API Pipes

The American Petroleum Institute (API), founded in 1919, is the largest petroleum and natural gas industry association in the United States. The main contribution of API is to develop a series of standards for oil and gas industry in accordance with legislative and environmental requirements. The purpose of standards is to help enterprises to improve efficiency and cost-effectiveness.

API 5L pipe production is currently using micro alloy heating treatment process. The production costs of seamless stainless steel pipe are significantly higher than the welding pipe and with the increase of steel grade, the limit of carbon content is more and more strict. At present, all the major manufacturers carry out research work in order to improve the corrosion resistance of the pipeline and ensure the stable performance in low and high temperature.

This API 5L specification Covers Seamless and Welded Steel Line Pipe. It includes standard-weight and Extra-Strong threaded Line Pipe. It includes standard-weight and extra-strong threaded line pipe; and standard-weight plain-end, regular-weight plain-end, special plain-end, extra-strong plain-end, special plain-end, extra-strong plain-end pipe; as as well as bell and spigot and through-the-flow line (TFL) pipe.

The purpose of this specification is to provide standards for pipe suitable for use in conveying gas, water, and oil in both the oil and natural gas industries. Grades covered by this specification are A25 ,A ,B (and the following "X" Grades), X42, X46, X52, X56, X60, X65, X70, X80. The two digit number following the "X" indicates the Minimum Yield Strength (in 000's psi) of pipe produced to this grade.

API 5L Grade Yield Strength min. (ksi) Tensile Strength min. (ksi) Yield to Tensile Ratio (max) Elongation min. (%)*
A 30 48 0,93 28
B 35 60 0,93 23
X42 42 60 0,93 23
X46 46 63 0,93 22
X52 52 66 0,93 21
X56 56 71 0,93 19
X60 60 75 0,93 19
X65 65 77 0,93 18
X70 70 82 0,93 17
X80 80 90 0,93 16

* : API 5L elongation figures vary with specimen dimensions. Values shown for 0.2 sq. in. specimen.