Hollow Drill Steel Optimal Pass Design Based On Genetic Algorithm And Experimental Study

With the economic development, the domestic industries are increasingly demandingfor mineral resources and the electrical energy. The demand for various types of rockdrilling tools also shows substantial growth. Thus, the product quality requirements of thedrill steel are heightened accordingly, especially for the small hollow drill steel with hugemarket demand. Because of the harsh working conditions, not only does the rod steelwithstand tension and compression, bending, torsional stress at work, but the core holealso suffers the impact of corrosion caused by high-pressure water, the service life of thehollow drill steel is very short.Improving the quality of hollow steel is very important for extending its servicelife, and developing a reasonable rolling process plays important part in improving thequality. In the hollow steel rolling process, the pros and cons of the pass system design iskey to achieve high-quality hollow steel rolling. With the rapid development of computertechnology, combined with the pass design theory, the finite element method, theexperience of the designers and genetic algorithms, computer-aided pass design andoptimization can be achieved. Therefore, this paper pays attention to the drill steelproduction process, and focuses on the analysis of the rolling process, with the help ofcomputer-aided design and rolling theory, to design and optimize reasonable rolling passprocess parameters to improve the ovality and eccentricity of the hollow steel core holes.This paper is based on the rolling process of the hollow drill steel mechanical drillmethod. Firstly, the finite element software DEFORM-3D is applied to analyze the hollowsteel rolling process. Through the analysis, each pass rolling inhomogeneous deformationprocess is given, and the rolling force of each pass, the temperature field, stress field,equivalent strain field, and the geometry of the rolling, the changes of ovality andeccentricity is obtained. The main factors influencing the ovality and eccentricity of therolled plate core hole are initial blank temperature distribution, pass asymmetric andreduction. The eccentricity should be adjusted on the sixth and seventh lane and theovality should be adjusted on the twenty-first lane in the original pass system. Then, taking ovality and eccentricity as optimization objectives, together with the application oforthogonal experiment, nonlinear regression, genetic algorithms and the finite elementsimulation analysis, the impact of pass asymmetric and reduction on eccentricity, and theimpact of reduction on ovality are analyzed. The optimal parameters of the pass areobtained to ensure product geometry. Finally, taking lead as the experiment material, theexperimental study of the hollow steel asymmetric rolling process is carried out to analyzeand verify the impact of pass asymmetric and reduction on eccentricity, and reduction onovality. The comparison of dimensional accuracy and rolling force between experimentaland finite element simulated results coincide with each other well, which conforms thecorrectness and reliability of the finite element results.