Acceptance mark of straight seam steel pipe

Posted by chase Liu on May 22nd, 2023

Acceptance of straight seam steel pipes (such as ERW pipes and LSAW pipes)

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 delivery of straight seam steel pipes meets the requirements of the corresponding product standards. The buyer has the right to inspect and accept the products according to the corresponding product standards.

3. Straight seam steel pipes should be submitted for acceptance in batches, and the batching rules should comply with the provisions of the corresponding product standards.

4. The inspection items, sampling quantity, sampling location and test method of straight seam steel pipe shall be in accordance with the provisions of the corresponding product standards.

5. Test results of straight seam steel pipes. When a certain item does not meet the requirements of the product standard, the unqualified ones should be picked out, and double the number of samples should be randomly taken from the same batch of straight seam steel pipes for re-inspection of 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. For the following inspection items, if the initial inspection fails, re-inspection is not allowed: white spots in low-magnification tissue; microstructure.

6. For the straight seam steel pipes whose re-inspection results are unqualified (including those whose microstructure is unqualified in the preliminary inspection results and re-inspection is not allowed), the supplier can submit them for acceptance one by one. Or re-heat treatment (the number of re-heat treatment shall not exceed twice), and submit a new batch for acceptance.

7. If there is no special regulation in the product standard, the chemical composition of the straight seam steel pipe shall be checked and accepted according to the melting composition.

Mark of straight seam steel pipe

1. Straight seam steel pipes with an outer diameter of not less than 36mm and special-shaped straight seam steel pipes with a cross-sectional circumference of not less than 150mm should have spray printing, stamping, rolling, steel stamping or pasting marks on one end of each straight seam steel pipe. The imprint should be clear and obvious, not easy to fall off. The imprint shall include the steel grade, product specification, production standard number and the supplier's imprint or registered trademark. For alloy steel straight seam steel pipes, the furnace number and batch number should be printed after the steel grade. The pipe joints of straight seam steel pipes for geological and petroleum use shall be marked with grades or steel grades. For left threaded straight seam steel pipes, the word "left" should be printed after the standard number. Welded straight seam steel pipes and galvanized welded straight seam steel pipes for low-pressure fluid transportation, electric welded straight seam steel pipes for general purposes, welded straight seam steel pipes with special-shaped cross-sections, special-shaped seamless straight-seam steel pipes with complex cross-sections,it is not necessary to print a mark on each straight seam steel pipe.

2. Straight seam steel pipes with an outer diameter of less than 36mm and special-shaped straight seam steel pipes with a section circumference of less than 150mm may not be marked.

3. There should be no less than 2 signs on each bundle of straight seam steel pipes packed in bundles (one sign can be hung on each straight seam steel pipe with a mark). The label should indicate: the supplier's seal or registered trademark, steel grade (except for those not specified in the product standard to be delivered according to the furnace number), batch number, contract number, product regulations, product standard number, weight or root number, date of manufacture and The imprint of the supplier's technical supervision department.

4. For straight seam steel pipes and pipe joints packed in containers, a label should be attached in the container. A label should also be hung on the outer end face of the container.

5. If there is any requirement for increase or decrease of the mark of straight seam steel pipe, it shall be stipulated in the product standard, or it shall be agreed between the supplier and the buyer.