注入時における下注用各煉瓦の破壊原因について : 造塊用粘土質耐火物に関する研究(第1報)

概要

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Studies on the main cause of fracture of various bricks for bottom casting pit and the physical-mechanical load taking place at the time of teeming of molten steel have been carried out.The distribution of internal stress in hollow circular cylinder bodies of various bricks due to the pressure of molten steel was calculated. Comparing the internal stress with the mechanical strength it was confirmed that the pressure of molten steel is not the immediate cause of the fracture of bricks. And, on the basis of above results, the economic lower limit of wall thickness of the bricks for standing the pressure of molten steel has been worked out.Then, an analysis of temperature gradient and thermal stress developing in a brick due to the rapid heating by molten steel at the time of teeming was carried out, and it was made clear that the immediate cause of fracture is the thermal stress.It was found by dimensional analysis that the factor f in the thermal stress equation is the number of dimensionless products, and that its factor is expressed byf=c(r/K1/2⋅ρ-1/2⋅Cp-1/2) or f=c′(rh/K)a′.The effect of pyroplastic property, which fire clay bricks show at higher temperatures, on the distribution of thermal stress was estimated. And the author was able to elucidate the importance of the pyroplastic property for taking the preventive measure of the fracture of fire clay bricks.
社団法人日本セラミックス協会の論文
1960-11-01