Manufacturing method of high-strength and high-toughness plate coil for high-precision spiral submerged arc welding pipe

Abstract

The invention belongs to the field of manufacturing of low-carbon microalloy pipeline steel, and particularly relates to a manufacturing method of a high-strength and high-toughness plate coil for a high-precision spiral submerged arc welding pipe. According to the method, a high-strength pipeline steel low-temperature toughness control system with organizational unit regulation as the core is constructed, a low-temperature accumulated large deformation and low-temperature phase change process technology is developed, the problems of refining and homogenization of the organizational unit of a thick plate coil under the low compression ratio are solved, and the breakthrough of the low-temperature toughness control technology (DBTT85% is smaller than or equal to -40 DEG C) is achieved. The ultra-fast cooling water temperature-pressure coupling control and section temperature feedback control technology and the plate coil camber compensation control technology are developed, the problems that the plate coil low-temperature controlled cooling (smaller than 500 DEG C) temperature field is unstable and the plate coil shape control deviation exists are solved, the through coil performance homogenization (the strength fluctuation is smaller than or equal to 40 MPa) and the camber being smaller than or equal to 8 mm / 5 m are achieved, and the pipe manufacturing forming precision is guaranteed.

Description

Technical field [0001] The present invention belongs to the field of manufacturing low carbon micro-alloyed pipeline, particularly relates to a high precision SAW spiral pipe coil manufacturing method of high strength and toughness. Background technique [0002] With steel demand delivery volume, delivery pressure increases and natural gas pipeline network moving large thickness, high grade and excellent low-temperature toughness direction. TECHNICAL pipe in addition to the requirements for mechanical properties with strict technical requirements of the oval shape of the steel pipe, forming higher dimensional accuracy than welds are made stringent technical requirements, engineering requirements as a fault on both sides of the weld ≤ 1.5mm sides, the pair of front roll forming process of the steel plate coils during the dimensional accuracy, the stress control are further demands, while the thickness of high strength steel, high-grade pipeline itself has high strength and toughne...

AI Technical Summary

Problems solved by technology

[0007] In order to solve the technical problems of producing high-strength, high-toughness and high-precision coils in the hot continuous rolling production line, there are mainly two problems, the problem of thinning the microstructure of thick plates with low compression ratio, and the low-temperature controlled cooling (<500°C) temperature of high-strength coils. Field instability and coil shape control deviation problems

The present invention aims at the difficulties in the production of X70 and X80 pipeline steel coils with a wall thickness of 17-25.4mm for high-precision spiral welded pipes in the current hot continuous rolling production line, and constructs a high-strength pipeline steel low-temperature toughness control system centered on tissue unit regulation, and develops "Low-temperature cumulative large deformation + low-temperature phase transformation" process technology solves the problem of thinning and homogenizing the structure unit of thick plate coils under low compression ratio, and realizes a breakthrough in low-temperature toughness control technology

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