X stands for pipeline steel in the API standard, 70 is the strength level, and its unit is kpsi.X70 represents the pipeline steel with a minimum yield strength of 70kpsi.
1.Mechanical properties:
Non-proportional extension strength RP0.2 (MPa): 485-605
Tensile strength RM(): ≥570
Elongation A (%): ≥ 18
2. Chemical analysis
C: ≤ 0.16
Si: ≤ 0.45
Mn: ≤ 1.70
P: ≤0.020
S: ≤0.010
V: ≤ 0.06
Nb: ≤ 0.05
Ti: ≤0.06