Mixing Process And Ingredients Of Centrifugal Shs Ceramic Lined Composite Steel Pipe Structure And Properties Of Impact

Firstly the performances such as particle size,density and homoqeneous of thermite reaction raw material mixed bylwin-screw and ball milling mixing procedures were studied.The power particle抯 microstructure was observed by SEM.It shows that mixing procedure effects obviously thermite reaction raw material抯 performances and power particle抯 microstructure. Then the combustion characteristic of thermite green-compact and centrifugal-SI-IS were investigated,and the variety of ceramic in phrases composition and porosity in ceramic-lined pipes were studied too,of which the thermit material was mixed by different methods.Furthermore,the quadric electro-image of ceramic section was inspected with SEM.According to the research,the major factors,which affects the combustion performance,are the structure of the powder particles and the mixing uniformity.There is a corresponding relation between the igniting time and the mixing uniformity .the double helix mixing process makes Fe203 particles grew up solely .and the time of reaction,between them and the Al melt uplaying , is prolonged.Because the Fe203 particles have small external specific surface and the Al melt is relatively insufficient,the reaction cannot be entire,and the FeOAl2O3 phrases were apt to produced,the giving out quantity of heat was reduced ,and the combustion speed was decreased.After ballmilling ,the grown-up particles have a samdwich.the combustion synthesis was seldom affected by the size of particles ,the effective factor was the fine powder ,which blocked the capillary expang of the Al melt ,and prevented Al from contacting with Fe203 particles.In the Al enriching areas,the FeOAl2O3 phrases were produced,and the giving out quantity of heat was decreased.Also,the combustion speed was reduced.The quantity of heat transmitted by gas and the gasfitying quantity were determined by the mixing procedure through affecting the centrifugal SHS combustion process .The more was the heat quantity transmitted by gas ,the more was the gasfitying quantity,and the easier was the ignition of the thermit when the ceramic-lined piples were made by method of centrifugal SHS.However,because the phenomina of re-ignition appeared when the piple was some longer and the mixing time was too long .It was thought that the re-ignition process had some things to do with the quantitive insufficiencyof the heat transmittedby gas and the qasflty. The industrial material of Fe203 was used .A prescription was designed to make ceramic-lined piples.Also,the pressure fracturing and shearing intensity was invovled in the research ,it was the same with the performance of wear and corrupt resistance.The more ideal prescriptions were the 33#,45# and 43# samples.In 42# prescription,the porosity of the ceramic layer was lower,and the quantity of unwanted phrases was small,and the performance of wear and corrupt resistance was excellent.and the pressure Iv It fracturing intensity was high.But ,the shear intensity was some lower.this was the shortage.In 33# and 43# prescriptions,the ceramic layer was compact.but the FeOA12O3 content in phrase composition was higher ,and the performance of wear and corrupt resistance was not so good. In general,the 42# prescription was the most ideal.