Low-cost and dead-head-free gate valve casting

Abstract

The invention discloses a low-cost and dead-head-free gate valve casting. The low-cost and dead-head-free gate valve casting comprises an upper sand box (1) and a lower sand box (2), wherein an upper gate valve mold cavity (3) is arranged in the upper sand box (1), and an upper mold core (4) is arranged in the upper gate valve mold cavity (3); a lower gate valve mold cavity (5) is arranged in the lower sand box (2), and a lower mold core (6) is arranged in the lower gate valve mold cavity (5); the upper gate valve mold cavity (3) comprises an upper gate board groove mold cavity (31) of which one end is provided with an upper pipe port mold cavity (32); an upper rib mold cavity (33) is arranged on the upper gate board groove mold cavity (31); an air exhausting sheet (34) is arranged on the upper rib mold cavity (33). The low-cost and dead-head-free gate valve casting has the characteristics that the surface structure of a gate valve product is compact, the qualification rate of the gate valve product is improved, the production cost is reduced, and the production efficiency is improved.

Description

technical field [0001] The invention relates to a gate valve production process, which is a practical technique for producing gate valve castings with low cost and no riser. Background technique [0002] The structure of the large-diameter gate valve is relatively complex, and its thickness distribution is uneven. When casting the gate valve with the upper and lower parting surfaces of the sand box, after the molten iron fills the cavity, it needs to undergo secondary expansion, and then cool down and shrink from the bottom to the top. Due to the characteristics of the nodular cast iron used, the uppermost part and the part with large wall thickness will be relatively loose and the structure will not be tight. Gate valve castings often require secondary processing after the casting is completed. Bolt holes, bearing holes, etc. are processed on the surface and internal thick-walled parts of the gate valve. In this way, the looser surface is extremely easy to damage, making th...

AI Technical Summary

Problems solved by technology

[0002] The structure of the large-diameter gate valve is relatively complex, and its thickness distribution is uneven. When casting the gate valve with the upper and lower parting surfaces of the sand box, after the molten iron fills the cavity, it needs to undergo secondary expansion, and then cool down and shrink from the bottom to the top. Due to the characteristics of the nodular cast iron used, the uppermost part and the large area of ​​wall thickness will be relatively loose and the structure will not be tight

Gate valve castings often require secondary processing after the casting is completed. Bolt holes, bearing holes, etc. are processed on the surface and internal thick-walled parts of the gate valve. In this way, the relatively loose surface is extremely easy to damage, making the gate valve unusable. Scrapping and recasting reduces the pass rate, increases production costs, and reduces production efficiency

Moreover, when the existing gate valve is produced, it is necessary to set up a plurality of riser feeding processes, so that after the casting is completed, a huge gating system and a large number of risers will be formed, and each riser weighs 30- More than 50 kilograms, resulting in more raw materials required for the product and higher production costs. At the same time, the riser needs to be removed after production is completed, which not only increases labor intensity, but also wastes raw materials

Therefore, the existing technology has problems such as loose gate valve surface structure, low product qualification rate, high production cost and low production efficiency.

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