Classification of welds. Classification of welds

Welded joints and seams are classified according to the following main features:

type of compound;
the provision in which welding is performed;
configuration and length;
applied welding type;
method of holding molten metal seam;
the amount of layers imposition;
used for welding material;
the location of the welded parts relative to each other;
acting on the seam effort;
volume of the weld metal;
the form of a weldable design;
form of prepared edges for welding

By type of compounds, weld seams are butt and angular. By location in the space of the seam welded connections divided into lower, vertical, horizontal and ceiling. The seam yield from the ceiling position into vertical when welding cylindrical products is called a semi-fat position.

The configuration of the welded joints is straight, ring, vertical and horizontal. For the length of the seams are divided into solid and intermittent. The solid seams in turn are divided into short, medium and long.

By type welding seams of welded connections are divided into:

arc welding seams
suts of automatic and semi-automatic welding under flux
seams arc welding in protective gases
suts of electroslag welding
electro-chain seams
suts of contact electric welding
suts of soldering connections

According to the method of retention of the molten metal, the seams of welded connections are divided into seams made without linings and pillows; On removable and remaining steel lining: on copper, fluxed. Ceramic and asbestos lining, as well as flux and gas pillows. Depending on which side it is superimposed, seams are distinguished by one-sided and double-sided seams.

According to the welds used for welding, the seams of welded joints are divided into seds of the compound of carbon and alloyed steels; seams of non-ferrous metals; bimetal compound seams; The joints of the joint of the viniplast and polyethylene.

By the location of the welded parts, the seams of welded connections may be under an acute or blunt angle, at a right angle, and also be located in the same plane.

According to the volume of the weld metal, normal, weakened and reinforced seams are distinguished.

In the form of the welded design, the seams of welded compounds are performed on flat and spherical structures, and by location on the product of the seams are longitudinal and transverse.

Welded called all-point connections performed using welding. They may be butt, angular, pestile, brand and end (Fig. 1).

The butt is called the connection of two parts by their ends, located in the same plane or on one surface. The thickness of the welded surfaces may be the same or differ one from another. In practice, the joint compound is most often used when welding pipelines and various tanks.

Angular - welded connection of two elements located at an angle relative to each other and cooked in the place of adjoining their edges. Such welded compounds were widely used in construction practice.

Falling - the weld compound provides for the overlay of one element to another in one plane with partial overlap of each other. Such compounds are most often found in construction and installation work, when facing farms, tanks, etc.

Taving is called a compound in which another compound is applied to the plane of one element at a certain angle.
Welding seams

The welded plot formed as the result of the crystallization of the molten metal is called the welding seam. Unlike compounds, weld seams are butt and angular (Fig. 2).

The butt is the weld of the butt joint. Corner is a welded seam of angular, naughty and taving compounds.

The welding seams are distinguished by the number of layers of overlay, orientate them in space, in length, etc. So, if the seam fully covers the connection, then it is called solid. If within one joint is broken, it is called intermittent. A variety of intermittent seam is a tap seam, which is used to fix the elements relative to each other before welding. If a welding seams Apply one to another, then such seds are called multi-layered.

In the form of the outer surface, welding seams can be flat, concave or convex. The shape of the welding seam affects its physicomechanical properties and the consumption of electrode metal associated with its formation. The most economical flat and concave seams, which, moreover, are better working at dynamic loads, since there is no sharp transition from the main metal to the welded seam. Excessive influx of convex, seams leads to an overvoltage of the electrode metal, and a sharp transition from the base metal to the weld with concentrated voltages can cause the connection to be destructed. Therefore, in the manufacture of responsible structures, the convexity on the seams is removed by the mechanical method (cutters, abrasive circles, etc.).

Split welding seams on their position in space. It is lower, horizontal, vertical and ceiling seams.

Elements of the geometric shape of the preparation of edges for welding

Elements of the geometric shape of the preparation of edges for welding (Fig. 3, a) are: the angle of cutting edges α; the gap between the jammed edges A; dulling edges s; Length List Length L With a difference of metal thickness; The displacement of the edges relative to each other Δ.

