This specification covers high-test line pipe In grades X42 and higher. Requirements on grades X42@ X46@ and X52@ are fully specified. Requirements on grade X60 seamless@ electric flash welded@ and automatic submerged-arc welded high-test line pipe are fully specified except that other chemical compositions are permitted subject to agreement between the purchaser and manufacturer. Requirements on grade X60 electric-resistance welded high-test line pipe are subject to agreement between the purchaser and manufacturer. Requirements on intermediate wall thicknesses and/or intermediate grades (those between grades X4!!@ X46@ X52 and X60) and on grades higher than X60 are specified except !or chemical compositions and certain physical. properties which arc subject to agreement between the purchaser and manufacturer@ within the limitation that the agreed upon requirements must be consistent with the corresponding requirements specified herein !or grades X42@ X46@ X52@ and X60. Nothing contained in this specification is to be construed as granting any right@ by implication or otherwise@ !or manufacture@ sale@ or use in connection with any method@ apparatus@ or product covered by letters patent@ nor as insuring anyone against liability !or infringement of letters patent. This specification is !or the convenience of purchasers and manufacturers in ordering and producing pipe and is not intended to inhibit Purchasers and producers from purchasing and producing pipe meeting specification other than those contained herein nor is it intended in any way to inhibit purchasers !rom purchasing pipe from companies not authorized to use the API monogram.