Low Pressure Fluid Pipe Detection Method

1. Tensile property test
Before the test, calibrate the test equipment to ensure the accuracy of the test data; prepare the test piece and mark the original gauge length; set the zero point of the test force to ensure that the force measurement system should not change during the test; choose the appropriate Clamp to ensure that the clamped specimen is subject to axial tension. At the beginning of the test, the sample is stretched at a specified rate until the sample breaks. Pay attention to recording the data.
Determination of tensile strength: Tensile strength is the stress corresponding to the corresponding maximum force.
Determination of upper yield strength: It can be measured from the force-extension curve or the peak force display, and is defined as the stress corresponding to the maximum force value before the force first decreases. The upper yield strength is calculated by dividing this force by the original cross-sectional area of the specimen.
Determination of elongation after fracture: The fractured parts of the sample should be carefully matched together so that their axes are on the same straight line. Special measures should be taken to ensure that the fractured parts of the sample are in proper contact and the gauge length after fracture should be measured and calculated according to the formula Elongation after break.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2. Flattening performance test
Place the sample between the two pressure plates of the testing machine. Note that the edges of the sample are allowed to be rounded or chamfered by filing or other methods; the width of the pressure plate should exceed the width of the flattened sample. Move the pressing plate in the direction perpendicular to the longitudinal axis of the pipe for flattening. The moving speed of the pressing plate should not exceed 25mm/min. After the test, observe the sample. Without using a magnifying glass, if there are no visible cracks, it should be evaluated as qualified; if there are only slight cracks at the edges and corners of the sample, it should not be used as a basis for rejection.
3. Galvanized layer uniformity test
The uniformity of the galvanized layer was tested using the copper sulfate dipping method. The oil stains on the surface of the sample should be removed first, and then wiped clean with a clean soft cloth. The specimen should be immersed with the cut end downward, the length immersed in the solution should not be less than 100mm, and immersed in the copper sulfate solution for 5 consecutive times. During the test, the temperature of the sample and solution should be maintained within the specified range, and no stirring is allowed. Each immersion time of the sample needs to last 1 minute. After taking it out, it should be washed immediately in flowing water, and all black sediment should be cleaned up with a soft brush and then dried with a soft cloth. Except for the last immersion, the specimen shall be immediately re-immersed in the solution. Note that the test solution should be discarded and should not be used after 20 times of immersing the sample.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4. Determination of galvanized layer weight
The weight of the galvanized layer is measured using the antimony chloride method. The surface of the sample is not allowed to have rough surfaces and zinc nodules, and the surface of the sample should be washed with a pure solvent, rinsed with ethanol, washed with clean water, and then painted with varnish on both ends of the sample and fully dried. . Use a balance to weigh the sample, and immerse the sample into the test solution, one sample at a time. The liquid level should be higher than the sample. The solution temperature should not exceed 38°C during the measurement process. When the hydrogen generation of the sample in the solution becomes very small and the zinc coating has disappeared, take out the sample. Rinse the sample in clean water and dry it with cotton or clean cloth. After it is completely dry, weigh it on the balance. After the zinc layer of the sample is peeled off, the outer diameter and inner diameter should be measured in two mutually perpendicular directions at the end of the sample, and the average value should be taken as the actual outer diameter and inner diameter. The sample solution can be reused if the zinc layer can be easily removed.