Grasp the laws of temperature field to ensure the quality of crusher castings

Because the crusher rolls are long-term supply of metallurgical spare parts, in order to ensure the quality of castings, improve the sand compaction, prevent the expansion of the castings, shrinkage holes, determine the model, the core box using real wood modelling. In order to facilitate the core making, the middle core is divided into two parts. In order to prevent the eccentric core, a core seat is arranged on the lower core. The core seat height is designed to be 100mm. Reasonable selection of sand, taking into account the surface roughness and solve the problem of sand cleaning that the internal surface contact with the molten steel and the steel by the heat of the liquid for a long time. The use of high temperature resistant chromite sands on the surface of the core. This sand has a high degree of refractoriness to prevent castings from sticking and ensure smooth castings. However, the price of this sand is relatively high. In order to save costs, only a thin layer can be used. Thickness of about 10 mm ~ 15 mm. The core inner layer can be automatically decomposed at high temperatures. Low-cost artificially crushed limestone sand that is easily broken. To facilitate sand cleaning: sand-type cavity using quartz sand, brush zirconium powder coating twice.
To set up a reasonable riser system, it is necessary to accurately calculate the thermal section of the casting. Place a suitable feeder at the hot spot. Subsidies are added under the riser to ensure that the riser forms in a sequence of solidification, obtaining dense castings, based on calculations and experience. Formulate the initial process plan. According to the initial process, the roller is subjected to simulated solidification simulation, analysis and demonstration, and the temperature and flow field changes are grasped to adjust the size and quantity of the riser and the gate, and the beneficiation process is optimized to ensure the sequential solidification of the casting and the molten metal. Effective feeding ensures that there is no shrinkage, no shrinkage, and dense tissue roll castings. Casting simulation solid simulation castings see no shrinkage hole. Waist-shaped 13th thermal riser 4 Height 500 mm. The pouring system adopts the bottom pouring and quick pouring method, the sprue, and the gate gate adopts the refractory brick special grate, each with a diameter of 80 mm, and the inner gate adopts a special gate of 60 mm firebrick.
The purity of the molten steel and the pouring temperature directly affect the quality of the roll castings. The higher the content of S, P and other harmful elements, the greater the tendency of cracks, and the more serious the inclusions and segregation in steel. The easier it is to cause stress concentration, the higher the pouring temperature, the greater the solidification shrinkage, the greater the probability of hot cracks, shrinkage holes, shrinkage, and sticking, and the strengthening of process quality control. The use of metamorphism treatment and ladle bottom argon blowing technology strictly controls the quality of molten steel and reduces the content of gas and harmful elements in molten steel. Control pouring temperature and pouring speed. Increase the liquid steel's feeding capacity, ensure the compactness of the castings, smelt the components according to the midline control, deoxidize in the furnace, use the rare earth silicon in the package for gestation and modification treatment, the tapping temperature is controlled at 1 600 °C ~ 1 620 °C.