What are the types of welds?

Welds: classification, types of welding joints, basic geometric parameters of the seam - Machine

Welding seams are zones of welded joints that are formed by metal that was initially molten and then crystallized upon cooling.

Welding parameters

The service life of the entire welding structure depends on the quality of the welds. Welding quality is characterized by the following geometric parameters of the weld:

• Width – the distance between its edges;
• The root is the inner part opposite its outer surface;
• Convexity - the largest protrusion from the surface of the metal being joined;
• Concavity - the greatest deflection from the surface of the metal being connected;
• A leg is one of the equal sides of a triangle inscribed in the cross section of two connected elements.

What are the types of welds and connections, classification

Table 1 shows the main types of welding joints, grouped by cross-sectional shape.

No.	Welded joints and seams	Location Features	Main Application	Note
1	Butt	The connected parts and elements are in the same plane.	Welding of sheet metal structures, tanks and pipelines.	Saving consumables and welding time, joint strength. Careful preparation of the metal and selection of electrodes.
2	Corner	The connected parts and elements are located at any angle relative to each other.	Welding of containers and reservoirs.	Maximum metal thickness 3 mm.
3	Overlapping	Parallel arrangement of parts.	Welding of sheet metal structures up to 12 mm.	Large consumption of material without careful processing.
4	T-bar (letter T)	The end of one element and the side of the other are at an angle	Welding of load-bearing structures.	Careful processing of vertical sheet.
5	Face	The side surfaces of the parts are adjacent to each other	Welding of vessels without pressure	Material savings and ease of execution

 By way of execution:

• Double-sided - welding from two opposite sides with removal of the root of the first side;
•  Single-layer – performed in one “pass”, with one weld bead;
•  Multilayer – the number of layers is equal to the number of “passes”. Used for large metal thicknesses.

 By degree of convexity:

• Convex – reinforced;
• Concave – weakened;
•  Normal - flat.

The convexity of the seam is influenced by the welding materials used, welding modes and speed, and the width of the edges.

By position in space:

• Bottom – welding is carried out at an angle of 0° – the most optimal option, high productivity and quality;
•  Horizontal - welding is carried out at an angle from 0 to 60° require increased
•  Vertical - welding is carried out at an angle from 60 to 120° to the welder’s qualifications;
•   Ceiling - welding is carried out at an angle from 120 to 180° - the most labor-intensive, unsafe, welders undergo special training.

 By length:

•  Solid - the most common;
•  Intermittent – ​​leaking structure.

 Types of welded joints and seams by relative position:

•  Located in a straight line;
•  Located along a curved line;
•  Located in a circle.

In the direction of the acting force and the vector of action of external forces:

• flank - along the axis of the welded joint;
• frontal - across the axis of the welded joint;
• combined - a combination of flank and frontal;
• oblique - at a certain angle to the axis of the welded joint.

Types of welds according to the shape of the products being welded:

• on flat surfaces;
• on spherical ones.

 The types of seams also depend on the thickness of the working material and the length of the joint itself:

• short – not > 25 cm, and welding is carried out using the “one pass” method;
• medium - length < 100 cm - a reverse-step welding method is used, in which the line is divided into small sections 100-300 mm long;

All extended seams are processed in a reverse-step manner, from the center to the edges.

Cutting edges for welding

To create a strong and high-quality weld, the edges of the joined products undergo the necessary preparation and are given a certain shape (V, X, U, I, K, J, Y - shaped). To avoid burn-through, edge preparation can be done with a metal thickness of at least 3 mm.

Edge preparation procedure:

1. Cleaning metal edges from rust and dirt;
2. Chamfering a certain size - depending on the welding method;
3. The size of the gap depends on the type of welded joints.

Edge preparation options:

•  Edge cutting angle – α;
• Gap between edges –b;
• Blurring of edges –c.

Table 2 shows the features of edge preparation depending on the thickness of the metal.

https://www.youtube.com/watch?v=qBf24cIxYuU

table 2

No., no.	Metal thickness, mm	Edge cutting	Angle, α	Gap b,mm	Blunting of edges c, mm
1	3-25	Single-sided V-shaped	50	–	–
2	12-60	Double-sidedX-shaped	60	–	–
3	20-60	Single-sided, double-sided U-shaped	–	2	1-2
4	>60	I-shape	–	–	–

We recommend! How to weld a muffler using cold or electric welding

Source: https://regionvtormet.ru/svarka/svarnye-shvy-klassifikatsiya-tipy-svarochnyh-soedinenij-osnovnye-geometricheskie-parametry-shva.html

Main types of welded joints and seams

Greetings, dear readers. In today's article we will tell you about the main types of welded joints and seams . Many welding specialists call these connections welded, some call them welded , although this does not change the meaning.

In this article they will also be mentioned differently, depending on the turn of phrase, but remember: welded and welded in relation to joints and seams are the same thing.

Welded joints and seams are classified according to several criteria

There are a number of types of welds depending on the type of connection :

• - butt joint seam
• - T-joint seam
• - lap joint seam
• - corner joint seam

Butt joint

A butt joint is a connection between two sheets or pipes at their end surfaces. This connection is the most common due to lower metal consumption and welding time.

The butt joint can be, depending on the location of the seam:

• — One-sided
• — Double-sided

To prepare a joint for welding, depending on the thickness of the products being welded:

• — No beveled edges
• — With beveled edges

One-sided connection without beveled edges involves welding sheets up to 4 mm thick (with the exception of the Laser Hybrid Weld process). It is recommended to perform a two-sided connection of non-beveled edges when welding thicknesses up to 8 mm. In both cases, to ensure high-quality penetration, it is necessary to make a small gap when connecting sheets for welding, about 1-2 mm.

It is recommended to bevel the edges of a one-sided welded joint with thicknesses from 4 to 25 mm. The most popular is the V-type bevel connection. Less popular, but also used are single-sided edge bevels and U-type bevels. To prevent the possibility of burns, the edges are slightly dulled in all cases.

