API 5L X 52 PSL 1

a 0.50% maximum for copper, 0.50% maximum for nickel, 0.50% maximum for chromium, and 0.15% maximum for molybdenum. b For each reduction of 0.01% below the specified maximum concetration for carbon, an increase of 0.05% above the specified maximum concentration for manganese is permissible, up to a maximum of 1.65% c unless otherwise agreed, the sum of the niobium and vanadium contents shall be ≤0.06%. d The sum of the niobium ,vanadium and titanium concentratons shall be ≤0.06%. e Unless otheriwse agreed. f unless otherwise agreed, the sum of niobium, vanadium and titanium concentrations shall be ≤ 0.15%