How To Read Welding Blueprints

How To Read Welding Blueprints

It is essential to understand the various forms of welds and their symbols to read the welding blueprints.

Each welding location has its mark, which is always located close to the middle of the reference line. This emblem occurs as a sketch depicting a simplified cross-section of the weld.

How To Read Welding Blueprints
welding guide material

What are welding blueprints and how are they used?

Welding blueprint symbols are used for communicating with builders,  shop managers, welding technicians or bosses, and welders.

Essentially, they are a series of icons used as a shortcut code to define the type of weld,  sizes, and finishing detail. They appear on technical and industrial sketches alluded to by the welder to establish their welding.

Welders abide by the 1/16th law, meaning that their welds may be larger or smaller than the 1/16th of an inch limit. Precision is crucial to this business, so welders must recognize the blueprints and implement them to produce welds that are up to the mark.

Before beginning their welding, welders will generally look at the Welding Process Specification (WPS), which would be a manual that guides the welder by presenting details such as material thickness, the general location of the component to be welded in, the electrodes to be used, and more.

From here, the welder will glance at the welding blueprint, which includes the welding symbols, precise dimensions, and other details required to complete the job. These blueprints come in a variety of ways, such as orthographic, isometric, and 3D.

There is a wide range of welding blueprint symbols that represent all sorts of welds. These symbols are not used in any industry besides widely used in industries such as manufacturing, which require components and parts that conform with exact requirements. Welders in their job sectors rely on blueprints to direct their work daily.

Reading welding blueprint terminology

welder with project blueprint

It is essential to understand the various forms of welds and their symbols to read the welding blueprints.

Each welding location has its mark, which is always located close to the middle of the reference line. This emblem occurs as a sketch depicting a simplified cross-section of the weld.

Although there are several different types of welding symbols, there are six basic types of welds:


Spot welding attaches neighboring metal parts at small points by applying pressure and using an electrical current. Next, the electrodes are taken to the surface of the pieces were attached, and the pressure is applied. The pressure is first applied to the electrodes to heat the material, and the current is finally extracted as the electrodes remain in place while the material cools and solidifies.


A seam weld uses a procedure identical to a spot weld. Essentially, welding progresses through the upper surface and melts through to the other component with the heat input. The symbol is similar, but it also has two parallel lines along with it.


Stud welding is widely done in many shops. In this process, the metal stud is connected to the workpiece surface by heating both pieces with an arc. It is an extremely efficient approach that offers to fasten for many applications.

Understanding welding blueprint icons and symbols

icons and symbols on welding blueprint

According to the  Welding industry, the welding sign is made up of many elements.

The skeleton welding symbol includes a horizontal line, called a reference line, which serves as an anchor to which all the welding symbols are connected. The directions for welding appear in this reference line. After this, an arrow attaches to this horizontal line to indicate the joint to be welded.

In addition to these two elements, welding symbols can include additional components for transmitting correct welding details. Welding symbols can also represent other ways, such as drawing notes or definitions, descriptions, laws, directions, or other sketches, which preclude the corresponding elements from being used in the symbol.

The welding symbol tail is used to designate the welding, brazing, and cutting method in addition to the welding or brazing requirements, techniques, and additional material to be used in the welding or laser welding process. The process, the name of the filler metal to be used, and other data are stored in the symbol’s tail.

Letters on the Welding Symbols

The welding symbol is not the same as the welding symbol. The weld symbol specifies the form of weld to be used for the component. The welding symbol consists of several sections, including the line segment, the arrow, and the welding icon as needed.

The icon in this book is a description of what welding and welding symbols look the same. When used in compliance with a blueprint, there are unique construction criteria.

Here are the basic welding symbols:

Reference Line and Arrow

Two sections make up the main body of a welding mark. It includes the reference line and the arrow. The horizontal line that makes up the main body refer to as the reference line. It is the anchor to which all the other welding symbols are attached.

The details related to the welding process is put on the reference line at particular positions. The arrow guides the reference line to the joint at which the weld(s) is created. There are many variations of the reference line and the star, but the reference line will still be oriented horizontally.

Arrow vs Other Side

The placement of the weld depends on the position of the mark above or below the reference line. If the symbol has been above the reference line, the other hand would be named.

It is behind the reference line that is called the arrow hand. The other hand and the arrow describe just what it is asking.  The symbol is directed on the right side of the joint weld. The weld will be on the right side of the weld, and the arrow side of the weld out.   The weld blueprint stretched to the left side of the component.

It is essential to consider the distinction between these two sides since it may finish the product or, if done poorly, give it back to be reworked to achieve the right result.

The idea behind this may sound straightforward at the moment, but as we work through this book and start adding more components to the welding sign, the thinking process may become more taxing. The most critical aspect is to break it down piece by piece and better appreciate what the symbol is asking/requiring for the weld.

There may be several points of reference at times. If this is the case, it is essential to know the order where the welding is to take place. The reference line closest to the arrow is the first operation, preceded by the second, and so forth until all procedures are complete.

