Single Use Crucible


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Single Use Crucible by Thermitrex

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Single Use Crucible

  1. 1. THERMITREX Improves railsingle use crucible The welding
  2. 2. THERMITREX Brings Improved Rail Welding Thermitrex, the leading South African While this process worked well, there The single-use crucible is much lighter supplier of Thermit welding kits, related were certain disadvantages. The than the conventional crucible and equipment and consumables, is now robust steel crucible was heavy and in requires only one person to carry it to able to offer a greater refinement to inaccessible sections of track, at least site. The reduction in labour needed will its already-proven system for welding two people would be needed to carry lead to substantial cost reductions. In railway track joints together. the weighty crucible to the site. addition, weighty crucible stand, crucible extension and adaptor assembly are no The conventional Thermit welding The conventional crucible is made to be longer needed. system has been in use for more than 100 used as many as forty times. Because years. Early in the 20th century, Professor of this, this unit is constructed of four The single-use crucible reduces the Heinz Goldschmidt demonstrated the components, any of which could be time taken to carry out a weld by a reduction of metal oxides by using damaged during the high temperatures considerable margin. aluminium powder. This was the basis generated by the exothermic reaction. If of the Thermit welding system. By 1928, any of the components were damaged, The largest factor in favour of the single- the Thermit rail welding process was or simply went missing during moves adopted as the standard for the German from one site to another, it would not be use crucible is that it reduces the risk of State Railways. possible to continue with rail repairs. human error. The single-use crucible is made from a bonded refractory Since then, the Goldschmidt-Thermit After each use, the crucible needed to material, which is contained in a five Group, which is today Thermitrex’s be cleaned out carefully to ensure the litre steel canister. The automatic holding company, has invested effectiveness of the next weld. Where substantially in research and design, to crews are unsupervised, or where the self-tapping thimble is incorporated ensure that its customers receive the need for pre-cleaning the crucible is not during manufacture. The single-use most effective rail welding solutions. fully understood, the resulting welds crucible requires no preheating or could be sub-standard. drying before it can be used. Now Thermitrex is able to offer its South African customers the latest Although all rail welds are inspected When preheating of the rail using X-rays, this process might only ends has been completed, innovation from Goldschmidt-Thermit happen some days or even weeks later. the single-use crucible is – the single-use Thermitrex crucible. During this period, as a precaution, the placed on the mould, which newly welded joint is protected by a has four lugs into which clamping device known as a ‘joggle the canister fits. A standard plate’. In South Africa, these have been Thermit portion is placed in stolen for their scrap metal value, leaving the crucible and ignited for the joint unprotected. Should a weld fail the weld to proceed. while a train is passing over it, a calamity could ensue. The downtime while the track is out of service could run into many hundreds of thousands of rands. The amount of rework needed when using a single-use crucible would be Until now, the Thermit welding system considerably reduced. has used a conventional multi component crucible, which could be reused a number of times. In this process, a two- part mould would be clamped around the gap between the two rail ends. The rail ends would then be heated to 800°C using either propane or a petrol/air mix. A steel crucible would then be swung into position over the mould, and the Thermit welding material or ‘portion’ placed inside it. The portion would then be ignited. The exothermic reaction would melt a plug in the bottom of the crucible, and the molten contents would then flow into the mould filling the gap between the two rails and effectively welding them together.
  3. 3. The Goldschmidt-Thermit group and Thermitrex have a commitment to maintaining the highest environmental standards, as it witnessed by their ISO 9001:2000 accreditation. The recycling of waste is very much in line with this philosophy. With the conventional crucible, once the In terms of cost, the single-use crucible weld had been completed, the waste is slightly more expensive than the products from the procedure were conventional unit. However, the usually buried next to the track. numerous benefits of the new system will give its users an increased return, This waste consists of the welding slag which will outweigh the minor cash and the excess steel sheared from the outlay many times over. weld during the re-profiling of the track. On occasions this unsightly waste was left lying next to the track, as the crews had not a convenient way of returning this material to a central depot. With the single-use crucible, the used canister makes a handy container in Safety is also a key concern of Thermitrex which to return all and its parent company. The single- waste material. The use crucible reduces the amount of five kilograms of waste sparks that are released during welding, steel and four kilograms diminishing the possibility of a member As the single-use crucible reduces the slag from a single weld of the crew being injured. The smoke steps involved in the welding process. have value and can from the reaction is also reduced which Thus training of exothermic rail welders is be recycled, indirectly is a major benefit when joining rails in considerably simplified. Thermitrex offers contributing to job tunnels or other confined areas. fully accredited training and support creation. in the Thermit welding processes, after which a formal certificate of competence is issued.
  4. 4. Contact: PO Box 6070, Thermitrex (PTY) Ltd Dunswart, Tel: +27 (0)11 914 2540 Johannesburg, Fax: +27 (0)11 914 4627 Gauteng South Africa Email: 1508 Website: