What are the testing items and methods for seamless steel pipes

Seamless steel pipes, as important transportation pipelines, are widely used in industries such as petroleum, natural gas, chemical, and power. During use, they must undergo rigorous testing to ensure pipeline quality and safety.

The testing items for seamless steel pipes include shape, dimensions, surface quality, chemical composition, tensile strength, impact testing, flattening, flaring, bending, hydraulic testing, and galvanizing.

Testing methods for seamless steel pipes:

1. Tensile test: Conducted according to GB/T 228.1.

2. Impact test: Conducted according to GB/T 229. For seamless steel pipes of grades Q345, Q390, Q420, and Q460 with quality grades B, C, D, and E, a longitudinal impact test should be performed when the outer diameter is not less than 70mm, and the wall thickness is not less than 6.5mm.

3. Flattening test: Conducted according to GB/T 246. For seamless steel pipes of grades 10, 20, Q345, and Q390 with an outer diameter greater than 22 mm to 600 mm and a wall thickness to outer diameter ratio not exceeding 10%, a flattening test should be performed.

4. Flaring test: Conducted according to GB/T 242. For seamless steel pipes of grades 10, 20, and Q345 with an outer diameter not exceeding 76mm and a wall thickness not exceeding 8mm, a flaring test can be performed.

5. Bending test: Conducted according to GB/T 244. Seamless steel pipes with an outer diameter not exceeding 22mm can undergo a bending test. The bending angle is 90°, and the bending mandrel radius is 6 times the outer diameter of the steel pipe. No cracks or splits should appear at the bend after bending.

6. Hydraulic test: Conducted according to GB/T 241. For hydraulic testing of seamless steel pipes, each pipe must be tested individually.

7. The galvanized layer inspection of seamless steel pipes shall be conducted in accordance with GB/T 8163-2018.

8. Surface quality requirements: The inner and outer surfaces of seamless steel pipes shall be free from visually visible cracks, folds, scabs, cuts, and delamination.