Georg Fischer Aktiengesellschaft

Anton Alt

Ludwig Wilhelm

Peter Toelke

Fritz Mahnig

Klaus Hornung

Gunter Schulte

Guenter Schulte

Urban Zimmermann

A method of flash butt welding high-carbon materials, in particular nodular cast iron wherein the arcing craters produced by intermitting contact of the contact faces have a maximum roughness depth R.sub.T such that this roughness depth lies within the narrowest thickness of the plasticized zone. As a result, when the upsetting pressure is applied, the entire molten material areas on the contact faces are pressed out of the contact faces into the welding bead thereby prohibiting the creation of hardening structures, such as, for example, ledeburite in the welding zone. The method is especially suitable for flash butt welding workpieces having wall thicknesses of over 12 mm.

Method of flash butt welding high-carbon material, in particular nodular

A magnesium-treated, decarburizingly-annealed cast iron material includes 4% or less carbon by weight, 2% or less silicon by weight, at least 0.010% magnesium by weight, and at least 0.001% sulphur by weight, the remainder being iron. The cast iron material is subjected to a first annealing phase in which graphitic carbon portions are formed. Thereafter, the cast iron material undergoes a second annealing phase during which certain of the graphitic carbon portions are burned out. The resultant structure includes cavities in place of certain of the graphitic carbon portions in a substantially ferritic matrix. The resultant cast iron material exhibits good welding and cutting properties with little susceptibility to hard cracking.

Magnesium-treated, decarburizingly-annealed cast iron material

A method is disclosed for improving the immunity to temperature changes of cast iron containing lamellar graphite. The structure of the cast iron melt is suitably adjusted by means of carbide forming agents, to wit chromium and/or molybdenum and an annealing treatment in such a manner that the gray cast iron withstands increased thermal shock and dynamic stresses.

Method for improving the immunity to temperature changes of cast iron

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Schaffhausen, Switzerland

Anton Alt