API 5L Line pipe spec

The American Petroleum Institute specification API 5L 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-flowline(TFL) pipe.

Seamless API pipes

+ API 5L SSAW Pipe

Line Pipe with Plain End and Beveled

+ Tubing and Casing, Line Pipes

Material X52

+ API 5L LSAW 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.

1.2 Dimensional requirements on threads and thread gauges, stipulations on gauging practice, gauge specifications and certification, as well as instruments and methods for inspecition of threads are given in API Standard 5B and are applicable to products covered by this specification.

Grades covered by this specification are A25, A, B, X42, X46, X52, X56, X60, X65, X70, and X80 and grades intermediate to the Grades X42 and higher listed (see note). The chemical composition and mechanical properties of intermediate grades that are subject to agreement between the purchaser and the menufacturer must be consistent with the corresponding requirements for the grades to which the material is intermediate.
Note : The grade disignations used herein for Grades A and B do not include reference to the specified minimum yield strength. Other grade designations used herein comprise the letter A or X followed by the first two digits of the specified minimum yield strength.
1.3 Pipe manufactured as Grade X60 or higher shall not be substituted for pipe ordered for Grade X52 or lower with-out purchaser approval.
1.4 Although plain-end line pipe meeting this specifiecation is primarily intended for field makeup by circumferential welding, the manufacturer will not assume responsibility for field welding.
1.5 For regular-weight and special plain-end pipe(special weight) whown in Tables 6A, 6B, and 6C and for standard weight threaded pipe larger than nominal size 12, the size designations used herein are outside diameter sizes. For all other pipe, the size designations are nominal pipe sizes. In the text of this specification, pipe size limits(or size ranges)are outside diameter sizes except where stated to be nominal. These outside diameter size limits and ranges also apply to the corresponding nominal sizes.
1.6 Class Ⅱ steel is rephosphorized and problbly has better threading properties than Class I. Because Class Ⅱ has higher chemical properties than Class I, it may be somewhat more difficult to bend.
1.7 U.S. customary units are used in this specification; metric(SI) units are shown in parenthese in the text and in many tables. See Appendix J for specific information about rounding procedures and conversion factors.

Material Requirements

2.1.1 Chemical Composition
The composition of pipe furnished to this specification, as determined by heat analysis for pipe other than Grade X 80, shall conform to the chemical requirements specified in Table 2, except that by agreement between the purchaser and the manufacturer carbon contents higher than those specified may be used. the composition of intermediate grades(higher than X42)shall conform to chenical requirements agreed upon between the manufacturer and the purchaser, and such requirements shall be consistent with the requirements specified in Table 2 for the applicable type of pipe For Grades X42 and higher, by agreement between the purchaser and the manufacturer, element other than columbium, vanadium, and titanium may be used; however, caution should be exercised in determining the quantity that may be present for any particular size and thickness of pipe because the addition of such otherwise desirable elements may alter the weldability of the pipe.

2.1.2 Elements Analyzed
As a minimum, each required analysis shall determine the following;
a. Carbon, manganese, phosphorus, sulphur, and silicon.
b. Columbium, vanadium, titanium, or combinations thereof, if added during steelmaking.
c. Any other alloying element added during steelmaking for other than deoxidation purpose.
2.1.3 Product analysis Variation
product analyses shall conform to the chemical requirements shown in Table 2, within the following permissible variations for product analyses, except for Grade X80 pipe where the requirments in Table2 are for product analysis;

Percent of Variation
a. Carbon:
Seamless pipe-all nonexpanded and cold expanded smaller than size20
seamless pipe-cold expanded size 20 and larger in Grades X42 and higher
Welded pipe
b. Manganese:
All grades through B
Where minimum is specified
Grade X42 and higher
c. Phosphorus:
Where minimum is specified
d. Sulfur

Table 1-Chemical Requriements for Heat Analyses by Percentage of Weight

Table2 Tensile Requirements

*The minimum elongation in 2 in. (50.80mm)shall be that determined by the following equation;

U.S. Custiomary Equaution

Metric Equation


See Appendix D for minimum elongation values for various size tensile specimens and grades. The minimum elongations for round bar tensile specimens [0.350 in.(8.9mm)diameter with 1.4 in. (35mm) gauge length, and 0.500 in.

(12.5mm) diamter with 2.00 in (50.8mm) gauge length] shall be that shown in the Area A line of 0.20sq. in. in Table D-1, Appendix D.


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