Slab-based Ring Rolling Heat Treatment Process Research

This project derived from the National Natural Science Foundation project"The fundamental theories and key technologies based on the casting-rollingforming"(51075290).Casting-rolling forming technology is an advancedmanufacturing technology which is newly proposed in recent years. Comparedto the traditional ring rolling technology, it has the advantages of short process,energy and materials saving, high efficiency and good benefits, and has a broadapplication prospect. I undertake the content of the project: the coupled fieldsimulation and heat treatment process parameters design in the process of heattreatment before and after forging. The purpose of research on the heattreatment before forging is reducing casting defects, homogenizing the structurecomposition and reducing the deformation resistance, provide the good structurefor the follow-up rolling. The purpose of research on the heat treatment afterforging is improving the comprehensive mechanical properties of workpiece,meeting the requirements.This paper has designed the heat treatment process parameters using theheat treatment empirical formula,the superposition principle of incubationperiod and the least squares method. The numerical simulation of heat treatmentwas carried out based on large-scale nonlinear finite element softwareDeform-3D, and the necessary experiment was done.According to on the actual heat treatment production experience, this paperhad firstly formulated the improving process based on the existing process ofpre-heat treatment and the final heat treatment combined with the compositioncharacteristics of42CrMo steel. Then, using the thermodynamics law,theincremental theory and the elastic-plasticity model, considering the factors suchas nonlinear thermal parameters and the latent heat, the numerical simulation oftemperature field, stress field and structure field was carried out. The results ofsimulation were consistent with the experimental results and proved thesuperiority of the improving process. Final heat treatment process applied to the workpiece of this size was preferred. At last, the rationality of the preferredprocess verified by experiments, the mechanical performance achieved to agood match and met the requirements of the mechanical properties.The study can provide theoretical guide for the heat treatment designbefore and after forging and lay foundation for the development ofcasting-rolling compound forming process.