Thick plate with excellent plasticity and toughness for pipelines and production method of thick plate

Abstract

The invention provides a thick plate with excellent plasticity and toughness for pipelines and a production method of the thick plate. The thick plate is prepared from components in percent by weight:0.025%-0.055% of C, 0.26%-0.40% of Si, 1.51%-1.75% of Mn, smaller than or equal to 0.010% of P, smaller than or equal to 0.0015% of S, 0.02%-0.05% of Nb, 0.010%-0.030% of Ti, 0.16%-0.35% of Cr, 0.06%-0.19% of Mo, smaller than or equal to 0.20% of Ni, smaller than or equal to 0.15% of Cu, 0.010%-0.025% of Al, 0.0010%-0.0040% of N, 0.0015%-0.0040% of Ca and the balance iron and inevitable impurities, wherein Ca / S is larger than or equal to 1.6. The production method includes the steps of converter smelting, external refining, continuous casting, heating, rolling and cooling. The thickness of the thick plate produced through the method is larger than 26 mm, and the transverse yield ratio does not exceed 0.83; and the longitudinal yield strength is 450-530 MPa, the longitudinal tensile strength is 590-670 MPa, the longitudinal uniform elongation UEL is larger than or equal to 10%, the longitudinal yield ratio does not exceed 0.82, and the strain hardening exponent n is larger than or equal to 0.1.

Description

technical field [0001] The invention belongs to the field of low-carbon and low-alloy steels, and in particular relates to a thick plate for pipelines with excellent plasticity and toughness and a production method thereof. Background technique [0002] With the development of economy and society, the demand and consumption of oil, natural gas and other energy sources continue to increase. In order to increase the exploitation of oil and gas resources, new oil and gas projects continue to develop in remote, oceanic, alpine and other areas with harsh climates and environments. Due to the harsh service conditions of oil and gas pipelines in such areas, more stringent technical requirements are put forward for the corresponding oil and gas pipeline steel; the products must not only achieve the corresponding strength, but also must have good low temperature toughness, ductility and strain resistance At the same time, in order to improve the conveying pressure and safety, the st...

AI Technical Summary

Problems solved by technology

[0010] To sum up, the existing technology is still insufficient in the research on thick plates with excellent plasticity and toughness for oil and gas transmission pipelines in geologically active areas, oceans, permafrost and other regions.

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