At present, China's excavator bucket teeth of the process are forging casting, precision casting sand and three categories. The main manufacturing process in the market the bucket teeth is a precision casting, forgingproductionthan the bucket tooth prices low, two is good appearance and dimension precision, moderate cost,three is as long asraw materials are well controlled, precision casting quality and wear resistance of bucket tooth very radical thanbucket tooth forging manufacturing. Because the sand casting cost minimum, so the market is still in great demand,but the quality of its production than precision casting and forging parts.
The surface adhering sand castings or partly covered with a mixture of metal or metal oxide and othermaterials (or compounds) sintered layer, so that the casting surface roughness. Unable to get rid of the sandis serious, especially the casting cavity with iron sand the sand with access to casting scrap. The sand castingwear-resisting low-alloy steelmaterial sand casting defects are common problems. Bucket tooth shapecastings, which is easy to do on the wall thickness of castings, alloy steel as belonging to a thin castings, low temperature is not easy to shape, temperature is too high will produce sticky sand. To make the castingsurface is smooth, cannot use coarse sand. Foundry silica sand are used in production, but its refractorydegree is low, easy to form sand.
The increase in pouring temperature, liquid FeO into the gap between grains in the metal, and generate the SIOeffect of sand in the sticky sand, longitudinal and is under the thin thick wedge section, on the basis of it is the chemical reaction after mechanical penetrated sand adhering sand, chemical and mechanical penetrationtwo typescoexist. In the upper core sand around bucket teeth by the high temperature liquid steel package, sothe sand coreeasily overheat, easy to be high temperature liquid steel erosion, the erosion scab, serious whenthe liquid steel into the sand core. This is because the sand core silica sand with low melting point, heat storage coefficient is small, so itis easy to form corrosion. Instead of zircon sand instead of silica sand, thenpoured in the other conditions remain unchanged, only about 3% of bonded sand, the effect is very obvious.