Manufacturing method of low-density, high-strength and high-toughness hot-rolled steel plate

Abstract

The invention relates to a manufacturing method of a low-density, high-strength and high-toughness hot-rolled steel plate, the produced steel plate is a Fe-Mn-Al-C austenite low-density steel plate, the density of the steel plate is 6.75-7.05 g / cm < 3 >, and the material lightweight is remarkable. The yield strength of the steel plate is larger than or equal to 800 MPa, the tensile strength of the steel plate is larger than or equal to 900 MPa, the low-temperature impact toughness of the steel plate is kept at a high level while high strength is guaranteed, and the-40 DEG C V-type impact is larger than or equal to 50 J; the steel plate is excellent in machining performance, the material elongation is larger than or equal to 30%, cold bending meets D = 2a and 180 degrees (D represents the bending center diameter, and a represents the steel plate thickness), the surface quality is high, and internal flaw detection meets the requirement that the single defect equivalent flat-bottom hole diameter is smaller than or equal to phi 2 mm and is higher than the NB / T 47013.3-2015 forging ultrasonic detection I-level requirement. The high-strength and high-toughness steel plate is obtained by taking the steel ingot as a material and through an improved heating, multi-process rolling and rolled steel plate cooling mode, and industrial production is realized.

Description

technical field [0001] The present application relates to a method for manufacturing a low-density hot-rolled steel sheet, and in particular, to a method for manufacturing a Fe-Mn-Al-C series austenitic low-density steel sheet. Background technique [0002] Weight reduction is a problem faced in the current manufacturing process of all vehicles or special equipment. For the weight reduction of steel materials that are widely used, relevant research is currently carried out at home and abroad. The main direction is to add a certain content of Al, Mn, C Elements to reduce the density of steel materials. This type of steel is generally called low-density steel or light-weight steel. The degree of density reduction depends on the addition of Al, Mn, and C-type light elements. Density has the greatest effect, and the density of steel can be reduced by 0.101g / cm for every 1% content added. 3 . According to different phase compositions, Fe-Mn-Al-C type low-density steels include ...

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Problems solved by technology

[0004] In large-scale industrial production, the production of Fe-Mn-Al-C austenitic low-density steel plate is mainly reflected in the following aspects: 1) Precise control of alloying elements, large-scale production of low-density steel is involved in steelmaking A series of production operations of molten iron decarburization, molten steel deoxidation, alloying, and degassing, non-laboratory simple "alloy ratio-melting-casting" process, the precise control of Al content in the steelmaking process is difficult, and its metal is active Mold strength is easy to wear and tear, and the Al content in molten steel is closely related to the selection of steelmaking slag system and the control of steelmaking time; 2) Casting of large steel ingots requires a reasonable matching of casting time due to the high alloy content of low-density molten steel and poor fluidity of molten steel In addition, the preparation work before casting and the slag filling operation during the casting process have a great impact on the quality of the steel ingot; 3) The formulation of heating, rolling and cooling processes, low-density steel ingots with high alloy content are heated and rolled It is very easy to break during the rolling process, and different cooling processes after rolling have a great influence on the performance of the steel plate

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