Wide and thick steel plate for hot-bent elbow pipes at X65-X80 levels and manufacturing method of wide and thick steel plate

The invention relates to a wide and thick steel plate for hot-bent elbow pipes at X65-X80 levels and a manufacturing method of the wide and thick steel plate. Especially, proper ingredients, structures and technologies for the steel plate for the elbow pipes at X65, X70 and X80 levels are designed respectively according to different pipe bending technologies of pipe bending factories, and the pipeline steel performance requirement for reaching the related strength levels after hot bending of the pipes is met. The steel plate is 20-40 mm thick and 2,500-4,000 mm wide, the hot-rolled steel plate with excellent toughness, thermal formability and thermal stability is obtained, a solution is provided for steel plates for high-pressure elbow pipes in long delivery pipeline projects, and the usage security of the high-level pipeline steel plate is improved.