New QST Order at Nucor Yamato Steel (USA)

Nucor Yamato Steel, the largest producer of heavy beams and sheet piles in the USA, selected Danieli to supply the QST, Quenching and Self Tempering technological package, for beams.

This QST process involves intensive cooling applied to the entire surface of the section after rolling.
QST makes it possible to increase the mechanical properties of the beams with reduced quantities of expensive alloys, such as vanadium and niobium, and to achieve top quality grades with fine grain structure, excellent weldability, high yield stress and low temperature resilience.
The new technology will allow NYS to achieve substantial savings in terms of material and transformation costs for a wide range of product applications, such as beams used in high-rise buildings, long span bridges, seismic areas and offshore structures.
Danieli will be the first plant-maker to supply this technology. Only a few beam manufacturers have developed and installed a similar system in the past, based on their own processes.

NYS awarded the contract to Danieli also for its intense research and development activity (almost five years of tests) that combined theoretical studies and quenching trials on jumbo beams in the Danieli pilot plant. These efforts were followed by accurate measurement of metallurgical and mechanical properties of the treated beams.