New Type Controlled Rolling & Controlled Cooling Technology

●Process of refining crystal grain through controlled rolling and cooling in the threaded rebar production is adopted, which can reach 10 grade and above grain size, having features of high strength, high yield ratio and satisfying quakeproof requirement, and can reduce the production cost significantly.

Technical Features:

●Combine the process arrangement with deformation thermal phase so that rolling temperature after controlled rolling will be stably controlled in the non-recrystallization area.

●Combine forcible cooling and controlled rolling unit with recovery after controlled rolling, control the temperature gradient to reduce to the range of not generating closing organization.

●Combine the adequate reduction rate with heavy duty equipment and release the function that deformation will induce phase change to get the fine-crystal organization.

φ12mm controlled rolling and controlled cooling (4-split) grain size and structure detection drawing

Core 10.0 (area method) average dia.: 0.00644mm, structure: ferrite + pearlite

Grain size of intermediate layer: grade 100 (area method) average dia.: 0.00660mm, structure: ferrite + pearlite

Grain size of external layer: grade 10.5 (area method) average dia: 0.00550mm, structure: some tempered martensite with thickness of 0-375μm exists, but it is not closed and there is no tempered structure at the angle of two longitudinal ribs and base circle.

1MTPA Fine grained Steel Rolling Line Project of Shiheng Special Steel