The history of the Thermit^® process: one of the inventions of the century

On 1st January 1919, Th. Goldschmidt AG, Essen and the accumulator factory, Berlin-Hagen, founded Elektro-Thermit G.m.b.H. in Berlin-Tempelhof. This brought together years of knowledge and experience gathered in the welding sector. From the beginning, the new company was very successful and able to leverage the Thermit^® welding procedure worldwide.

Its basis  was the aluminothermic procedure patented in 1895 by Professor Hans Goldschmidt. He had successfully developed the reduction of metal oxides with aluminium powder to a technical standard. On 13th March 1895, the Goldschmidt company in Essen was granted German patent no. 96317: “Process to manufacture metals and alloys”.

Professor Goldschmidt soon realised that the enormous amount of heat resulting from this reaction could also be used to weld metals together. At the beginning of the 20th century, Goldschmidt performed the first trials to weld rails together. In 1928 the first continuously welded rails were produced for the German Reichsbahn.

After the 2nd World War almost all of the railway companies in the world decided to continuously weld their railway infrastructure, which led to a rapid growth of the Thermit^® companies. With the development of the new welding process “SmW” in 1955, it was possible to drastically reduce the time required to weld rails together, thereby greatly improving the economic efficiency. A further step forward was the development of the “SkV” process in 1972 which was chosen as the standard welding process by the German Bundesbahn and many railway companies throughout the world.

In addition, the Thermit^® companies started to develop electric welding systems to rebuild the profile of laid and worn rails and to improve the performance of the running surface. Here, the submerged arc welding process known as the ELLIRA^® process was mainly used. The process was enhanced in response to the requirements of the rail companies, resulting in the ETEKA 5^® and RIFLEX^® welding processes. In addition, supplementary special grinding devices were used to reconstruct the running surface. As a result of the success of this service, new tracks are now also tempered by similar technologies, leading to a marked improvement in their smoothness and wear-resistance.

Not only the welding process, but also the equipment and devices required have been consistently enhanced by the Group over the years; worthy of particular mention here are the hydraulic trimming device (1970), the automatic crucible thimble (1982) and the single use crucible (1998). In 1970, an insulated joint type “MT” was introduced to the market. Further insulated joints as well as other products and services complete the versatile portfolio.

Prior to the 1st World War, the Thermit^® process had already been introduced all over the world through local representatives and companies. The international market was consistently developed through establishing new or joint venture companies, in particular in Italy (1950), India (1951), Brazil (1952), Austria (1952), England (1958), USA (1967), Australia (1986), Czech Republic (1993) and Hungary (1995). In 1999, the Thermit^® Group separated from the parent company Goldschmidt AG and was taken over by the “Vermögensverwaltung Erben Dr. Karl Goldschmidt GmbH”, Essen.

Over the decades, Elektro-Thermit GmbH & Co. KG, located in Halle (Saale) since 2005, has become one of the most important pillars of the Goldschmidt Group. Today, the Halle site is the main centre for Thermit^® manufacture –  and the most modern Thermit^® production site worldwide.