Research On Hot Pressure Molding Process Of PI/45Steel Composite Material

Polyimide (PI) as a raw material for construction of high performance engineering,can withstand the high and low temperature performance wear resistance, corrosionresistance and self lubrication properties. But pure PI is too brittle to bear large loads andother defects. Composite material manufactured by metal materials combined with PI, caneffectively improve the mechanical properties, machinery parts and components made ofcomposite material can replace the traditional metal parts. But because composite materialpreparation process is complex, few researches are reported at present.At first, the paper takes PI as raw material to analyze its molding methods andcomposite material preparation methods. Through lots of experiments, a systematic studycompares with the impact of cold pressing sintering method and vacuum heat moldingmethod on the effect of PI molding. Then the tensile strength and bending strength of thespecimens made of different processing parameters are compared and analyzed byorthogonal experiment, on the basis of the optimal molding method the optimal PImolding parameters are obtained. Finally, using different methods combine PI with45steel, the fatigue strength and shear strength of the composite materials made of differentcombination methods are tested, composite materials before and after combing surfaceseparation are observed with microscope and scanning electron microscope and theircombing mechanism are analyzed.The results show that the vacuum heat molding method is suitable for PI molding, theoptimal molding parameters, and the holding time, and molding temperature are theimportant molding process parameters. The influence degree of various factors on the PIdensity after molding is as follow molded load> molding temperature> holding time. Theinfluence degree of various factors on the PI bending strength after molding is as followmolding temperature> molded load>holding time. The influence degree of variousfactors on the PI tensile strength after molding is as follow molding temperature> holdingtime> molded load. For preparation of PI/45steel laminated gradient composite materials,the best method is the combination of PI and45steel by adding copper medium. Both the fatigue strength and the shear strength are superior to rough treatment specimen, withspecimen notch and processing drilling specimen respectively.