Inspection standard of seamless steel pipe

Steel pipe geometry and shape inspection:

` Inspection of steel pipe wall thickness: micrometer, ultrasonic thickness gauge, no less than 8 points at both ends and record.

aExamination of steel pipe outer diameter and ovality: caliper, vernier caliper, ring gauge, measure the maximum and minimum points.

b Steel pipe length inspection: steel tape measure, manual and automatic length measurement.

c Inspection of steel pipe curvature: straightedge, level (1m), feeler gauge, thin wire to measure curvature per meter and full length curvature.

d Inspection of bevel angle and blunt edge of steel pipe end face:

Square, card board. Steel pipe surface quality inspection: 100%

` Manual visual inspection: lighting conditions, standards, experience, signs, steel pipe rotation.

aNon-destructive inspection:

1. 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

1. Eddy current flaw detection ET: (electromagnetic induction) is mainly sensitive to point-shaped (hole-shaped) defects.

�� Standard: GB/T 7735-2004 Level: Level B

1. 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
2. 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.
3. Penetration inspection: fluorescence, coloring, and detection of surface defects of steel pipes.

Steel management performance inspection:

`Tensile 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 (à10, à12.5) 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

aImpact 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) bHardness test: Brinell hardness HB , Rockwell hardness HRC, Vickers hardness HV, etc. cHydraulic test: test pressure, voltage stabilization time, p=2Sδ/D

Steel pipe process performance inspection: ` 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 aRing test: L=15mm, no cracks are qualified bFlaring and crimping test: the top center taper is 30°, 40°, 60° cBending 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.

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