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cracks of magnesia brick

qua, 10/14/2015 - 07:14 — sunriserefractory

No matter what kind of magnesia brick, different degrees of crack will be produced in the drying process. There are two types of cracks of magnesia brick, one is mechanical crack, and another is non mechanical crack.

Under normal circumstances, the direction and location characteristics of mechanical crack are obvious, intuitive, crack longer and clearly visible. Mechanical cracking is because the body is subject to the impact of a collision, vibration caused by pressing. Mechanical crack is caused by the impact of the body and the vibration caused by the press.

Non mechanical crack, the form of its expression is varied, generally speaking, the direction is not so obvious. But quite a lot of time, non mechanical crack, the location of the crack is also more regular; therefore, it can not be simply considered that as long as the obvious direction is mechanical cracking. In many times, mechanical crack and non mechanical crack are easily confused and easy to make people wrongly judgment and cause significant losses, so this must be paid the special attention to the problem.

The basic reason for billet cracking during drying process of magnesia brick is as below,

1. There is no full understanding of the characteristics of the three stages which are equilibrium temperature, low temperature and high temperature during the drying process, and the requirements of drying technology.

2. Hot air supply is short and Body can not be fully dry

3. The drying temperature curve is not reasonable which could not meet the requirements of the temperature curve of the billet during the drying process.

4. Wet control is not good, and the temperature of each section is not reasonable in the drying kiln which is failed to meet the requirements of the temperature of the body drying temperature.

5. Hot air and wet air is not uniform which cause temperature difference in dry kiln and thermal shocks in some place, so the thermal stress caused by this way can cause the body to break and cause the billet crack.