1. Copper alloys with different compositions exhibit distinct crystallization characteristics, varying casting performance, and require different casting processes.

1. Tin bronze: Its crystallization characteristics include a wide crystallization temperature range and a broad solidification zone. In terms of casting performance, it exhibits poor fluidity, is prone to shrinkage porosity, and is not easily oxidized. As for processing techniques, parts with thick walls should adopt directional solidification, while complex thin-walled parts and parts with typical wall thicknesses should use simultaneous solidification.

2. Aluminum bronze and aluminum brass: Their crystallization characteristics are marked by a narrow temperature range and a sequential solidification pattern. In terms of casting performance, they exhibit good fluidity but tend to form concentrated shrinkage cavities and are highly susceptible to oxidation. As for processing techniques, the gating system for aluminum bronze is bottom-pouring, while that for aluminum brass is open-type.

3. Silicon brass: Its crystallization characteristics lie between those of tin bronze and aluminum bronze; it exhibits the best casting performance; its process features include sequential solidification, a central gating system, and relatively small risers.

II. Connection Techniques for Copper Tubes

Copper pipes are exceptionally robust, especially when it comes to connections. Today, the market offers a wide variety of pipe materials, and copper fittings are the primary choice for pipe joints. For example, at the point where a copper pipe connects to a faucet, a copper fitting is absolutely essential. This is because if copper pipe fittings are connected to other types of pipes—given the differences in material properties between the pipe and the fitting—their physical and mechanical behaviors during thermal expansion and contraction will differ significantly, naturally posing additional challenges to the strength of the connection. Therefore, when copper pipes are connected to copper fittings, the overall connection strength is greatly enhanced.

III. Development Directions for Copper Tubes

Although copper pipes boast superior performance and can adapt to various working environments, their development lacks certainty due to market uncertainties. In the future, before seizing new opportunities, it remains crucial to ensure the quality of copper pipes. This not only requires stringent regulatory oversight from the market but also calls for rigorous self-monitoring by manufacturers themselves. Moreover, water piping systems in the construction sector represent a relatively complete system, and currently, the application of copper pipes in this area is just a small segment. However, if we can expand the use of complementary supporting facilities and integrate copper pipes more rationally into these comprehensive systems, it will not only simplify the installation of water pipelines but also open up new markets for copper pipes.