The edge cutting angle is performed with a metal thickness of more than 3 mm, since its absence (cutting edges) can lead to an undeclosure by cross section of the welded joint, as well as to overheating and the metal facing; In the absence of cutting edges to provide a provider, the electric welder always tries to increase the welding current.

The edge cutting allows you to weld with separate layers of a small cross section, which improves the structure of the welded joint and reduces the occurrence. welding stresses and deformations.

The clearance, which is properly installed before welding, allows you to provide a complete provider in cross section when the first (root) seam layer is applied if the appropriate welding mode is selected.

The leaflet length is adjusted by a smooth transition from a thick welded part to a thinner, the voltage hubs are eliminated in welded structures.

The dullness of the edges is performed to ensure the steady maintenance of the welding process when the root layer of the seam is performed. The lack of dullness contributes to the formation of burns during welding.

The edge displacement worsens the strength properties of the welded joint and contributes to the formation of non-measure and stress concentrations. GOST 5264-69 admits the shift of the welded edges relative to each other to 10% of the metal thickness, but not more than 3 mm.

Geometry and Classification of Welds

The elements of the geometric shape of the weld are: at the butt compounds - the width of the seam "b", the height of the seam "H", during brazen, angular and filaous compounds - the weld "b", the height of the seam "H" and the knife of the seam "K" (rice . 3, b).

Welded seams are classified by the number of weld rollers - and laminated and multilayer (Fig. 4, a); By location in space - bottom, horizontal, vertical and ceiling (Fig. 4, b); in relation to the current efforts on the seams-stand, windy (end) (Fig. 4, c); In the direction - straight, circular, vertical and horizontal (Fig. 4, d).

Properties of welded seams

The high-quality indicators of welded joints imposes a plunder of many factors to which the weldability of metals, their sensitivity to thermal effects, oxidation, etc. Therefore, to comply with welded joints with one way or another, these criteria should be considered.

The weldability of metals determines the ability of individual metals or their alloys to form with the appropriate technological processing of the connection corresponding to the specified parameters. This indicator is influenced by physical and chemical properties Metals, the structure of their crystal lattice, the presence of impurities, degree of doping, etc. Weldability can be physical and technological.

Under physical weldability, the property of the material or its compositions is to create a monolithic compound with a sustainable chemical bond. Virtually all pure metals, their technical alloys and a number of combinations of metal with non-metals have physical weldability.

The process welding material includes its reaction to the welding process and the ability to create a compound satisfying the specified parameters.

§ 5. Classification welded seams

Welded seams are classified according to the following basic features. By see The welded joint is distinguished by the seams of butt and angular. The seams located in the butt welded joints are called butt, located in brazers, angular and nashel-fucked connections - corner.
By position In which welding is performed, weld seams are: "into the boat", lower, semi-risal, horizontal, semi-propical, vertical, semi-meter and ceiling (Fig. 6).

Fig. 6. Classification of welds by location in space:
a - the lower "into the boat", b - the bottom corner, in - the lower butt, g - horizontal, d - vertical, e - semi-meter, g - ceiling

By configuration welded joints are straight, ring and curvilinear; In terms of length - solid and intermittent. The solid seams in turn are divided into short, medium and long (Fig. 7).

Fig. 7. Classification of welds on configuration and length:
a - straight, b - ring, in - curvilinear, r - solid, d - intermittent

By applied welding type The seams of welded joints are separated on the seams of manual arc welding, the seams of automatic and mechanized welding under the flux, seams of arc welding in protective gases, seams of electroslag welding, stroke seams, seams of contact electric welding, gas welding seams.
By hold method The molten metal during welding welded joints is divided into seams made without lining and pillows, on removable and remaining steel lining, on copper, fluxed, ceramic and asbestos lining, as well as flux and gas pillows (Fig. 8).

Fig. 8. Schemes of performing seams:
a - on lining, b - on the flux pillow, in - with a blowing gas, g - on weight;
1 - Copper removable lining, 2 - steel remaining lining, 3 - asbestos lining, 4 - flux, 5 - tarpaulin, 6 - metal box, 7 - Air hoses, 8 - welded seam, 9 - Welded Product

By quantity of layers and rollers welded seams are: unilateral, bilateral, multi-layered and multi-layered multi-commodities (Fig. 9).