For thicknesses of 12 mm or more, when welding on both sides, it is recommended to use an X-shaped groove, which has a number of advantages over a V-shaped groove. These advantages consist in reducing the volume of metal required to fill the groove (almost 2 times), and accordingly increasing the welding speed and saving welding materials.

T-joint

A T-joint consists of two sheets of paper when a “T” shaped joint is formed between them. As with butt joints, depending on the thickness of the metal, welding is performed on one or both sides, with or without groove. The main types of T-welded joints are shown in the figure.

Some tips for welding a T joint:

• 1. When welding a T-joint of thin metal to thicker metal, it is necessary that the angle of inclination of the electrode or welding torch be about 60° to the thicker metal. As shown below:

• 2. Welding a T-joint (and a corner joint to the same extent) can be greatly simplified by positioning it for welding “in a boat”. This allows welding to be carried out predominantly in the down position, increasing welding speed and reducing the likelihood of undercuts, which are a very common defect in T-weld joints, along with lack of fusion. In some cases, one pass will not be enough, so for filling seams it is necessary to oscillate the torch. Boat welding is also used in automatic and robotic welding, where the product is turned using a special tilter to the position required for welding.

• 3. Currently, there are special welding processes for increased penetration. Using them, you can achieve one-sided welding of fairly thick metal with guaranteed penetration and the formation of a reverse bead on the other side. More information about the Rapid Weld welding process can be found here. You can learn about welding equipment for one-sided welding of a T-seam with reverse welding of the bead in the section “QINEO TRONIC PULSE semi-automatic welding machine”

Lap joint

This type of connection is recommended for welding sheets up to 10 mm thick, and the sheets must be welded on both sides. This is done so that there is no possibility of moisture getting between them. Since there are two welding seams in this connection, the time for welding and the consumable welding materials increase accordingly.

Gusset

A corner welding joint is a type of connection between two metal sheets located at right or other angles to each other. These connections can also be with or without beveled edges, depending on the thickness. Sometimes the corner joint is also welded from the inside.

Classification according to other criteria

Welded joints and seams are also classified according to other criteria.

Types of connections by degree of convexity:

• - normal
• - convex
• - concave

The convexity of the seam depends on both the welding materials used and the welding modes. For example, with a long arc, the seam turns out flat and wide, and, conversely, when welding with a short arc, the seam turns out to be narrower and more convex. The degree of convexity is also affected by the welding speed and the width of the edges.

Types of connections by position in space:

• - lower
• - horizontal
• - vertical
• - ceiling

The most optimal position for welding is the lower position of the seam. Therefore, when designing a product and drawing up a welding process technology, this should be taken into account. Welding in the lower position promotes high productivity and is the simplest process to obtain a high-quality weld.

The horizontal and vertical position of the welded joint requires advanced qualifications from the welder, and the ceiling position is the most labor-intensive and unsafe.

Types of welded joints by extent:

• - solid (continuous)
• - intermittent

Intermittent welds are used in connections where tightness is not required.

I hope you find this information on types of welds and joints useful and help you increase the quality and productivity of your welded structures in your design. It will also help make the welding process itself safe and optimal. Thank you for your attention, read also other articles.

Smart Technics

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Welding seams: types of welded joints and classification of welding methods

The modern welding process is a high technology with classification and quality criteria. Since the main final product is welding seams, they are also well described, classified and have their own quality criteria and methods of execution.

Welding standards in the form of GOSTs contain comprehensive information and symbols for options for a wide variety of purposes.

What is a weld seam

To begin with, let’s define the concepts of “welding seam” and “welding joint”, because some sources consider them to be one and the same thing, others separate the formulations.

The shortest definition: a weld is a permanent connection by welding.

The second option reveals the physics of the welding process as such: a weld is a section in which two or more parts are connected as a result of crystallization or deformation of a substance, or one and the other together. One way or another, it is more logical to take welding seams and joints as one and the same process.

One of the oldest and most famous standards among specialists is “GOST 5264 – 80 Manual arc welding. Welded connections." This GOST was put into effect back in 1981, it still copes with its tasks perfectly: the main types of welds, their sizes, structural elements and instructions on how to correctly lay a weld are clearly listed. An excellent example of a document that does not need adjustments over time.

Types of welding seams

Types of welding joints.

Like welding methods, types of welding seams fall under a strict classification according to different criteria:

• The method of connecting parts;
• Position during welding;
• Seam length;
• Location of the force acting on the seam.

The most popular and important types of seams are grouped according to the method of joining parts:

1. Butt.
2. Angular.
3. T-bars.
4. Overlapping.

Butt seams

Classification of electrodes for welding.

Types of welded joints include both very popular methods and rare ones. Butt methods can be considered highly popular: they are used when welding sheet metal or pipe ends. The fundamental requirement for the butt method is rigid fixation of the parts to be joined with a gap of 1 - 2 mm, which is filled with metal during the welding process.

The most important “butt” issue is the edges of the parts that will melt and join. Or rather, the way to process these edges. The butt connection is considered one of the most reliable and economical in terms of strength. This is especially true when cooking on both sides. Preliminary preparation of the edges is an important component of a high-quality seam. All 32 types of butt joints with edge processing options are set out in the GOST 5264-80 standard.

Here are some examples:

1. If the metal sheet is thin - less than 4 mm, no pre-treatment is required; this is a family with symbols C1, C2, C3.
2. If the sheet thickness is between 4 and 12 mm, the seam can be welded on both one and both sides. But in this case, edge processing by stripping is necessary. It all depends on the requirements for welding quality. If you choose to weld on one side, you will have to make multiple passes to fill the seam. If high quality is required, you need to peel and cook on both sides. Strippings come in the form of V or U. There are many options, all are listed in GOST, for example, symbols C28, C42.
3. If the metal sheet is thicker than 12 mm, only double seams are used with edge processing on both sides in the form of the letter X. V or U shapes for stripping edges with large thicknesses are unprofitable: too much metal will be required to fill them. And this reduces the speed of the process and increases the consumption of electrodes. Symbols C27, C39, C40.

