Steel with high low temperature fracture toughness and used for ocean engineering and manufacturing method thereof

Abstract

The invention discloses steel with high low temperature fracture toughness and used for ocean engineering and a manufacturing method thereof. The steel comprises the following components: 0.05%-0.10%of C, 0.2%-0.5% of Si, 1.0%-1.5% of Mn, 0.20%-0.50% of Cu, 1.00%-1.50% of Cr, 1.6%-1.8% of Ni, equal to or less than 0.01% of P, equal to or less than 0.01% of S, 0.01%-0.05% of Als, 0.02%-0.04% of Nb, 0.01%-0.02% of Ti, 0.05%-0.07% of V and the balance of Fe and unavoidable impurities. Rolling is controlled by adopting two phases, at the first phase, the rolling temperature is 950-1050 DEG C, andthe single-pass reduction rate is equal to or greater than 15%; at the second phase, the rolling temperature is 840-880 DEG C, and the single-pass reduction rate is greater than 10%; the average cooling rate is greater than 3 DEG C/s, and the self-tempering temperature is 500-600 DEG C; thermal treatment adopts twice quenching and tempering; the yield strength of a steel plate is equal to or greater than 620 MPa, the thickness of the steel plate is 60-100 mm, and the low temperature fracture toughness is high.

Description

technical field [0001] The invention belongs to the field of iron and steel material preparation, in particular a steel plate with high strength, thick specifications, excellent low-temperature toughness and fracture toughness and a manufacturing method thereof. Background technique [0002] With the increasing exploitation of offshore oil and natural gas resources, the demand for equipment and materials for offshore engineering is increasing, and the requirements are also increasing. Steel plates for offshore platforms must have high strength, high toughness, good weldability and strict requirements for thick specifications, especially the fracture toughness of materials. [0003] The manufacturing process of high-strength and thick-gauge steel for offshore platforms generally adopts the quenching and tempering process, and how to use the quenching and tempering process to produce thick-gauge, high-strength, excellent low-temperature toughness and fracture toughness steel p...

AI Technical Summary

Problems solved by technology

The steel plate achieved by this patented chemical composition and manufacturing process has low strength, insufficient low temperature toughness, and failed to achieve good fracture toughness

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