Multi-layer multiplex hydraulic valve mold and casting technique thereof

Abstract

The invention discloses a mould for a multilayer multi-way hydraulic valve and a casting process thereof. The casting process comprises: cleaning a mould, adjusting the mould, selecting a shell mold and a sand core material, then entering a manufacturing and molding working procedure, and finally casting and mold stripping. The process matched with the mould for the multilayer multi-way hydraulic valve adopts a method with the shrinkage characteristic of the process to control shrinkage amount of a casting, namely controlling the shrinkage amount of the casting by placing a plurality of layers of asbestos cloth at a sand core head of a main flow passage of the casting, finely adjusts the tolerance of the dimension of the casting by adjusting the layer number of the asbestos cloth, smoothly solves the problem of requirement on the dimensional precision of a CAT casting, and is a casting process which can manufacture the multilayer multi-way hydraulic valve with higher precision requirement and stable quality.

Description

technical field [0001] The invention designs a hydraulic valve mold and its casting process, and in particular relates to a multilayer and multi-channel hydraulic valve mold and its production process. Background technique [0002] The multi-layer multi-way hydraulic valve is characterized by three-layer multi-way, which is composed of 8 mud cores. The inner cavity of the valve has a complex shape, and the space of the mud core accounts for about 25% of the volume of the casting. Structural characteristics of castings: uneven wall thickness, multiple isolated thermal joints in the casting, poor feeding channels, easy to produce loosening; multiple mud cores with large air volume; many mud core joints, easy to produce cracks; large thermal joint modulus , the nearby flow channel is easy to stick to sand; the buoyancy in the casting process is large, the diameter of the main flow channel is small and long, and it is easy to deform and twist. This feature makes the general cas...

AI Technical Summary

Problems solved by technology

This feature makes the general casting process unable to meet its demanding process requirements; especially when there are many undercut grooves in the main channel, the general domestic processing is achieved by machining, but when the products are sold abroad, their requirements are Guarantee quality by casting process

And only based on the current domestic existing technology, a casting is cast with a length of 333.5. Because the thermal joint at the riser of the casting is large, the shell mold softens when the casting shrinks in the liquid state. Shrinkage, and graphitization expansion occurs when solidification shrinks, and at this time the riser shell has formed a hard shell and cannot be deformed, so the casting cannot expand, and the middle part is cooled first due to the small thermal section modulus, so it is 50% close to the gate. The shrinkage within the range is over 3%, and the dimensional tolerance exceeds 1.6mm. Various molding methods, such as sand casting, resin sand casting, and composite casting of the two, have failed in vain.