API 5L Standard has the provisions of the two product specification levels (PSL1 and PSL2). The two kinds of PSL grade level of the product to the standard stipulated in the technical requirements of different, PSL2 of carbon equivalent, notch toughness, maximum yield strength and tensile strength have mandatory requirements. PSL is short for product specification level.Line pipe product specification level is divided into PSL1 and PSL2, also can say quality grades are divided into PSL1 and PSL2. PSL2 above PSL1, these two levels is not only different inspection requirements, and chemical composition, mechanical performance requirements are different, so the order in API 5 l, the terms of the contract in addition to indicate the specifications and grade of steel usually indicators, must also indicate the level of product specification, namely PSL1 or PSL2. PSL2 in chemical composition, tensile properties, impact energy, and nondestructive testing which strict in PSL1 indicators. PSL1 does not require impact performance, PSL2 all except x80 grade steel, full size 0 ℃ average Akv: longitudinal p j, 41 lateral acuity 27 j.Average grade X80 steel, full size 0 ℃ Akv: longitudinal 101 j, or lateral acuity 68 j. Line pipe should do water pressure test, and the standards are not allowed to nondestructive generation of hydraulic pressure, which is also the API standard and one big difference between our country standard.PSL1 does not require the nondestructive inspection, PSL2 shall by a nondestructive examination.