In the construction industry when welding massivemetal structures in the junctions there are serious loads, which in case of non-compliance with the technology carries the risk of collapse of the structure. This is relevant in the shipbuilding industry and in mechanical engineering (with the construction of large-size automatic machines), with the erection of massive structures. A qualitative connection must be initially calculated to avoid possible future deformations. The easiest way to check the correctness of the welded line is to find out the joint seam.

The cut of the welded seam is the conduit of the conditionaltriangle, which fits into the cross section. There is no single figure that would be an indicator of a reliable and qualitative seam in determining its leg. The larger the size of an isosceles triangle can be inscribed in place of the seam, the greater the load it can withstand. Often this characteristic depends on the type of metal and the voltage limit, which it can resist. Increasing the leg gives the opposite effect - the part is deformed and will not be able to work in the desired mode.

## How to determine the size of the leg?

To determine the optimal weld joint, you need to calculate the weld, and also determine the weld joint for welding. The following factors are taken into account:

- thickness of metalworking;
- the position of the parts relative to each other;
- The type of seam used when connecting.

For each product, the catete is selectedindividually, but here it is only about working with heavy loads. For private use of welding, thin calculations are not needed, but still professionals take into account the properties of metal and try to make the seam durable and at the same time not to damage the details. Suture the seam at the edge in the event that the two parts have the same thickness. If different, then the catheter is determined by the thinner metal. It is important to choose and calculate its size correctly. After all, depends on this maximum power, which can resist the part. The weld joint is defined by the standardization system GOST 5264-80.

The weld seam is equal to the thickness of the sheets when weldinglap joint, but it should not exceed 4 mm. If this parameter is greater, then you should take 40% of the thickness of the metal and add 2 mm. So you can determine the maximum value of the suture.

## How to choose a cat?

The joint seam is determined when welding the reinforcement soThe same as with the connection of any other elements of metal structures. The size depends on several parameters, including the position of the blanks, their length and thickness. Professionals use templates, which welders have already worked up to them. The main parameter is the length of the weld, because it affects the strength of the future design. The material consumption and the probability of deformation are the main hazards for a long seam. Much depends on the type of seam to which the parts will be connected.

## Welded butt weld

The welded butt seam assumes the followingtechnology - to connect two elements of butt welding (ie, arrange the details of the faces of surfaces in one or different planes). Varieties of butt joints more than 30, all of them are provided by GOST. In this case, the dependence on the thickness of the welded elements, equipment and welding technology is carried out. If the structure is subjected to a variable voltage, then this type of joint is the most reliable. Docking and welding can be various parts. It can be not only sheets of metal, but also pipes, corners, channels. To weld two sheets, they do not even need to touch each other, - welding is carried out with a minimum distance of two blanks.

## Lap joint

Lap joint is a welding method whenthe parts are parallel and their edges overlap. Unlike the weld, there are only two varieties of overlapping joints. The ends of products can be welded on two sides or with one. Also there is a connection with the help of an additional lining, which is welded to two parts, connecting them at the right angle. Lap weld parts using two types of seams - end and front. The welding mode for this connection can be higher, since there is no danger of burnt surfaces.

## Gusset

Welding of two parts, the edges of which are locatedat an angle relative to each other, occurs by the method of a corner joint. The standard distinguishes up to 10 types of such joints. Sometimes for strength and reliability of the welded seam use a special metal lining, which allows you to better join the elements and makes the designs more reliable. In power structures, you can rarely see this type of connection, so calculations for such seams do not. Nevertheless, if this type of welding is necessary, the calculations are carried out by analogy with the T-joint and the obligatory account of the type of the seam.

## T-welded connection

Often there is a need to connect elements,which are located in different planes. The best solution in this case is the T-joint, where the end of one piece is adjacent to a straight or other angle to the other. The types of such compounds vary within the limits of 9 kinds provided by GOST. The T-joint requires deep penetration at the junction site, the seam is usually made by automatic welding, or pre-prepared edges, for example, with an angular seam that can be made by hand or by a seam. The type of joint that has been bonded affects its calculation. Here, it is taken into account the fact that the welded spot, pretreated, will be much stronger than the base metal.

## Seam quality control

In any of the seams, one should not forget about the suturewhen welding, the formula of which is not complicated and consists in determining the thickness of the metal. If it is less than 4 mm, then the catheter is taken equal to it, if more, then in the range of 40% - 45% of the thickness with the addition of 2 mm. The formula for calculating the leg: T = S cos 45º, here T - the desired cathete, and S - the hypotenuse or width of the seam bead.

Monitor the connection of workpiecessimple, while using visual and instrumental methods (using instruments). A tool is developed that defines the weld seam in welding. How to measure the seam of interest to him? To do this, attach the device to two parts of the workpiece, and place the middle on the seam, then write down the indicators and perform a simple calculation. Usually the seam turns out to be convex, but this is the most unreliable option. It is in this form that tension is concentrated.

The ideal option is a concave seam,which is difficult to obtain. Here it is necessary to observe the welding speed, and also to achieve the correct operation of the welding machine. Experienced masters will be able to make such a seam. But more often it is obtained mechanically, simply by cutting an unnecessary part of the seam.

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