In short, according to GOST, the joint family is divided into:

• Single-sided and double-sided without edge treatment;
• With processing of one of the edges;
• With processing of both edges;
• Sawing in the form of a V or X;
• With double-sided processing of both edges.

T-joints

The T-type method is cut into the shape of the letter “T”: the end of one part is welded to the side surface of another part. Most often, the elements are located perpendicular to each other. GOST 5264-80 describes 9 T-type types: T1 to T9. For a high-quality T-joint, deep melting is required, which is performed using automatic welding. If welding is done by hand, careful processing of the edges is required.

An interesting feature of deep fusion T-welds: they are stronger than the base metal. The strength of fillet welds (see below about them), on the contrary, is less than the base metal. These kinds of differences must not only be taken into account, but calculations must be made in advance. The concept of “calculation of welded joints” is included in a special section of technical mechanics, which is studied at engineering faculties.

These strength-of-materials tasks take into account the main features and disadvantages of welding joints: uneven strength, uneven heating and cooling processes, as a result, possible warping, residual stress or hidden defects.

Corner connections

Scheme for creating a vertical seam.

In some sources, fillet welds during welding are described as part of T-welds. They are as easy to describe as T-bars: the corner profile resembles the letter “G”, and in GOST 5264-80 they are designated with the initial letter “U”: from U1 to U10.

Despite the apparent simplicity of welding a corner joint, sometimes difficulties arise: metal flows from a corner or vertical surface onto a horizontal one. The solution to this problem is to control the movement of the electrode in order to maintain the correct angles of inclination and so that this movement is smooth. In this case, you will receive a high-quality, evenly filled seam.

An excellent way of high-quality corner welding is the method called “boat welding”: the parts are located at right angles to each other, the length of the seams is 8 mm or more.

If welding corner joints involves sheets of metal of different thicknesses - thin and thick - the electrode should be located at an angle of 60 degrees to the thicker part so that more heating is applied to it. Then the thin metal will not burn out.

Welding fillet welds requires compliance with the rules of the geometry of welding joints.

The main geometric criteria are as follows:

• Width - the gap between the edges of the fusion of metals;
• Curvature – the gap at the point of maximum concavity;
• Convexity – the gap at the point of maximum convexity;
• The root of the joint is the edge farthest from the profile (the actual wrong side)

Main types of welds.

Basic standards of electric welding for the size of the seam:

• Arc voltage;
• Pace of work;
• Wire cross-section size;
• Magnitude, density, polarity of voltage.

For example, as the current increases, the penetration depth increases (the size does not change). But at a time when the arc intensifies, the seam expands and, as a result, the depth of penetration decreases.

If the cross-sectional size of the welded wire decreases, the current in the wire increases, the penetration depth increases, and the seam itself decreases in size. There are many examples of the optimal combination of welding factors. All types of welded joints contain the main requirement - not to violate the execution technology, plan in advance and calculate the values ​​of all input parameters.

Overlapping seams

Overlap joints: surfaces are parallel to each other, partially overlap each other, welded in a corner manner. These are the easiest stitches to make - a great start for beginners.

Lap joint - diagram.

All types of overlap welds have a strict limitation on the thickness of the sheet metal - it should be no more than 8 mm. Here it is important to find the correct angle of inclination of the electrode - the range is from 15 to 45 degrees. In GOST, overlap joints are conventionally designated as H1 and H2.

When working with two workpieces, one-sided turned welding is often used, which has a serious drawback: gaps form between the parts. Moisture and corrosion become the main enemies with this method. The result of this kind of defect is described in one word - fragility.

However, lap joints have a very wide range of applications, here are a few examples:

• Installation of lightweight structures such as pavilions or stalls;
• Installation of billboards and other structures;
• Assembly of awnings and awnings.

Compare, evaluate

Of the above options, butt welding is considered the most reliable and economical. In terms of current loads, they are almost equal to whole elements that were not welded, in other words, to the base material. Naturally, such strength is achieved only with adequate quality of work.

At the same time, it must be remembered that the reliability and efficiency of the method does not mean that it is easy to implement. Requirements for edge processing, adjustment of many factors to the conditions of a specific welding, certain restrictions in application due to the shape - all this requires strict professional discipline.

T-joints (including corner ones) are also quite popular. They are especially often used when welding massive structures.

The simplest ones to perform are overlapping joints. They do not require edge processing, and general preparation is also much simpler. Very popular in welding sheets of small thickness (thickness up to 60 mm is allowed). Simplicity does not mean efficiency: excessive consumption of deposited and base metals is a common situation for such options.

Seams according to position in space

The next classification criterion is the position of surfaces in space. There are four such provisions:

1. Bottom seams
2. Horizontal
3. Vertical
4. Ceiling

If it were possible to choose, experienced craftsmen would choose welding in the lower position. This is the most convenient method, and the weld pool is better controlled. A suitable method for debut works of beginners - there are practically no difficulties here. But the other three spatial options are associated with technical nuances and special requirements for execution.

Choose, try, the main thing is that the bathtub does not tend to fall down. If the metal still drains, you need to reduce its heating - this can be done by increasing the speed of movement. The second option is to periodically tear off the arc so that the metal cools at least a little. The arc lift method is more suitable for beginners

Source: https://tutsvarka.ru/vidy/svarochnye-shvy

Types of welds and joints | Types of Welds

Welding seams are zones of welded joints that are formed by metal that was initially molten and then crystallized upon cooling.

Types of welded joints

To permanently connect metal parts to each other by welding, various types of welded joints are used.

Permanent connection of parts made from metal blanks and obtained by melting their edges with an electric arc or gas. At the same time, additional metal is deposited; this can be a molten electrode or a rod specially supplied to the heating zone. As a result of these manipulations, a weld seam is formed at the junction of the workpieces.

Various types of welding are used to connect metal parts. The list of welding technologies is quite large, but the main types include:

• electric arc;
• gas-flame;
• plasma;
• laser and many others.

