1. This specification covers high-test line pipe in grades X42 and higher. The grade designations to be used under this specification comprise the letter X followed by the first two digits of the specified minimum yield strength. Requirements on process of manufacture@ physical properties@ methods of test dimensions@ and test pressures are specified for grades X42@ and X52. Chemical and flattening test requirements are specified for grade X42 only@ such requirements for grades X46 and X52 being subject to agreement between the purchaser and the manufacturer. Other grades@ available under this specification@ are subject to agreement between the purchaser and the manufacturer as to chemical tensile@ and flattening test requirements@ but are subject to all other requirements as given herein. 2.Nothing contained in this specification is to be construed as granting any right by implication or otherwise@ for manufacture@ sale@ or use in connection with any method@ apparatus@ or product covered by letters patent@ nor as insuring anyone against liability for infringement of letters patent.