1. Introduction
Copper tubes are widely used in a variety of industries due to their properties of having thermal and electrical conductivity, hardness and corrosion resistance. Due to this, the manufacturing process and quality control of copper tubes are of great importance. Copper tubes can be manufactured by several processes: extrusion, drawing, pilgering and others.
2. Extrusion of Copper Tubes
Extrusion is one of the most common processes adopted for fabricating copper tubes. In the extrusion process, a metallic billet is forced through a die with an aperture in the desired profile. The process is automated and the copper tube obtained from this process is usually used in plumbing and heating applications due to its perfect geometry, good surface finish and high dimensional accuracy. For copper pipes, it is desirable for the wall-thickness to be uniform throughout the length. In order to achieve that, the initial billet used for extrusion is first heated to a very high temperature and then forced through the die.
3. GB1528-87 Standard
The GB1528-87 is the national standard of China for the extruded copper tubes. It covers the manufacture and inspection of copper tubes obtained by the process of extrusion. The standard specifies the chemical composition, mechanical properties, and the technical requirements to be met by the manufacturer. According to the standard, the wall-thickness of the copper tube obtained should be uniform. Furthermore, the mechanical testing performed on the tube should have an elongation of 1-3%. The standard also ensures that the proper temperature is maintained for extrusion.
4. Manufacturing process
The manufacturing process of copper tubes is quite simple, but there are several factors that together make up all the necessary criteria laid down by the standard. First, the raw material used should be free from any defects as it will ultimately affect the finished product. The material for the tube is heated up to a very high temperature inside a furnace. The billet is then extruded through the die with an aperture in the desired profile. The extrusion process has to be maintained in such a way that the material should not be exposed to too much of heat, as that would affect its properties.
5. Quality Control
The quality control of the extruded copper tubes is of utmost importance as it involves ensuring that the product meets the requirements laid down by the standard. To maintain the quality, a set of tests are conducted during the manufacturing process. These tests include hardness tests, tensile strength tests, ductility tests, and chemical tests. These tests are performed carefully in order to ensure the safety of the product. On the basis of the test results, the product is further sorted and checked for any defects.
6. Conclusion
Extrusion is one of the most popular and cost effective processes for manufacturing copper tubes. In order to ensure that these tubes meet the quality requirements laid down by the national standard GB1528-87, the manufacture and quality control of the same involves certification, mechanical tests, and chemical tests. The manufacturing process is carefully monitored to ensure that the extruded copper tubes have uniform wall thickness, good geometry, and high dimensional accuracy.
