Several basic methods of seamless steel tube inspection:
1.Inspection of steel pipe geometry and appearance:
(1)Inspection of slope Angle and blunt edge of steel pipe end face: Angle ruler, card plate.
(2)Investigation of bending degree of steel tube: measurement of bending degree and full length of bending degree per meter by linear ruler, horizontal ruler (1m), plug ruler and thin wire.
(3)Torque tube length inspection: steel tape, manual, automatic measuring length.
(4)Inspection of outer diameter and ellipticity of steel pipe: calipers, vernier calipers, ring gauges, measuring the maximum and minimum points.
(5)Inspection of steel tube wall thickness: micrometer and ultrasonic thickness gauge with at least 8 points at both ends recorded.
2. Chemical composition analysis: chemical analysis, instrumental analysis (infrared c-s instrument, direct reading spectrometer, zcP, etc.).
Gas content analysis N, O
Carbon, Si, Mn, P, S, Cr, Mo, Ni, Cn, A1, W, V, Ti, B, Nb, As, Sn, Sb, Pb, Bi in bulk samples
As an infrared c-s meter, it analyzes the C and S elements in iron alloy, steelmaking raw materials and steel.
3. Physical and chemical properties of steel pipes:
(1)Brinell hardness test: brinell hardness HB, rockwell hardness HRC, vickers hardness HV, etc
Note: the elongation after sample breaking is related to sample size GB/T 1760
(2)Vacuum impact test: CVN, gap C, V, work J/cm2
Standard sample 10 x 10 x 55 (mm) non-standard sample 5 x 10 x 55 (mm)
(3) tensile test: stress and deformation measurement, determine the strength of the material (YS, TS) and plasticity index (A, Z) longitudinal and transverse section, arc, circle sample (￠, 10 ￠12.5) diameter, thin wall of large diameter and thick wall scaling.
Hydraulic test: test pressure, pressure stabilizing time, p=2S easier /D
4. Steel tube surface quality inspection: 100%
Manual visual inspection: lighting conditions, standards, experience, marking, steel tube rotation.
Parliamentary non-destructive inspection:
A. Eddy current inspection ET :(electromagnetic induction)
Mainly sensitive to point (hole) defects. Standard: GB/T 7735-2004 level: level B
B. ultrasonic testing UT:
It is sensitive to surface and internal crack defects of materials with uniform materials.
Standard: GB/T 577-1996 level: C5 level
C. Magnetic particle MT and leakage magnetic inspection: magnetic inspection, applicable to the detection of surface and near-surface defects of ferromagnetic materials.
Standard: GB/T 12606-1999 level: C4
D. electromagnetic ultrasonic testing:
No coupling medium is required. It can be applied to the surface inspection of high temperature, high speed and rough dry steel tube.
E. penetration detection:
Fluorescence, coloring and testing of steel tube surface defects