Elements of Technology for Producing Cold-Formed Rebar from C86D Steel Using an Idle Stand

Abstract

For the production of high-strength reinforcing bars with a diameter of 9.5 mm from C86D steel, cold-formed rebar with a diameter of 9.7 mm was used, made according to the direct drawing scheme from hot-rolled coiled steel with a diameter of 16.0 mm, which was subjected to cold profiling with a dent depth of 0.20 mm in an idle three-roller stand and subsequent stabilization at a temperature of 390 ± 10°C with a specific technological tension of 480 MPa. The power parameters of the application of a periodic profile on the conversion workpiece, the maximum value of the forces acting on the rollers, as well as the values of the required pulling force, have been determined. It has been experimentally shown that a 5.0% decrease in the idle cross-section of a reinforcing bar after deposition of indentations and stabilization is compensated by an increase in σu and σ0.2 by 4.6 and 8.7%, respectively. It has been shown that correction of roll adjustment is necessary during the line riding period and development of process tension. The proposed methodological approach with the use of modeling makes it possible to design equipment for the profiling of rebar integrated into the line of the stabilization section with a pulling device.