Many friends find it inconvenient to identify the quality of copper tubes when purchasing copper mould tubes. According to the current inspection of copper mo

Many friends find it inconvenient to identify the quality of copper tubes when purchasing copper mould tubes. According to the current inspection of copper mould tubes, there are three standards according to ASTM b88-1996, en1057-x and GB / t18033-2000. Let's analyze:

1. Dimension and deviation

Strictly speaking, the dimensions and deviations of these three standards are different. We should strictly follow the standards selected when ordering. The pipe fitting standard of GB / t18033-2000 is not perfect, so it is recommended to try it carefully. (explanation: deviation indicators include wall thickness and outer diameter, which shall not exceed the standard range, otherwise it will affect pressure bearing and assembly.)

2. Chemical composition

We all know that when purchasing copper pipe, the standard stipulates that copper + silver shall not be set at 99.90%, otherwise it will seriously affect the service life of the copper mould tube.

3. Mechanical property test -- tensile strength and elongation

Tensile strength test shall be conducted for ASTM B88-M pipe, and elongation test items shall be added for EN1057-X pipe.

4. Hydrostatic test and eddy current flaw detection

The hydrostatic test shall be conducted according to 1.5 times the maximum working pressure of the pipe (which can be calculated or found from the standard). According to ASTM, the copper pipe below 80mm must pass eddy current flaw detection.

5. Surface quality

The inner and outer walls of the pipe shall be smooth and clean without defects such as delamination, sand hole and crack. However, slight scratches and slight oxidation that do not exceed the wall thickness deviation shall not be used as the basis for scrapping.

When required by the ordering party, the inner surface of the pipe shall pass the carbon layer test. Applicable to water supply with high quality requirements, such as direct drinking water pipeline, etc.