Inspection standard of seamless steel pipe

Steel pipe geometry and shape inspection:
① Inspection of steel pipe wall thickness: micrometer, ultrasonic thickness gauge, no less than 8 points at both ends and record.
②Examination of steel pipe outer diameter and ovality: caliper, vernier caliper, ring gauge, measure the maximum and minimum points.
③ Steel pipe length inspection: steel tape measure, manual and automatic length measurement.
④ Inspection of steel pipe curvature: straightedge, level (1m), feeler gauge, thin wire to measure curvature per meter and full length curvature.
⑤ Inspection of bevel angle and blunt edge of steel pipe end face:

Square, card board. Steel pipe surface quality inspection: 100%
① Manual visual inspection: lighting conditions, standards, experience, signs, steel pipe rotation.
②Non-destructive inspection:
a. Ultrasonic flaw detection UT: It is more sensitive to the surface and internal crack defects of various materials with uniform materials.
　　 Standard: GB/T 5777-1996 Level: C5
b. Eddy current flaw detection ET: (electromagnetic induction) is mainly sensitive to point-shaped (hole-shaped) defects.
　　 Standard: GB/T 7735-2004 Level: Level B
c. Magnetic powder MT and magnetic flux leakage inspection: magnetic inspection, suitable for the detection of surface and near surface defects of ferromagnetic materials. Standard: GB/T 12606-1999 Level: C4
d. Electromagnetic ultrasonic flaw detection: No coupling medium is required, and it can be applied to high temperature, high speed, rough surface flaw detection of steel pipes.
e. Penetration inspection: fluorescence, coloring, and detection of surface defects of steel pipes.

Steel management performance inspection:
①Tensile test: measure the stress and deformation, determine the strength (YS, TS) and plasticity index (A, Z) of the material, longitudinal and transverse sample tube sections, arc, round sample (￠10, ￠12.5) small diameter , Thin-walled large-diameter, thick-walled calibration distance. Note: The elongation of the sample after breaking is related to the size of the sample GB/T 1760
②Impact test: CVN, notch 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, voltage stabilization time, p=2Sδ/D

Steel pipe process performance inspection: ① Flattening test: round specimen C-shaped specimen (S/D>0.15) H=(1+2)S/(∝+S/D)L=40～100mm deformation coefficient per unit length =0.07～0.08 ②Ring test: L=15mm, no cracks are qualified ③Flaring and crimping test: the top center taper is 30°, 40°, 60° ④Bending test: Can replace flattening test

Tips:
ASTM A500 is a carbon steel cold-formed round section and special-shaped section welded square pipe and seamless square pipe for structural use.