"80" in X80 indicates carbon content, is it right?

      Answer: No.  "80" in X80 does not indicate the carbon content. X80 steel is API 5L specification is a pipeline steel used for oil and gas transportation. The number 80 in API 5L X80 indicates the minimum yield strength of line pipe 80,000psi (552MPa).

      API 5L X80 is generally known as PSL1 and PSL2. Among PSL2, the delivery status is delivered in normalized, quenched and tempered state, and the normalized state is X80N, Quenching and tempering state is X80Q, TMCP state is X80M.