Fig. 9. Classification of welds by the amount of layers and rollers

By used for welding material The seams of welded compounds are divided into seams of compounds of carbon and alloyed steels, seams of non-ferrous metals compound, bimetal compound seams, vessel joints and polyethylene.
By the location of the welded details Regarding each other, the seams of welded joints can be under an acute or blunt angle, at a right angle, and also be located in the same plane.
By acting on the seam effort Seams are flanking, windy, combined and oblique (Fig. 10).

Fig. 10. Classification of seams on their current effort:
a - flanking, b - frontal, in - combined, g - oblique

By volume of the weld metal There are normal, weakened and reinforced seams (Fig. 11).

Fig. 11. Classification of seams in terms of the weld metal

By the shape of a welded design welded joints are performed on flat and spherical structures, location on the product There are longitudinal seams and transverse.

Classification of welded seams

TO Manager:

Welded connections

Classification of welded seams

The welds are divided into the type of welded compound and the geometric outline of the seam section onto the butt and angular. The butt is characterized by a width (b) and the amplification of the LV, the depth of the province Hn, the corner - cathe, the width of the B, the thickness of N. The butt seams are used to perform butt, end, bent, and sometimes angular connections. Corner seams are used in peeling, brass and corner connections. The sizes of the sections of the seams are set to GOST 5264-69.

On the shape of the outer surface, the butt seams can be flat or convex. Corner seams can be performed and concave. Welded joints with convex seams are better working on a static load than compounds with flat or concave seams. However, the seams with too large convexity due to the large amount of the weld metal are not economical. The butt joints with flat seams and angular, brand and threaded connections with concave seams are better working on a dynamic or alternating load than compounds with convex seams. This is due to the fact that with flat and concave seams there are no sharp transitions from the main to the deposited metal, in which there is a concentration of stresses and on which the destruction of the connection can begin. In accordance with the standard, the seam convexity is allowed at lower welding to 2 mm and not more than 3 mm for the seams performed in the remaining positions. Bending is allowed in all cases no more than 3 mm.

On position in space, the seams are lower, vertical, horizontal and ceiling.

Fig. 1. Classification of welds on the geometric outline of the section

The welding of the lower seams is most convenient, it is easily amenable to mechanization. The most complicated and difficult ceiling seam is fulfilled by which requires a special workout. The execution of the burning of umbrella and vertical seams on the vertical plane is not how much harder than the lower, but lighter ceiling. Vertical, horizontal and ceiling seams in most cases are used in construction and installation of large structures and much less often - in the factory conditions, where with the help of fixtures it is possible to almost fully weld the design only in the lower position. Many highly qualified welders perform vertical seams With better quality than the lower, since in this case, contamination and metal seam metal becomes easier from the welding bath becomes clearer, more denser.

Fig. 2. Classification of welds: A - by position in space, b - in length, e - in relation to the direction of active effort, G - in the form of an outer surface

In relation to the direction of the existing efforts, the seams are divided into flanking (side) and longitudinal, the axes of which are parallel to the direction of effort; frontal, whose axes are perpendicular to the direction of force; Combined and oblique.

In terms of extension, the seams are solid and intermittent. Intermittent seam can be chain or chess. The chain seam is a double-sided intermittent seam of a taving compound, in which the sections of welding and gaps are located on both sides of the wall one against the other. Chess seam is a double-sided intermittent seam of a taving compound, in which the gaps on one side of the wall are located against the weld seams on the other side. The distance from the beginning of the failed seam site to the beginning of the next site is called a step of a seam. Intermittent seams are used in compounds that do not require tightness (impermeability) and when the solid seams are weakly loaded. Welded joints with solid seams is better to withstand the alternate load and less corrosive than compounds with intermittent seams. Particularly responsible welders are usually carried out with solid seams.

Under the working conditions, the seams are divided into workers that perceive external loads, and binders (connecting seams) intended only for fastening parts of the product. Binding seams are often called non-working seams.

Terms and definitions for welded structures, nodes, connections and seams are installed GOST 2601-84.

