A New Type of Twisted Sheet Tube Investment Mold

Abstract

A novel twisted slice tube investment pattern comprises a pouring cup and a twisted slice tube. A transverse pouring gate is formed in the lower side of the pouring cup, rotary pouring gates are formed in two sides of the lower side of the transverse pouring gate and are connected with the twisted slice tube through a plurality of sprues, and the sprues are horizontally symmetric. The novel twisted slice tube investment pattern is reasonable in structure, the occurrence probability of liquid steel impurities is reduced, the rotation directions of the rotary pouring gates are the same as that of twisted blades in the twisted slice tube, partial shrinkage porosity of the twisted blades of the twisted slice tube is avoided, the service life of the twisted slice tube is prolonged, meanwhile, the qualified rate of radiography testing of the twisted slice tube is increased to 98% from 20% before, the waste of labor is avoided and the production cost is reduced.

Description

technical field [0001] The invention relates to the application in cracking furnaces, in particular to a novel twisted sheet tube investment mold. Background technique [0002] The application of twisted sheet tubes in cracking furnaces is a major technological breakthrough in the development of the ethylene industry. The twisted sheet tube is the core of cracking furnace enhanced heat transfer technology. After the cracking furnace is equipped with twisted sheet tubes, when the fluid passes through the twisted sheet tubes with the same width as the furnace tube, the original piston flow changes into a swirling flow, which greatly increases the tangential flow velocity of the fluid and forms a strong scouring effect on the tube wall , greatly reducing the thickness of the boundary layer with high thermal resistance, increasing the total heat transfer coefficient of the furnace tube, thereby reducing the temperature of the furnace tube wall, achieving enhanced heat transfer ...

AI Technical Summary

Problems solved by technology

[0003] At present, the structure of the twisted sheet tube is complex, and it is difficult to form it by centrifugal casting. It can only be formed by investment casting. Since the solidification time of each part of the furnace tube is different, if the final solidified part is insufficiently fed, it is easy to form shrinkage cavity or porosity, while the twisted sheet and Due to the large heat capacity, the junction of the pipe wall is likely to be the last part to solidify. If it cannot be fed, it is easy to produce casting defects.

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