Research on the Performance and Application of Centrifugal Casting Grey Cast Iron Pipe Floor Coating

Floor paint coating is one of the key factors in centrifugal casting process. The quality of the coating not only directly affects the life of the mold and the quality of the cast pipe, but also affects productivity. However, due to<a href=“ http://www.search.hc360.com/cgi-bin/seinterface.cgi?word=%3Ca%20href= Http:="" p.jinfengpaint. com=""="" title="Floor Paint" target="_ blue" class="tar" style="text decoration line: none;  color: rgb(0, 51, 153);  font-weight: bold; Floor coating "target=" -blank ">Floor coating has excessive air release, which can cause defects such as porosity in cast pipes; Due to issues with coating viscosity or uneven coating, it not only affects the lifespan of the casting mold, but also causes defects such as unevenness and even leakage on the surface of the cast pipe. Therefore, it is necessary to conduct in-depth research on centrifugal casting gray iron pipe floor coatings.

The function of centrifugal casting gray iron pipe floor coating

The production process of centrifugal cast pipes requires that the coating can withstand the erosion of high-temperature molten iron during pouring without falling off. After the cast pipe cools and solidifies, the coating can adhere to the mold wall and be pulled out from the mold together with the cast pipe, and the cooled coating is easy to remove. It is also required that the coating has insulation function to prevent the cast pipe from producing white spots. In addition, the coating should have the ability to store and exhaust gas, so that the cast pipe does not have defects such as pores and depressions.    

2. Requirements for centrifugal casting gray iron pipe floor coating

Requirements for metal centrifugal casting coatings: ① The coating should have high fire resistance to prevent melting by high-temperature metal liquid; ② The coating should have high cohesive strength and adhesion strength to prevent the coating from being washed off during pouring; At the same time, it should also have the ability to be easily pulled out of the mold after the solidification of the cast pipe; ③ The coating should have a small gas release rate to prevent defects such as porosity and * * in the cast pipe; ④ Coatings should have appropriate viscosity, sufficient fluidity, and suspension to ensure the stability and uniformity of various properties of the coating.

3. Factors affecting the gas generation of centrifugal casting gray iron pipe floor coating

The raw materials of coatings themselves contain crystalline water and organic matter, which release gases at high temperatures, thereby affecting the gas generation of coatings. ① The influence of refractory powder aggregate on the gas generation of coatings. The gas generating substances of refractory powder aggregate are mainly adsorbed water and crystalline water. In addition, refractory powder may contain a small amount of organic matter; ② The influence of binders and suspending agents on gas generation, although they occupy a small amount in coatings, their gas generation is large. Therefore, the dosage of binders and suspending agents has a certain impact on the gas generation of coatings.

4. Factors affecting the suspension of centrifugal casting gray iron pipe floor coating

The quality of coating suspension is directly related to the atomization of the coating during spraying, therefore, suspension is also one of the main properties of metallic coatings.

(1) The influence of refractory aggregates on the suspension of coatings is manifested in their fire resistance.

The size of the particle size of the powder aggregate; The larger the particle size, the worse the suspension; On the premise of ensuring the original structure of refractory powder aggregates, the finer the particle size of refractory aggregates, the better the suspension of coatings.

(2) The effect of suspending agents on suspension properties: Bentonite is used to prevent the precipitation of refractory aggregates; As the content of bentonite increases, the suspension performance of the coating also improves, while also increasing the strength of the coating. But the gas generation of bentonite is very large. In the experiment, when the amount of bentonite added is 2% to 5%, it can meet the requirements of suspension performance for centrifugal casting coatings and reduce gas generation.