Step 1: appearance

　　To judge whether the copper pipe is good or bad, first look at the inside and outside of the copper pipe. Generally, it should be clean, bright, no obvious oxidation discoloration, no sand holes, pinholes, cracks, peeling, bubbles, black inclusions, green rust, bumps, mold marks, etc; There should be no free wrinkles, scratches, pits, obvious ring marks and other defects. If there are no obvious defects above, and the hand feels lubricated, the appearance is purplish red, and the light is common, the discrimination is completed.

　　Step 2: function

　　Copper has good ductility and plasticity, so it is also a good way to check the function of copper pipe after bending. Generally, the copper pipes processed and formed are mainly divided into hard state, semi-hard state and soft state. The ductility, plasticity and flexibility of copper pipes under different conditions are also different. The length of commonly used soft copper pipes is often easy to bend and insist on no cracking. When bending, it is difficult to bend or the surface crack and fracture of copper pipes indicate that the quality of copper pipes is not very good.

　　Step 3: maintenance

　　To confirm the quality of copper pipe, it also needs to be identified by means of detection scale deviation, chemical composition, mechanical function, process function, grain size, eddy current flaw detection and so on.

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