Multiroller straightening analytical model of H-beam

Abstract

H-beams are currently the largest output section steel in the world. Straightening is an important finishing step in the manufacturing process and directly determines the ultimate straightness of the beams. To analyse the straightening process, a multiroller straightening analytical model of an H-beam was established and is based on the pure bending springback equation of the symmetrical section curved beam. The purpose of the establishment of the model is to calculate the exit residual deflection by inputting the reduction rules and ultimately get the best reduction rules. In the model, the concept of plastic region ratio is proposed. The larger are the plastic region ratios, the easier are the initial curvatures unified, and the fewer straightening roller systems are required, however the greater is the residual stresses. Another innovation of this paper is the definition of a cosine function to express the relationship between reduction and curvature. The function of curvature, which plays an important role in the analytical model, was developed by a large number of finite element simulation and numerical fittings. The principle of the multiroller straightening process is clearly reflected by the analytical model in the theoretical analysis. By contrast, the theoretical calculation results of the analytical model are consistent with the finite element simulation results and the field data. It is suggested that the multiroller straightening analytical model of an H-beam is a theoretical foundation to optimise the straightener parameters and the reduction rules with higher accuracy.

A novel analytical model for straightening process of rectangle-section metal bars considering asymmetrical hardening features

“…Song and Yu 4 established the predictive model of springback for the T-section rail, as well as the analytical equations of residual curvature, considering the work hardening material model. Yin et al 5 proposed an analytical model of H-beam about the multi-roller straightening process based on pure bending theory to explore the relationship between curvature and residual deflection.…”

A novel control strategy for the multi-step straightening process of long/extra-long linear guideways

“…At present, the main straightening approaches of metal bars are three-point pressure straightening process and roller straightening process. 1 Normally, long and extra-long metal bars with regular cross-section features are straightened by roller straightening machine. 2,3 However, the roller straightening method is not applicable to the metal bars with asymmetrical cross-section features, especially the long and extra-long ones.…”

Analytical Model of a Multi-Step Straightening Process for Linear Guideways Considering Neutral Axis Deviation

“…LG15.5 × 14.5 × 400 Distance between two clamps ( s L 2 /mm) 300 Initial deflection ( δ 0 /mm) 1.581 Most of research on the simulation of straightening processes generally applied concentrated force on the workpiece [8,9,14,16]. However, it is difficult to accurately control the force in the actual straightening process.…”

“…The distribution of residual stress σ c1 can be expressed as Equation (16) according to the springback of bending. In case that the reverse bending may occur after the first step straightening process, the bending direction needs to be detected during the calculation process.…”

“…Baseri et al [15] established a fuzzy learning back-propagation algorithm to predict springback of V-die bending process. Based on the bending springback equation of the symmetrical section curved beam, a multi-roller straightening analytical model of H-beams was developed by Yin et al [16], and Kato et al [17] was mainly focused on the analysis of elasto-plastic theories of round bars and a simple three-point bending model was applied in actual operation. However, all the predictive models were established by simplifying irregular cross-sections as a rectangular shape, and the offset of neutral surface caused by the entire features of parts was also neglected.…”