DE2018921B2 - Process for producing a welded joint with a high seam factor - Google Patents

Description

The invention relates to a method within the meaning of the preamble of the patent claim.

It is primarily used to produce endless, pliable conveyor belts that run over rollers Manufacture thin cold-rolled steel by welding the ends of the webs, as they are used for the manufacture of flooring membranes to serve. Such conveyor belts are subject to very high long-term stress, especially at the welding point.

Accordingly, the invention aims at the weld joining of thin cold-rolled steel strip, e.g. B. 1 mm thick, by welding its transverse edges with a high weld seam factor of at least 80% and without loss of the high strength of the tape next to the seam. In fact, a gas-shielded fusion weld is used used, as is the case with such sheets, e.g. B. in body shop, is common. aside from that Care must be taken when welding that the heating remains localized so that next to the seam a decrease in strength is prevented. From the preamble of the claim is as closest prior art addressed the teaching of German patent specification 10 85 981, the welding together the transverse edges of a hot-rolled steel strip that is thin in relation to its width it is based on a pipe mill for the Hc ;. '..' development of welded seam tubes. The one aimed at high seam factor is to be achieved there by inductive heating of the transverse edges, followed by pressure welding by pressing the transverse edges against each other in connection with a limited upsetting of the transverse edges, by subsequently removing the welding beads by cutting using steels and then Rolling of the connection point to tape thickness can be achieved in the direction of the seam. That Machining is used to remove slag, scale, impurities, etc. and thus to prepare the compensation phase by rolling. So there comes through the welding first a large cross-sectional joining seam is created, the strength of which is finally increased by the rolling Sheet thickness is reduced. A loss of cross-section, such as that caused by welding the band without upsetting would occur is already avoided in the known case.

The task asserted above is achieved by the characterizing measure according to the patent claim solved. Since the thickened seam has no impurities, it can open as a whole Belt thickness can be leveled.

Only the overall combination of the claim theory is under protection.

The following also applies to the state of the art

to say:

While in the prior art according to the German patent 10 85 981 the heating of the tape ends in the course of inductive effects from medium or high frequency heat on the welding area is limited that in the area of the abutting edges on both sides of the tapes from fitting pieces a material with roughly the same electrical resistance, but a significantly higher melting point than it has the band material, are provided, measures belonging to the state of the art are also included known, in which the heat generation on the weld seam area by means of a burner dadurdi is limited that heat-dissipating metal parts are provided at these points (see. L) SA patents 18 40 737, 26 31 215). Such a limitation of the heat flow away from the seam takes place also in the case of the invention, so as to keep the areas next to the seam as cool as possible the good strength properties of the cold-rolled steel strip are preserved as far as possible.

The cold upsetting of strip edges when manufacturing seam tubes is also known Reinforcement of the seam. The aim here is to prevent loss of strength due to weld penetration (see USA.-Patentschnft 17 65 368). The compression or thickening remains there; so she is not only of a temporary nature, as is the case with the genre of the invention.

It is also known to bend metal sheets to form slotted tubes and to weld them together, with the welding point Welding losses are formed by subsequent hot rolling from the outside and inside be eliminated (see. USA. Patent 20 44 491). Also known is the production of wide ribbons, namely hot and cold rolled strips, by welding together several narrow strips of width after and subsequent rolling with a reduction in thickness, in which the seam disappears completely and a high seam factor is achieved (cf. German Patent 625 584).

The present invention is explained in more detail with reference to the drawing.

Fig. 1 shows the dimensional change of the steel strip edge when upsetting.

F i g. 2 shows an exemplary embodiment of the device for restricting the flow of heat on the weld seam area.

Since the yield point of the cold-rolled steel strips is 110 to 120 kg / mm ² , the required upsetting forces are very high. The upsetting width b and upsetting depth t resulting from upsetting are dependent on the upsetting height h for a certain sheet thickness. The individual sizes are shown in FIG. 1 for a steel belt 2 is shown. In the table below, for a tape 2 thickness of 1 mm, the at

different upsetting heights A achievable upsetting widths b listed.

Compression height h

0.7 mm
1.0 mm
1.5 mm

Compression width b

1.6 to 1.75 mm 1.5 to 1.8 mm 2.0 to 2.4 mm

The steel strips, for example made of a steel of the Weikatoff number 4301, are upset after upsetting their welding edges on a plate 1, which can consist of steel, for example, so arranged, that the Sdiwsisskanten meet along level 3, as shown in FIG. 2 is shown. In the plate 1 is a block S made of a material that conducts heat well, for example copper, let in, which has a recess 6 in which the adjacent, upset welding edges of the steel strips 2 come to rest. This copper block 5 provides together with two more arranged on the steel strips 2 on both ropes of the weld seam to be formed Copper blocks 4 ensure that the heat flow generated during welding on the seam area remains limited, as the heat flowing into the strips is dissipated immediately through the copper blocks. The upper copper blocks 4 are pushed as close as possible to the welding edges, the Limits set by the onset of upsetting and the space required for welding are.

Because of the thermal stresses that occur during welding, the strips 2 must be firmly clamped. This jig is not shown in FIG. The clamping forces, however, expediently act on the copper blocks 4, so that the steel strips 2 are in good contact with the copper blocks 4 for favorable heat dissipation.
ίο After the steel strips have been arranged in the manner described, they are welded together. Since there is enough weldable material due to the upsetting, the welding is carried out according to the Argonarc process. The heat-affected zone is kept as small as possible by the heat dissipation through the copper blocks 4 and 5.

After welding, the blocks 4 are removed and the weld is made by the action of The stain has been freed from the scale and the tarnish. The weld seam is then strengthened, by rolling it in the direction of the seam.

The endless steel belts produced by this process advantageously retain the mechanics see properties of the cold rolled strips at the joints essentially in. Strength tests have shown that the sweat factor is greater than 80%.

1 sheet of drawings

Claims (1)

Claim: Process for producing a welded joint with a high seam factor between the Transverse edges of rolled strip, in which the transverse edges of the strip are thickened by upsetting and after welding, consolidating the upsetting or seam area by leveling it Area is carried out to strip thickness by rolling in the seam direction, thereby characterized that in the course of manufacturing a protective gas Schnielzschweißverbindungen on thin, z. B. 1 mm thick cold rolled strip the upsetting of the Cuerkanten takes place before welding while the strip is cold, Furthermore, during subsequent welding, the heat flow is limited to the upsetting or seam area and the leveling of this area is carried out solely by rolling. »0