DE1239915B - Mold for aluminothermic welding - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

B23k

German KL: 49 h -35/01

Number: 1239 915

File number: E 309591 b / 49 h

Filing date: January 29, 1966

Open date: May 3, 1967

The invention relates to; a mold for the alummothermal Welding, in which not only channels for the inlet of the molten steel but also channels are provided for the extraction of the preheating flames or the combustion gases.

In the aluminothermic joint welding of workpieces, especially rails, it is known that the welding cross-sections before casting through a laterally into the mold cavity fuel-air mixture blown in and ignited there or through from above to preheat burners that are arranged above the casting mold and deliver a ribbon-shaped flame.

In addition to the channels for the supply of the fuel mixtures or preheating flames, these casting molds have and the inlet of the aluminothermically produced steel also has channels through which the combustion gases or preheating flames are discharged to the outside after flowing through the mold and the steel can rise.

Those arranged in the casting molds for the removal of the combustion gases or preheating flames Mold channels fill with the aluminothermically produced steel during casting. This will be the workpiece zones in the area of these channels are washed through or around by a hot liquid amount of steel, which in many cases is far larger than the melting required. This creates in these Areas of undesirably wide melting zones, caused by the subsequent cooling, increased Shrinkage stresses and thus the risk of cracking can result. aside from that Such a larger filling of these channels with steel, which is undesirable from a welding point of view, causes an enlargement the loss of weld metal and thus in many cases the use of a larger weld portion than for a proper weld would be required.

The invention is based on the object of eliminating these disadvantages. This succeeds according to the invention by steel closures, which at least partially fill the drainage channels and themselves support on the edge. The locking pieces are preferably supported by limiting pins.

To carry out series welds, such as B. of rail welds, the Channels used for preheating in the casting mold preferably also have different cross-sectional dimensions extend from the mold cavity upwards, with z. B. in the rail welding forms that of the area of the rail mold for aluminothermic welding

Applicant:

Elektro-Theimit G. mb H.,
Essen, Salkenbergsweg 14

Named as inventor:

Dipl.-Ing. Dr. Ernst Kruger, Essen

outgoing channels up to a certain height the required and from then on an extended one Have cross-section, so that the closure pieces adapted to the expanded cross-sections inevitably can only be introduced into the channels up to the cross-sectional transitions. the Height of the smaller cross-sectional sections of the mold channels that go up through the closure pieces are limited, depends on the one in the remaining channel cavities to be absorbed, the flushing steel amount used for melting these zones as was determined from a welding point of view. A regulation of the capacity or the filling level the mold channels with constant cross-sectional area and shape can continue to be achieved thereby be that the closure pieces have different bores, in which depending on the desired Insertion depth the limiting pins are pushed in.

Furthermore, the end faces that come into contact with the aluminothermically produced steel are with a refractory coating, such as e.g. B. plastic molding sand or graphite provided.

The casting mold according to the invention is based on a drawing in a simplified representation on Example of the rail connection welding with preheating of the rail ends from above explained and it shows

F i g. 1 the molded-in rail ends with a preheating burner arranged above the casting mold in perspective view,

FIG. 2 shows a section along the line AB in FIG. 1,

F i g. 3 the rail ends with the casting mold and introduced, inventive locking pieces in the perspective,

4 shows the casting mold surrounding the rail ends with inserted locking pieces according to the Section C-D of FIG. 3 with above the mold

709 578/173

Claims (3)

arranged reaction crucible when pouring the aluminothermically produced steel into the mold. According to the Fi g. 1 to 4, the rail ends 1 and 2 to be welded, laid with a gap, are surrounded by a casting mold 3 open at the top, which has channels 4 extending from the area of the rail foot edges, which open into the casting mold cavity 5 surrounding the rail ends and emerge from the mold at the top. Above the rail head, the casting mold cavity 5 merges into a riser channel 6, in or above which, for preheating the rail ends 1 and 2 to be welded, for. B. a ribbon or shower burner 7 is arranged. Furthermore, the mold has inlet channels S for guiding the aluminothermically produced steel, which open into the casting mold cavity above the rail foot and via gates 9 and 10. During preheating, according to FIGS. 1 and 2, the band of flames emanating from the preheating burner 7 strikes through the riser duct 6 into the gap between the molded-in rail ends 1 and 2. 2 flames indicated by arrows are deflected in the area of the rail foot and, after their heat has been given off, are discharged to the outside through the channels 4 and, to a lesser extent, through the inlet channels. The channels 4 arranged in the area of the rail foot edges allow sufficient preheating of these rail foot areas and the simultaneous removal of the preheating flames or combustion gases. When the rail ends to be welded have reached the required preheating temperature, the preheating burner 7 is removed and, as shown in FIGS. Stops 12 rest on the form. The closure pieces 11 are dimensioned so that a small gap remains between the closure pieces and the channel walls in order to allow ventilation of the casting mold cavity in this area when the aluminothermically produced steel is poured in. The riser channel 6 is then covered by a refractory bolt 13 and the steel 15 produced aluminothermically in the reaction crucible 14 is poured into the mold in a known manner. The pouring stream pours onto the bolt 13, from where it is fed via the inlet channels 8 and via gates 10 and 9 to the casting mold cavity 5 surrounding the rail ends. The locking pieces 11 introduced into the channels 4 and limiting the filling height of these channels ensure that only as much steel flushing around the rail zones in these areas is absorbed in these channels after its heat has been given off as is necessary for a technically favorable welding of these zones. After the casting, the locking pieces 11, which are secured against welding, are pulled out of the mold and can thus be used again for further welds. The closure pieces can also be made of refractory material, such as. B. made of chamotte or CCVhardened molding sand, which must be secured against rising in the channels when pouring the steel into the mold. Patent claims: 1. Casting mold for aluminothermic welding, in addition to channels for the inlet of the molten steel also channels for the extraction of the preheating flames or the combustion gases are provided, characterized by steel locking pieces (11), which at least partially fill the exhaust ducts (4) and are supported on their edge. 2. Casting mold according to claim 1, characterized in that the support of the closure pieces (11) Limit pins (12) are. 3. Casting mold according to claim 1 or 2, characterized in that the end faces of the closure pieces (11) are provided with a fireproof coating. Considered publications:
German patent specification No. 1 046 449. 1 sheet of drawings 709 578/173 4.67 © Bundesdruckerei Berlin