Brass tube production process is a complex and delicate manufacturing process, from the preparation of raw materials to the quality inspection of the final product, each step is crucial. The following is a detailed analysis of the brass tube production process.
First, brass tube production begins with the preparation of raw materials. This step includes the selection of high-quality brass alloys, which usually consist of copper and zinc as the main components and may contain small amounts of other elements to improve their mechanical properties and corrosion resistance. The choice of brass alloy depends on the use and requirements of the end product. For example, applications requiring high strength and good corrosion resistance may require a higher percentage of zinc or other alloying elements.
Once a suitable brass alloy has been selected, it needs to be melted and held. This step is usually carried out in a gas-protected environment to prevent the brass from oxidizing during the melting process. The melting temperature is usually set above the melting point of the brass to ensure that the alloy is completely melted. At the same time, the use of gas protection (e.g. inert gas) prevents the brass from reacting with oxygen in the air and forming unwanted oxides. Once the melting is complete, the brass liquid is held within a certain temperature range to ensure uniformity and fluidity.
Next, the molten brass is fed into a horizontal continuous casting machine for continuous casting. Continuous casting is a method of casting molten metal directly into a continuous billet. In the production of brass tubes, the continuous casting machine pours molten brass liquid into a continuous mold, the shape of which determines the shape and size of the final brass tube. As the brass liquid cools and solidifies, it gradually forms a continuous billet of copper pipe. This step requires precise control of the casting speed and cooling rate to ensure the quality and uniformity of the billet.
After the continuous casting is completed, the surface of the copper tube billet may have some defects, such as cracks, inclusions or uneven surface. Therefore, milling of copper tube blanks is required to remove these surface defects. Milling is a method of removing material by rotating a tool, which effectively smooths the surface of the copper tube blank in preparation for subsequent machining steps.
After milling is complete, the copper tube blanks enter the three-roll planetary rolling stage. In this step, the copper tube blank is rolled by three rotating rolls to reduce its diameter and increase its wall thickness. Three-roll planetary rolling is a high-efficiency rolling method, which can complete rolling in multiple directions simultaneously in one operation, thus improving production efficiency and product quality. During the rolling process, precise control of the rolls and effective operation of the lubrication system are essential to ensure the uniformity and surface quality of the copper tube.
After rolling, copper tube blanks are coiled in-line for subsequent stretching and processing. In-line coiling is a method of winding continuous material into coils that saves space and increases productivity. During the winding process, the winding tension and speed need to be precisely controlled to prevent deformation or damage to the copper tube blank.
Next, the copper billet enters the triple tandem co-stretching stage. This step further thins the billet and increases its wall thickness and strength through multiple stretching operations. Triple tandem co-stretching is a multi-stage stretching method where the stretch ratio decreases at each stage to ensure uniformity and stability of the copper tube. During the stretching process, the stretching speed and ratio need to be precisely controlled to prevent cracking or fracture of the copper tube.
After the three tandem joint stretching, the copper tube enters the disc stretching stage. This step further stretches and straightens the copper tube by means of a disc stretching machine. The disc stretching machine utilizes a pair of rotating discs to hold and stretch the copper tube while it is straightened to ensure straightness and dimensional accuracy. During the stretching and straightening process, the stretching force and straightening angle need to be precisely controlled to obtain the best quality copper tube.
After stretching and straightening, the copper tubes need to be flaw detected and sized. Flaw detection is a method of detecting internal and surface defects in copper tubes by non-destructive testing methods such as ultrasonic or eddy current. It can effectively detect cracks, inclusions and other defects in copper tubes to ensure their quality and reliability. Cut-to-length processing, on the other hand, involves cutting copper tubes to specified lengths according to customer requirements. This step requires precise control of the cutting position and cutting accuracy to ensure that the dimensions of the copper pipe meet the design requirements.
After flaw detection and sizing, the copper tube enters the bright annealing stage. Bright annealing is a method of heating copper tubes to a certain temperature in a protective atmosphere and holding it for a certain period of time in order to remove internal stresses and improve their plasticity. The annealing temperature is usually between 250°C and 350°C, depending on the alloy composition and size of the copper tube. The bright annealing process requires precise control of the heating and cooling rates to obtain the best annealing results.
After the annealing is completed, the copper tube enters the co-finishing stage. Joint finishing is a method of removing oxidized skin, oil and other pollutants from the surface of copper tube by mechanical or chemical methods. It can effectively improve the surface quality of copper tube, making it more polished and beautiful. During the finishing process, it is necessary to choose the appropriate finishing method and process parameters to ensure the surface quality and consistency of the copper tube.
Finally, the copper tube is laminated and packaged after quality inspection. Quality inspection includes comprehensive testing of the size, shape, surface quality, chemical composition and mechanical properties of the copper tube. Only copper tubes that meet the quality standards can be accepted as final products. Laminating and packaging are designed to protect the copper tubes from oxidation, corrosion and other damages, while facilitating their transportation and storage. The laminating material is usually a plastic film such as polyethylene or polyvinyl chloride, while the packaging method is chosen according to the size and quantity of the copper tubes.
