Ship steel plate with ultrahigh strength and impact toughness and preparation method thereof

Abstract

The invention relates to a ship steel plate with ultrahigh strength and impact toughness and a preparation method thereof. The ship steel plate comprises the following components by weight percent: 0.03-0.05% of C, 0.20-0.30% of Si, 0.80-0.90% of Mn, 0.03-0.04% of Al, 1.6-1.8% of Ni, 1.1-1.3% of Cu, 0.4-0.6% of Cr, 0.4-0.6% of Mo, 0.03-0.05% of Nb, 0.01-0.02% of Ti, 0.01% or less of P, 0.005% or less of S and the balance Fe and impurities. The preparation method comprises the following step: using the continuous cast slab with the same components of the above ship steel plate to perform processes of heating, heat insulation, hot rolling and heat treatment to form the finished ship steel plate. The ship steel plate of the invention has both good intensity and low temperature toughness, and excellent mechanical properties and welding performance; and the manufacturing process is flexible. The ship steel plate is suitable to be used in shipbuilding industry, especially in ship plate manufacturing technology with strict requirements on the intensity and low temperature toughness.

Description

technical field [0001] The invention relates to a high-strength and high-toughness ship plate steel and its production process, in particular to a target yield strength of not less than 620MPa, a tensile strength of 720-890MPa, and a substrate and welding heat-affected zone (HAZ) -60°C Charpy impact Ultra-high-strength ship plate steel with work greater than 41J and its preparation method. Background technique [0002] With the development of the world economy and the growth of trade, people's demand for low-cost shipping methods continues to grow. At the same time, the development and research of marine organisms and mineral resources are becoming more and more in-depth. Before the influence of power politics is eliminated, Countries are still vigorously increasing their naval power. Based on the above factors, the shipbuilding industry will have broad prospects for development in the foreseeable future. In order to meet the service performance of ships under various cond...

AI Technical Summary

Problems solved by technology

For example, a low-alloy ultra-high-strength steel disclosed in the invention patent with the publication number CN1390972, although its yield strength can reach 860-1200MPa, its impact energy at 0°C is only ≥33J, which is far from meeting the requirements of modern large ships. need

[0005] (2) Although the strength and toughness meet the requirements, its plasticity is low

For example, the invention patent with the publication number CN101418417A discloses a wide and thick high-strength ship plate steel, although its tensile strength can reach 780MPa, but its elongation is obviously insufficient, only ≥ 10%. Another example is the invention with the publication number CN1888120A An ultra-high-strength steel with excellent corrosion resistance and fatigue resistance disclosed in the patent, although its yield strength and tensile strength can reach above 880MPa and 980MPa respectively, its elongation is relatively low, generally ≤20%

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