Based On The Slab Ring Hot Ring Rolling Process Numerical Simulation

As an advanced manufacturing technology, ring rolling process is widely used to product seamless circular part in aerospace, trains, energy and other high-tech fields. However, the traditional process of hot ring rolling concludes smelting steel, casting ingot, heating, cogging, heating, upsetting and piercing, hot ring rolling. The process is too lengthy. The materials and energy are wasted due to the several times heating. A new process to produce ring parts is proposed in this paper. The annular casting blank without forging is used directly to hot ring rolling. Compared to traditional process, the new process has many merits such as saving materials, reducing energy consumption, improveing productivity and economic benefits, and has a very good development and application prospects. Theoretical analysis, numerical simulation and experimental study were adopted to research the technology of the hot ring rolling on the casting blank. The main research contents and conclusions of this paper are as follows:The rolling forming condition, movement condition, processing parameters and key problems of hot rolling process on the annular casting blank were analyzed. The selection basis was determined and the limit ranges of rolling process parameters were obtained. Choosing the properly process parameters during the hot ring rolling, the as-cast microstructure grain can be refined and the mechanical properties of the ring parts can be improved.Coupled thermo-mechanical model and microstructure evolution model of as-cast 42CrMo steel for hot rolling process of annular casting blank were established. The new process were simulated on the DEFORM software. It was found that the equivalent strain and microstructure evolution were zonal distribution. The grain was refined obviously in outer and inner layer due to the large equivalent strain. The bulky grain existed in the middle layer of ring part due to the small equivalent strain. The influence of different feed rate and initialization temperature on rolling deformation and microstructure evolution was analyzed. The results show that the feed speed of the idle roll may be variable. Speeding up properly feed rate of the idle roll at the stable rolling stage, the deformation would be more uniform, the grain refinement would be better, and quality of ring and production efficiency would be improved. With improving of the initialization temperature, deformation of ring would be more uniform, and radial rolling force would be reduced, but when temperature exceed 1150℃, grain size grew up sharply.The hot ring rolling experiment of annular casting blank were performed on the D53K-4000 ring rolling machine. The distribution of radial rolling force and microstructure of ring were obtained. The experimental results was well agreement with simulation ones. The size precision, strength, toughness and hardness of ring parts achieved the standard of forging.The study can provide theoretical guide for the optimization of process parameters, the predication and control of product quality during hot rolling process of annular casting blank. Moreover, it will lay foundation for the development of casting-rolling compound forming process.