Quality inspection of seamless steel pipes

When seamless steel pipes are put into use, quality inspection is often required to judge whether they are qualified or not.

1. Chemical composition analysis. Instrumental analysis and chemical analysis can be used. The samples used for chemical analysis are divided into smelting samples, ingot cuttings samples, and pipe samples. The smelting sample generally adopts the instrumental analysis method, and the finished pipe sample adopts the chemical analysis method and the co-analysis method.

2. Size and shape detection. The inspection contents mainly include wall thickness, outer diameter, length, curvature, ovality, port slope, obtuse angle and cross-sectional shape of special-shaped steel pipe.

3. Surface quality inspection. There are many non-destructive testing methods for manual visual inspection and non-destructive testing, such as ultrasonic testing, eddy current testing, magnetic particle testing, magnetic flux leakage testing, electromagnetic ultrasonic testing and penetrant testing.

①Ultrasonic flaw detection: a non-destructive testing method for inspecting the internal defects of materials by using the influence of the acoustic performance differences of materials and their internal defects on the propagation of ultrasonic waves, which is represented by the symbol UT.

② Eddy current flaw detection: a flaw detection method for detecting surface and near-surface defects of steel pipes using the principle of electromagnetic induction, represented by the symbol ET.

③ Magnetic flux leakage detection: magnetize the surface of the steel pipe, pick up the leakage magnetic field of the defect, form a defect electrical signal, and achieve a non-destructive inspection method for finding defects, which is represented by the symbol LT.

④ Magnetic particle inspection: a kind of magnetic leakage inspection, which is a non-destructive inspection method using the phenomenon that the leakage magnetic field attracts magnetic particles in a strong magnetic field, the surface defects of ferromagnetic materials are generated, and it is represented by the symbol MT.

⑤ Radiographic inspection: The inspection method that uses rays to penetrate the object to find the internal defects of the object, which is represented by the symbol RT.

⑥Colored flaw detection: An inspection method of penetrant flaw detection (pt), which incorporates penetrating agents containing colored dyes (such as red dyes) into tiny cracks on the surface of the workpiece.After cleaning, apply adsorbent to make the colored oil in the defect penetrate to the surface, and find and judge the defect according to the colored spots and stripes.

4. Chemical property testing. Mechanical property test, hydraulic test and corrosion test at room temperature or a certain temperature.

5. Process performance test. Including flattening test, ring pull test, flaring and crimping test, bending test.

6. Metallographic analysis. Including low and high magnification examinations.

7. Thread parameter detection of special oil pipes. Including coupling pattern detection, pipe thread detection and detection after the pipe body and coupling are tightened.

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