Study On Roll Shape And Installation Angle For Two-roller Bar Straightener

Steel industry is a major industry of countries. In recent years, with the developmentof economy and the improvement of science and technology, people on the quality of steelproducts have become increasingly demanding. Finishing is an important step to improvethe quality of productions. Since many kinds of reasons, in the processes of heating rolling,colling, heat treatment and transportation, bars may have some defaults such as bend ofmulti-directions.In order to eliminate the defects and improve the mechanical properties ofbar, bars need the straightening machine for straightening. The two roller straighteningmachine has the unique advantage in the straightening process, which can straighten therod ends with the high precision and good quality.Along with the increase of the straightening device cost, how to improve the generaluse of straightening device, so that the same straightening machine can straighten differentspecification of the steel is a problem to be resolved. In the actual production process, theroll-shaped curve of two roller straightening machine is determined by a certain bardiameter and the size of the installation angle. When the straightening bars diameterchanging, the contaction between the straightening roller and the bar will change.This willaffect the bar straightening effect，usually by adjusting the installation angle of the ways toimprove the conditions of exposure of straightening roller and bar to raise the barstraightening quality.This paper bases on elastic-plastic bending theotry and uses the vector analysismethod to calculate the roll-spaced. When calculating the roll-spaced, rod diameter andinstallation angle values are certain. On the assumption of the full contact, calculate thelength of contact line. When the bar diameter changing, get the minimum averagedifference from bar and straightening roller space contact point coordinates with Lagrangenumder miltiplication to deduce the installation angle modulation principle.Built3D elastic-plastic fem model of the straightening process, simulate the wholeprocess of two-roll straightening dynamically by LS-DYNA. When the bar diameterbecomes large,adjusting the straightening roller installation angle,bar straighten process issimulated to verify the rationality and deficiency of the installation angle adjustment. The characteristics of stress and strain distribution duringthe two-roll straightening areobtained by the finite element analysis; analyzed the distribution of residual stress andstraightening precision.Study on the effect of installation angle on straightening quality, itprovides a theoretical basis for practical production process of two-roller straightenerinstallation angle adjustment.