A welded joint is a detailed connection of two or more elements (parts), made using welding. The welded joint includes the welded seam adjacent to it the zone of the base metal with structural and other changes as a result of the thermal action of welding (thermal influence zone) and the sections of the base metal adjacent to it.

The welded seam is a portion of the welded compound resulting from crystallization of the molten metal or as a result of plastic deformation when welding with pressure or combination of crystallization and deformation.

The welded node is a portion of the welded structure in which the elements adjacent to each other are welded.

A welded construct is a metal design made from individual parts or nodes using welding.

Metal parts to be compounded by welding are called the main metal.

The metal, supplied to the arc zone in addition to the molten base metal, is called the additive metal.

Weighted additive metal, introduced into the welding bath or filtered on the main metal, are called a weld metal.

The alloy formed by the composhable by the main or basic and deposited metals is called the seam metal.

The efficiency of the welded product is determined by the type of welded compound, shape and sizes of welded joints and seams, their location relative to the current forces, the smoothness of the transition from the weld to the main metal, etc.

When choosing a type of welded compound, the conditions of operation (static or dynamic loads), the method and conditions for the manufacture of the welded design (manual welding, automatic in factory or installation conditions), saving of base metal, electrodes, etc.

Types of welded connections. In the form of interfaces of the connected parts (elements), the following types of welded joints are distinguished: butt, angular, brazers, fatty (Figure 1).

The welds are divided into the shape of the cross section to the butt (Figure 2, a) and the angular (Figure 2, b). A variety of these types are cork seams (Figure 2, B) and slit (Figure 2, D) performed in naughty compounds. In the form in the longitudinal direction, the seams are continuous and intermittent.

With the help of the joints, the joints are formed mainly by the butt compounds (Figure 1, a), with the help of angular seams - brass, crusades, angular and fatty compounds (Figure 1, BC), threaded and slotted seams can be formed using cork and slit seams. Taving connections.

The butt seams are usually carried out continuous; A distinctive feature for them is usually the form of cutting edges of the parts of the combined parts in cross section. This feature distinguishes the following main types of joint seams: with beading edges (Figure 3, a); without cutting edges - one-sided and double-sided (Figure 3, b); with a cut of one edge - one-sided, bilateral; with a straight or curvilinear shape of the cut (Figure 3, B); with one-sided cutting of two edges; with a V-shaped cut (Figure 3, g); with double-sided cutting two edges; X-shaped cutting (Figure 3, e). The cutting can be formed by straight lines (edges of the edges) or have a curvilinear form (U-shaped cutting, Figure 3, E).

a) butt; b, c) brass; d) corner; e) fatty

Figure 1 - Main types of welded connections

a) butt; b) angular; c) cork; d) slit

Figure 2 - The main types of welds

The butt compound is most common in welded structures, since has several advantages over other types of compounds. It is used in a wide range of thickness of welded parts from the tenths of a millimeter to hundreds of millimeters in almost all welding methods. When connecting a joint for the formation of a seam, less than the additive material is consumed, easily and conveniently monitored quality.

a) with marching edges; b) without cutting edges;

in, g, d, e) with cutting edges

Figure 3 - Preparation of the edges of the butt seams

The angular seams differ in the form of the preparation of the welded edges in the cross section and the slurry of the seam along the length.

In the form of the cross section, the angular seams can be without cutting edges (Figure 4, a), with a one-sided cutting edge (Figure 4, b), with two-sided cutting edges (Figure 4, B). Under the length, the angular seams may be continuous (Figure 5, a) and intermittent (Figure 5, b), with chess (Figure 5, B) and chain (Figure 5, d) by the arrangement of seam segments. Taving, threaded and angular compounds can be performed by sections of seams of a small length - point seams (Figure 5, D).

The cork seams in their form in terms of (top view) usually have a round shape and are obtained as a result of the full peculiarization of the upper and partial carriage of the lower sheets (Figure 6, a) - they are often referred to as electroslates, or by regulation of the upper sheet through the previously done in the upper sheet Hole (Figure 6, b).

a) without cutting edges; b, c) with cutting edge

Figure 4 - Preparation of the edges of the corner seams of the brass

connections

Figure 5 - Corner seams of brass connections

Figure 6 - the shape of the transverse cross section and

promotional seams

Protective seams, usually an elongated form, are obtained by welding the upper (covering) sheet to the lower angular seam along the perimeter of the slot (Figure 6, B). In some cases, the slot can be filled and completely.

