Size design method of a large thin-wall ball valve

Abstract

The invention belongs to the technical field of casting, and relates to a size design method of a large thin-wall ball valve, which comprises the following steps of: marking a plurality of measuring points on the inner surface and/or the outer surface of the ball valve; Measuring the ball valve radius value of each measuring point; Subtracting the ball valve radius design sticking value of the corresponding angle measuring point from the ball valve radius value of the measuring point and the ball valve radius mold deviation value of the measuring point to obtain a deformation value; Adding thedeformation values to obtain the deformation sum value of the same angle measurement point, and dividing the deformation sum value of the same angle measurement point by the number of the same anglemeasurement points to obtain a deformation mean value of the same angle measurement point; Fitting the mean value of the deformation amounts of the angle measurement points through data statistical analysis software to obtain a formula of the anti-deformation process design sticking amount; According to the method, the sticking amount of each radius value of the ball valve is calculated by adopting a sticking amount formula designed by adopting a reverse deformation process, and the size process design of the ball valve is performed, so that the production period is remarkably prolonged and the cost is saved through the reverse deformation size process design of the method.

Description

technical field [0001] The invention belongs to the technical field of casting, and mainly relates to a size design method of a large thin-walled ball valve. Background technique [0002] The large ball valve casting structure is a hemispherical C-shaped structure, the general diameter range is 2800mm-5000mm, the spherical wall thickness range is 80mm-150mm, and the wall thickness is relatively thin. The dimensional tolerance standard of the casting requires CT12-CT14. Tolerance requirements are higher and, for sand casting dimensional requirements, very stringent. Since the casting structure of the ball valve casting is C-shaped, there is deformation during the casting process and the mass heat treatment process, and the main deformation trend is opening. [0003] In the prior art, when designing the size process of large ball valve castings, according to the tolerance requirements for the inner and outer spherical surfaces of the castings according to the drawings, the ov...

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Problems solved by technology

[0004]1. The area of ​​the outer spherical surface of the casting near the middle parting surface is large and large, seriously exceeding the standard tolerance requirements, and a large number of gouging repairs are required to make the outer wall size meet the standard requirements, increasing Production cycle and cost;

[0005]2. The lack of the inner spherical surface of the casting near the middle parting surface seriously exceeds the standard tolerance requirements. Corrective heat treatment or large-area welding repair is required to make the inner wall of the casting meet the Standard tolerance requirements increase production cycle and cost;

[0006]3. The machining allowance of the arc top of the inner circular surface of the casting becomes larger, and the machining allowance on both sides becomes smaller or has no machining allowance. It needs to be further improved through subsequent processing. If it cannot be improved, the casting will be scrapped and the production cost will be increased

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