Inspection of Seamless Steel Pipe

Sources: this site    Click:    Date: 2015-9-10 15:54:34
1.Chemical composition analysis of seamless steel pipe: chemical analysis, instrumental analysis method (infrared C-S instrument, direct reading spectrometer, zcP etc.).
① infrared C-S instrument: analysis of ferroalloys, steel materials, the C and S elements in the iron and steel.
② direct reading spectrometer:C, Si, Mn, P, S, Cr, Mo, Ni, Cn, A1, W, V, Ti, B, Nb, As, Sn, Sb, Pb, Bi  of bulk sample
③N-0 instrument: gas content analysis of N, O
2.geometry and appearance inspection of seamless steel pipe:
① pipe wall thickness check: micrometer, ultrasonic thickness gauge, no less than 8 points recorded in the ends.
② pipe diameter and ovality check: calipers, vernier caliper, ring gauge, measure the maximum points and minimum points.
③ pipe length inspection: steel tape, manual and automatic length measurement.
④ pipe bending tests: ruler, horizontal foot (1m), feeler, thin curved measured per meter, length of curvature.
⑤ pipe end beveling angles and blunt edge inspection: square, card board.
3. Surface quality inspection of seamless steel pipe: 100%
① artificial visual inspection: lighting conditions, standards, experience, identity, steel turning.
② NDT inspection:
a. ultrasonic testing UT:. More sensitive to a variety of materials uniform surface and internal defects in material cracks. Standard: GB/T 5777-1996 levels:. C5 grade
b. eddy current testing ET :( electromagnetic induction) mainly sensitive to point-like (hole-shaped) defect. Standard: GB/T 7735-2004 level: B grade
c. magnetic particle and magnetic flux leakage inspection MT: magnetic detection is suitable for detecting surface and near-surface defects of ferromagnetic materials. Standard: GB/T 12606-1999 Level: C4 grade
d. electromagnetic ultrasonic flaw: No coupling medium, can be applied to high temperature and high speed, rough pipe surface flaw detection.
e. penetrant: fluorescent, colored steel surface defect detection.
4.Physical and Chemical Properties test of seamless steel pipe:
① tensile test: measuring stress and deformation to determine the material strength (YS, TS) and plasticity index (A, Z) vertical and horizontal sample tube segment, arc, circle the specimen (¢ 10 , ¢ 12.5) small-diameter, thin-walled large diameter, thick-walled calibration distance.
② impact test: CVN, the gap C, V-type, power J value J / cm2
standard samples 10 × 10 × 55 (mm) non-standard test sample 5 × 10 × 55 (mm)
③ hardness test: Brinell hardness HB, Rockwell hardness HRC, Vickers hardness HV, etc.
④ hydraulic test: test the pressure and the regulator of time, p = 2Sδ / D
5.process performance inspection of seamless steel pipe:
① flattening test: Round Sample C-shaped specimen (S / D> 0.15) H = (1 + 2) S / (α + S / D) L = 40 ~ 100mm deformation coefficient per unit length = 0.07 ~ 0.08
② ring pull test: L = 15mm crack-free for qualified
③ flaring and curling trials: top center taper 30 °, 40 °, 60 °
④ bending test: can replace flattening test (for large diameter pipe)