1. Quality inspection and acceptance of carbon seamless steel tubes shall be undertaken by the supplier's technical quality supervision department.
2. Suppliers must ensure the delivery of steel pipes in accordance with the relevant product standards. Purchasers have the right to inspect and inspect products in accordance with relevant product standards.
3. Carbon seamless steel pipes shall be submitted for batch acceptance, and the rules approved by the Group shall conform to the relevant product standards.
4. Carbon seamless steel pipe inspection items, sampling numbers, sampling sites and inspection methods shall be carried out in accordance with the relevant product standards. With the consent of the demander, the hot rolled seamless steel tube can be sampled by rolling root array.
5. Carbon seamless steel tube test results do not meet the product standards, should not be eligible for single selection, and from the same batch of steel tubes, or take double the number of samples for re-test failure.


If the results of the re-inspection (including any requirement of the test) are not qualified, the pipeline shall not be delivered.
For the following test items, the initial check failed and no re-check was allowed:
A. White spots in low-magnification tissues.
B. Microstructure.


6. For pipes whose re-inspection results are not qualified (including the preliminary inspection results of microstructural failure, and the re-inspection items are not allowed), the supplier may submit them to the root for acceptance, or the re-heat treatment (re-heat treatment shall not exceed two times) to the latest batch for acceptance.
7. If there is no product standard, the chemical composition of steel tube smelting parts shall be checked and accepted.