The shape of the edge cutting and their welding assembly is characterized by four main structural elements (Figure 7): Clearance b, dulling with, edge bevel angle and edge cutting angle equal or 2 .

Existing arc welding methods without cutting edges allow you to weld metal thickness metal (with one-sided welding of manual - up to 4 mm, mechanized under flux - up to 18 mm). Therefore, when welding a metal of a large thickness, the edges must be separated. The angle of the edge of the edge provides a certain amount of the corner of the edge cutting, which is necessary for accessing the arc inland the compound and the full mode of the edges to all their thickness.

The standard edge cutting angle depending on the welding method and the type of compound varies in the range from 60 ± 5 to 20 ± 5 degrees. The type of cutting and the size of the edge cutting angle determine the amount of the required additional metal to fill the cutting, and therefore the welding performance. For example, the X-shaped cutting of the edges compared with the V-shaped allows to reduce the volume of the weld metal by 1.6-1.7 times. The time of processing edges is reduced. True, in this case, it is necessary to keep welding on one side of the seam in an inconvenient ceiling position or concentrate the welded products.

The dullness C is usually 2 ± 1 mm. His appointment is to ensure proper formation and prevent burns in the top of the seam. The gap B is usually equal to 1.5-2 mm, since when the angles of cutting edges are received, the presence of a gap is necessary for the provider of the seam vertex, but in some cases, with a particular technology, the gap can be zero or reach 8-10 mm and more.

For all types of seams, the full provision of the edges of the connectable elements and the outer form of the seam is important both from the front side (enhancement of the seam) and from the back side, i.e. the reverse roller form. In the butt, especially unilateral seams, it is difficult to taste the edges of the dullness to all their thickness without special techniques warning the burner and providing good formation of the reverse roller.

Figure 7 - The structural elements of the cutting edges and

assembling under welding

Welded seams are classified for a number of signs. According to the appearance of the seams, they are divided into convex, normal, concave (Figure 8). As a rule, all

the seams are performed with a slight amplification (convex). If the seams are required without amplification, it must be specified in the drawing. Weakened (concave) perform angular seams, which is also noted in the drawing. Such seams are required to improve the operation of welded connections, for example, with variable loads. Butt seams weakened do not make a concave in this case is a marriage. An increase in the sizes of welds compared with the predetermined leads to an increase in the mass of the welded design and overflow of the electrodes. As a result, the cost of welded structures increases, the complexity of welding works increases.

a) convex; b) normal; c) concave

Figure 8 - Classification of seams in appearance

The formation of a smooth transition of the metal of the facial and reverse rollers to the base metal is also of great importance, since this ensures high compound strength during dynamic loads. In the corner seams, it is also difficult to break the root of the seam for all its thickness, especially when welding with an inclined electrode. For these seams, a concave shape of the cross section of a seam with a smooth transition to the base metal is recommended, which reduces the concentration of stresses at the transition site and increases the strength of the compound during dynamic loads.

In terms of the number of layers and passes, one-layer, multi-layered, single-pass, multi-pass seams (Figure 9, 10) are distinguished.

The welded seam layer is part of the weld metal, which consists of one or more rollers located at one level of the cross section of the seam. Roller - metal weld, filtered or overwhelmed in one pass.

Figure 9 - Classification of seams for execution: A - one-sided; b - bilateral

Figure 10 - Classification of seams by number of layers and passes:

I-IV - the number of layers; 1 ~ 8 - number of passes

When welding, each layer of multi-layer seam is annealed when the subsequent layer is applied. As a result of such a thermal effect on the metal weld, its structure and mechanical properties are improved. The thickness of each layer in multi-layer seams is approximately 5-6 mm.

According to the active force, the seams are divided into longitudinal (flanks), transverse (frontal), combined, oblique (Figure 11). The frontal seam is perpendicular to the force p, the flank - in parallel, and the oblique - at an angle.

