Elaboration and industrial implementation of lean alloy steel rolled stock production for structures of road bridges

Within the national project “Safe and quality automobile roads” realization a big number of bridge passages will be constructed, including steel road bridges with small (14–42 m) spans instead of reinforced concrete bridges. Application of metal rolled products of 10ХСНД, 15ХСНД, 10ХСНДА, 15ХСНДА steels in the steel structures of bridges with small spans results in unreasonable increase the costs of the bridges structures. This circumstance stipulates necessity to elaboration and implementation of cheap lean alloy steel for manufacturing standard short-spanned bridges. The steel production should involve minimal and lean alloying method and ensure complex of operation properties in normalized state. At JSC “Ural Steel” an experiment work was accomplished for elaboration lean alloy steel 12Г2СБД due to STO 13657842-1 having standard yield strength 345 MPa. In cooperation with NIZ “Mosty”, OJSC “CNIIS” and CNIIchermet after I.P. Bardin technical specifications of plates for short-spanned bridges were elaborated and approved. Comprehensive technology of 12Г2СБД steel plate production was elaborated. A trial batch of 12Г2СБД steel plates was produced and shipped to ZAO “Kurganstalmost”. Study of welding and technological characteristics of the trial batch plates was carried out. The study showed, that the plates of 12Г2СБД steel have low sensitiveness against heat action of a welding thermal cycle and can be used in welding structures of steel bridge spans providing keeping the plant and assembling welding technology by standard regimes (due to welding technology of steel 10–15ХСНД). Application of the plant and assembling technology at welding by standard regimes makes it possible to use the plates of the elaborated steel for manufacturing metal structures of short-spanned metal bridges for various weather conditions. The plated can be used for both a regular performance (the calculated minimum temperature is down to –40 °С inclusive) and a northern performance Zone A (the calculated minimum temperature is down to –50 °С inclusive).