Cold-rolling method of steel plate and method of manufacturing steel plate

Abstract

When the steel plate is cold-rolled by a tandem rolling mill that circulates rolling oil, the rolling oil is supplied to the tandem rolling mill in the following manner, that is, the oil film thickness h, the final oil film thickness h, and Work roll roughness R of grade frame N And the work roll roughness R of the previous frame of the final stage N‑1 The numerical value of the following equation (2) is 0.5 or more, in which the roll gap introduction oil film thickness h at the final stage frame is calculated by the following equation (1). In formula (1), A: water separation efficiency (-); Q: rolling oil supply amount per unit area (kg / m 2 ); ρ: oil density (kg / m 3 ); σ: yield stress of material (Pa); Ld: contact arc length (mm); R': flat roller radius (mm); V 1 : Roller speed of the final stage frame (m / sec.); V 2 : Plate speed at the exit side of the final stand (m / sec.); η: Viscosity of rolling oil at 40°C·normal pressure (Pa·s); α: Pressure viscosity coefficient (1 / Pa); β: Temperature Viscosity coefficient (1 / °C); T: oil temperature at the entrance side of the roll gap (°C). In formula (2), R N : Work roll roughness of the final frame (μmRa); R N－1 : Work roll roughness (μmRa) of the previous frame of the final stage.

Description

technical field [0001] The present invention relates to a method for cold rolling steel sheets and a method for manufacturing steel sheets. In particular, it relates to a cold rolling method of a steel sheet suitable for efficiently manufacturing an electrical steel sheet excellent in sheet thickness accuracy, and a method of manufacturing a steel sheet. Background technique [0002] Magnetic steel sheets are used as iron core materials for electrical equipment such as rotary machines. In recent years, from the viewpoint of energy saving of electrical equipment, electrical steel sheets with lower iron loss and higher magnetic flux density have been demanded, and therefore it has become increasingly important to improve the magnetic properties of electrical steel sheets. In addition, electrical steel sheets are usually punched out into a predetermined shape, and then laminated to be used as an iron core. When laminated and used as an iron core, if the plate thickness variat...

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Problems solved by technology

However, in the method described in Patent Document 3, although it is possible to suppress the outflow of products with low plate thickness accuracy caused by chattering to the next process, it is difficult to manufacture products with excellent plate thickness accuracy.

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