On position in space, the lower, horizontal, vertical and ceiling seams are distinguished (Figure 12). They differ from each other angles, under which the surface of the weldable part is covered relative to the horizontal. Most difficult to perform ceiling seams, the best seam is formed in the lower position. Ceiling, vertical and horizontal seams are usually used in the manufacture and, especially when installing large-sized structures.

a) - longitudinal (flanking); b) - transverse (frontal);

c) - combined; d) - oblique

Figure 11- Classification of seams according to the current effort

Figure 12 - Classification of welds on their position

in space

Examples of the designation of welds on their position in space are given in Figure 13

N - bottom; P - ceiling; PP - semi-meter; G - horizontal;

PV -Polumetical; V - vertical; L - in the boat;

PG - semi-risal

Figure 13 - Designation of welds by their position

Performance and quality of work depends on the availability of the necessary tool, material and skills. For success in any case, whatever directions, it also significantly affects the knowledge of theory. It is considered to be one of the most common.

For this type of activity, we need material, equipment, experience, as well as theoretical knowledge. Mastering the necessary information, a person receives an idea of \u200b\u200bwhat the seam is which there is a classification of welds and how to choose the optimal option for the clutch of various metal products.

What is the welding seam?

During the welding work, three metal sections are involved in the process: with each other with the help of the third, which the electrode protrudes, two pieces of iron are fastened. In place of the connection with each other, metal parts there is a thermal process forming seams. Thus, seam is a part resulting as a result of the impact of the melted and hardened iron.

All metals can be connected by welding method. They have their own features of the structure, according to which a certain type of fastening is selected. The classification is performed depending on the type of clutch, material and other parameters. For each connection, there are instructions and your own execution order.

Dimensions

There is a classification of welds in length. Depending on the size, there are:

Short. The size does not exceed 30 cm. Such seam appears as a result of welding performed in one direction from the very beginning to the end.
Middle. Seam Length - from 30 cm to 1 meter. These seams are welded from the middle to the edges. For them, a reverse stepped method is perfect. Its essence is that the entire seam is divided into several sections, which are alternately processed by welding. Each of these segments has a length of 10 to 30 cm.
Long (over one meter). It is welded as well as the middle seams, with the only difference that the number of areas here will be more.

Types of welded connections

The classification of welds is also carried out by the type of fastening. There are four types of compounds:

butt;
brand;
vansel;
corner.

The most common appearance

During the butt clutch, the thickness of the product is taken into account. This saves a significant part of the material.

The butt clutch is considered the most popular. This is due to the fact that this welding process is the fastest and economical.

For this type of clutch, the T-shape of the compound of metal products is characteristic. As in the junction of the clutch, special attention is paid to the thickness of the metal, depending on which the seams are one-sided and double-sided.

By applying this type of clutch, you must follow the following recommendations:

Performing brazer welding during the adhesion of two products having a different thickness, it is necessary to keep the welding burner with respect to the product to keep it at an angle of 60 degrees.
Welding works can be facilitated if the design "in the boat" is placed. This position of the processed product will exclude sub-sized undercover areas, which are considered the most common defects for this type of clutch.
If one passage of the welding torch is ineffective, since there may be defective areas, they should be cooking, exercising oscillations of welding electrodes.
In the brand compound can be limited to one-sided welding. To do this, use Oineo Tronic Pulse welding equipment, which allows RW-cooking.

Welding Vangest

The principle of this type of compound is a bilateral welding of products, the thickness of which is not more than 1 cm. This welding is applied in cases where it is necessary to prevent moisture from entering the gap between steel sheets. As a result of this operation, two sutures are formed. This species The welded joint is considered long and is not economical, since more materials are required to work.

Angular clutch

This type of welding is used to connect metal products perpendicular to each other. Depending on the thickness of the sheets, the angular welding is characterized by the presence or absence of bevelled edges. If necessary, this is made from the inside of the product.

