作者：SHUICHI KINOSHITA;

作者单位：AGC Ceramics Co., Ltd.5-6-1, Umei, Takasago-shi, Hyogo 676-8655

刊名：Journal of the Technical Association of Refractories

ISSN：0285-0028

出版年：2008-01-05

卷：28

期：2

起页：113

止页：119

分类号：TQ175

语种：英文

关键词：

内容简介

In order to lighten the workload of measuring the working time for castable refractory material, an investigation on the design of an apparatus for measuring the working time and its automation was executed and, as a practical matter, the apparatus was fabricated and its utility was verified. It was shown that the stroke length obtained by the apparatus was located at a higher value or in the vicinity of the forward limit of the machine at the beginning stage of the measurement, but with time after repeated measurements it decreased rapidly and reached a fixed minimum value. Comparing the flow value and the hand feeling measurement methods, it was clarified that the working time obtained from these methods was just a little later than the beginning in the fall of the stroke length from the maximum value or during the period of the decrease of the stroke length. Next, a comparison of this method with the setting test method was done using alumina cement as the specimen in order to verify the utility of this apparatus to detect accurately the drop in fluidity of the mixture. It was shown that the starting point and the finishing point of the setting were clearly observed during the fall in the stroke length. In the vicinity of the setting finishing point an exothermal reaction was starting and the stroke length reached the minimum value in the vicinity where the temperature reached a maximum. Judging from the phenomena mentioned above, it was possible to say that this method was able to reveal the situation of lowering the mixture fluidity in an appropriate manner and it was possible to quantify the working time by establishing the "threshold value" of the stroke length change (percent) for each kind of castable refractory. As another advantage it is possible to say that this method was effective in a small raw material specimen volume for a rapid measurement and for materials exhibiting working times of more than a few hours. Further automation of the system could be easily realized. Consequently it is possible to say this is an effective apparatus for measuring the working time of castable refractories.