Ensuring the quality control of plug bricks is a key link in producing high-quality refractories. The following are the main methods and steps of plug brick quality control based on the search results:

I. Quality control of raw materials

Selection of raw materials: The main raw materials of the plug brick include pyrophyllite, graphite, high-purity carbon powder, etc., and the binder usually uses resin with solid content > 70%. The quality of these raw materials directly affects the performance of plug bricks, so the purity, particle size and performance of raw materials must be strictly controlled.

Chemical composition analysis: analyze the chemical composition of raw materials to ensure that they meet the production standards.

II. Quality control in the production process

Molding technology: Adopting proper molding technology, such as pressing and demoulding, can eliminate internal cracks and improve the quality of brick.

Drying control: the residual moisture of the brick should be strictly controlled during the drying process. For example, the residual moisture of clay products should be controlled below 2%.

Sintering process: the heating rate, holding time and the atmosphere in the kiln should be strictly controlled during the sintering process. For example, carbon-containing products need to be fired in a reducing atmosphere that is isolated from air.

III. Testing of finished products

Visual inspection: visually observe whether there are cracks, deformation or other defects on the surface of the plug brick.

Size measurement: Use calipers, vernier calipers and other tools to measure the size of the plug brick to ensure that it meets the design requirements.

Performance testing:

Fire resistance and load softening temperature: Check the fire resistance and load softening temperature of the plug brick to ensure its stable performance in high temperature environment.

Thermal shock stability: through thermal shock stability test, it is ensured that the plug brick will not break when the temperature changes sharply.

Corrosion resistance: check the slag resistance and oxidation resistance of the plug brick to ensure that it remains stable under the erosion of molten steel.

IV. Quality control standards

Sampling inspection: Conduct sampling inspection according to national standard GB/T10325—2012 or international standard ISO5022:1979 to ensure the reasonable sample size.

Defect control: Strictly control the defects such as edge loss, corner loss and cracks, and the products beyond the standard range should be inspected or treated again.

V. Packaging and transportation

Packaging: use pallet packaging, fix it with PET packing tape, and cover it with plastic film to prevent damage during transportation.

Transportation: Make sure to handle with care during transportation to avoid damage caused by improper operation.

VI. Quality Records and Traceability

Quality certificate: provide quality guarantee, theoretical indicators and test methods of ex-factory products to ensure that users can trace the product quality.

Construction guidance: provide construction instructions to help users use plug bricks correctly and avoid quality problems caused by improper use.

Through the above methods, the quality of plug bricks can be effectively ensured and the strict requirements of steelmaking process can be met.