Gravity casting process of lead-free brass tap

Abstract

The invention provides a gravity casting process of a lead-free brass tap, which has the advantages that a flowing distance of a product in a casting process is short, the simultaneous solidification is achieved, hot cracks are reduced; a heat balance effect of a mould is good, so that heat balance of the product is facilitated, and the stress micro-cracks during cooling are reduced. The gravity casting process of the lead-free brass tap comprises the following step of casting and forming lead-free brass liquid through a gravity casting device, wherein the gravity casting device comprises an upper half mould, a lower half mould and a sand core, wherein mould cavities matched with a tap body in shape are respectively and correspondingly arranged between the upper half mould and the lower half mould, the sand core is arranged in the mould cavities between the upper half mould and the lower half mould, the shape of the sand core is matched with the shapes of a water inlet part and a water outlet part of the tap and an inner cavity of an installing part of a valve core, a casting cavity is formed between the sand core and the mould cavity, a sprue in which lead-free molten copper is cast is arranged in the lower half mould, the sprue is connected with the casting cavity, the sprue is provided with an internal sprue and an external sprue, and the internal sprue is correspondingly arranged at the casting cavity for forming the water inlet part of the tap body.

Description

technical field [0001] The invention relates to a forming mold for a faucet, in particular to a gravity casting process for a lead-free brass faucet. Background technique [0002] In daily life, the faucet is a valve switch used to control the size of the water flow. The faucet is a product with a relatively complicated appearance and structure, so the faucet body is generally formed integrally through the casting process. The casting mold is a part of the casting tooling. The necessary gear to shape and obtain the desired casting. [0003] Such as figure 1 , the casting mold used for the casting process of the existing lead brass faucets generally includes an upper half-mold and a lower half-mold 2', and a sand core 3' is provided between the upper half-mold and the lower half-mold 2', and the lower half-mold 2' parting surface is provided with gate 4', the gate of this kind of casting mold is set on the side of lower half-mold 2', and it is poured from the rear of the fa...

AI Technical Summary

Problems solved by technology

[0003] like figure 1 , the casting mold used for the casting process of the existing lead brass faucets generally includes an upper half-mold and a lower half-mold 2', and a sand core 3' is provided between the upper half-mold and the lower half-mold 2', and the lower half-mold 2' parting surface is provided with gate 4', the gate of this kind of casting mold is set on the side of lower half-mold 2', and it is poured from the rear of the faucet body when pouring. This kind of mold has a simple structure and is easy to manufacture. However, the setting of the gate, the pouring time of copper water is longer, it is only suitable for the casting of lead brass water with excellent cold and hot processing performance, if it is applied to bismuth-containing Bi lead-free For copper, when casting, due to the poor fluidity of bismuth-containing Bi lead-free copper compared to ordinary lead brass, if the above-mentioned ordinary lead brass casting mold is used for casting, the position of the gate will lead to no The lead-copper liquid has a longer discharge time, which is not conducive to the rapid filling of the mold cavity with liquid metal. When the product is solidified, the temperature of each place is unbalanced, and it cannot be solidified at the same time. The product is easy to crack when it is solidified. Similarly, the heat balance of the mold is poor, and the cooling time of each part of the product is also different. When the product is poured and cooled, the temperature of each part of the mold is not uniform, resulting in uneven temperature of each part of the product. Easy to form thermal stress micro-strikes when cooling

In addition, the above-mentioned mold does not have a liquid metal filling port, and the product will shrink during the solidification process and cannot be replenished. The shrinkage of the product will affect the quality of the product. In severe cases, it will affect the function of the product and reduce the quality of the product.

[0004] Lead is one of the heavy metals that are relatively harmful to the human body. Moreover, lead is not easy to remove after being discharged into the environment, and accumulates in the environment. It is very easy to have certain toxic effects on organisms and humans, especially on children's cranial nerves and kidneys. The function will cause irreversible damage, and serious adverse consequences such as blood lead poisoning, brain lead poisoning, mental retardation, dementia, hyperactivity, etc.

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