Improving the technology used to make welded carbon-steel tubes

Electric-welded tubes made of carbon steels are less expensive, have a better-quality surface, and have more accurate dimensions than equivalent seamless tubes. An efficient method has been proposed for making the distribution of the strains and residual stresses in such tubes more uniform about their perimeter (and reducing the stress level in general). The method employs cold reduction in the final passes of the forming mill, which has a closed pass. Similar reductions are also made in the welding and guide stands. The authors constructed a model to control the voltage on the induction coil, and they determined the dependence of temperature in the welding zone on the length of the edges in the welding gap. The introduction of new tube-production methods and equipment developed as part of this research has made it possible to master the industrial production of new types of special-use tubes, tubes with fewer or no internal burrs, and tubes with stronger welds, better mechanical characteristics, and other improved quality indices. __________ Translated from Metallurg, No. 5, pp. 63–67, May, 2006.     

Improving the technology used to make spiral-seam large-diameter pipes for national pipeline projects

Measures that are being taken by the Volzhsk Pipe Plant to modernize and expand its production facilities will allow the plant to meet the increasingly stringent requirements on pipes in the future. Full-scale tests of large-diameter pipes show that spiral-and straight-seam pipes perform equally well under the same given conditions. The Metallurgical Pipe Company is ready to supply pipes for Russian and international gas and oil pipelines currently being built to operate at pressures up to 9.8 MPa.     

Changing the hydrogen content of alloy steel in relation to the technology used to cool cast slabs

Results are reported from the production of two trial heats of alloy steel in which the cast slabs were cooled in a thermostatted chamber and in a dense stack. It is shown that cooling slabs in such a chamber makes it possible to reduce the hydrogen content of the steel 30% compared to slabs that are cooled while stacked.     

Ensuring high quality indices for the wire rod used to make metal cord

Mastering the production of high-carbon wire rod — especially cord-grade wire rod — on a mini-complex originally built at the Moldavian Metallurgical Plant to make ordinary wire rod was a daunting problem that has been solved by a collaboration with the Ukrainian Academy of Science’s Institute of Metallurgy. Researchers developed an integrated technology for making the steel, continuous-cast semifinished products, and wire rod needed to make metal cord of ordinary, high, and ultrahigh strength. The wire rod is characterized by a good-quality surface (defect depth no greater than 0.15 mm, with 95% being no deeper than 0.10 mm), good deformability, and the ease with which it can be converted into wire, strands, and cord structures.