Main types of welding joints

All issues related to welding are, one way or another, standardized. One of the fundamental documents is GOST 2601-92. This document normalizes the terms and basic concepts in the field of welding. The same document also defines the main types of connections using welding. These include:

Butt

The ends fit tightly to each other. This is a widely used type of connection that can be obtained using various welding technologies. Butt welds have a number of advantages compared to others - high speed of work, and, accordingly, high productivity of work performed.

Minimum material consumption. High strength of the welded joint, of course, is achieved in full compliance with all technological norms and rules.

But the use of a butt joint requires preliminary preparation of the edges, that is, to prepare a chamfer, in addition, it is necessary to ensure the accuracy of the installation of the workpieces.

This type is used for joining sheets, pipes and long products.

Overlapping

With this assembly method, the workpieces are positioned so that their planes are parallel to each other and at the same time partially overlap each other. Connections of this type are most often used when performing spot and resistance welding.

In other cases, when making such a weld, the consumption of the metal itself and electrodes increases unjustifiably. When making an overlap joint, there is no need to pre-cut the edges. But in any case, the sheets must be cut using special equipment, for example, mechanical scissors.

To avoid corrosion that may occur between sheets of metal, it is advisable to weld such a connection along its entire length.

It is advisable to use such fastening of workpieces if their thickness does not exceed 10 mm.

Angular 

The workpieces are positioned relative to each other at a certain angle, and the seam lies at the point of their contact.

Corner connections can be single- or double-sided. They are used when merging parts from sheet metal, shaped products and pipes. The angle can be different, it all depends on the purpose of the structure. A slight complication is that it is necessary to cut the edges of the adjacent workpiece.

Tavrovoe 

The end of one workpiece is adjacent to the plane of another, most often at a right angle.

A part installed vertically must have a cut edge. Thus, the adjacency of one part to another is ensured. By the way, when preparing it for welding, depending on the thickness, preliminary cutting of the edge may be required. If the metal is quite thick, for example, over 20 mm, then the chamfer must be removed from both sides of the workpiece. This approach will ensure penetration of the connection.

Tortsovoye 

This is a form of merging of surfaces in which the edges of the workpieces being welded are adjacent to each other and the resulting part resembles a cross-section of a sandwich.

Connections made by welding have become widespread in industry and construction. Welding is widely used to replace forged and cast parts.

Technological features of welding work

Any job has its secrets, which for the most part are owned by professionals, and welding is no exception. For example, when making a T-joint consisting of sheets of different thicknesses, the electrode holder should be installed so that the angle between it and the thick sheet is 60 degrees.

Another feature of the T-type design is that the sheets are installed in a “boat”, that is, the angle between the workpiece and the horizontal plane should be 45 degrees. With this form of installation of workpieces, the electrode can be installed strictly vertically.

As a result, the welding speed increases and the likelihood of defects such as undercutting decreases; by the way, this is the most common defect in a T-weld. Depending on the thickness of the metal, it may be necessary to make several passes with the electrode.

Boat welding is used when using automatic welding.

Classification by connection location

In addition to the above qualifications, welds can be classified according to other characteristics. One of these is by the degree of convexity.

Welds can be divided into:

• normal;
• convex;
• concave.

This parameter largely depends on the parameters of the welding materials and the modes of the welding machine. If a long arc is used when welding, the seam will come out smooth and wide. When using a short arc, the width of the seam will decrease and it will become convex. We must not forget that the speed of movement of the electrode and, of course, the shape and dimensions of the edge cut have a great influence on the quality and geometry of the seam.

Welds can be classified according to their position in space. That is, they can be located - below, vertically and on the ceiling.

The optimal location of the weld seam is considered to be lower. This type of seam is recommended to be used when developing working documentation for products. The welder, when processing the lower seam, stands on top of it and perfectly sees both the movement of the electrode and the process of formation of the seam.

Vertical or ceiling welds can only be performed by welders of certain qualifications. The ceiling location of the seam is the most labor-intensive and unsafe job.

Qualification of welded joints by length

Permanent connections obtained by welding can be divided into continuous and intermittent. The first ones are performed where it is necessary to ensure the tightness of the connection or where, due to strength requirements, it is impossible to use the second option (intermittent)

Normative base

Welding joints can be classified according to different parameters - the geometry of the seam, the type of connection, and much more. When designing a product in which welding seams will be used, the designer must first of all be guided by the results of strength calculations. And only after that choose the method of joining the workpieces.

In their work, designers and manufacturers must be guided by the following documents:

• GOST 2601-84;
• GOST5264;
• GOST15878;
• GOST 15164.

Based on the data from these regulatory documents, it is necessary to determine the geometry of the seam and the type of welding. Only then should the criteria for edge separation, if required, be established. At the last stage, the permissible and maximum deviations of the seam dimensions are determined.

Welding defects

Welding work is considered particularly responsible. And this is understandable. Welding is also used in the manufacture of pressure vessels, pipelines and boilers.

And the performance and, most importantly, the safety of the equipment depends on the quality of the connection. Almost all industries and construction sites. Where welding is used, various quality control methods are used.

In accordance with the requirements of GOST 3242-79, several control methods are provided for monitoring welded joints. Among them are:

• Visual, it is used when monitoring non-essential connections.
• Ultrasonic - it is used to control various types of connections.

For particularly critical ones, for example, on bridge structures or high-pressure pipelines, the welder must leave a personal stamp.

Source: https://prompriem.ru/stati/tipy-svarnyh-soedinenij.html

Types and features of welds

In welding, as in any other technological process, not only the final result is important, but also all those nuances on which the final quality of the work depends. In our case, the equivalent of quality is the welding seam, since the strength (and therefore durability) of the metal structure directly depends on it.

For welding, a master needs not only high-quality components and equipment, but also invaluable experience. To accumulate it, you need to constantly study and practice. You will have to take care of the practice yourself, but we will help you with the theory. In this article we will describe in detail what types of welds exist and what features need to be taken into account in order to complete the job efficiently.

general information

Before you find out what types of welded joints and seams there are, you need to define the concept of the properties of a welded joint. Properties are, in essence, the characteristics of the seam, on which its quality depends. Properties include strength, toughness, elongation and contraction. But what determines the properties of a welded joint? The properties of a weld depend on the metal, welding method, components and many indirect factors (for example, welder fatigue).

