① Steel pipe wall thickness inspection: micrometer, ultrasonic thickness gauge, no less than 8 points at both ends and recorded.
② Steel pipe outer diameter and ovality inspection: snap gauge, vernier caliper, ring gauge, measuring point, minimum point.
③Steel pipe length inspection: steel tape measure, manual and automatic length measurement.
④ Steel pipe curvature inspection: Use a ruler, level (1m), feeler gauge, and thin wire to measure the curvature per meter and the curvature of the entire length.
⑤Inspection of steel pipe end bevel angle and blunt edge: square ruler, clamping plate.
Steel pipe surface quality inspection:
① Manual visual inspection: lighting conditions, standards, experience, markings, steel pipe rotation.
②Non-destructive testing inspection:
a. Ultrasonic flaw detection UT: It is sensitive to surface and internal crack defects of uniform materials of various materials. Standard: GB/T5777-1996 Level: C5
b. Eddy current flaw detection ET: (electromagnetic induction) is mainly sensitive to point-shaped (hole-shaped) defects. Standard: GB/T7735-2004 Level: Level B
c. Magnetic particle MT and magnetic flux leakage inspection: Magnetic inspection is suitable for detecting surface and near-surface defects of ferromagnetic materials. Standard: GB/T12606-1999 Level: C4
d. Electromagnetic ultrasonic flaw detection: No coupling medium is required, and it can be used for surface flaw detection of high-temperature, high-speed, rough steel pipes.
e. Penetrant testing: fluorescence, coloring, detecting surface defects of steel pipes.
Steel management performance inspection:
① Tensile test: measure stress and deformation, and determine the strength (YS, TS) and plasticity index (A, Z) of the material. Longitudinal and transverse sample pipe sections, arc-shaped, and circular samples (￠10, ￠12.5)
Small diameter, thin wall, large diameter, thick wall fixed gauge. Note: The elongation of the sample after breaking is related to the size of the sample GB/T1760
②Impact test: CVN, notched C-type, V-type, work J value J/cm2. Standard sample 10×10×55 (mm) Non-standard sample 5×10×55 (mm)
③Hardness test: Brinell hardness HB, Rockwell hardness HRC, Vickers hardness HV, etc.
④Hydraulic test: test pressure, pressure stabilization time, p=2Sδ/D
Steel pipe process performance inspection:
① Flattening test: round sample C-shaped sample (S/D>0.15) H=(12)S/(∝S/D)L=40~100mm unit length deformation coefficient=0.07~0.08
② Ring pull test: L=15mm without cracks is qualified
③Expansion and curling test: top-center taper is 30°, 40°, 60°
④Bending test: can replace the flattening test (for large diameter pipes)
Post time: Dec-13-2023