Forms of welded seams

The classification of welds on the form of an outer surface defines three types:

Flat. Effective with dynamic and alternating load, since these seams (as both concentrated) there is no voltage concentration that can cause sharp drops and destroy the welding grip.
Concave. A permissible is considered a shortness of a seam not exceeding 0.3 cm. Otherwise, the concavity of the weld is considered excessive and regarded as a defect. The level of concreteness is measured in the area where there is the greatest deflection.
Convex seams. Arise as a result of the accumulation of a large number of frozen metal and are considered uneconomical. But at the same time, a welded compound, which gives a convex seam, more efficiently with a static load than a compound with a flat or concave weld. The bulge indicator is the distance from the surface of the main metal to the point of the greatest protrusion. Standard is considered convexities that do not exceed 0.2 cm for lower welding and not more than 0.3 cm for welding made in other positions.

Classification of welds on position in space

According to the placement criterion, there are four types of seams, each of which has its own features and recommendations for welding:

Lower seams. Technical aspects are considered the most simple. The bottom seams are welded on a flat surface at the bottom. This process is characterized by high performance and quality. This is due to more comfortable conditions for the welder. Metal metal is sent to the welded bath located in a horizontal position. Behind the cooking lower seams is easy to keep track. Work is performed quickly.
Horizontal seams. Welded a little harder. The problem lies in the fact that the melt metal under the influence of its weight lies on the lower edges. This may entail the appearance of sub-edges in the top edge.
Vertical seams. Are the result of compounds of metal products placed in the vertical plane.
Ceiling seams. This welding is considered the most difficult and responsible. Characterized by minimal comfort. In the process of welding, the selection of slags and gases is awesy. Not everyone will cope with this work. great experienceSo to keep the slag falling on the face in the course of work. It is important to comply with the quality and strength of the connection.

How are welded seams and connections designate?

Classification and designation of welds are performed using special icons, lines and tuning. They are placed on both the design itself. The classification of welded joints and seams is indicated according to the regulatory document using special lines that can be solid or bar. Continuously denoted visible welds, stroke - invisible.

The conventions of the seam are put on the shelf from the callout (if the seam is located on the front part). Or, on the contrary, under the shelf, if the seam is placed on the reverse side. With the help of icons, the classification of welds is indicated, their intermittentness, placement of segments for welding.

Next to the main icons are extra. They contain supporting information:

about removing the increase in the weld;
on surface processing for a smooth transition to the main metal and preventing the influx and irregularities;
about the line on which the seam is produced (whether it is closed).

For identical designs and products of one GOST, standard conventions and technical requirements are provided. If there are identical seams in the design, then they are better to give sequence numbers and smash on groups that are also assigned numbers for convenience. All information about the number of groups and seams should be specified in the regulatory document.

Position of seam

Classification of welds is carried out based on the position of the seam. They are:

Unilateral. They are formed as a result of welding sheets whose thickness does not exceed 0.4 cm.
Double-sided. There are two-sided welding of metal sheets with a thickness of 0.8 cm. For each case, it is recommended to leave 2-millimeter gaps that ensure the quality of the clutch.

Possible flaws

Defects during welding may occur due to excessively high current and stress on the arc. It may also be the result of incorrect manipulations with electrodes. Classification of weld defects at their location:

Internal. To identify them, a technique consists in control: not destroying a design that destructs is completely or partially.
External. They are easily detected with an external inspection.

Due to the violation of the welding regime caused by the absence of necessary experience, insufficient preparatory work, improper measurements, defects are divided into:

Nevel. It is manifested in the local absence of fusion between the connected elements. The defect leads to an increase in the concentration of the voltage and decrease in the seam section. The design with such flaw is characterized by low strength and reliability. The cause of the undevelopment can be both insufficient current and welding in fast mode.
Cutting The defect is to determine the thickness of the base metal. This problem is observed near the borders of the welds.
Burner. The flaw has a form of cavity in the weld. It arises due to the leakage of the molten metal from the welding bath. The burner is an unacceptable defect, it needs to be urgent.
Unwitted crater or deepening. There arises due to the cliffs of the arc during the approach to the end of the seam.
Influx. The defect is manifested in the pitch of the weld metal on the main metal without fusion.

The causes of defects can be the most different, but they are equally able to reduce the strength of the clutch, operational reliability, accuracy and spoil appearance Products.