API Steel Grade – K55, N80, L80, C90, T95, P110, Q125

API, shorted for American Petroleum Institute, is considered as the most authoritative and comprehensive principles for oil and gas industry. API 5B and API 5CT are mainly used for tubing and casing, which standard the chemical properties, steel grades, manufacturing methods, color coding, heat treatment, inspection and other information.

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The API steel grade is also used in the floating equipment production, such as the K-55 steel grade floating shoes.

Here we will introduce the classification and properties of different steel grade in API standard.

Steel grade refers to the yield strength of the products. It can be divided into nine categories of steel grade: H-40, J-55, K-55, N-80, L-80, C-90, T-95, P-110, Q-125.

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In it, the letters are stand for the steel grade, which has no relation with the properties and the number refers to the minimum yield strength. The bigger the number is, the higher yield strength will be.

Besides, the API standard divide the nine categories into four groups, H, J, K, N in the first ground, L, C, T in the second ground, P in the third group and Q in the fourth group.

API was formed in as a standards-setting organization and is the global leader in convening subject matter experts across segments to establish, maintain, and distribute consensus standards for the oil and gas industry. In its first 100 years, API has developed more than 800 standards to enhance operational safety, environmental protection and sustainability across the industry, especially through these standards being adopted globally.

API standards are developed under API’s American National Standards Institute accredited process, ensuring that the API standards are recognized not only for their technical rigor but also their third-party accreditation which facilitates acceptance by state, federal, and increasingly international regulators.

If you are looking for more details, kindly visit api spec 5ct(vi,ar,pl).