Acceptance of ERW,LSAW straight seam steel pipe:
1 The quality inspection and acceptance of straight seam steel pipes shall be carried out by the technical quality supervision department of the supplier.
2 The supplier must ensure that the delivered straight seam steel pipe meets the requirements of the corresponding product standard. The purchaser has the right to inspect and accept according to the corresponding product standards.
3 Straight seam steel pipes should be submitted for acceptance in batches, and the batching rules should meet the requirements of the corresponding product standards.
4 The inspection items, sampling quantity, sampling location and test method of the straight seam steel pipe shall be in accordance with the provisions of the corresponding product standards.
With the consent of the purchaser, hot-rolled seamless longitudinally seam steel pipes can be sampled in batches according to the rolling roots.
5 Longitudinal seam steel pipe test results, when certain does not meet the requirements of the product standard, the unqualified should be picked out, and double the number of pieces from the same batch of straight seam steel pipes shall be selected for re-inspection of the unqualified items.
If the re-inspection result (including any index required by the project test) is unqualified, the batch of straight seam steel pipes shall not be delivered.
The following inspection items are not allowed to be re-inspected when the initial inspection fails:
a. There are white spots in the low-power tissue;
6 If the re-inspection results are unqualified (including the unqualified microstructure of the initial inspection results and items that are not allowed to be re-inspected), the supplier can submit the inspection and acceptance one by one; or re-heat treatment (the number of re-heat treatments shall not exceed two) , To submit a new batch for acceptance.
7 If there are no special regulations in the product standard, the chemical composition of the straight seam steel pipe shall be checked and accepted according to the melting composition.
Steel pipe marking:
a. Straight seam steel pipes with an outer diameter of not less than 36mm and special-shaped straight seam steel pipes with a section circumference of not less than 150mm shall be sprayed, stamped, rolled, steel stamped or pasted on the end of each straight seam steel pipe. The mark should be clear and obvious, not easy to fall off. The imprint shall include the steel grade, product specification, production standard number and supplier’s imprint or registered trademark. The alloy steel straight seam steel pipe shall be printed with the heat number and batch number after the steel grade. The joints of straight-seam steel pipes for geological and petroleum use shall be marked with brand or steel grade. The left-hand threaded straight seam steel pipe shall be printed with the word "Left" after the standard number. Welded longitudinal seam steel pipes and galvanized welded longitudinal seam steel pipes for low-pressure fluid transportation, electric wire casing, general-purpose electric welded longitudinal seam steel pipes, special-shaped section welded longitudinal seam steel pipes, and complex section special-shaped seamless longitudinal seam steel pipes may not Print a note on the seam steel pipe.
b. Straight seam steel pipe with outer diameter less than 36mm and special-shaped straight seam steel pipe with section circumference less than 150mm may not be printed.
Tips: In case ASTM A53 Grade B in ERW (electric resistance welded) pipe, the weld seam shall be done the heat treatment with a minimum 1000°F [540°C]. In this way the no untempered martensite remains.
In case ASTM A53 B pipe in cold expanded, then expansion should not exceed 1.5% of the required OD.