硅溶胶-煤矸石型壳高温性能及机理分析  

High temperature properties of silica sol-gangue shell and its mechanism analysis

作　　者：郭馨[1] 吕志刚[1] 李晓飞[1] 

机构地区：[1]清华大学机械工程系先进成形制造教育部重点实验室,北京100084

出　　处：《中南大学学报（自然科学版）》2013年第11期4442-4447,共6页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(50875144)

摘　　要：采用高温抗折仪、高温卧式膨胀仪、扫描电镜、X线荧光仪和X线衍射仪等研究高温下型壳强度、热膨胀性能的变化规律和高温断口的形貌特征。研究结果表明:在950～1 150℃时,型壳强度基本稳定,线膨胀率缓慢下降;在1 150～1 350℃时,型壳强度随温度升高而增加,线膨胀率在1 200℃附近基本不变,随后迅速减小;在1 350～1 450℃时,型壳高温强度迅速减小,残留强度显著增加,线膨胀率直线下降。不同温度条件下,型壳材料物相成分相同,但相对含量存在差异。在1 350℃附近,型壳迅速软化变形,可见硅溶胶煤矸石型壳不适宜长时间处于1 350℃以上高温环境。原材料中的碱性元素在高温下生成低共熔点玻璃相,降低型壳软化温度,应严格控制氧化物杂质的含量。The strength, thermal expansion and the surface morphology of the silica-gangue shell under high temperature condition were studied by hot strength device, horizontal thermal expansion device （TED）, scanning electron microscopy （SEM）, X-ray fluorescence （XRF） and X-ray diffraction （XRD）. The results show that from 950℃ to 1 150 ℃, the strength of the shell keeps constant, while the linear expansion percentage （LEP） decreases; from 1 150 to 1 350℃, the strength increases, LEP stays the same at around 1 200℃, then decreases quickly; from 1 350℃ to 1 450℃, the hot strength decreases rapidly and the residual strength increases significantly, while LEP decreases dramatically. By the phase analysis it is proved that there are no new phases formed during heating, but the content of each phase varies. Calcination temperature over 1 350 ℃, the shell begins to soften, so it does not fit to work over 1 350 ℃ for a long time To avoid the shell softening at lower temperature, it is necessary to control the percentage of alkaline oxide impurities which may produce low viscosity and low melting point substance in refractory cast material.

关 键 词：熔模铸造 型壳 强度 热膨胀 微观结构 

分 类 号：TG249.5[机械工程—精密仪器及机械]