浇注料在不同加热过程中的弹性模量变化

Young's modulus variation of castables with heating process

为了研究浇注料烘烤过程中其内部状态变化与其弹性模量变化的相关性，将纯铝酸钙水泥结合的刚玉质浇注料振动成型，自然养护24 h后脱模，部分脱模后试样继续在烘箱中于110℃干燥48 h，部分干燥后试样继续在500℃热处理3 h，采用弯曲共振法检测试样在不同加热过程中的弹性模量变化：1）对脱模后试样，以5℃·min－1的速率升温，并在50℃及其整数倍温度点保温60～90 min，检测试样在加热过程中的弹性模量变化；2）对干燥后试样，以5℃·min－1的速率连续升温至500℃，检测试样在加热过程中的弹性模量变化；3）对500℃热处理后试样，以15℃·min－1的速率连续升温至500℃后保温35 min，检测试样在保温过程中的弹性模量变化。结果表明：1）自由水的排出使试样的弹性模量增大，结合水的排出则使其弹性模量减小；2）在连续升温的加热过程中，自由水和结合水的排出滞后于设置保温的加热过程，试样弹性模量的变化也出现相应的滞后现象；3）快速连续升温过程中试样内部存在热应力，温度和热应力的存在会影响试样的弹性模量；4）浇注料烘烤过程中弹性模量的变化可综合反映其内部状态变化尤其是水分排出情况的变化。

Calcium aluminate cement bonded corundum castable specimens were prepared by vibration molding in order to research the relativity between internal state and Young’s modulus.After natural curing for 24 h and demolding,some specimens were dried at 110 ℃ for 48 h in the oven,and other specimens were heated at 500 ℃ for 3 h.Through bending resonance method,Young’s modulus variation was re-searched during different heating processes：1）for demolded specimens,heat at 5 ℃·min -1 and hold for 60-90 min at the temperatures of 50 ℃integer times,and test Young’s modulus variation during heating;2）for dried specimens,heat to 500 ℃at 5 ℃·min -1,and research Young’s modulus variation during con-tinuous heating;3）for specimens after heating at 500 ℃,heat to 500 ℃ at 15 ℃·min -1 and then hold for 35 min,and test Young’s modulus variation during holding process.The results indicate that：1）the remov-al of free water can increase Young’s modulus,but the release of hydrate water can reduce Young’s mod-ulus;2）the removal of free water and hydrate water during continuous heating lags behind the heating process containing holding,Young’s modulus variation also lags;3）thermal stress exists in the specimens during continuous rapid heating,the existence of temperature and thermal stress can influence Young’s modulus;4）Young’s modulus can well reflect the internal changes of castables during heating,especially the behavior in the dehydration process.