| 摘要 |
<p>The invention relates to a process and a device for carrying out aluminothermic welds particularly intended to building and maintaining the railways. According to the invention, the process provides the aluminothermic welding of the rails without the removal of the mould and before the trimming operation, the weld-mould assembly is wrapped in a ceramic fibre web and let to cool for 40 minutes, this wrapping and the presence of some crop ends allowing the controlled cooling of the weld. According to the invention, the device for carrying out the process comprises a mould (A) arranged about the ends of two railway rails to be welded, above which there is located a melting crucible wherefrom the molten metal resulting from the aluminothermic reaction flows into the mould thereby carrying out the weld (5). The mould (A) is made of a mechanic mixture consisting of sand with a grain size of 0.4 ... 0.6 mm, resol, bentonite, ABS hardener and methanol, the material determining a quality profiled adequately to the rail section, being in connection with some side crop ends (2) and an upper crop end (3) partially constricted by an enclosure (4). The mould is crossed by a network of channels (1) for draining the reaction gases. The melting crucible (B) is made by stamping from magnesite powder, wetted with sodium silicate and dried at a temperature of 300 ... 400 C and it is provided at the lower side with a self- triggering plug (8) which allows the passing of the molten steel into the mould, the active side of the plug comprising a thermite based on copper oxides.</p> |
