1. Introduction of rod coupling
The sucker rod coupling have the same box thread size in each end are used for connecting sucker rod and/or pony rod, and/or sinker bars with sucker rod threads.
The polished rod coupling have the same box thread size in each end are used for connecting polished rod and/or sinker bars with polished rod threads to the sucker rod string.
The sub-coupling have different sizes of box threads in each end are used for connecting two sizes of sucker rods or a polished rod to a sucker rod string.
2. Manufacturing specification: API 11B
3. Material
3.1. Chemical Composition
The material shall be per manufacturer’s specification and shall have a maximum sulfur content of 0.05%.
3.2. Mechanical Properties
Mechanical properties shall be in accordance with the manufacturer’s specification with a minimum tensile strength of 95,000psi(655MPa). One of the following means shall be used to conform to the tensile requirements:
---determination of the metal material hardness of 56 to 62 HRA inclusive; or
---material test report per 6.3.2.2 for the heat of steel from the original mill if further processing does not change mechanical properties; or
---a tensile test per ASTM A370, OR ISO 6892 with s minimum of two tests performed after final thermal processing.
4. Sprayed metal coating requirements
4.1. Chemical composition
4.2. Coating thickness
Spraying metal coating thickness is 0.010in to 0.020in. (0.25mm to 0.51mm) per side and cover the outside diameter. Spraying metal coating shall extend to the outside diameter of the contact face.
