Simulation calculation of feeder feeding distance of plate-shaped steel castings - Master's thesis - Dissertation

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During the solidification process of the cast steel, due to liquid and solidification shrinkage, shrinkage defects may occur if the molten steel is not replenished at the final solidified portion of the casting. Shrinkage defects can be divided into macro shrinkage and microscopic shrinkage according to their size and distribution in the casting. The macroscopic shrinkage hole can be directly observed on the outer surface of the casting or on the cross section of the casting by the naked eye. The volume of the shrinkage hole is large, and it is concentrated on the upper part or the last solidified part of the casting; the volume of the shrinkage is small, for the cast iron piece. It is mainly distributed in the axial region of the casting wall, usually called the axis shrinkage. The dense portion of the plate member without shrinkage is the effective feeding distance of the plate member. There are many influencing factors, such as: the solidification characteristics of the alloy, the amount of shrinkage required for the casting body, the heat distribution of the mold and the degree of superheat of the cavity, the chilling measures to produce the cold end effect, and the pouring industry. The axial shrinkage of the steel castings is usually produced within a cast wall having a uniform wall thickness. Seen from the longitudinal section, it is produced at the axis; when viewed from the cross section, it is generated at the center, so it is also called the axis shrinkage or the center shrinkage. Flat plate castings of uniform thickness are divided into three zones, the riser zone - due to the thermal action of the molten steel in the riser, there is a temperature difference in the longitudinal direction of this section. The closer the liquidus and equal solidus lines are to the riser, the slower the advancement to the casting. Therefore, a wedge-shaped feeding passage is formed in the riser, the expansion angle is Ф ₂ , and the expansion is made to the riser, which is advantageous for the feeder to be replenished. In this area, the casting is sequentially solidified, and the casting is solidified in a compact state. In this paper, a flat steel casting is taken as the research object. By changing the diameter of the riser, the height of the riser and the thickness of the plate, the effect of the riser on the effective shrinkage distance is studied. The NBJX automatic metallographic analyzer can quickly and automatically detect various metals. Internal organization, cooperation

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