Quality Test

A tube sample, one sample per 6 meters of 10 lengths, must stand and be flared with a tool to form a 60 degree of wide-open mouth of flare without any cracks or imperfections.

Tube sample shall be split longitudinally 90 degree on each side of the weld and the sample opened and flattened with the weld at the point of maximum bend without cracking or lack of penetration or overlaps resulting from flash removal in the weld.

Hardness test is an method to evaluate tensile strength, yield strength and elongation of a tube whether it can endure high pressure.

Each tube, with internal surface clean and dry, shall be internally pressurized to 150 psi (1034 kPa) minimum with clean and dry compressed air while being submerged in clear water. The tube shall be well lighted, preferably by underwater illumination. Any evidence of air leakage of the pneumatic couplings shall be corrected prior to testing. Inspection shall be made of the entire external surface of tube after holding the pressure for not less than 5 seconds after the surface of the water has become calm. If the tube shows leakage during the air underwater test, it must be rejected. Any leaking areas may be cut out and the tube retested.

After the surface is finished by mechanical polishing, the roughness measurement (RA) must be applied in longitudinal direction. Moreover, this measurement must be a matter of agreement with our customers.

We test a sample from the first tube from a batch and compare it to the specimen.

1. If the sample passes, continue polishing. Thereafter, all of them must be measured in roughness test.
2. If the sample doesn’t pass, readjust the machines, re-polish the sample and re-test.