The Study Of Formation Mechanism Of Mixed Grain Structure In ML08Al Wire

Hot rolling is an important means of production of wire products. In the process of hot rolling, the rolled piece has experienced a complicated process of deformation and the heat transformation, the formation and evolution of structure property is closely related to the quality of continuous casting slab, various parameters in the rolling process such as deformation degree, deformation velocity, convection between contact friction and the external environment, conduction and radiation can also have an important impact on it. Mixed grain structure is a very common defect in the steel material. With the increasing of the people’s requirements on organization and mechanical properties of steel material, the study of the distribution, formation mechanism of mixed grain structure and its effects on organization and mechanical properties of steel, is more and more important.This topic is finished the research of experiment and simulation for high speed wire rod products of mix crystal group questions. A lot of forefathers’researches have made low carbon steel in dynamic recrystallization of hot deformation process, the dynamic recrystallization, static recrystallization and grain growth model. In this paper, all of the recrystallization simulation of the rolling process is summarized from the literature. According to the experimental analysis, regularities of distribution are obtained the ML08A1wire rod products mixed crystal organization, and simulation of rolling process, the evolution regularities are obtained, the ML08A1Φ6.5wire size in the process of pre-finishing and finishing, the temperature of finishing rolling piece from the surface to the heart, the deformation process, grain structure evolution law. The causes of the formation of mixed crystal organization have made the explanation. The main conclusions of this paper are as following:(1) Mixed crystal factor is represented the degree of mixed crystal organization in ML08A1. Mixed crystal factor of Φ6.5sample size is2.97. Mixed crystal factor of Φ10sample size is2.27. Mixed crystal factor of Φ14sample size is2.04. Mixed crystal factor of Φ16sample size is1.91.(2) Mixed crystal has effect on the reduction of area of ML08Al. There is a little influence when mixed crystal factor between1and2; There is mutation phenomenon when mixed crystal factor is near2; When mixed crystal factor is greater than2, the area performance is dropped rapidly with the increasing of mixed crystal factor. (3) The results of grain organization simulation on rolling process of φ6.5wire show that：the heart grain and diagonal grain of rolled pieces have priority of refinement; the uneven grain size and uneven distribution on workpiece surface cause the formation of mixed crystal.(4) Increasing water beforehand cooling intensity is beneficial to inhibit the grain growth; high finishing temperature causes mixed crystal formation and aggravation in ML08Al wire.