Bulten- Kanthal

Coincidence resulted in a world-leading metals company

Ratos’s first stock acquisition was made in 1935 in Bultfabriksaktiebolaget (”Bulten”) in Hallstahammar. This acquisition was in conjunction with the reorganisation that was done by Eskilstuna Fabriks AB in 1934.

Eskilstuna Fabriks AB, generally known as ”Fabriksbolaget”, had been established in 1908 with the Söderberg family and other related parties as owners. Olof Söderberg became chairman of the board. The company initially manufactured small-gauge manufacturing in iron and steel, but soon came to focus on bolt products and eventually also transmission chains. Söderberg & Haak had exclusive rights to Fabriksbolaget’s products.

In 1934, Fabriksbolaget’s assets were sold to Bulten, at which time Torsten and Ragnar Söderberg received shares in Bulten. Bolt manufacturing in Eskilstuna was incrementally shifted to Hallstahammar, while Eskilstuna became the home for Bulten’s manufacture of chains.

Bulten was founded in 1873, based on British prototypes, for the manufacture of bolts and other fasteners using standardised measurements. Previously, Swedish industry had imported fasters or manufactured such according to their own measurements. In 1938, AB Kanthal became a subsidiary of Bulten.

Ratos became one of the largest owners in Bulten. Ragnar Söderberg was elected to the board in 1934 and he served as chairman of the board from 1949-73, with a break 1957-58. He was also chairman of Kanthal. In 1970, Kanthal merged with its parent company to form Bulten-Kanthal. Johan Söderberg was elected to the board in 1971, where he later served as chairman.

In 1943, Ramnäs Bruk was acquired by Bulten. That works was founded in 1590 by the widow of King Gustav Vasa, Katarina Stenbock. The main product at Ramnäs was large dimension chains. This manufacture began in 1876 and continues to this day at Ramnäs.

The Bulten Group underwent a rapid expansion during the post-war period. Åshammar’s Bolt factory in Gästrikland was acquired in 1947. The facilities at Hallstahammar were modernised. Several subsidiaries were established around the world.

A plant was started in Kalix in 1966. Bulten became one of the biggest manufacturers of fasteners in Europe, and Kanthal acheived great successes, including as a specialty foundry for components for jet engines and nuclear power plants.

As part of Ratos’s strategy to exit the steel sector, shares in Bulten-Kanthal were sold in 1982.


Kanthal is an alloy consisting of chromium, aluminium, cobalt and iron. The name is derived from Hans von Kantzow in Hallstahammar. The alloy can withstand temperatures up to 1,375 C. Because of its heat resistance, the material is used for things like electric ovens for industrial purposes, as well as household appliances such as toasters, hair dryers and hot plates.

Its origins are rather unusual. It all started back in 1916 when Hans von Kantzow was working as a production engineer at the Degerfors steelworks. He had just placed two test bars in a steel oven when there was an alarm about an accident at the plant. As a result, the bars remained in the oven for a longer period than planned. When von Kantzow took them out, he noticed that they had survived the high temperature surprisingly well.

Hans von Kantzow served as managing director of Bulten between the years 1918-1957. During a trip to the US in 1925, he got into contact with a company that manufactured electrical resistance materials that could withstand temperatures up to 1,100 degrees C. That give him the impulse to conduct experiments based on this random discovery in Degerfors to see if he could find an alloy that could withstand even higher temperatures. By 1926, he was seeking a patent for his Kanthal alloy. Five years later, AB Kanthal had been formed, with Kantzow serving as managing director until 1956.