About copper pipe quality identification and weight and length calculation methods
Copper pipe refers to copper material made of pressed or drawn copper. Because of its strong and wear-resistant properties, it is often used in the electrical, industrial and construction industries. Copper pipes can be produced by extrusion, continuous casting and rolling, and up-drawing methods. Copper tube is an important raw material for the processing and manufacturing of refrigeration equipment. It has two main uses:
1. Make a heat exchanger;
2. Make connecting pipes and fittings;
1. Classification of copper pipes
1. Air-conditioning copper pipes can be roughly divided into ordinary air-conditioning copper pipes and degreasing air-conditioning copper pipes:
Ordinary air conditioners: The thickness is generally 0.5mm thick for 2-point and 3-point tubes, 0.6mm thick for 4-point tubes, and 0.7mm thick for 5-point and 6-point tubes. Mainly used for R22.
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Degreased air-conditioning copper pipe: also called "degreased air-conditioning copper pipe", the 2-point and 3-point pipes are 0.8mm thick, and the 4-point, 5-point and 6-point pipes are 1.0mm thick. Mainly used for refrigerants such as R410.
2. Specific classification of air conditioning copper pipe materials:
Oxygen-free copper: including high-purity oxygen-free copper (TU0, TU1, TU2) and phosphorus deoxidized copper (TUP, TP1, TP2, etc.), which are characterized by very little oxygen content and a small amount of deoxidizer remaining in the deoxidized copper;
Oxygen copper: mainly includes ordinary pure copper (T1, T2, T3, etc.) and tough copper, which are characterized by high oxygen content;
Special copper: There are arsenic copper, silver copper, tellurium copper, etc. The characteristic is that different trace alloy elements are added to achieve the purpose of improving the overall performance of the material.
Now let's focus on copper and brass.
Copper tube: The copper tube used in our refrigeration industry is pure copper, with a copper content of more than 99.90%. It has the good properties of copper, a high-quality basic metal, and is widely used in various industrial and civil fields and plays an important role. effect. There are mainly three categories: TP2, T2 and TU1.
TP2 is phosphorus deoxidized copper, containing 0.015-0.04% phosphorus. It has excellent welding and cold bending properties and is widely used in the manufacturing fields of air conditioning and refrigeration connecting pipes, stove gas connection pipes, electric heating pipes and other manufacturing fields.
T2 is pure copper with a copper content higher than 99.90%. When users have higher conductive performance requirements for materials, T2 copper tubes will be the best choice.
TU1 is oxygen-free copper, with copper content ≥99.97%, extremely low oxygen and impurity content, high purity, excellent electrical and thermal conductivity, good ductility, and good processing performance, welding, corrosion resistance, and cold resistance. Due to the high production requirements and high costs, its product price is much higher than other types of copper tubes.
Brass tube: copper-zinc alloy tube. The number after the H letter in the grade often represents the intermediate value of its copper content, and the zinc content is the remaining amount. Brass tubes of different grades, as the copper content becomes higher and higher, generally show better quality and elongation performance. Mainly used as connectors for water pipes and water wading.
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2. Judgment of the quality of copper tubes
1. Generally, when purchasing, you need to observe the appearance of the copper pipe to judge. The first thing is to look at the color of the copper pipe. Make different color judgments according to the type of copper pipe purchased. For example, red copper pipes, generally red copper with a reddish color is better. Copper, inferior copper has impurities in it.
2. Generally, good copper pipes are made of pure copper and have better extensibility, so high-quality copper pipes will have a deep line. After scratching the inside of the copper pipe, if it is the same as the outer wall, it means that the overall quality of the copper pipe fitting is relatively high. But if the color or other aspects are different, it is very likely that some substances similar to iron are added to it. However, better copper pipes are mostly used in the military industry and other special industries.
3. Generally processed copper tubes are mainly divided into three types: hard, semi-hard and soft. Different shapes have different flexibility. Generally, they can be determined by bending the copper tube. High-quality copper tubes are very easy to bend. It is bent, but if it is difficult to bend or cracks appear after bending, it indicates that the quality of the copper pipe fittings is not very good.
Conclusion: High-quality copper pipes have strong plasticity, while inferior copper pipes have no metallic luster on the surface and are prone to scabs and pits, holes, etc. on the surface.
3. Calculation formula of weight and length of air conditioner TP2 copper tube
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Weight per meter (㎏/m) = 0.02796 × wall thickness (㎜) × (outer diameter - wall thickness) (㎜)
Length per kilogram (m/kg)=1/weight per meter
