SU1254024A1 - Steel melting process - Google Patents

Description

one

The invention relates to metallurgy and can be used in the smelting of steel in electric arc furnaces, furnaces and in the preparation of electrodes for remelting processes.

The aim of the invention is to improve the quality of the metal.

Example. Steel SP28 was smelted in a DT-25 electric arc furnace with a capacity of 25 tons with full metal oxidation with iron ore. In the recovery period, the chemical composition of the steel was corrected. Melting released into the bucket under a white donkey. The final metal deoxidation in the furnace before the release was made with aluminum in the amount of 0.15-0.6 kg / t, and silicocalcium in the amount of 2, 5 kg / silicon-zirconium — 1.5-4.0 kg / t was placed on the bottom of the ladle in layers, The bottom layer is silicocalcium. The casting was carried out at the MShZhZ and 55Q mm consumable electrodes; an electrode melting was performed on DSB-8-G16-M1 vacuum-arc reheating furnaces mm mold without the use of deoxidizers according to the current technological instructions. The quality of the metal was evaluated using the developed methods in finished rolled products and 195 mm

For comparison, smelting was performed by a known method.

The test results are presented in the table.

The application of the final metal deoxidation technology in the furnace before aluminum release and in silicocalcium and silicon-dirconium bucket with the layering of silicocalcium and silicon-zirconium at the bottom of the bucket allows to obtain chalk in the metal: cored globular dispersed metal-bearing metals and improve the mechanical properties of the metal in the metal: it can be used for improving the mechanical properties of the metallic metal particles and improve the mechanical properties of the metal:

When aluminum is added in excess of 0.50 kg / t, large lines of oxides are noted, consisting mainly of alumina grains.

Entering silicocalcium in the amount of 2.5–4.0 kg / t provides deoxidation of the metal and modification of the genetic impurities. With the introduction of silicocalcium less than 2.5 kg / t oxide

The incorporation of calcium with oxygen eliminates its participation in the desulfurization of steel. In the case of addition of silicocalcium to more than 4.0 kg / ton, the content of calcium hydroxy sulfides increases, the size of globular inclusions increases.

With the introduction of silicocyrconium in the amount of 2.0-3.5 kg / t, solid sulfides and oxysulfides are rapidly formed, and the sulfur segregation model is modified.

The addition of silicocyrconium of less than 2.0 kg / ton does not eliminate the formation of large non-deforming silicates and high-grade sulfides.

With the addition of silicocyrconium of more than 3.5 kg / t, large oxide lines are observed in the metal, which leads to a deterioration of the mechanical properties of the finished rolled products.

Layered addition of silicocalcium and silicozirconium to the bottom of the ladle, and the lower layer of silicocalcium, allows complete calcium modification of the inclusions of oxides and sulfides in steel to be achieved.

The mechanism for modifying the inclusion is that silicozirconium, interacting with the metal, blocks (prevents) calcium from being oxidized by oxygen. When the ladle is filled with metal, the calcium bubbles rise, react with the sulfur and oxygen dissolved in the steel. In this case, the oxygen activity is reduced so that calcium can act as a desulfurizer.

The ratio of kalidi and zirconium (1.0-1.5-): (1, 5-2.0) provides for the modification (globulization) of inclusions, allows to reduce the size of inclusions, to prevent calcium, from oxidation. If the ratio of calcium is less than 1.0, then unmodified MnS-type inclusions remain in the steel. If more than 5, then the content of large oxysulfide Ca will increase. If the zirconium ratio is less than 1.5, then conditions preventing calcium oxidation are not created (i.e., the blocking is broken). If more than 2.0, this leads to a very significant deterioration in the quality of the metal due to the formation of large hard-to-remove inclusions.

Compiled by I. Zhurin. Editor L. Povhan Tehred L. Kravchuk

Order 4689/30 Circulation 552Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Design, And

Proof-reader I. Erdeyi

Claims (1)

METHOD OF MELTING STEEL, including preliminary deoxidation with aluminum followed by oxidation with silicocalcium and zirconium-containing material, 'characterized in that, in order to improve the quality of the metal, aluminum is introduced in an amount of 0.20-0.50 kg / t of steel, and silico-zirconium in an amount of 2, 0-3.5 kg / t of steel are seated on a layer of silicocalcium, introduced in an amount of 2.5-4.0 kg / t of steel on the bottom of the bucket, while the ratio of zirconium and calcium is 1.0-1.5: 1.5 -2.0. o SS (L CZ No. οι o ke 4 ^