Preparation method of hot rolled steel coil used for oil and gas pipeline

Abstract

The invention relates to a preparation method of a hot rolled steel coil used for an oil and gas pipeline. The preparation method comprises the following steps of: (1) after designing components, desulphurizing molten iron, then smelting in a converter, switching from nitrogen to argon, then carrying out deep desulfurization and calcium treatment in a ladle furnace, and tapping to obtain molten steel; (2) continuously casting the molten steel to obtain a slab, afterwards heating the obtained slab, then carrying out rough rolling and finish rolling on the slab after dephosphorization by using high-pressure water, and finally winding to obtain the hot rolled steel coil. The preparation method provided by the invention can be used for reducing surface cracks of the slab, improving the one-time qualified rate of the slab, realizing the direct and hot charging rolling of the slab, raising the hot delivery rate of direct charging, saving energy and reducing emission; through reasonable optimization and control of hot rolling process parameters, the water is used for replacing metals, so that the production cost is reduced.

Description

technical field [0001] The invention belongs to the field of steel preparation for oil and gas pipelines, in particular to a method for preparing hot-rolled steel coils for oil and gas pipelines. Background technique [0002] L360M hot-rolled steel coil is a series of steel grades used in oil and gas pipelines. Currently, urban pipe network steel basically uses this steel grade. The market share of pipeline steel is relatively large. L360M steel grade requires a large deformation pipe-making process within a certain temperature range. The specified value of the final mechanical properties remains unchanged, and the surface quality of the steel coil is required to have no defects, good welding performance and high strength and toughness. [0003] Production performance of L360M steel grade steel coil: [0004] Table 1 Statistics of L360M steel coil thickness and performance range [0005] [0006] It can be seen from Table 1 that: [0007] The production thickness of L3...

AI Technical Summary

Problems solved by technology

[0017] At present, the composition design of all steel plants adopts low C, low P, low S, high Nb, V, Ti composite microalloying design to ensure good welding performance and high strength and toughness, but this design has many cracks on the surface of the slab (especially Cracks at the corners of the slab), the probability of cracks on the surface of the slab is high, it is not easy to organize straight, hot charging, and it is necessary to clean the surface after the off-line cold inspection is qualified before loading and rolling, which is not conducive to energy saving and emission reduction; the amount of surface defects of steel coils More, the strength margin is larger, the yield strength is relatively high, and the cold processing performance is affected; the surface cracks of the slab are cold-checked off the line, which not only prolongs the production delivery period, but also brings obstacles to the smooth production, and the production cost is high.

Images