Pouring system for large valve casing type steel castings

Abstract

The invention provides a pouring system for large valve casing type steel castings. The pouring system structurally comprises a sprue cup, a sprue, a slow-flow cross gate, a cross gate and an inner gate which are connected sequentially; the slow-flow cross gate is a first-class cross gate and is connected with a second-stage cross gate above the slow-flow cross gate through a vertical drainage gate; the second-stage cross gate has the V-shaped longitudinal section; the tail end of the second-stage cross gate is connected with a third-stage cross gate at the upper end of the second-stage crossgate through the vertical drainage gate; the third-stage cross gate has the V-shaped longitudinal section; the inner gate is perpendicularly connected with the third-stage cross gate and faces vertically upwards; and the tail end of the third-stage cross gate is sequentially connected with a slag guiding gate, a reducing gate and a slag collecting gate which is perpendicularly connected with the reducing gate and faces vertically upwards. By the aid of the pouring system, the mold filling process of molten steel is stable, the slag collecting effect is remarkable, and slag inclusion and impurity inclusion defects on the surfaces of the castings are reduced.

Description

technical field [0001] The invention relates to a gating system for castings, in particular to a gating system suitable for large valve shell castings. Background technique [0002] Regulating valve casing steel castings are an important part of large steam turbine generators. By changing the opening of the regulating valve, the steam flow rate and related steam parameters entering the steam turbine can be changed, and the start and stop of the steam turbine and the power change can be controlled. A high-pressure main valve regulating valve casing casting weighs 22.8t, and the pouring weight reaches 40t. Casting structure such as figure 1 As shown, it is mainly responsible for the steam adjustment of the main steam valve. The working environment is a high temperature and high pressure environment, and the maximum required working pressure is 300 kg. The quality requirements for castings are very high, especially for all nozzles, insulation straps and lifting lugs. There ca...

AI Technical Summary

Problems solved by technology

[0004] The technicians conducted a simulation test on the high-speed liquid flow entering the closed cavity and found that: when the liquid flow continues to enter the closed cavity at a relatively high speed (V>0.9m / s), turbulent flow will occur in the cavity. The existing technology produces large-scale The gating system used in cast steel for valve shells has an instantaneous flow velocity of 1.15m / s, indicating that the existing gating system does have turbulent flow after the molten steel enters

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