Refractory castable cracking at high temperature

The top of the annealing furnace using refractory castable is made, oven for four days, to a high temperature during normal use, at high temperature to the top of the tapping hole cracks of about 1 cm, will fall down, and ask the baking time of our four day is enough, in the end, the main reason is where there is a problem. But in the oven when there is crack.
The general method to delay the setting is very simple with 4/10000 white sugar is enough, the general setting in four to five hours, the final setting in six hours or so, because the mixing powder in the casting material is cement, or buy some retarded cement, the mixing powder in the casting material removed without using corrosion cement bought by equivalent volume mix can be. But before you use a small experiment, so that we can grasp the setting time, no waste.

Taurus Refractory ramming mass Factory mainly engaged in professional manufacturer of development, production and sales of the refractory mixture such as melting copper, aluminum and zinc furnace lining. And supply castable refractory for copper smelting, ramming mass for molten copper,fire clay,refractory mortar, refractory cement ,refractory mixture, refractory concrete and silica sand for copper smelting.
Website: http://www.jnrefractory.com  
Contact: Mr. Niu
Tel: +86-371-64372566
Fax: +86-371-64372588
Mobile Phone: +86-15137151612
Email: info@jnrefractory.com
          gyjinniu@163.com
products list : castable refractory cement for up lead copper rod  Molten Zinc Refractory castable     Molten Zinc Ramming Mass     Molten Aluminum Refractory Material      refractory castable for up lead copper rod    Special Refractory Ramming Mass     Copper alloy refractory materials for electric furnace      acidic refractory for electric furnace body   electric furnace refractory material for copper smelting     Corrosion resistance       Molen Zinc Refractory Castable for up lead copper rod    High Strength Refractory Mortar      Refractory mortar installation services Fireclay   Light-weight Castable Refractory    castable Refractory    Accessory Refractory Material   Corrosion resistance Quartz sand    High Grade Composite Silica Ramming Mass    Corundum Plastic Refractory     Alumina Composite Ramming Mass for horizontal continuous castable     Silica Refractory Ramming Mass for horizontal continuou castable    quartz sand refractory for copper smelting     silica sand refractory for core induction furnace      refractory concrete block      pre-cast refractory block      refractory ramming mixture     fire clay for up lead copper rod      refractory mortar for non core induction furnace    refractory cement for copper smelting      high grade composite silica mortar     silica refractory cement     Magnesia refractory cement