Ultra-high strength bainite armour steel and manufacturing method thereof

Abstract

The invention relates to ultra-high strength bainite armour steel and a manufacturing method thereof. The technical proposal is as follows: the casting billet comprises the following chemical components: 0.70-1.10wt% of C, 1.20-1.80wt% of Si, 1.60-2.20wt% of Mn, 1.00-1.60wt% of Cr, 0.10-0.60wt% of Mo, 0.05-1.20wt% of Al, 0.05-0.50wt% of Co, P less than 0.015wt%, S less than 0.010wt% and the balance Fe and inevitable impurities. The method is characterized by carrying out die casting or continuous casting after steel making and refining; soaking the casting billet at the temperature of 1150-1250 DEG C for 2.0-3.0h, hot rolling and cooling the casting billet; austenitizing the casting billet at the temperature of 850-1050 DEG C for 0.2-0.6h; then insulating the casting billet at the temperature of 200-500 DEG C in the nitrogen atmosphere for 10.0-240.0h, or insulating the casting billet at the temperature of 200-500 DEG C in the nitrogen atmosphere and in the strong magnetic field of 8-12T for 1.0-4.0h and cooling the casting billet. The invention has the characteristics of low cost and simple process, and the manufactured steel plates have good properties.

Description

technical field [0001] The invention belongs to the technical field of steel for armor. In particular, it relates to an ultra-high-strength bainite armor steel and a manufacturing method thereof. Background technique [0002] Armor types include steel armor, aluminum alloy armor, titanium alloy armor, composite material armor, ceramic armor, explosive reactive armor, and composite armor composed of multiple material armors. At present, great progress has been made in the research on the strength, hardness, notched impact toughness and ballistic limit of armor materials, but there are the following problems: [0003] (1) At present, although there are many types of armor steel, they are basically medium-carbon alloy steel. If you want to continue to increase the hardness, although the strength will increase accordingly, its impact toughness and fracture toughness will decrease sharply, so that it cannot withstand the huge energy of the shell. Impact load, resulting in fragm...

AI Technical Summary

Problems solved by technology

[0004] (2) For aluminum alloy armor, the hardness suitable for armored vehicles is relatively high, but it is prone to fracture due to stress corrosion; the fragmentation strength of aluminum is lower than that of steel armor, and it is easier to "scar". In addition, the melting point of aluminum To be lower than steel, it is easy to soften at high temperature and the particles of aluminum are easy to burn

[0005] (3) For titanium alloy armor, under certain loading conditions, because the projectile only needs to consume very little energy to cause shear failure cracks and form fatal bottom knots, this defect cannot be ignored; titanium is expensive , use on armored fighting vehicles is limited by cost

[0006] (4) For composite material armor, there will be obvious cracking and delamination in a large area at the bonding of the armor panel and the back plate, causing the armor to lose the ability to continue to resist bullets in a larger area, thus greatly affecting the armor The ability to resist multiple bullets has shown obvious deficiencies in the anti-ballistic performance

[0007] (5) For ceramic material armor, because it is too brittle, the fracture toughness is extremely poor, and because of its fragility, the armor material does not have the ability to withstand multiple hits and penetrations, and the production process of this technology is complex, with many links and high production costs , they are usually only used to form part of the armor system

[0008] (6) For air-cooled bainitic steel armor without heat treatment or less heat treatment, the structure is bainite / martensite multiphase structure, the fracture toughness is lower than that of tempered martensite at the same yield strength, and the strength is not particularly high. The toughness is not particularly good

[0009] (7) For general medium (ultra) low carbon bainitic steel armor, the carbon content is not high, the main alloying elements Si, Mn, Cr, and Mo content are small, and the bainite transformation temperature is high. In this technology, the alloys Al, Co With little or no content, the bainite transformation time is very long, the production process is complicated, there are many links, and the production cost is high; the toughness and plasticity are good, but the strength generally does not exceed 1500MPa

[0011] (1) All kinds of armor materials are high-strength grades (1000-1500MPa), and no ultra-high-strength grades are involved

[0012] (2) Various armor materials use precious alloy elements Ni or Ti, etc., and the alloy cost is high

[0013] (3) It is difficult to match the strength, toughness and elongation properties of various armor materials at the same time

[0014] (4) The manufacturing and processing techniques of various armor materials are complex