or other side.

How to write a welding symbol

Here are some guidelines to follow when creating a welding symbol.

  • In writing the bevel, flare, bevel groove, and fillet, the perpendicular part should be at the left side.
  • Additional pieces of information like the measurements should always be written in a manner that is read from left to right.
  • When writing a j-groove or a bevel, the arrow should be directed to the piece that should be chopped off.
  • If the joints have 2 or more welds, make sure to put a symbol on every weld.
  • You can use more than one reference line to describe the sequence of processes to be made. The first process should be on the reference line that is nearest to the arrow.
  • If the weld-all-around symbol is used, it should be placed on the spot where the arrow line and reference line intersect. The flag symbol should also be placed at the same spot.
  • The resistance spot and seam symbols could be written at the desired location where you want to put the weld.

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