A Study on Potential Strip Shape Control of High‐Strength Steel during Hot Pinch Rolling Process

Abstract

Hot‐rolled high‐strength steel (HSS) strips always present side‐camber after they are cut into subsections along the rolling direction. To deal with the potential strip shape defect of hot‐rolled HSS, the nonlinear finite element (FE) software is applied to establish a 3D model of pinch roll and strips to simulate the pinch rolling process before the hot rolling coiler. The effects of temperature distribution, roll wear, friction coefficient, initial strip flatness defects, and tension on the strip longitudinal extension distribution are studied along the width direction. The results indicate that the pinch roll wear presents a great influence on both the tendency and quantitative value of the strip longitudinal extension distribution. The maximum unevenness value is 178%, and the maximum differences of longitudinal strain between the center and edge of the strips reach to 51.43%. A newly pinch roll contour is proposed to improve the potential strip shape defects. After the industrial application, the average pinch roll wear thickness decreases from 180 to 120 μm. The hot rolled strips are cut into substrips and the maximum side‐camber value decreases from 12 to 3 mm, which meets the requirement from the auto part manufacturers.

Experimental Investigation on the Inhomogeneities of Transverse Microstructure and Internal Stress of High‐Strength Low‐Alloy Hot‐Rolled Strip

“…Equation ( 4) describes the variation of thermal strain with temperature. For the convenience of calculation in this study, Equation ( 4) was rewritten as a formula for the variation of thermal strain with time, which is shown in Equation (5).…”

“…[3] Further, it leads to the inhomogeneities in mechanical properties and deteriorates the plate shape, which affects the direct use of the steel plate and the subsequent processing. [4][5][6][7] The problems of low-alloy high-strength hotrolled strips caused by inhomogeneous cooling are more serious than those of conventional strips. [8] Han et al developed a numerical model considering deformation, temperature, and transformation behavior in both thickness and width direction of the strip in the cooling process.…”

“…[ 3 ] Further, it leads to the inhomogeneities in mechanical properties and deteriorates the plate shape, which affects the direct use of the steel plate and the subsequent processing. [ 4–7 ] The problems of low‐alloy high‐strength hot‐rolled strips caused by inhomogeneous cooling are more serious than those of conventional strips. [ 8 ]…”