SU631539A1 - Method of manufacturing nitrided steel - Google Patents

Description

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The invention relates to ferrous metallurgy, and more specifically to the production of nitrogen-containing low alloyed and alloyed steels and alloys.

A known method of producing nitrogen-containing steels, for example, in arc furnaces, in which nitrated ferrochrome is introduced after the metal is alloyed with manganese, and chromium (l.

The uptake of nitrogen in this case is 60-70%. Such a low uptake of nitrogen is due to the fact that with the introduction of nitrated ferrochrome, a methyl zone is formed, oversaturated with nitrogen XB of ferrochrome to 10% nitrogen, and the latter, not absorbed by the metal, passes into the gas phase.

A known method for the production of nitrogen-containing steel, involving the partial alloying of metal with nitrogen in the furnace, and the rest in the ladle 2

The method does not ensure proper absorption of nitrogen for the same reason. In addition, the known methods do not provide for the deep deoxidation of the metal at the time of its doping with nitrogen, which is crucial for nitrogen absorption. Since nitrogen is a surface-active element, the degree of nitrogen in the microvolume substantially depends on the level of oxygen concentration in it. A known method for the production of nitrogen-containing steel, in which after

melting of the charge, oxidation of impurities with oxygen, carrying out deoxidation and alloying of the metal, the latter is released into a ladle, to the bottom of which nitrated manganese and aluminum are preloaded

The disadvantages of this method are low nitrogen absorption - 20–40%; large variations in the final nitrogen content (0.013 to 0.035%);

low yield of steel due to the insufficient nitrogen content in the steel or due to unsatisfactory macrostructure at high (above 0.025%) contents

nitrogen.

The aim of the invention is to increase the degree of nitrogen uptake, decrease the sulfur content, increase the yield of steel.

This goal is achieved due to the fact that during the release of the metal into the ladle, it is acidified with aluminum in the amount of 0.3-4 kg / ton, the metal and slag are poured into the second bucket with simultaneous introduction of 0.1-1.5 kg / metal into the metal. t