In the production process of refractory bricks, quality control is very important. The following are the key points of quality control that should be paid attention to in each production link:

I. Quality control of raw materials

Chemical composition and impurity content: chemical analysis of raw materials entering the factory to ensure that their chemical composition meets the requirements, while strictly controlling the impurity content. For example, alumina content is the key factor affecting the performance of refractory bricks, which must meet the product standards.

Particle size distribution: the particle size distribution of raw materials needs to be strictly controlled to ensure the structural uniformity and strength of refractory bricks. Unqualified particle size distribution may lead to uneven internal structure of brick and affect its performance.

II. Quality control of molding process

Forming pressure and moisture control: the forming pressure and moisture content in the mud must be appropriate to ensure the density and strength of the brick. Insufficient molding pressure may lead to low density and insufficient strength of brick; Too much water may cause cracks during drying and firing.

Dimensional accuracy and appearance quality: the molded brick has high dimensional accuracy and no obvious defects in appearance, such as cracks and deformation. Dimensional tolerance should be strictly controlled, such as height tolerance less than 1% and thickness error of brick head less than 1 mm.

III. Quality control of drying process

Control drying speed and temperature: During the drying process, the drying speed and temperature should be strictly controlled to avoid cracks caused by the rapid discharge of water. The moisture content of dried bricks should be strictly controlled below 2%.

Prevention of deformation and cracking: During the drying process, bricks should be inspected regularly to prevent deformation and cracking caused by uneven drying.

IV. Quality control of sintering process

Temperature and time control: sintering temperature and time are the key factors affecting the performance of refractory bricks. The firing temperature is usually between 1000℃ and 1200℃, so it is necessary to ensure the uniformity and stability of the temperature. Too short firing time may lead to insufficient sintering and insufficient strength of brick.

Atmosphere control: the firing atmosphere also has an important influence on the performance of refractory bricks, so it is necessary to choose appropriate atmosphere conditions according to product requirements.

V. Inspection of finished products

Chemical composition and physical properties inspection: the chemical composition analysis and physical properties test of the finished refractory brick, including refractoriness, load softening temperature, thermal shock resistance, compressive strength, etc.

Appearance and dimension inspection: check the appearance quality of finished bricks, such as cracks, deformation, lack of edges and corners, and strictly control the dimensional accuracy.

VI. Packaging and storage

Packaging quality: ensure that the packaging is firm and prevent damage during transportation.

Storage conditions: the finished product should be stored in a dry and ventilated environment to avoid moisture and pollution.

Through strict quality control, the performance and stability of refractory bricks can be ensured and the use requirements of different industrial furnaces can be met.