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Personalvermittlung, Zeitarbeit, Werkverträge

The weld seam

There are many different types of weld seams. The most well-known are the butt weld and the fillet weld. However, various other types are used depending on the shape of the components being joined.

Table of contents:

The butt and fillet weld

A butt weld is created between two sheets of metal that lie flat next to each other and are welded on the two opposite edges. This creates a continuous sheet of metal with a flat surface from both sheets.
The fillet weld, on the other hand, places one workpiece perpendicular to the other.

There is an angle of 90° between the two edges. At the contact surface, they are welded either on one side, i.e. on one of the two 90° angles, or on both sides of the angle. The difference between the butt weld and the fillet weld is that with butt welds, the two workpieces are in the same plane. With fillet welds, on the other hand, there is an angle between the two that is not 180°.

Different types of joints

The joints also depend on the butt joint. There are different types of joints:

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The butt joint
For the butt joint, both workpieces are on a single plane. Their opposite ends can have different shapes. These shapes then determine the shape of the weld.
The T-join
The T-joint is the best example of fillet welds. The two workpieces are placed in such a way that a right angle is formed between them. They are not on the same plane. Rather, their shape forms the letter 'T' with one of the workpieces forming the vertical bar and the other the horizontal bar of the 'T'.
The double T-joint
The double T joint is made between three workpieces. One workpiece forms the horizontal component. The second workpiece is placed on top of this and the third workpiece is placed underneath. Together they form a double T. To put it even more simply, the workpieces form a 'plus' sign or a cross.
The diagonal joint
The diagonal join is essentially similar to the T-joint. However, the angle that is created between the components is not exactly 90°. Instead, it can be larger or smaller than the right angle.
The corner joint
The two workpieces are connected at the corners of an edge. They are not in the same plane, but are at an angle to each other. It does not matter whether it is a right angle or another angle, as long as it is not 180°.
The multiple joint
For the multiple joint, 3 or more parts are connected to each other. They are at different angles to each other. This can be symmetrical, but does not have to be. These parts are then welded at the edges that touch each other.
The parallel joint
The parallel joint is placed between two workpieces. These must be parallel to each other. They are then connected with a spot weld or a hole weld.
The lap joint
With the lap joint, several workpieces are placed parallel to each other. They overlap in such a way that one of the workpieces still protrudes over the other. These are then welded on one side or on both sides of the overlap.
The brödel joint
The brödel joint is created between two workpieces, each of which is bent. They touch each other at their rim. This is where they are then welded.

The shapes of the weld seams

There are a whole range of shapes that can be used to create a weld seam. The exact shape that is chosen depends on the joint and the ends of the components that are to be connected. Here are the most common shapes for the weld seam:

The fillet weld
The fillet weld can be made as a simple fillet weld or as a double fillet weld. It is placed between two workpieces, one of which is perpendicular to the other. With simple fillet welds, the right angle is welded on one of the two sides of the standing workpiece. With a double fillet weld, the two right angles to the left and right of the standing workpiece are welded to the surface of the lying workpiece.
The I-seam
The I-seam is placed in a butt joint between two sheets that are on the same level. The two edges are exactly perpendicular and parallel to each other. They are therefore not bevelled, so that the resulting weld seam takes on the shape of a standing 'I' between the two sheets.
The V and DV seam
The V seam is placed between two workpieces that are on the same level. The edges to be welded are facing each other. They are bevelled so that they form a "V", with each of the two edges forming one side of the "V".
For the DV seam, the "V" does not extend over the entire height of the edge. Instead, there is a vertical "V" from the middle upwards and an inverted "V" from the middle of the edges downwards. In cross-section, this results in a double "V" or a cross or even an "X".
The HV and DHV seam
The HV seam is similar to the V seam. The difference, however, is that not both edges are bevelled over the entire height. Instead, the edge of one workpiece is completely vertical, while the edge of the other workpiece is more bevelled than would be the case with a V seam.
The DHV seam is similar to the DV seam. But here too, a workpiece must have a completely vertical edge. The double V is only achieved by beveling the edge of the other material on both sides. This also makes it resemble half an "X".
The Y and DY seams
The Y seam consists of two parts. The lower part is an I seam. The upper part is a V seam. This means that two workpieces are placed opposite each other with the respective edge to which they are to be connected. Both edges are bevelled from halfway up to the top. This area forms the "V". From halfway down, however, both edges are vertical, so that the "I" is formed here.
With the DY seam, an I seam is connected to a DV seam. This means that the middle part of the edges of the workpieces is vertical and touches in the shape of an "I". The upper and lower thirds are bevelled, so that an upright "V" is created at the top and an inverted "V" at the bottom.
The HY and DHY seams
The HY seam is similar to the Y seam. The difference is that the bevelled parts are only on the edge of one of the workpieces. The edge of the other workpiece is vertical along its entire height. This results in an "I" for the lower half and a one-sided "V" for the upper half.
The same applies to the DHY seam with regard to the DY seam. Here, too, the workpiece is simply vertical on its edge. There is a double bevel on the edge of the other workpiece, so that a one-sided "V" is formed in the upper third. In the middle part there is then an "I" and for the lower third an inverted, one-sided "V" is formed.
The U and DU seams
The U seam is made up of a lower part that resembles an "I" and an upper part that resembles half a tube, i.e. one that is open at the top. To do this, the edges of both workpieces, which are opposite each other, are cut into a round shape so that they form half a pipe when they are placed together.
The same applies to the DU seam, except that the half pipe is formed on the top and bottom. In between there are vertical edges on both sides, which then form an I-seam between the two half pipes.
The steep flank seam
The steep flank seam resembles a V-seam. However, the tip of the "V" is cut off so that the two beveled edges face each other with a little space between them.
The spot seam
The spot seam is placed between two workpieces in a parallel or overlap joint. It is located on the outer edge of the workpiece and has the shape of a point in cross-section.
The hole seam
The hole seam is used to connect two workpieces that are positioned parallel to each other or overlapping each other. The seam is placed through the upper workpiece to the workpiece below.
The counter seam
For the counter seam, there must already be a weld seam that connects two workpieces. The counter seam is then placed on the back of the components exactly above the position of the first weld seam. This doubles the connection and thus strengthens it. The counter seam is curved outwards.

The weld seam elevations

In addition to the shape of the seam within the connection point, the external shape is also important. There are hollow seams, flat seams and curved seams.
The hollow seam
The hollow seam has an elevation above the former melt pool of less than 0. This makes it concave, i.e. rounded inwards. If, for example, a fillet weld is made with this, the curvature in the cross section points to the angle formed by the workpieces. The semicircular opening points outwards.
The flat seam
The flat seam lies flat above the former melt pool, which has now solidified. The weld elevation is exactly 0. It can also appear as a flat side in a fillet weld, which forms a triangle in the cross section with the angle that connects the workpieces.

The arched weld

The arched weld stretches in a convex shape over the former melt pool. The camber is therefore greater than 0. The weld forms a rounded surface that is higher than the surrounding area. In a fillet weld, the outside of the curve faces away from the angle formed by the workpieces in the cross-section. The opening, i.e. the inside of the curve, faces the angle.

Conclusion

A good weld can be made in various shapes and types of joints. From the butt weld to the fillet weld, from the V-seam to the DU weld, it depends on the desired strength and the nature of the workpieces. These also determine whether the connection is ultimately made as a hollow, flat or arched weld.