The specialist should know how to determine the weld leg for a structure with a huge bearing structure, having complex corners and consisting of a multitude of connections. Note that this concept is used not only in conventional construction, but also in shipbuilding, and in heavy engineering. For proper welding of corners, overlap, T-type connections, an economical (when compared with such a view as a split edge) angular view is used, since its implementation is much simpler and there is no need to prepare edges.
Types of welds and joints.
During the design of the seams take into account the fact that:
- it is necessary to use as few compounds as possible, and their sizes should be as small as possible;
- apply highly efficient welding methods;
- when working using special electrodes, fluxes, gases and wires;
- apply the dimensions of the seams for which there is no need to produce a subsequent edging of the product;
- there must be open access to the connecting points, in which the technology of suturing and applying electrodes is not disturbed.
To determine the strength of the joint, it is necessary to calculate the derivative not only of the calculated thickness, but also of its value (actual). Note that the size of such a weld is determined by applying the value of the leg of the corner joint, and therefore it is easy to calculate. To measure it, it is necessary to calculate the size of one of the sides of the largest rectangular triangle, which fit into a longitudinal section.
The leg of the weld (corner) makes it possible to determine its calculated thickness. And in order for it to withstand a certain pressure, the sides that make up the right angle do not have to be long, since not only the individual seams, but the whole structure can be deformed, and it is also possible that the cost of the entire structure increases.
What types of joints are required for different elements
Electrode position when welding a T-joint in a vertical position with a single-pass fillet weld.
For example, in an I-pillar and a centrally compressed column, one-sided belt connection techniques are used, and in the fastener joints of a beam or bundle, as well as in the zone intended for voltage transmission, a double-sided lumbar connection that extends beyond the attached element is used.
For attachment of reinforcement ribs to beams, belt continuous joints are necessary, but the use of a one-sided waist joint in an I-beam is allowed.
To strengthen the packing to the truss grid, a welding seam is used, which allows to bring it to the end of the element (20 mm), while not using the technique of frontal joints. If there is a belt of brands, I-beam or single, then for welding them with shelves, welding is done over the entire thickness of the flanges.
There are special rules and regulations for the implementation of steel structures. Consider one of them, for example, AWS Dl.1, which is used to calculate the minimum side dimensions of a right-angled triangle (which makes an angle of 90º). Moreover, when using material with different thickness of the leg, it also changes. The standard specifies what the maximum reinforcement of the joints is possible, because if you noticeably increase this value, it will cause the process of destruction of all welded joints.
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The formula that determines the size of the joint
In order to correctly determine the theoretical thickness of the corner welds, consider the image.
Here it is shown that using the formula:
- T = S cos 45º, where S is the side of a right triangle,
- T is the width of the joint
You can make a qualitative calculation that will help determine the required value.
Consider an example: S = 3 mm. In this particular case, T = 3 x 0.7 = 2.1 mm. This takes into account the fact that when the thickness of the material is 12.7 - 19 mm, S = 6 mm (according to the above standard).
To control the quality of this type of connection on a real product, its size, size, amplification or weakening, a so-called welding pattern is used.
It shows how to measure the angle of the junction, using a special tool.
Here's how to determine the size of the leg of the fillet weld.