Coupling stock is the seamless pipe used for producing coupling of casing and tubing.It has widely use in the oil industry. Why ? Because the coupling has an important role in transport oil.The coupling stock is a very important oil pipe that is used to connect the oil pipeline. In order to ensure that oil does not leak during transmission, it is necessary to ensure that the roundness error of the threaded internal thread is within the allowable error range.
The coupling is a high requirement by connecting the tubing to the tubing and bearing the weight. Due to the particularity of oil and gas exploitation, working condition is very complex, conditions are harsh, and therefore is very strict with the quality requirements. Such as tubing in use process not only withstand the weight of tubing string itself, also need to bear the oil (gas), such as water, acid corrosion, thus linking to its appearance, size, strength, impermeability and comprehensive mechanical properties and corrosion resistance and so on have strict requirements.
The main steel grades of the coupling stock are as per API 5CT SPEC; J55、K55、N80Q、L80-1、L80-9Cr、L80-13Cr、T95、C110.Sour Service grade, such as CB80S-CB110SS.The standard is API SPEC 5CT 9th.The coupling stock is rolled by KPE mill, with good dimension control, high qualified product ratio, stable mechanical and impact property.The range of outside diameter is Φ52.2mm-Φ244.48mm.The wall thickness is 4.2mm-22mm