scope:

Foreword

a. This recommended practice was prepared by and is under the jurisdiction of the API Committee on Standardization of Tubular Goods.

b. The statements on corrosion of casing and tubing as given herein, were developed with the cooperation of the Technical Products Committee on Corrosion of Oil and Gas Well Equipment, National Association of Corrosion Engineers.

c. Other specifications and recommended practices Standardization of Tubular Goods include the following:

5A: Specification for Casing, Tubing, and Drill Pipe.

Covers seamless and welded steel, welded open-hearth iron, and welded wrought-iron casing and tubing, seamless steel drill pipe, also (as tentative) seamless and electric-welded steel liners. It includes regular and internal-upset casing with short and long threads, plain-end liners, non-upset and external-upset tubing, and internal-upset and external-upset drill pipe-in the sizes and wall thicknesses applicable to the various grades of pipe as shown in the standard lists and in the dimensional tables. Dimensional requirements on threads and gages, and stipulations on gaging practice also are covered, as well as requirements for couplings and thread protectors.

5B: Specification for Inspection of Threads.

Covers methods of inspecting internal and external pipe threads and descriptions of instruments for measuring thread elements.

5L: Specification for Line Pipe.

covers seamless and welded steel, seamless and welded open-hearth-iron, and welded wrought-iron line pipe in various grades. It includes standard-weight threaded line pipe, and regular-weight, special, extra-strong, and double-extra strong plain-end line pipe. Processes of manufacture, chemical and physical requirements, methods of test, and dimensions are included, also thread and gage dimensions are included, also thread and gage dimensions, gaging practice, and requirements on couplings and thread protectors.

5LX: Specification for High-Test Line Pipe.

Covers various grades of seamless and welded steel line pipe having greater tensile and bursting strengths than for pipe manufactured under API Std 5L. Processes of manufacture, chemical and physical requirements, methods of test and dimensions are included.

5A1: Minimum Performance Properties for Proposed API High-Strength Casing Joints.

Covers joint strength for short and long thread, non-upset and internal-upset casing joints.

5C2: Bulletin on Performance Properties of Casing and Tubing.

Gives collapse pressure, internal yield pressures, and joint strengths for casing and tubing conforming to API Std 5A.

d. No recommendations on materials for use as thread compounds are given herein. An investigation of such materials by the Institute is expected to provide information on which recommendations can be based at a later date. For the present it is suggested that the selection of a thread compound be given careful consideration by the user, bearing in mind that a satisfactory, compound should possess certain properties, the major of which are (1) to lubricate the thread surfaces to facilitate joint make-up and break-out without galling, and (2) to seal voids between the mating thread surfaces and effectively prevent leakage.

e. No recommendations are given herein on materials, chemicals, or coatings for the protection of tubular products from corrosion or the control of corrosive conditions. Several organizations are actively investigating such corrosion problems and it is suggested that use be made of the latest information available on this subject.