35kg/mm2 grade hot-rolled steel sheet with a good pipe formability by the mini-mill process and method for manufacturing thereof

摘要

The present invention before and after the Tube Mill by relates to jeonseonbae low carbon minimil for excellent bending properties during the production pipes, tolerance steel tube hot-rolled steel sheet, and its object is used instead of acid soluble aluminum boron (Boron) reduce the employment of nitrogen causing the work hardening minimil steel tube hot-rolled steel sheet to reduce the yield strength and the increase amount to provide a method of manufacturing the same.; The present invention for achieving the above object, in weight% C: 0.05% or less, Mn: 0.35 ~ 0.45%, Si: 0.05% or less, P: 0.03% or less, S: 0.015% or less, acid soluble Al: 0.001 ~ 0.10%, N: 0.008 ~ 0.015%, B: 0.0015 ~ 0.0035%, of the total content of tramp elements of 0.25% or less, tramp elements coming from the scrap Cu: 0.20% or less, Sn: 0.05% or less, Sb: 0.05% or less, and the rest Fe with excellent pipe formability which composition tensile strength 35kg / mm2 class minimil hot-rolled steel sheet and; Casting the molten steel to be the composition as described above to the thin slab, and then the pipe workability, excellent tensile strength 35kg / mm2 class comprises the winding the thin slab from the finish rolling temperature of the hot rolling, and 550 ~ 700 ℃ more than 860 ℃ conditions and to a method of manufacturing a hot rolled steel sheet by the technique minimil base.