Prospects for the production of welded and seamless tubes at reduced temperatures

A technology has been developed and tested for making welded reduced tubes. The technology includes heating of the semifinished product to temperatures in the α [arrow right] γ transformation range before the forming operation, HFC preheating of the edges of the semifinished product, welding, and reduction of the tube within the same indicated temperature range. The technology makes use of the high ductility of the steel, reduces oxidation losses, and allow the tubes to undergo thermomechanical treatment. Compared to continuous furnace welding, the technology reduces gas consumption twofold, reduces metal loss tenfold, prevents grain growth and decarbonization of the steel, and increases the strength of the weld by increasing the temperature gradient between the edges and the base metal. All this in turn makes it possible to produce tubes of high-carbon and low-alloy steels and to make tubes of almost an type.[PUBLICATION ABSTRACT]