NEWS

check before acceptance
1.1 the quality inspection and acceptance of straight seam steel pipes shall be carried out by the technical quality supervision department of the supplier.
1.2 the supplier shall ensure that the delivered straight seam steel pipes meet the requirements of corresponding product standards. The demander has the right to conduct inspection and acceptance according to the corresponding product standards.
1.3 straight seam steel pipes shall be submitted for acceptance in batches, and the batch rules shall comply with the provisions of corresponding product standards.
1.4 the inspection items, sampling quantities, sampling positions and test methods of straight seam steel pipes shall be in accordance with the provisions of corresponding product standards.
With the consent of the demander, hot-rolled seamless straight seam steel pipes can be sampled in batches according to the rolled root groups.
1.5 if the test results of straight seam steel pipes do not meet the requirements of product standards, the unqualified ones shall be picked out, and double number of samples shall be 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.
If the following inspection items fail to pass the initial inspection, re inspection is not allowed:
a. There are white spots in the macroploid tissue;
b. Microstructure.
1.6 for straight seam steel pipes with unqualified re inspection results (including items with unqualified microstructure in the preliminary inspection results and not allowed to be re inspected), 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 a new batch shall be proposed for acceptance.
1.7 if there are no special provisions in the product standard, the chemical composition of the straight seam steel pipe shall be accepted according to the melting composition.
(2) signs
2.1 for 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, the end of one end of each straight seam steel pipe shall be provided with spray, seal, roll, steel seal or paste mark. The mark shall be clear and not easy to fall off. The stamp shall include the steel brand, product specification, production standard number and the supplier's stamp or registered trademark. Alloy steel straight seam steel pipe shall be printed with heat number and batch number after the steel grade. The pipe joint of geological and petroleum straight seam steel pipe shall be marked with grade or steel grade. For left threaded straight seam steel pipes, the word "left" shall be printed after the standard number. Welded straight seam steel pipes and galvanized welded straight seam steel pipes for low-pressure fluid transmission, wire sleeves, electric welded straight seam steel pipes for general purposes, welded straight seam steel pipes with special sections, and special seamless straight seam steel pipes with complex sections may not be printed on each straight seam steel pipe.
2.2 the straight seam steel pipe with outer diameter less than 36mm and the special straight seam steel pipe with section circumference less than 150mm may not be printed.