K65 control-rolled steel plate and longitudinal submerged arc welded pipe used in frigid zone and manufacturing method of longitudinal submerged arc welded pipe

Abstract

The invention discloses a K65 control-rolled steel plate and a longitudinal submerged arc welded pipe used in a frigid zone and a manufacturing method of the longitudinal submerged arc welded pipe, and belongs to the technical field of manufacturing of submerged arc welded pipes. The K65 control-rolled steel plate comprises the following various components in percentages by mass: 0.04-0.08% of C, 1.50-1.75% of Mn, 0.20-0.35% of Si, less than or equal to 0.006% of S, less than or equal to 0.010% of P, less than or equal to 0.23% of Ni, less than or equal to 0.009% of Mo, less than or equal to 0.020% of Ti, 0.025-0.050% of Al, 0.06-0.09% of Nb, less than or equal to 0.01% of N, less than or equal to 0.25% of Cu, 0.10-0.30% of Cr, less than or equal to 0.0005% of B, 0.085-0.224% of V+Nb+Ti, and the balance Fe; Ceq is less than or equal to 0.43, and Pcm is less than or equal to 0.20; and in a microscopic structure of the K65 control-rolled steel plate, the content of bainite is 45-65%, and the content of ferrite is 35-55%. Alloy ingredients and rolling technology parameters of the K65 control-rolled steel plate are optimized, so that the K65 control-rolled steel plate has good low-temperature impact toughness and DWTT performance, and is suitable for manufacturing a K65 steel longitudinal submerged arc welded pipe which is used in the frigid zone, and has the diameter phi equal to 1,422 mm and the wall thickness being 23-27.7 mm, and safe use of the steel pipein the frigid zone is ensured.

Description

technical field [0001] The invention relates to a K65 controlled-rolling steel plate, a straight seam submerged arc welded pipe and a manufacturing method thereof for alpine regions, and belongs to the technical field of submerged arc welded pipe manufacturing. Background technique [0002] With the development of exploration and development of oil and gas resources to remote areas, the construction of transmission pipelines in alpine areas has become a hot spot. In the past, oil and gas pipelines in alpine regions have always adopted the technical route of large diameter and low pressure. The maximum delivery pressure is lower than 9.8MPa, and K60 grade steel pipes are mainly used. In recent years, due to the significant progress made in the development of international oil and gas pipeline technology, the construction of oil and gas pipelines in such areas is also developing towards higher pressure and greater transmission capacity, and the single-pipeline gas transmission...

AI Technical Summary

Problems solved by technology

[0004] In the process of realizing the present invention, the inventors found that there are at least the following problems in the prior art: the properties of the base material of the steel pipe, the weld seam of the steel pipe, and the hot zone in the prior art cannot meet the requirements at low temperatures, so that the steel pipe cannot Use in alpine areas

Images