Smelting method for low-silicon ultralow-sulphur steel

A smelting method for a low-silicon ultralow-sulphur steel belongs to the metallurgy technical field. The smelting process for producing low-silicon ultralow-sulphur steel comprises: molten iron 'complete-three-removal' pretreatment, decarburization converter smelting, and LF refining process. In order to ensure that silicon increase in molten steel during deep desulphurization is prevented, the sulphur content in molten steel for refining pull-in is firstly decreased by KR molten iron desulphurization pretreatment, and the pressure for LF deep desulphurization is reduced; then the silicon content in molten iron in a decarburization converter is decreased by desilication pretreatment in a dephosphorization converter to ensure the alkalinity of the slag in the decarburization converter is more than 4.0. The advantages are that the problem of the easy increase of silicon during the LF refining desulphurization process in the prior art is solved; the refining time is shortened; and the production efficiency is improved.