Model for predicting resilience of bar subjected to two roll straightening

Abstract

The invention relates to a method for predicting resilience of a bar subjected to two roll straightening, and belongs to the technical field of two-roll straightening machines. The method comprises the followings steps: firstly, determining the offset of a stress neutral layer when the rod is subjected to straightening; then, determining a deformation-hardening coefficient and tension-compression stress distribution according to different straightening processes and deformation characteristics of rods in different specifications; finally, determining the model for predicting rebound bending moment and straightening rebound deflection by combining a pure bending and rebound theory, wherein the rebound deflection delta is related to the following variables of R, sigma<t>, lambda, xi, psi, kappa, I, E, L, B, n, R0, Rw, P and tau; R represents a rod radius; sigma<t> represents the yield limit; lambda represents a hardening coefficient; xi represents an elastic region ratio; psi represents a neutral layer offset radius ratio; k represents an anti-bend rate; I represents rod section moment of inertia; E represents modulus of elasticity; L represents the distance between the two end points in three-point bending; B represents a plastic coefficient; n represents a hardening index; R0 represents an initial bending radius; Rw represents an anti-bend radius; P represents straightening force; tau represents a correction coefficient. According to the method, a straightening and deformation process can be truly reflected, and the straightening theory can be perfected; resilience in the straightening process can be accurately predicted, and bases for the roll shape design and process parameter establishment are provided.

Description

technical field [0001] The invention belongs to the technical field of two-roller straightening machines, and in particular relates to a method for establishing a springback prediction model for bar two-roller straightening and an accurate calculation method for the springback amount. Background technique [0002] With the rapid development of society and the domestic machinery industry, the demand and quality requirements for high-strength alloy steel bars are increasing day by day, among which the straightness requirement reaches 1mm / m, or even less than 0.5mm / m, otherwise the removal of materials in subsequent processing The amount is very large, the loss is serious, and the cost increases sharply. Therefore, the requirements for the straightness of the bar after straightening are very strict. Two-roll straightening, as the last process of bar finishing, is the key technology to ensure the straightness index of bar after straightening. At the same time, two-roll straighte...

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Problems solved by technology

At the same time, the neutral layer will shift to the compression side during the straightening process, which w

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