Steel for large container hull box board and preparation method thereof

Abstract

Steel for a large container hull box board is provided. The steel includes, by weight, 0.06-0.14% of C, 0.20-0.25% of Si, 2.51-2.79% of Mn, not more than 0.015% of P, not more than 0.005% of S, 0.09-0.18% of Mo, and 0.095-0.22% of Ce. A preparation method includes continuous casting after smelting to obtain a billet; rough rolling; finish rolling to the thickness of a product; cooling; and pit cooling to room temperature. The chemical composition and a production process of the steel are relatively simple, process parameters are easy to control; the thickness of a slab is not more than 2 [mu]munder the optical metallographic morphology; the yield strength is not less than 475 MPa; the crack tip opening displacement CTOD which is a fracture toughness index is not less than 3 mm; and the non-plastic drop test NDT is not more than -65 DEG C. Large container hull box boards made of the steel are free of breakage, and can safely sail in the extremely cold Arctic region, and the service lifetime can be 45 years.

Description

technical field [0001] The invention belongs to low-alloy high-strength steel and a preparation method thereof, and relates to a steel for a ship hull and a preparation method thereof, in particular to steel for a large-scale ship hull box plate packed in a container and a preparation method thereof. Background technique [0002] With the development of the ocean transportation industry, more and more containers are required to be carried, and the number of standard containers loaded on ships has reached more than 20,000. In this case, the performance requirements for the hull of the ship carrying the containers are even higher. For example, the requirements for the fracture performance, strength performance and service life of the ship plate are higher. This is because the box plate of the hull is impacted by the container during the ocean voyage. Low, the surface crack resistance is weak, the surface of ordinary box plate steel is easy to initiate cracks, and the cracks a...

AI Technical Summary

Problems solved by technology

The patented technology obtains a ferrite fine-grained structure, which is not as capable of crack initiation and expansion as the fine and interwoven bainite structure, that is, its fracture toughness is relatively low, and it is not suitable for building large-scale container ship hull panels

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