Research And Application Of Direct Calculation Method For High-Strength Square Pipe Cold Rolling Process

Square pipe is widely used in ocean engineering, which is usually adopted cold rolling technology in practical production process. A crack generates at the inner side of the corner position of the square pipe during its cold rolling production process. The direct computing method for high-strength steel square pipe cold rolling process is explored in order to build the direct computing model. On the basis of the model, the reason why a crack generates at the inner side of the corner position of the square pipe while the outer side of the corner position is secure is found. At last, influences of the cold roll process factors to the crack generation are discussed in order to put forward the comprehensive improvement cold rolling process measures.The explicit or standard method selection, mesh density confirmation and contact handle are discussed when determining the numerical model of the direct computing method for high-strength steel square pipe cold rolling process. A two-dimensional computing model and standard method are selected when considering the instability of the three-dimensional computing model, stimulating the spring back phenomenon, detail analysis of the corner and computational cost. According to former discussion of the algorithm, the direct computing model of the direct computing method for high-strength steel square pipe cold rolling process is built.This paper firstly proposes a simple criterion for the crack generation, namely judging whether a critical point generates a crack through combining the both aspects of the stress condition and Levy—Mises material flow rule. At the basis of succeeding in completing the numerical stimulation of the full passes of the square pipe cold forming, a precisely good meet between the theory explanation for the reason of crack generation through the criterion and real crack phenomenon during the factory production is obtained.The hypothesis that production factors are independent of each other is adopted when discussing the influences of the cold roll process factors to the crack generation. Each production factor is deeply explored for finding the optimum sub factor. Comprehensive optimization production process is obtained through combining the optimum sub factors at the basis of overall coordination.