A Method for Producing Conical Segment Drums Using Vertical Centrifugal Casting Technology

Abstract

The invention discloses a method for producing a conical section drum by using a vertically centrifugal casting process. The method comprises the following steps: a metal mold external mold and a sand mold core are combined, and the combination is vertically centrifugally cast; before casting, paint is sprayed in the inner cavity of the metal mold external mold so as to reduce the temperature of high-temperature molten metal liquid poured in the cast metal mold external mold; and besides, a protective gas, that is, argon is introduced in a cavity formed by the metal mold external mold and the sand mold core, and a cast conical section drum cylinder has no harmful defects such as air holes, included slag and cracks, is compact in structure, and is free from welding seams, and the overall strength of the cast conical section drum cylinder is improved greatly. According to the shape of the conical section drum, through the reasonable combination and control of the metal mold external mold and the sand mold core, the processing volume of a conical section drum blank is effectively controlled, the technological yield can reach more than 70% or even higher, after the metal mold external mold is adopted, the product qualified rate can reach more than 90%, and moreover, the comprehensive cost of the produced conical section drum can be reduced by more than 30%.

Description

technical field [0001] The invention relates to the technical field of production of a cone-section drum, in particular to a method for producing a cone-section drum by using a vertical centrifugal casting process. Background technique [0002] At present, there are mainly the following methods for producing conical section drums: [0003] The first method is the rolling welding forming method, which mainly uses the three-roll rolling method to roll the steel plate into a conical cylinder blank, then conduct longitudinal weld welding, and then mechanically process the cone segment drum. Its disadvantages It is the cold work hardening stress of the conical cylinder blank during the rolling process, especially the thicker steel plate is more prone to cold work hardening, the thickness of the rolled steel plate is limited to a certain extent, and the welding produces heat affected zone and welding stress, which affects Weld seam performance, the weld seam is easy to become the...

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Problems solved by technology

[0003] The first method is the rolling welding forming method, which mainly uses the three-roll rolling method to roll the steel plate into a conical cylinder blank, then conduct longitudinal weld welding, and then mechanically process the cone segment drum. Its disadvantages It is the cold work hardening stress of the conical cylinder blank during the rolling process, especially the thicker steel plate is more prone to cold work hardening, the thickness of the rolled steel plate is limited to a certain extent, and the welding produces heat affected zone and welding stress, which affects Weld seam performance, the weld seam is easy to become the source of cracks and corrosion, which reduces the overall strength of the cone section drum, and cannot meet the requirements for seamless manufacturing of the cone section drum in special application environments. The cone section drum operates at high speed , the risk of bursting is relatively high, the safety factor is low, and the service life is short, so it can only be used in general low-speed centrifuge separators

[0004] The second method is the static casting method, which is to cast a blank similar to the cone-section drum at one time by sand casting, and then machine the cone-section drum. The disadvantage is that the produced cone-section drum is easy to Pores, sticky sand, slag inclusions, cracks and other harmful defects are produced, resulting in high scrap rate and relatively low process yield in the production process

[0005] The third method is the forging method, which is to use steel ingots to forge the blank of the cone-section drum, and then machine the cone-section drum. The cost of the blank of the cone section drum is relatively high, resulting in the overall cost of producing the cone section drum generally being 30% or even higher, which cannot be afforded by general manufacturers, nor can end users bear such a high cost

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