Improvement and verification of casting process of vermicular graphite cast iron brake disc

(1) Increase the use of return material

In order to reduce cost and increase efficiency, the consumption of return material is gradually increased from 20% to 55%. Nodular cast iron, gray iron, Cape joint, etc. can also be added as reheating materials to reduce the use of pig iron, scrap steel and ferroalloy and effectively reduce the smelting cost on the premise of ensuring the quality.

(2) Improving furnace building and packing process

Automatic ejection mechanism is used for furnace beating, electric vibration mechanism is used for furnace building, and suitable refractory materials and furnace building process are adopted. Strictly implement the oven drying process, carefully repair the key parts of furnace wall, furnace bottom and taphole before opening, so as to make the average furnace life reach 300 heats.

The worm gear turnover package was originally made of refractory bricks, and the package age was 80 packages. The new process of overall knotting of refractory materials is now used. The cladding wall is clean and flat, the cladding pit is clean and does not deform, and the average cladding age can reach 400 bales, which saves the comprehensive cost of cladding, reduces the labor intensity of foreman and reduces the defects of slag inclusion casting.

(3) Optimized operation

In order to reduce flue gas emission, top suction is installed at the station in front of the furnace and side suction is installed at the pouring line for flue gas dust removal. However, during pouring, operators are prone to congestion and potential safety hazards. By reasonably optimizing the personnel allocation, the pouring team can relieve the congestion and ensure that the process meets the requirements and personnel safety.

(4) Improve the fast judgment ability in front of the furnace

With the technical progress of vermicular graphite cast iron, instruments such as direct reading spectrum, metallography in front of the furnace and rapid temperature measurement are equipped. In order to improve the quality of smelting personnel and prevent over reliance on instruments, the level is improved through technical training. The observation and judgment of molten iron color, molten iron spark and triangular test piece are combined with the instruments to accurately determine the temperature, composition, vermicular rate and other indicators of molten iron, Improve the fast judgment ability in front of the furnace.

(5) Subcontracting and instantaneous inoculation

The molten iron of a large furnace is divided into several small packages for tapping, which requires the foreman to accurately control the tapping amount, especially in Vermicular Iron production. The tapping amount is 1500 kg, and the error should be less than 5 kg. Due to the large ratio of molten iron and strong impact on the electronic scale, accurate prediction ability is required during tapping.

The stirring process is the key in the inoculation process. Good inoculation can increase the number of graphite balls, refine grains and reduce white mouth. However, the mixing in the large package is not complete. In order to prevent inoculation recession and poor inoculation, the ladle inversion inoculation process is adopted to ensure sufficient mixing of molten iron and less cooling, reduce labor intensity, improve production safety and reduce waste products caused by poor inoculation.

The instantaneous inoculation process can effectively improve the inoculation effect and reduce the amount of inoculant. It is mainly used for nodular cast iron. In the past, inoculant powder was added manually, which has a bad and inaccurate environment. Now the semi-automatic instantaneous inoculant feeder is adopted to reduce operators, and the amount of inoculant is accurate.