Test method for API 5L pipelines

　　API 5L is the implementation standard of steel pipe for pipeline transportation system. As we know, this standard specification includes Grade B, X42, X46, X52, X56, X60, X65, X70, X80 etc. And divided in two product specification level, PSL1 and PSL2. More over, API 5L pipe is also the pipeline steel pipe, applied to the oil and gas transmission system. Meanwhile, other fluids like steam, water, slurry adopts the API 5L standard for the transmission purposes. Below we will introduce the methods for API 5L line pipe.

　　1). Hydrostatic test

　　a. Jointers need not be hydrostatically level, provided that the portions of pipe used in making the jointers were successfully hydrostatically tested prior to the joining operation.

　　b. Except the previous situation, the pipe shall withstand the hydrostatic test without leakage through the weld seam or the pipe body.

　　2). Bend test

　　Cracks should not occur in any part of the sample and opening of weld shall not occur as well.

　　Please Note: For all bend test, the weld extends to a distance of 6.4 mm (0.25 in) on each side of fusion line.

　　3). Flattening test

　　The flattening test method is used to verify the deformation performance of line pipe to the specified size, and display its defects. According to the stress and deformation characteristics of the specimen during the flattening process, the flattening test shall show the resistance to longitudinal cracking and circumferential cracking of the pipe, and display its internal defects and surface defects.