It is also important to know what load the weld can withstand. There is a lot of controversy about this on the Internet. Every craftsman believes that he knows how long a weld seam can withstand. All we will say is that there is no single answer to this question. For each type of metal this is a separate value, since different types of seams have their own tensile strength.

Types of seams

Here are the main types of welded joints and seams:

• butt
• overlap
• angular
• tee

In this article we examined in detail each type of welded joint.

Peculiarities

Seams have their own additional features that you need to know. First of all, this is the form of connection. It can be protruding, sunken or flat. The choice of form depends on the specific tasks to be performed.

For example, a protruding (or simply convex) seam is used when welding metal structures that are subject to increased load requirements. Sunken (or concave) seams can easily withstand various types of dynamic loads. But in most cases you will find flat seams, since their characteristics are the most versatile and can be applied to most types of work.

Also, the seams can be extended and intermittent. Extended (or continuous) are seams that are performed in one approach and do not have intervals. Intermittent, respectively, on the contrary, are performed at intervals. Intermittent welds and connections will suffice for most jobs. Continuous seams are used when welding reinforced metal structures.

The most technologically advanced and high-quality way to make an intermittent type connection is resistance welding. It is performed using rotating disk electrodes. In home welding, this method is rather useless, but in large industries it has no equal. With the help of resistance welding, a large amount of work can be completed in a short time, while the quality of the joints will not suffer, but will only improve.

There is also roller welding, with which you can make a high-quality continuous seam. The resulting weld is strong, tight and durable. In most cases, roller welding is suitable for industrial welding (for example, pipes or modules that require increased tightness).

Now let's talk about layers. Welded joints can be single-layer or double-layer. If the seam was made in one approach, then it is called single-layer. If the metal is very thick or the connection must be very strong, then a two-layer method is used, when the seam is formed in several approaches, literally layer by layer. It is impossible to say unequivocally which seam is better because it depends on what tasks you face.

Knowing all this, it should not surprise you that the seams themselves can have different spatial orientations, which also depend on the tasks that need to be performed. The connection can be bottom, top (or ceiling), vertical or horizontal.

When welding a vertical seam, the electrode must be guided from bottom to top, and there are many ways to move the electrode. We will not list them in this article, we will simply recommend the “crescent” method to beginners. More experienced craftsmen move the electrode in a herringbone pattern. To prevent the metal from flowing down, set the power on your device to low. This way you can control the rate at which the metal melts.

If you need to weld the bottom seam, then draw the arc at an angle of 45 degrees, this will achieve a good result. We also recommend using the asymmetrical “boat” method if you are welding in a hard-to-reach place.

Welding a ceiling seam is the most labor-intensive, since here the metal willingly flows down under the influence of gravity. We do not recommend doing ceiling joints unless you are generally experienced. But if you still decide, then use a short arc and significantly reduce the current.

The position in which the electrode will move depends on the spatial orientation. For most jobs (such as welding vertical, horizontal and overhead seams), hold the electrode at a forward angle. And when welding a butt or fillet weld, point the rod at an angle back. If you need to weld a hard-to-reach place, then a right angle will do.

Completion of work

The types of weld joints are important, but without the correct finishing work, you will not be able to call the weld truly high-quality. The finishing work is no less important than the preparatory work, so take it seriously. Follow our simple recommendations and you can significantly improve the quality of your work.

All novice and experienced welders produce slag when welding. This is absolutely normal. But you need to make sure that slag does not get into the seam, otherwise it will negatively affect the quality of the connection. You can use flux, but if this is not possible, then thoroughly clean the seams after welding. We will tell you in more detail how to do this.

If you form a seam in several approaches, then the seams are cleaned after each approach. You can use any method convenient for you. But we will talk about the universal. To begin, knock off the excess slag with a hammer and clean the seam with a stiff wire brush. This can be done manually.

Then we recommend performing mechanical cleaning using a hard metal circle. If the seam is too large, then it needs to be cleaned using a special machine. Then the welded joint must be thoroughly polished. To do this, you can also use a grinding machine, but replace the hard metal wheel with a grinding wheel. Such equipment is well suited for quick grinding.

Instead of a conclusion

The features and types of welded joints are constantly changing due to technological progress. Welding does not stand still and is constantly developing. Not only new materials are emerging, but also methods of welding and metal processing. Don't ignore these changes, learn new things. This way you can improve your professional level. We told you in detail what types of welding seams exist and application methods.

In addition to this information, we recommend that you study the regulatory documents to know what the requirements are for welds. This is really important if you want to work in a large production facility or become a DIYer rather than take welding as a hobby. The connection for a part plays as important a role as the experience of the craftsman and the quality of the metal. We wish you good luck in your work!

Source: https://svarkaed.ru/svarka/shvy-i-soedineniya/vidy-i-osobennosti-svarnyh-shvov.html

Are all welding seams the same: types, classification, scope of application

A weld or weld seam is a section of a welding joint where, under the influence of a welding machine, an inextricable connection of parts with a future structure is formed. There are different types of welds, which are classified according to different criteria.

What does a welding joint consist of?

The welding joint consists of the following elements:

1. The weld itself is the area where the parts meet.
2. Fusion zone.
3. The heat-affected zone of a welding machine is an area of ​​metal where thermal changes are noticeable as a result of the effects of welding.
4. Base metal - the remaining area of ​​metal parts that are connected by welding.

The terms “welded joint” and “weld seam” are sometimes confused. The permanent connection of two or more metal elements is called a welded joint. A seam is the area where two metal parts meet. In turn, the welded joint is part of a welded structure - a metal structure consisting of several elements welded into one.

When welding in several layers, the root seam is also isolated - this is the very first welding layer, located deeper than the others. When performing it, the impact should be maximum and, if possible, continuous.

