1. What are the methods for inspecting the geometric dimensions and shape of seamless steel pipes?
① Inspection of the end face bevel angle and blunt edge of seamless steel pipes: using a square or caliper.
② Inspection of the curvature of seamless steel pipes: using a ruler, level, feeler gauge, and fine string to measure the curvature per meter and the overall length.
③ Inspection of the length of seamless steel pipes: using a steel tape measure, manual or automatic length measurement.
④ Inspection of the outer diameter and ovality of seamless steel pipes: using calipers, vernier calipers, and ring gauges to measure the maximum and minimum points.
⑤ Inspection of the wall thickness of seamless steel pipes: using a micrometer or ultrasonic thickness gauge, recording the thickness at at least 8 points at both ends.

2. What are the methods for chemical composition analysis of seamless steel pipes?
Chemical analysis methods and instrumental analysis methods (infrared C-S spectrometer, direct-reading spectrometer, ZCP, etc.). 
① N-O analyzer: Analyzes the gas content of N and O.
② Direct-reading spectrometer: Analyzes C, Si, Mn, P, S, Cr, Mo, Ni, Cn, Al, W, V, Ti, B, Nb, As, Sn, Sb, Pb, and Bi in bulk samples.
③ Infrared C-S analyzer: Analyzes C and S elements in ferroalloys, steelmaking raw materials, and steel.

3. What are the physical and chemical property tests for seamless steel pipes? 
① Hardness Test: Brinell hardness HB, Rockwell hardness HRC, Vickers hardness HV, etc.
Note: Elongation after fracture is related to specimen size. GB/T 1760
② Impact Test: CVN, notched C-type, V-type, energy J/cm2. Standard specimen 10×10×55 (mm); Non-standard specimen 5×10×55 (mm)
③ Tensile Test: Measure stress and deformation to determine the material's strength (YS, TS) and plasticity (A, Z). Longitudinal and transverse specimens, pipe sections, arc-shaped, and circular specimens (￠10, ￠12.5). Pipe diameter, thin wall; large diameter, thick wall, gauge length.
④ Hydraulic Test: Test pressure, stabilization time, p=2Sδ/D

4. What are the surface quality inspection methods for seamless steel pipes?
① Manual visual inspection of seamless steel pipes: lighting conditions, standards, experience, markings, and pipe rotation. 
② Non-destructive testing of seamless steel pipes:
a. Eddy current testing (ET): Primarily sensitive to point-like (hole-like) defects. Standard: GB/T 7735-2004. Level: B.
b. Ultrasonic testing (UT): Relatively sensitive to surface and internal crack defects in materials of various homogeneous types.
c. Magnetic particle testing (MT) and magnetic flux leakage testing: Magnetic testing suitable for detecting surface and near-surface defects in ferromagnetic materials.
d. Electromagnetic ultrasonic testing: Does not require a coupling medium and can be applied to the surface testing of rough steel pipes at high temperatures and speeds.
e. Penetrant testing: Fluorescent and dye penetrant testing for detecting surface defects in steel pipes.