Copper castings can be divided into brass castings, bronze castings, and white copper castings. Brass is a copper alloy with zinc as the main alloying element, such as ordinary brass H62, H68, and special brass such as lead brass, tin brass, etc; Bronze originally referred to copper tin alloy. Nowadays, except for brass and white copper, all other copper alloys are called bronze, including tin bronze, aluminum bronze, beryllium bronze, etc; White copper is a copper alloy with nickel as the main alloying element, which can be divided into ordinary white copper and complex white copper.

In the field of architecture, copper castings are commonly used for decorative components such as door handles, hinges, decorative sculptures, etc. Their unique metallic luster and texture can add a beautiful and luxurious atmosphere to buildings, while also having good durability. Due to its corrosion resistance and hygiene performance, copper is widely used in plumbing and bathroom products such as faucets, showerheads, valves, etc. It can ensure the quality and safety of water use, and has a beautiful appearance that is easy to clean and maintain.

How to choose welding rods or wires when repairing copper castings by welding?

The selection of welding rod or wire is crucial in the repair of copper castings by welding, as it directly affects the welding effect and the performance of the repaired castings. You can consider choosing from the following aspects:

According to the material of copper castings

Pure copper castings: If it is a pure copper casting, pure copper welding rods or wires are generally used, such as T107 pure copper welding rods, which are mainly composed of copper. The weld metal has good conductivity, thermal conductivity, and crack resistance, and can fuse well with the pure copper casting to ensure that the composition and properties of the weld layer are similar to those of the base metal.

Brass castings: For brass castings, brass welding rods or wires should be selected. For example, T227 aluminum yellow copper welding rod contains alloy elements such as aluminum, which can improve the strength, hardness, and corrosion resistance of the weld seam. It is suitable for welding general brass castings, especially in situations with certain strength and corrosion resistance requirements.

Bronze castings: There are many types of bronze, and different bronze castings require the use of corresponding welding rods or wires. For example, for tin bronze castings, T237 tin bronze welding rod can be used, and the weld metal has good wear resistance and fatigue resistance; Aluminum bronze castings can use aluminum bronze welding wire, such as QAl9-4 aluminum bronze welding wire, which can make the weld overlay have high strength, hardness, and corrosion resistance.

Consider the performance requirements of the weld overlay layer

Wear resistance requirements: When copper castings need to improve wear resistance, welding rods or wires containing alloy elements such as chromium, nickel, molybdenum, etc. can be selected. These alloying elements can form strengthening phases such as carbides with higher hardness, improving the hardness and wear resistance of the weld overlay. For example, some chromium containing copper based alloy welding wires can significantly improve the wear resistance of copper castings after surfacing, and are suitable for parts that can withstand friction and wear, such as copper molds, bearings, etc.

Corrosion resistance requirements: Copper castings used in environments with corrosive media require a weld overlay with good corrosion resistance. At this time, welding rods or wires containing corrosion-resistant elements such as aluminum, silicon, and nickel should be selected. Aluminum bronze welding rods or wires, due to the formation of a dense oxide film on the surface of aluminum, can effectively improve the corrosion resistance of the overlay layer, making them suitable for copper casting overlay repair in marine environments, chemical equipment, etc.

Strength and toughness requirements: For copper castings that can withstand large loads and impacts, the weld overlay layer needs to have high strength and toughness. Copper alloy welding rods or wires with good comprehensive performance can be selected to ensure the strength and toughness of the weld overlay layer through a reasonable alloy ratio. For example, some copper alloy welding wires with an appropriate amount of nickel added can refine the grain size, improve the strength and toughness of the weld overlay, and are suitable for repairing copper gears, connecting rods, and other parts under high stress.

Combining the characteristics of welding process

Welding method: Different welding methods have different requirements for welding rods or wires. Manual arc welding generally uses welding rods and should choose welding rods with suitable coating types, such as alkaline coating welding rods, which have good crack resistance and mechanical properties of the weld metal, but relatively poor processability; Acid coated welding rods have good processability, but the crack resistance and toughness of the weld metal are relatively low. Gas shielded welding uses welding wire, such as solid welding wire or flux cored welding wire commonly used in argon arc welding. The appropriate diameter and composition of the welding wire should be selected according to the welding equipment and process parameters.

Welding position: The position of the weld overlay can also affect the selection of welding rod or wire. In the flat welding position, welding rods or wires with higher deposition efficiency can be selected; In vertical welding, overhead welding and other positions, it is necessary to choose welding rods with good slag fluidity and easy slag removal, or use gas shielded welding wires with short-circuit transition to ensure the smooth progress of welding operations and the quality of welds.

Consider economy

On the premise of meeting the requirements for welding quality and performance, the cost of welding rods or wires should be considered. The prices of welding rods or wires of different brands, specifications, and compositions vary greatly. By comparing the prices of products from different suppliers, one can choose the cost-effective welding rod or wire. At the same time, it is necessary to comprehensively consider the complexity and production efficiency of the welding process, in order to avoid increasing welding costs and production cycles due to improper selection of welding rods or wires.

Copper's conductivity and thermal conductivity are among the best in metals, making copper castings widely used in fields such as electrical, electronic, and heat exchange. For example, in electrical equipment, copper terminal blocks, busbars, and other castings can efficiently transmit current and reduce energy loss. Copper has good corrosion resistance in atmospheric and freshwater environments, and can form a dense oxide film on the surface to prevent further corrosion. In the field of architectural decoration, outdoor copper sculptures, decorative pieces, etc. can still maintain good appearance and performance after prolonged exposure to wind and rain.