Continuous casting method for big round billet of medium-high-carbon medium-high-alloy tool steel

Abstract

The invention discloses a continuous casting method for big round billet of medium-high-carbon medium-high-alloy tool steel. The method comprises the following steps of: in a casting process, controlling degree of superheat of molten steel to 10 DEG C to 30 DEG C, controlling electromagnetic stirring current of a crystallizer to 250 A to 350 A, controlling frequency to 1.0 Hz to 2.0 Hz, controlling electromagnetic stirring current of a solidification end to 300 A to 400 A, and controlling frequency to 5.0 Hz to 8.0 Hz. The molten steel consists of the following components in percentage by weight: greater than or equal to 0.30% of C, greater than or equal to 3.0% of Cr and greater than or equal to 5% of total alloys. According to the continuous casting method disclosed by the invention, the defects that high-alloy tool steel is high in hardness and is not liable to straighten can be overcome by setting and optimizing technological parameters; and meanwhile, secondary oxidization of molten steel is avoided, product quality is guaranteed, the production process is simple, and the yield is high. The produced alloy tool steel has the characteristics of good structure uniformity and excellent comprehensive mechanical property.

Description

technical field [0001] The invention belongs to the field of metallurgy, and in particular relates to a method for continuous casting of a large round billet of medium-high carbon medium-high alloy tool steel. Background technique [0002] Tool and mold is known as the "mother of modern industry". It has made an indelible contribution to modern industry, and its importance in modern industry is self-evident. Tool and die steel is the most important part of the mold, and it is also the most widely used material in the mold material. It is an important material carrier and technical basis for the tool and mold manufacturing industry. Cycles play a decisive role. [0003] At present, domestic medium-high-carbon high-alloy tool steel mainly relies on die casting for production. The difficulty of using continuous casting to produce medium-high-carbon high-alloy tool steel is that the content of C, Cr, Mo and other elements is relatively high, and this type of steel has better hi...

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Problems solved by technology

[0003] At present, domestic medium-high-carbon high-alloy tool steel mainly relies on die casting for production. The difficulty of using continuous casting to produce medium-high-carbon high-alloy tool steel is that the content of C, Cr, Mo and other elements is relatively high, and this type of steel has better high temperature resistance. Strength and thermal fatigue stability, for example, H13, 9Cr5Mo, etc., which makes this type of steel require a large straightening force when it is produced by an arc continuous casting machine. The existing process is difficult to achieve, and there are only a few enterprises currently Can be produced from billets

[0004] There are many disadvantages in the existing tool steel production process: first, die casting production cannot be continuous, and the efficiency is low. Some billet processes can only produce billets with a maximum cross-section of 400mm×380mm, which is controlled by the shape of the electroslag furnace, and round billets with a diameter of Φ450-700mm are required as raw materials for electroslag remelting. In addition, in order to obtain a larger rolling In order to obtain better internal quality, large-scale continuous casting round billets are also required as rolling stock

[0007] At present, there have been reports of continuous casting methods for the production of round billets in China, but the steel types and product performances cannot meet the needs of current enterprises. The main reason is that these methods are mainly suitable for low-alloy structural steel and low-carbon structural steel. In the production of medium-high carbon medium-high alloy tool steel, it is difficult to straighten the billet, and the problems of porosity and serious shrinkage cavity are exposed. The existing continuous casting method is difficult to meet the needs

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