Mechanical Properties Of API 5CT J55 And K55 Oil Casing

Oil casing can be divided into different steel grades according to the strength of the steel itself. Different well conditions require oil casing of different steel materials. This article will introduce in detail the mechanical properties of API 5CT J55 and K55 oil casing.

1. Heat treatment

PSL1 requirements: J55 and K55 in API 5CT are required to be delivered in a rolled state;

PSL2 requirements: In API 5CT, J55 and K55 oil casings should be normalized and tempered as a whole.

2. Tensile test

J55: Yield strength: 379MPa～552MPa; Tensile strength≥517MPa; The minimum elongation of J55 is 19%;

K55: Yield strength: 379MPa ~ 552MPa; tensile strength≥655MPa; the minimum elongation of K55 is 15%.

3. Impact test

J55 and K55 in API 5CT must undergo impact testing. The impact test energy of the minimum size sample is 20J, and the minimum longitudinal impact energy of the full-size sample is 27J.

4. Wall thickness detection

PSL1: There is no coverage requirement for wall thickness measurement of J55 and K55;

PSL2: The optimal surface area coverage of wall thickness measurement J55 and K55 processing full-length automatic inspection systems should reach 25%.

5. Non-destructive testing

PSL1: J55 and K55 do not have mandatory requirements for destructive testing;

PSL2: For all pipelines, J55 and K55 oil casing shall be tested according to one or more standards specified in the API 5CT specification to determine the internal and external surfaces of the pipeline. J55 and K55 can accept L4 longitudinal defect level.