API tubing is very important in the oil industry, But do you know What are the criteria for classification of the tubing? Now I will introduce the different kinds of the tubing. Tubing is divided into three groups: tubing in grades H40, J55, and N80; restricted-yield tubing grades L80, C90, and T95; high-strength tubing in seamless grade P110. The number in the grade designation represents the lowest yield strength of the steel in thousand psi. API defines the yield strength as the tensile stress required to produce a specific total elongation per unit length on a standard test specimen.
Due to the relatively low yield strength, grade H40 is generally not used in tubing sizes. J55, commonly used grade for most wells, has been the “standard” grade for tubing in most relatively shallow (< 9,000 ft) and low-pressure (< 4,000 psi) wells on land. N80, a relatively old grade with open chemical requirements, is susceptible to H2S and acceptable for sweet oil and gas wells in design conditions. L80 is a restricted yield-tubing grade that is available in Type 1, 9Cr, or 13Cr. L80Type 1 is less expensive, but more subjects to weight-loss corrosion, commonly used in oil and gas fields.
Despite the popularity for CO2-and mild H2S-contaminated wells in the past, Type 9Cr has largely been supplanted by Type 13Cr. L80 13Cr tubing pipe has become popular for its good CO2-induced weight-loss corrosion resistance properties. We have different kinds of tubing,you can contact with me when you need.