Process Of Forming Isostatic Graphite And So On

Isostatic graphite materials with high strength, high density, high purity and isotropic, widely used in metallurgical, chemical, aerospace, electronic, mechanical, nuclear power and other industrial fields. Especially the large size, high quality, high purity graphite as alternative material, in the field of high-tech, new technology has a broad application space, and has wide application prospects, has been hailed as the21st century the most promising materials. This article mainly aims at the research of graphite molding process, the molding process conditions of cold/hot isostatic pressing that they are main influence factors, and test and analysis the compacts under different conditions.In this study, petroleum coke (or calcined petroleum coke) as aggregate, coal tar pitch as binder and impregnating agents, isostatic pressing process can be prepared compacts for the production of high purity graphite. The aggregate and coal tar pitch after purified, kneaded, flaked and crushed, we can get the press powder that we need. The way of filling are mechanical vibrating and hand tamping, the press powder material need vacuum before putting into the cylinder. Pressed powder after the cold isostatic pressing molding, explored the optimum process parameters:pressure is300MPa, the holding time is10min, pressure rise rate and the pressure release speed is1MPa/s, the aspect ratio of bag is36:5. The green body made by petroleum coke, its bulk density and apparent porosity are1.327g/cm3and9.94%; The green body made by calcined petroleum coke, its bulk density, apparent porosity and compressive strength are1.475g/cm3,9.04%and5.9368N/mm2.For the hot isostatic pressing, we mainly do the hot isostatic pressing roasting and hot isostatic pressing impregnating-roasting experiment. Through the experiment to explore, we can get the hot isostatic pressing roasting process conditions:a temperature of1000℃, the initial pressure of30MPa, the heat preservation and pressure maintaining time are5h, the tapping temperature of100℃or less; Hot isostatic pressing impregnating-roasting process conditions:temperature900℃, the initial pressure of35MPa, heat preservation and pressure maintaining time are5h, tapping temperature of100℃or less. And compared the experimental results with the atmospheric atmosphere impregnating-roasting products, The bulk density, apparent porosity and compressive strength of the isostatic pressing roasting compacts are1.57g/cm3,17.6%and82.5151N/mm2, the hot isostatic pressing impregnating-roasting compacts1.656g/cm3,12%and108.6250N/mm2, the atmospheric atmosphere impregnating-roasting products are1.74g/cm3,9%and192N/mm2. Consider the product performance and process cycle, the hot isostatic pressing impregnation-roasting process is excellent.