Rolling method of submarine pipeline steel X56Mo

Abstract

The invention relates to a rolling method of submarine pipeline steel X56Mo. The rolling method of the submarine pipeline steel X56Mo comprises the following steps that the total heating time is limited to 270 to 330 minutes, the high-temperature section time is limited to 120 to 180 minutes, the temperature of the third heating section is limited to 1230 to 1250 DEG C, the temperature of the soaking section is limited to 1210 to 1230 DEG C, the tapping temperature of a plate blank is 1210 DEG C or above; two-stage controlled rolling is adopted, the initial rolling temperature in the rough rolling stage is not lower than 1000 DEG C, the single-pass reduction of three passes after the rough rolling stage is larger than or equal to 20 mm, the thickness of an intermediate billet is 2.5 to 3 times that of a finished product; in the finish rolling stage, the initial rolling temperature ranges from 820 DEG C to 840 DEG C, the finish rolling temperature ranges from 780 DEG C to 800 DEG C, water enters immediately without staying after rolling is completed, and the water entering temperature ranges from 800 DEG C to 810 DEG C; and a semi-automatic controlled cooling mode is adopted. According to the rolling method of the submarine pipeline steel X56Mo, all performance indexes of the produced steel plate meet ideal requirements, the performance qualification rate of the steel plate exceeds 95% or above; and according to the mechanical properties of the steel plate, the transverse yield strength value is 470 to 580MPa, the tensile strength is 570 to 620MPa, the transverse yield ratiois smaller than or equal to 0.90, and the DWTT mean value at -15 DEG C is greater than or equal to 85%.

Description

technical field [0001] The invention relates to the field of steel wire steel, in particular to a rolling method of steel X56Mo for submarine pipelines. Background technique [0002] In order to meet the development needs of energy transportation, underwater oil and gas transportation has developed rapidly. The difference between submarine pipelines and land pipelines is that the requirements for high pressure resistance and corrosion resistance are more stringent, and the performance test for steel plates is also increasing. [0003] Patent 201810436793.X is a submarine pipeline steel and its rolling method. The chemical composition of the submarine pipeline steel is: C0.030%-0.070%, Si 0.15%-0.30%, Mn 1.35%-1.65%, Nb0 .030%~0.060%, V 0.020%~0.040%, Ti 0.010%~0.040%, Mo 0.05%~0.30%, S≤0.0020%, P≤0.015%, the rest are Fe and unavoidable impurity elements; / n The rolling method of the submarine pipeline steel is: deep desulfurization of molten iron to S≤0.0050%, compound blow...

AI Technical Summary

Problems solved by technology

This patent adds Mo element in the alloy composition design, which is relatively high in production cost control