Method for producing ocean engineering steel plate with low compression ratio, thick specification and ultrahigh strength

Abstract

The invention discloses a method for producing an ocean engineering steel plate with a low compression ratio, thick specification and ultrahigh strength, which has a uniform performance in a thickness direction. The method comprises the following steps: carrying out smelting and continuous casting production through a converter, carrying out rolling on a medium-thickness plate coil by using a controlled rolling and controlled cooling process, carrying out laminar cooling at the finish cooling temperature of 650-700 DEG C and the cooling rate of 5-10 DEG C/s after rolling, and finally carrying out normalizing, quenching and tempering thermal treatment. The ocean engineering steel plate with a low compression ratio, thick specification and ultrahigh strength, which has the uniform performance in the thickness direction and is obtained according to the invention is good in performance, and on the basis of meeting the certification requirements of classification societies, such as DNV (Det Norske Veritas), CCS (China Classification Society) and ABS (American Bureau of Shipping), for steel E690, the thickness-specification steel plate is smaller than 15MPa in the thickness direction in terms of thickness difference, is smaller than 20J in terms of the difference of lateral impact average values at the low temperature of minus 40 DEG C, is smaller than 1% in terms of elongation difference, and in addition, has the characteristics of batch production condition, stable production process, strong operability and the like.

Description

technical field [0001] The invention relates to a production method of a steel plate for ocean engineering, in particular to a production method of a steel plate for ultra-high-strength ocean engineering with low compression ratio and thick specifications. Background technique [0002] Due to the increasing development of the utilization of marine resources, human beings continue to advance the development of the ocean from the coastal area to the deep sea. As important equipment for the development of marine resources, such as ocean platforms, large ships, and supporting structures for development operations, marine engineering equipment has broad prospects and a strong development momentum. strong. The further development of marine engineering equipment driven by the development of marine resources will drive the development of steel for marine engineering to higher strength, such as offshore oil platforms and ships and other equipment for cargo loading and unloading and p...

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Problems solved by technology

[0003]The existing patents related to the production method of steel for marine engineering are mainly to obtain steel plates for marine engineering through controlled rolling, controlled cooling or heat treatment. The technical shortcomings are as follows: : The strength is low, the structure is mostly voxel body + pearlite structure, and there is less consideration for improving the uniformity of the structure and performance in the thickness direction of the low compression ratio thick specification, such as: "a large-thickness steel plate for marine engineering and its production method" (Chinese patent CN 102400043), "Wide and thick high-strength ship plate steel and its production process" (Chinese patent CN 101418417), "a large thickness quenched and tempered steel for offshore platforms" (Chinese patent CN 101709432), "a 80mm thick and low compression ratio marine engineering steel plate and its manufacturing method” (Chinese patent CN 102392192), “An easy-weldable, high-strength, high-toughness ship plate steel and its production process” (Chinese patent CN 101775559), “780MPa steel with excellent low-temperature toughness Manufacture of High Tensile Steel Plate” (Chinese patent CN 101688262)

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