Analysis Of Forming Quality And Impact Abrasive Wear Properties On Extruded Parts Of Hypereutectic High Chromium Cast Iron

The hypereutectic high chromium cast iron was extruded by flat punch mold, cone-shaped punch mold and cone-shaped punch pressure forming mold to semi-solid extrusion forming. Analysis the relationship between the structure of the mold, extrusion process forming and pieces of macro-quality, microstructure, the impact abrasive wear properties. And studied the relationship between the microstructure of semi-solid extrusion sample and its impact abrasive wear properties.The extrusion pressure, extrusion temperature and pressure time of the extruded parts are similar. The surface quality of the flat punch mold extruded parts is poor, dispersed shrinkage, shrinkage cavity and crack defects. The shape of proeutectic carbide was thick. The abrasive wear properties of the extrusion parts was the worst. The surface quality of cone-shaped punch mold extruded parts was more smooth, eliminated cracks, but there still had some shrinkage and shrinkage cavity defects. The shape of proeutectic carbide, the microstructure uniformity and the abrasive wear properties have improved. The surface quality of cone-shaped punch pressure forming mold extruded parts was the best. The shape of its proeutectic carbide is small and smooth. The microstructure uniformity and the impact abrasive wear properties of the extruded parts was the best.For cone-shaped punch pressure forming mold semi-solid thixo-extrusion forming parts, when the extrusion temperature increasing, the surface of the parts appeared flash and cold shut defects. The macro-morphology of the extruded parts got worse and appeared shrinkage and shrinkage cavity defects. Meanwhile the microstructure uniformity of the extruded parts got worse. The wear surface was more and more rough. Impact abrasive wear properties of the extruded parts got worse. When the extrusion temperature is the same, the microstructure uniformity and the impact abrasive wear properties of edge sample was better than central sample.For the cast thixo-extrusion forming parts, when the extrusion temperature was 1300℃, the surface quality of the extruded parts was better. The microstructure uniformity and the abrasive wear properties was better. When the extrusion temperature rised to 1320℃, the surface quality of the extruded parts was poor and the number of shrinkage and shrinkage cavity defects increased. The microstructure uniformity and the impact abrasive wear properties of the extruded parts was getting worse. Above all,the quality of thixo-extrusion forming parts wad far less than that of semi-solid thixo-extrusion forming parts.