Kinds

Welds are classified according to several basic characteristics - depending on the type of joint, section, spatial location, etc. Each seam is used depending on the general idea of ​​the design, feasibility, and other conditions.

By type of connection

• Butt welds

Butt or butt seams are the simplest and most common. They are formed when two parts are connected by their end surfaces. Thanks to the joining method, the metal consumption is less than when using other methods of joining parts.

The seam in this case can be:

• Single-sided with a beveled edge - recommended for welding parts with a thickness of 8-25 mm. The most popular type of bevel is V-shaped, but sometimes a U-shaped connection is also used.
• Single-sided without bevel of the edge - used when welding metal sheets up to 4 mm thick.

• Double-sided with beveled edges - thickness from 12 mm. In this case, X-shaped beveling of edges is most often used, which requires less metal consumption compared to V-shaped.
• Double-sided without beveled edges - when welding parts up to 8 mm thick.

When connecting without bevel of edges, it is recommended to leave a small gap (1-2 mm) between the sheets of metal. This is necessary to ensure quality welding. If the edges are beveled, they must be slightly dulled to avoid welding defects.

They are formed when two sheets of metal, or other metal parts, are joined in a "T" shape. One part of the future structure is leaned against the side surface of the other part. T-joints can also be without beveled edges, with one-sided or double-sided bevel.

They are used when two parts need to be positioned in parallel planes, slightly overlapping with respect to each other. Such seams are recommended for welding sheets with a thickness of 10 mm or more. Weld the parts on both sides.

• Fillet welds

They are formed if parts are connected at a right angle or any other angle. Sometimes, for strength, such seams are made on both sides of the connection. Depending on the thickness of the parts, they can be with beveled edges or without them.

Fillet welds are also divided according to the length of the welding sections (areas of welding impact) into:

• Continuous - continuous welding seam.
• With a staggered arrangement of welding sections - the areas of welding influence on one side are opposite to the areas on the other side.
• Chain - welding areas on both sides of the joint are located equally.

By degree of convexity

It is generally accepted that the weld should be smooth and almost invisible. However, the depth or concavity of the weld depends primarily on the type of welded joint and the selected welding mode.

Based on this feature, seams are divided into the following types:

• Convex - recommended for static welding machine mode. These are the so-called reinforced seams.
• Normal - with minimal convexity.
• Concave, or weakened - used for corner connections. A defect is the presence of a concave seam in a butt joint of a structure.

The default is that all connections should be reinforced and slightly convex. The concave seam should be indicated on the drawing of the future structure.

By number of passes

Multi-pass welding seam.

Depending on the number of passes with the welding machine and layers, the seams can be:

• Single-pass (or single-layer).

• Multi-pass (multi-layer).

The term “weld layer” refers to the amount of metal deposited in one pass by a welding machine (welding beads).

For small metal thicknesses (up to 5 mm), it is recommended to perform single-pass welds. In corner joints with a thickness of 6-8 mm, one layer is also sufficient, and for butt joints - two. Seams with a large number of layers (5-6) can only be used for thick metal - at least 18-20 mm.

By actual force

According to this criterion, welds are divided into several types:

• Flank - the acting force is parallel to the seam area.
• Frontal - the force of the device is directed perpendicularly.

• Oblique - the force occurs at an angle of less than 90 degrees.
• Combined - combine several types.

By configuration and position in space

Based on this feature, all seams can be divided as follows:

• Ring - used for welding cylindrical parts, welding occurs only from the outside.
• Straight-line.

• Vertical - the seam is located in a vertical plane.
• Horizontal - welding occurs in a horizontal plane.

A special type of welding seam is the ceiling one. In this case, the force is in the horizontal plane, but above the level of the welding machine. Therefore, the ceiling seam is considered the most difficult type of welding. It is very important to follow safety precautions when performing this task - protect yourself as much as possible with a welding mask and thick clothing.

In ceiling welding, the metal is held on the surface due to the force of surface tension. Therefore, it is recommended to minimize the size of the weld beads - in other words, periodically move the electrode to the side and allow the weld area to harden. You need to weld in the direction “towards you” - this makes it easier to observe the process.

According to welded materials

Another classification is based on the materials that are connected to each other.

According to this criterion, the following are distinguished:

• Seams on carbon and alloy steel.
• On non-ferrous metal.

• On bimetal.
• On plastic and polyethylene.

The size of the electrodes, the force applied during welding, and the number of welding layers depend on the type of material. Generally, non-ferrous metals require less exposure than alloy steel.

Stripping

Do your welds often have defects?

Never! Rarely, but they happen

After welding, it is recommended to clean the seam.

This process is carried out in 3 stages:

1. Cleaning the area closest to the seam - often drops of metal get here. They are beaten with a hammer or chisel.
2. Polishing the seam - so that the seam does not catch the eye, it is polished using a grinder.
3. Tinning the seam - this stage is necessary if soft metals are welded. A thin layer of molten tin is applied to the seam.

Before stripping, you need to check the seam for the following defects:

• Cracks on the seam.
• Holes that are formed from sparking.

• Scale from electrodes.
• Uncooked areas.

All these errors can be easily avoided if you follow the welding technology, use high-quality and clean electrodes, and monitor the condition of the seam during operation.

Thus, there are many types of welds. Each of them is used depending on the welding joint, position in space, and other factors. The key when choosing the type of seam is its feasibility and justification for the future design.

other useful articles:

• Welding electrodes: classification, marking, popular brands, storage rules, recommendations - which ones are best to choose for welding various metals
• Inverter welding machines: types, model ratings, their pros and cons, how to choose the best one, tips for use and maintenance
• How to use cold welding: instructions and tips, varieties, instructions for use

tip: how to learn to weld beautiful seams

Source: https://tehno-gid.net/inf/vse-li-svarochnye-shvy-odinakovy-vidy-svarochnyh-shvov.html

What types of welds exist and their features

Welded metal joints are among the main methods of fastening structures used in everyday life and production. This is a very reliable method of obtaining a single design, which is also relatively cheap.

