What is the API 5L X65 PSL1 pipe?

API SPEC 5L has grades from B to X70 in common use pipelines, so Grade X65 pipe is one of the premium class material.

Same with other API 5L pipe, X65 pipe has two product specification levels of PSL1 and PSL2, and in some cases required for sour service use.

Chemical composition(a, %) of API 5L X65 PSL1 pipe  

a, Cu≤0.50; Ni≤0.50; Cr≤0.50; and Mo≤0.15;

c, Unless otherwise agreed,Nb+V≤0.06;

d, Nb+V+Ti≤0.15;

API 5L Grade X65 or L450 PSL1 pipe is normal carbon steel material among the tree types and for common use, (None corrosion environment but in high pressure pipelines required a certain mechanical properties). so it has the highest content of C, Mn, Si, P, S than the other two types. (These chemical elements is lower the steel is purer). X65 PSL1 pipe Minimum yield strength is 450 Mpa (65300 psi), minimum tensile strength 535 Mpa (77600 psi).