The quality of fused-cast zirconium corundum bricks is also related to many factors such as electric fusion process control, body casting process control, mold making process control, annealing process control and processing process control in the entire production process. Therefore, each batch of fused cast zirconium corundum bricks produced by the selected manufacturer must be in accordance with Article 8 of JC493 "Fused Cast Zirconium Corundum Products for Glass Furnace" and "Rules for the Production and Use of Fused Cast Zirconium Corundum Products for Glass Furnace". Article 4 stipulates that before the batch of products are used, the following inspection procedures shall be strictly followed to determine whether the products are qualified and whether they can be used:
(1) When the product leaves the factory, the manufacturer must carry out the factory inspection in accordance with JC493 "Fused and Cast Zirconium Corundum Refractory Products for Glass Furnace". The inspection items include chemical composition, bulk density (bulk density), dimensional deviation and appearance quality. Fused-cast zirconium corundum bricks in contact with molten glass should all undergo bulk density inspection, and products whose bulk density unit is lower than the specified index must be replaced. For the fused cast zirconium corundum bricks in the main parts, the internal quality of the products must be inspected by the inspection of the internal structure of the bricks.
(2) When each batch of fused-cast zirconium corundum products leaves the factory, the user shall conduct quality judgment and inspection according to the sampling method and inspection rules specified in JC493 "Fused-cast Zirconium Corundum Products for Glass Furnace", and shall be inspected by the national-level refractory quality supervision and inspection The unit issues a quality inspection report, and the inspection report is regarded as the only legal basis for determining whether the loaf product is qualified or unqualified in accordance with the delivery contract.
(3) After the product is delivered to the user, the user or the manufacturer together with the manufacturer shall conduct a landing check on the quantity and appearance quality of the product within the time limit specified in the delivery contract. The manufacturer shall replace the product with missing quantity or damaged during transportation free of charge. . For the fused cast zirconium corundum bricks in important parts, the user must also conduct a floor inspection on the internal quality of the product through ultrasonic nondestructive testing.
Research data shows that after the fused cast zirconium corundum brick is used in the furnace, the mineral phase composition and chemical composition of the remaining part of the original brick have changed. For example, the German Berhard Fleisclmiann published in the "Refractory World Forum" magazine "Electro-fused AZS refractories-structure and structural changes during use", observed and detailed the microstructure of fused AZS bricks before and after use (Mineral phase, grain size) and changes in chemical composition;
In addition, in another domestic dispute over the quality of materials attached to the glass melting furnace. Through X-diffraction pattern analysis, it was also detected that other mineral phases such as cristobalite appeared during use of the used fused AZS bricks (see Figure 1). ), cristobalite undergoes a crystalline phase transformation (from β-cristobalite to α-cristobalite) at 180~270℃, and the volume expansion reaches 2.8%. Therefore, the sample taken from the remaining part of the original brick is heated during the corrosion resistance test It is extremely easy to produce cracks and fractures, and the test results cannot be used as a basis for judging product quality at all.
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