Study On The Simulation On Forming Mechanism Of Three-Cross Wedg Rolling

Cross wedge rolling is a highly efficient technology to produce shaft parts plastic, is the metallurgical rolling machine forging technology, a combination of new technology developed. But due to the complex principle of its forming, internal cracks often occur in the products, this phenomenon is called Mannesmann effect. This defect is an important barrier which Constraints the development of cross wedge rolling process. For this reason, this article does research on forming mechanism of three-roll cross wedge rolling, and it is of far reaching importance to theoretical significance and practical application value.In order to settle the problem of wall unevenness, bad gyratory condition and rolling instability during hollow work piece forming process. In this paper, the numerical simulation on the wholly rolling process of three-cross wedge rolling has been finished, by using finite element method DEFORM. Different kinds of influencing factors of draught pressure have been overall and systematically lucubrated, by utilizing orthogonal experiment. Besides, the article analyzes the effect of inner diameter to the radial strain of rolling wall. It is important reference value to the rolling of hollow shaft parts.People had made a great deal of studies in this defect, they generally believe that Mannesmann effect is due to alternating shear stress and tensile stress effects of rolling central part. This paper studies stress and strain field distribution of the solid parts, hollow parts and parts with a hollow mandrel. It offers theoretical principle for realizing and researching the Mannesmann effect of the three-roll cross wedge rolling is made.Based on the before investigative substructure, this paper finds out the location of weakness by using the method of equivalent strain gradient, and uses radial strain gradient method to describe the formation process of weakness, and finds out that alternating stress and strain are the important causes to the ring weakness at work piece's centre. Different kinds of rolling parameters of solid shaft parts weakness have been analyzed, by utilizing equivalent strain gradient method. It proved that adopting a reasonable internal diameter of the hollow rolling can effectively reduce the weakness damage on the rolling.This paper makes a practical hot rolling process and tests rolling force on the DS200 three-roll cross wedge rolling mill. Meanwhile, this paper observes the position of rolling weakness occurred. At last, by comparing with the simulation result and the experiment, it finds that get substantial agreement.