Bonds of this type are formed by melting the metal in the joint area and then crystallizing it as it cools. Their quality depends on the correct choice of operating mode of the electric welding machine, electrode, and seam penetration. This is regulated by current regulations and standards. They indicate all types of welds, as well as types of joints and their characteristics.

Numerous metals have their own welding characteristics, different work conditions, and requirements for fastening. For them, appropriate types of electric welded connections are used. When welding metal elements, the main types of electric welding fasteners are used, which are discussed below.

Classification

Welding joints are divided into several varieties, depending on their characteristics. The classification of welds covers the entire range of their uses. According to external parameters they are:

• convex type (with reinforcement);
• concave (weakened design);
• flat type (normal).

According to the type of execution, they are found in one-sided, as well as double-sided, according to the number of passes with the electrode: single-pass, double-pass. In addition, there are single-layer and double-layer welding methods.

According to their length, suture fastenings are:

• unilateral with intermittent pitch;
• solid one-sided;
• spot (with contact electric welding);
• chain double-sided;
• double-sided checkerboard pattern.

Separation by spatial location:

• horizontal, lower;
• vertical, ceiling;
• into a boat;
• semi-horizontal design;
• semi-ceiling type;
• semi-vertical.

According to the force vector:

• longitudinal (flank) – the force has a vector parallel to the penetration;
• transverse - the force acts perpendicularly;
• combined - a type of frontal, as well as flank;
• oblique - the impact occurs at an angle.

According to their purpose and function, electric welding penetrations can be durable, as well as durable and tight, hermetically sealed. Based on their width, they are distinguished into thread type, which does not exceed the diameter of the electric welding electrode rod, and widened, performed using oscillatory movements when welding in the transverse direction.

To simplify the understanding of the classification and application of certain varieties, a special table has been compiled.

All types of seams have strict designations according to GOST. The drawings use special icons that contain complete information about the type of fastening and its method of execution. For those who are thinking of seriously engaging in welding work at a professional level, they should additionally study the drawing symbols of welded fasteners.

Types of welds

Depending on the material used, thickness, and design features, different types of welds are used. To do this, you need to undergo the necessary theoretical training. This will allow you to better understand the specifics of welding parts and avoid defects in work. Novice welders often do not sufficiently weld the joint areas, which affects the weak mechanical resistance of the joints.

By choosing the right operating modes and types of welding, you can obtain welding seams of sufficient strength and quality. Welder training consists not only of practical training, but also of theoretical training with the study of requirements, norms and rules, as well as including the types of welding joints and equipment used.

Knowledge of the principles of using certain electric welding fasteners, the techniques for producing them, the joints will be very strong and durable.

T-bar

These types of electric welding connections are made like a regular letter “T”. They connect objects of the same or different thickness, which determines the width of the weld seam. In addition, these types are used single- or double-sided, which is influenced by the characteristics of the fastening.

When working with metal elements of varying thickness, the electrode is held in an inclined position at an angle of about 60 degrees. The welding process can be greatly simplified by using tacks, as well as boat welding. This method significantly reduces the occurrence of undercuts. The T-weld is applied in one welding pass.

In addition to manual arc welding, automatic electric welding machines are widely used for this type.

Corner

These connections include fastenings of elements made at a certain angle to each other. They are characterized by the use of preliminary bevels to ensure the best weld penetration.

This will increase the depth of the welding joint, which will increase the reliability of the structure. To enhance strength, double-sided welding of metal products is used, while gaps in the joined edges are not allowed.

These types of electric welds are characterized by increased use of the volume of deposited metal.

Ceiling

Welding with a ceiling seam, the seam of which is located above the welder, is one of the most difficult types of electric welding work. It is applied by intermittent welding at a low electric current.

Vertical and ceiling connections are very difficult, so not all welders can perform them with sufficient quality. They are used in places where it is not possible to change the position of the structures being welded. These are pipes, various metal structures, as well as ceiling beams and channels at construction sites.

The specifics of making ceiling seams, the video of which will explain the nuances, can be mastered through constant practice.

Weld geometry

Having studied numerous types and methods of obtaining joints by welding, it is necessary to familiarize yourself with the geometry of the joints, which photos of welding seams will help with.

The main parameters of a seam joint include its width - e, welding thickness - c, convexity - q, gap - b, welding depth - h, and the thickness of the material being welded - S.

For corner joints, the following designations are used: convexity - q, thickness - a, leg - k and design height - p.

Various methods of applying welds, their numerous types, as well as the parameters of the prepared edges affect the volume of use of the deposited and base metals. Its quantity may differ markedly when any calculated values ​​change.

Types of welding joints are characterized by a shape coefficient, which is calculated by the ratio of the width to the thickness of the seam joint. For butt fastenings, this parameter is in the range of 1.2-2 (limit values ​​0.8-4). The convexity coefficient is calculated by the ratio of width to convexity, the value of which should be from 0.8 to 4.

Welding metal materials at an angle relative to each other requires precise adherence to the geometry of the seam. The reliability of the connection, as well as its durability of use, directly depends on the quality of welding and compliance with the required parameters.

Types of control

The further operation of the structure depends on the high-quality execution of electric welded fastening. Various defects significantly reduce the strength and reduce the period of use of the product.

To prevent defects, as well as to prevent emergency situations, various types of control of welds are used.

These include an external inspection, which can visually determine violations, their types, as well as the use of special equipment to determine hidden defects in welds.

Control methods are divided into non-destructible and destructible. When using the first method, the strength of the welded joint is determined without changing its appearance or parameters. Destructible methods are used for mass production of structures using the same type of electric welding work. This makes it possible to accurately detect internal defects in welding joints.

Download GOST

GOST 5264-80. Manual arc welding. Welded connections. Main types, structural elements and dimensions

Source: https://oxmetall.ru/svarka/vidy-shvov

We study the types of welded joints

Welding still remains one of the most popular methods for producing permanent structures from metals and polymers. This popularity also determines the variety of welded joints, which are similar in some ways, but fundamentally different in others. In this article we will look at all the main types of thermal welding joints.

