X80 steel bend pipe and bending technique thereof

Abstract

The invention relates to an X80 steel bent pipe and a process for bending the same, wherein the bent pipe is made of X80 steel. The weight percentage compositions of the steel are: 0.06 to 0.15 percent of C, 0.1 to 0.3 percent of Si, 1.4 to 2.0 percent of Mn, less than or equal to 0.015 percent of P, 0.01 percent of S, 0 to 0.45 percent of Cr, 0 to 0.3 percent of Mo, 0 to 0.3 percent of Cu, 0 to 0.5 percent of Ni, 0.05 to 0.15 percent of Nb, 0 to 0.06 percent of Ti, 0 to 0.06 percent of V, Ceq controlled between 0.36 and 0.44 percent, Pcm controlled between 0.17 and 0.23 percent. The steel controlled rolled steel plate is made into steel pipe and is formed into bent pipe by induction heating bending process. The properties of the bent pipe can completely meet the technical requirement on X80 steel pipes by controlling parameters of heating temperature of the induction heating, bending velocity, cooling velocity, etc. during the bending process, thereby being suitable to be used as bent pipes for oil and gas pipelines.

Description

technical field [0001] The invention belongs to the field of iron and steel, and in particular relates to an X80 steel bent pipe and a bending process thereof. Background technique [0002] The bent pipe can be bent with steel pipes such as seamless steel pipe, straight seam welded pipe or spiral welded pipe according to requirements. The large-diameter elbow is mainly made of straight seam welded pipe and spiral welded pipe. The large-diameter elbow is made by intermediate frequency heating and bending. The two ends of the steel pipe are fixed, and local heating is adopted by induction. Driven by the machine, it moves along a certain bending radius at a certain speed. According to the performance requirements, the steel pipe adopts water spray and other cooling methods to control its structure and performance to meet the performance indicators specified in the technical requirements. At present, the production of large-scale bent pipes is mostly low-strength bent pipes, a...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to overcome the disadvantages of ordinary X80 steel bending performance reduction caused by heating, bending and cooling in the bending process, and provide a kind of X80 steel bending pipe and its bending process. The strength is greater than 555MPa, and the low-temperature impact toughness is greater than 120J. The performance can fully meet the technical requirements of X80 steel elbows, and can be used as X80 elbows for high-pressure transportation of oil and natural gas.