Study On The Pelletizing Process And Wear Mechanism For The Key Components Of Hoop Standard Granulator

The hoop standard granulator is the main machine to ensure the high-yield and high-quality of grass product. The wideer gap in the pelletizing technology between China and developed countries is,mainly embodied in the short life of key components, the poorer quality of pelletizing, the higher consumption of power and the lower productivity and so on. In this paper, the pelletizing processes of alfalfa particles and the wear and friction mechanisms for the key components of hoop standard granulator were studied, and the some important results were achieved as follows:1. The pelletizing processes of hoop standard granulator and the molding mechanisms of granulated alfalfa were analyzed. Discussed the stress on the work space of material layer and the pelletizing processes of alfalfa particles, the functional relationships were established between the thickness of the material layer and the ring mold corners. Finally, the strain equilibrium equations of differential units were deduced under the normal conditions, and the total forces of ring mold on the material layer were calculated.2. Using the orthogonal rotational combining design, the forming processes were optimized and the best parameter combinations were obtained as following:the extrusion force was4.47KN, the material moisture content was16.96%, the size was5.34mm, and the density of the granulation was1.241g/cm3. On this basis, the microstructure changes and the molding mechanisms of the grass particles were analyzed under different processes parameters.3. The wear rules and mechanisms for45#steel were systematically studied with the Alfalfa powders as the abrasive. The influence of load, speed, grass powder size and moisture content on the steel wear was analyzed. On this basis, the wear tests were conducted under the different conditions of abrasives and metals, and discussed the wear mechanisms of plant abrasives for metal materials.4. Based on the digital image technology, selected the alfalfa powder as a typical abrasive, using the SEM grayscale image of the worn surface on different metal materials, the wear surface characteristics of metal materials were studied according to the fractal and wavelet theory.5.45#steel which was commonly used in ring mold pressure rollers, was acted as the test material and treated by laser transformation hardening.The wear-resistant performances and the mechanisms of45#steel were analyzed under the different parameters of the laser quenching processes, By using the quadratic regression orthogonal rotational combining design, the best laser transformation hardening process parameters were obtained as following:laser power2050W, scanning speed of20mm/s, spot diameter4mm. And it was verified with the experiments.This paper has provided theoretical bases for optimizing the structure of the pellet mill, increasing the pelleting quality and pelleting efficiency by studying the granulation processes and technologies, as well as grass particles forming mechanisms, which has provided the references for the study of anti-friction of the key components of hoop standard granulator and the wear mechanism and wear process of agricultural machines.