Research on the influence of the strip tension on contact stress and cold rolling force with a strain-hardening

K Ilin,G Baranov

doi:10.1088/1757-899x/966/1/012026

Abstract

The influence of strip tension on contact stress and cold rolling force with strain-hardening has been investigated by using a numerical method. Dependences between roll pressure and strip tension for one rolling case have been studied. A comparison of the results provided by an introduced method to the already known methods allowed measurements of inaccuracy when the arc of contact has been replaced by chord and whenthe yield strength value for each step has been replaced by the average value of yield strength. Approaching to the real shape of the deformation zone and step-by-step calculations of strain-hardening increases magnitudes of average normal stress and rolling force. The highest difference between obtained results in comparison with the introduced method and already known methods reaches the largest value in the case with intensely hardening steels without strip tension. The increase of strip tension shows less difference between methods. The introduced method lets to calculate the rolling force for different metals depending on strip tension with more precision. Obtained results of the numerical analysis of the influence strip tension on the average normal stress and rolling force were summarized in the form of functions convenient for engineering calculations, with inaccuracy less than 5%.

Highlights

Strip tension one of the important factors defining energy intensity, rolling force and contact stresses during cold strip rolling
According to the method proposed by A Tselikov [1] for computing contacts stresses, the arc of contact replaced by chord and start strip tensions are taken into account via coefficients ξi: for backward slip zone: pA
When average normal stress is defined by equations (1)–(3) and (5)–(6), and metal hardening has been taken into account via the average value of pure shear stress and the arc of contact replaced by chord, which may lead to imprecision [10]

Summary

Introduction

Strip tension one of the important factors defining energy intensity, rolling force and contact stresses during cold strip rolling. When average normal stress is defined by equations (1)–(3) and (5)–(6), and metal hardening has been taken into account via the average value of pure shear stress and the arc of contact replaced by chord, which may lead to imprecision [10]. Determination of dependency of rolling pressure from strip tension, estimating imprecision from replacing arc of contact by chord and equivalent yield stress by average yield stress. In this method arc of contact was replaced by a lot of numbers of small chords, while mechanic characteristics of metal in these spaces were set up as average value.

Cos α γ i

Findings

Conclusions