Types of welded joints

So, what are the types of welded joints? The types of welding joints are as follows:

Butt

The most widely used variety, which can be single- or double-sided, with a removable or non-removable lining or without it at all. A butt welding joint can be used to connect parts with a flange, with a locking edge, as well as with a variety of bevels: two- and one-sided, symmetrical and asymmetrical, broken and curved.

Angular

As the name itself makes clear, this connection welds corner structures. In addition, using corner joints, it welds structural elements in hard-to-reach places. This type of connection is used in the following cases:

• Bevels (one-sided or two-sided) are available at the edges of the two parts being connected;
• The edges of the parts being connected do not have bevels;
• There is a flange at one edge.

In other cases, a corner connection cannot be used, since due to the complexity of the edges, the quality of the connection deteriorates sharply.

Tavrovoe

It is used for welding T-shaped structures, as well as for parts that are connected at a slight angle to each other. This connection is compatible with the following types of edges:

• There is no bevel;
• The edge can have symmetrical or asymmetrical one- and two-sided bevels;
• The edge has a curved one- or two-sided bevel located in the same plane.

Overlapping

This type of welding connects the ends of parts or structural elements. Overlap welding work is carried out only with edges without bevels.

End

A rather rare type of connection, since it involves welding one part to the end of another. Therefore, often the main types of welding joints do not include the end joint as a separate item, but combine it with an overlap joint.

Classifications of seams

Also, the types of welded joints differ in the seam obtained as a result of welding work. Current standards imply several classifications:

By spatial location

According to their location, welds can be:

• Bottom, if their angle relative to the horizontal does not exceed 60 degrees;
• Vertical, if their angle relative to the horizontal is in the range of 60-120 degrees;
• Ceiling, if their angle relative to the horizontal is in the range of 120-180 degrees.

By their continuity

Welds can be continuous (without breaks) or intermittent (with breaks). The latter are most typical for corner and T-joints.

According to the nature of the ruptures, intermittent seams are divided into:

• Chain - uniform breaks, like cells in a chain;
• Chess - tears move small seams relative to each other, like white squares on a chessboard;
• Dotted seams are similar to checkerboard seams, only the seams do not look like lines, but in the form of single dots.

Note that continuous seams are more reliable and more resistant to corrosive destruction, but they are often impossible to use for technological reasons.

By type of welded joint

Welded joints also differ from each other in the resulting seam:

• Butt joint is obtained by joining parts of the same name;
• Corner is formed not only when welding parts with corners, but also during T- and butt welding;
• It is obtained through T-welding and overlapping joints of parts whose thickness does not exceed 1 cm;
• Electric riveting is obtained by welding T-joints and overlaps. The technology for making these seams is as follows. Metal parts whose thickness does not exceed 3 mm are welded without pre-treatment, since the electric arc penetrates them through. If the thickness of the parts being welded exceeds 3 mm, then one part is drilled and the second is tacked through it by welding;
• End welds are obtained by welding parts at their ends.

According to the nature of the profile section

This classification indicates the cross-sectional shape of the weld in section:

• Convex ones protrude in a semicircle above the surface of the connected parts;
• Concave form a small depression relative to the surface of the connected parts;
• Normal are one line with the surface;
• Special. They are formed when parts are joined at an angle or a tee. In cross section they look like an isosceles triangle.

The internal cross-section determines the performance characteristics of welded joints. For example, a convex section gives good resistance to static loads; such seams are considered reinforced.

While concave ones, on the contrary, are considered weakened, they are better able to withstand dynamic and multidirectional loads. The performance characteristics of normal welds are similar to those of concave welds. Special seams cope well with variable loads.

They also reduce the stress that occurs in welded parts during their daily use.

According to the technology of welding work

Here, welds are classified according to the path of the electrode during welding:

• Longitudinal is formed when the electrode moves along the joint of the parts being connected;
• Transverse is obtained when the electrode moves across the joint of the parts being connected;
• An oblique is formed when the electrode moves at a certain angle relative to the extreme points of its trajectory;
• Combined is formed by alternately using the three above mentioned seams.

By number of layers

The specified welding work is carried out in one or several layers (passes). With one pass, a bead of molten metal is formed. Rollers can be performed at the same or at different levels. In the first case, one layer will consist of several rollers. The bead farthest from the facing level is called the root of the seam.

Multi-layer and multi-pass welded joints are used when welding thick-walled elements or to avoid thermal deformation in the structure of a steel alloy.

Results of violation of welding technology

If the welding technology is violated at the joint, the following may occur:

• Burns (undercuts) are zones of critical heating of the metal, in which various chemical reactions (crystalline corrosion, etc.) began under the influence of high temperatures;
• Lack of penetration - zones in which the temperature was insufficient for mutual penetration of the edges into each other and the formation of a single monolithic structure;
• Non-fusion - the edges being joined have not heated to the melting temperature and have not fused to each other;
• Slag clogging - points of concentration of slag substances that have penetrated in a liquid state from low-quality electrodes into the weld pool and, upon solidification, formed foreign crystalline inclusions;
• Pores appear due to spattering metal due to sudden peak temperatures in the weld pool;
• Cracks appear due to poor-quality joining of two types of steel that have different melting points;
• Microcavities arise due to uneven heating and cooling of the metal.

Quality Control Technologies

All types of welded joints must be checked. Depending on the requirements for the quality of work, the following quality control technologies are performed:

• Visual inspection allows you to determine only visible quality defects (slag inclusions, cracks, burns, etc.);
• Measurements of length and width indicate compliance of the obtained result with the technical specifications and GOST;
• Checking tightness using crimp testing. Used in the manufacture of various containers;
• Special instrumentation establishes the characteristics of the internal structure of the resulting welded joint;
• Laboratory studies make it possible to determine the behavior of a welded structure under the influence of various loads and chemicals.

Source: https://electrod.biz/varim/soedinenie/izuchaem-vidyi-svarnyih-soedineniy.html