Welding Angles and Patterns

circular pattern

Welding patterns are the various ways in which you weave a weld around the joint to distribute the welding profile and add or remove heat from the bead at points. Each pattern creates a subtly different-looking profile and is particularly helpful for achieving more complex welding procedures.

People are attempting to weave some possible patterns, and it will take a long list of pages to cover any of them. These are the five basic patterns, and changes to each of them are necessary if you wish to emphasize an aspect of the stress pattern.


The circular pattern twists a continuous series of oval design around the joint. It offers even visibility and decent penetration since the bottom of the circular design carries the heat and the filler wire back into the weld so that there are no cold patches in the joint. It is an all helpful welding pattern that gives a tidy-looking weld even with heat transfer through the joint in every place.

Convex C

This pattern is similar to circular weaving, only that the torch stops halfway across the loop, makes a C, and cuts through the weld to create another C right in front of it. The tips of the C motion pause before the change of direction, bringing deeper penetration and more “meat” to the toes of the weld (weld edges). It is useful for overlap positions and a flat ass position where the distance is not too wide to fill.

Concave C

This pattern results between such a circular weave and a convex C pattern. It brings a little more weld to the middle of the joint than the convex C, so the torch carries the fire and the wire back to the center of the bead. It also leaves the edges of welding complete due to a gap between transformations, which adds a deep penetration of the top.

The concave C is efficient for either vertical up and down welding and efficiently covers wide holes where you don’t want the weld to blow through the core. It offers a strong fill over the whole joint, thus setting some pre-welding on the edges of the gap to help bridge the gap before too much heat enters the core.


The triangle pattern is similar to the circle design, but with extra focus on three points of the triangle than the flowing circular scarf. The bottom two points are where you stop on the left and the right of the joint, and the upper one of the triangles is where you stop at the center of the joint.


The zig-zag pattern stretches out the weave, but it doesn’t offer as much penetration. It is useful for overwhelming when several passes are made or keep excess heat out of the project when welding.

ANSI Welding Symbols

welding symbols

Welding specifies engineering and manufacturing drawings. A visual series of symbols is used as a kind of shorthand to describe the type of weld, its length, and other processing and finishing detail.

Here we are going to introduce you to the famous symbols and their definition. The full set of welding symbols is given in the specification are issued by  American National Standards Institute (ANSI).  The American Welding Society (AWS): ANSI/AWS A2.4, Symbols for Welding and Non-Destructive Testing.

Fillet end

The Filet Welding symbol is one of the most commonly known. It is used to render corner joints, lap joints, and T joints. It appears as a pyramid shape, but its form is not always an isosceles or a right triangle.  Welding metals are made up of two parts. Which is inserted in the corner and penetrates and fuses the central metal forming a joint.


Groove welding is used to create edge-to-edge joints. They are often frequently found in T joints, corner joints, and joints between flat and curved sections.

These welds can be rendered in several different ways, based on the geometry pieces that joined together and the preparation of their edges. Welding metal is deposited in the groove and fuses with the base metal to form the joint.  Different types of groove welds are available, including rectangle, double-bevel square, and V-groove welds.

J-Groove Welds

The J groove joint, either single J or double J groove, is used for multipass welding with much wider thicknesses than those with which the vee groove corner joint can be used. The welding method is similar to that used in the U groove butt joint.

A tiny back weld is often created before multipass arc welding is made. If no support weld is used, the maximum allowable root distance is 1/32-in. As only one side of the joint is planned, the slope of the edge and the radius circumference should be defined in the figure to provide an appropriate working area to position the welds at the root joint.

V-Groove Welds

For thicker joints, the preparation of a single-vee groove is advised to achieve sufficient penetration without undue reinforcing. If a welded arc is submerged, a deep root face must be used. A copper chiller bar can be useful for this joint as with a square butt joint.

Plug or Slot

angled welding joints

Plug and slot welding is used to connect different parts by cutting holes in one of the metals. Weld metal is put into the holes, and the base metal fuses the two sections to form the joint. For plug welds, the holes are circular, and in slot welds, the holes are slot-shaped.

Flare Groove Welds

Frequently used to tie a circular or curved piece to a flat cylindrical tube. As with the flare-V, the depth groove is created by the two curved surfaces. The expected depth weld itself is given to the left of the symbol, with the weld depth shown in the brackets.

Bevel Groove Welds

There is a bevel angle where only one piece of work is bent, as, with a single bevel weld and fillet weld, the face of a groove weld may have to be smooth, convex, or concave.

Square Groove Welds

For joint thicknesses up to 1/2-in, a square groove corner joint is preferred. A submerged arc filet weld is first made on the inside corner of the joint. A square groove butt weld is then made on the other side of the joint. The ass weld is intended to penetrate down and refuses a section of the back filet weld.


If you’re not comfortable with the welding blueprint symbols, don’t worry!

Although they can seem overwhelming at first, knowing the fundamentals behind what they say will change your welds. Read to learn more about what welding signals are, and the fundamentals of how to read them.