SU544507A1 - Exothermic Slag-Forming Mixture for Metal Casting - Google Patents

Description

 when casting steel, since burns and mixtures form slags with a low content of basic oxides (in particular, calcium oxides, etc.).

The presence of silicate lump in the mixture, and ziachite and sodium oxides in the slag, leads to the development of titanium in the ore of titanium-containing casting of titanium-containing steels, especially ner / cave.

Sui1, a natural disadvantage is also a high CToiiMocTij mixture, due to the presence of such scarce and costly com- monoites as nlavic shnat (268rub / ton) and silicate j-lyba (58 rub / ton). The high cost of semie reduces the economic efficiency of the nr nmeeni nx, especially when casting carbon steels.

The purpose of the invention is to ensure the economic efficiency of casting steel under the slag, reducing gas emissions, improving the physicochemical and technological properties of the slag, as well as allowing it to be used in ingot casting in vacuum.

The goal is achieved by the fact that in the exothermic mixture, which contains a combustible ingredient, a solid oxidizing agent, datolite is contained as a slag-forming ingredient and a low-melting ratio is given as follows. %:

Combustible ingredient from the group of active, easily oxidizing metals 15,0-25,0

Solid oxidizing agent from the group of easily reducing oxygen-containing compounds15, 0-25.0

Datolite10.0-60.0

Fusible glia

Slicated calcium, aluminum, magnesium, and silicobarium can be used as a fuel.

As a solid oxidant from the specified group - manganese ore, nitrate, scale.

Datolite (Ca2B2 (8104) 2) is a volcanic and mineralization mineral (it occurs in ore veins) from the group of silicates. It is a chemical compound of eutectic composition, it has a low melting point (950-1000 ° C) and a short 1H1 melting and solidifying interval (10-15 ° C). Low melting point increases the rate of slag formation, the fluidity of the slag and reduces its viscosity even at low pouring temperatures.

The above advantages of datolite compared with other slag-forming materials make it possible to produce high-quality exothermic slag-forming mixtures, not containing floating spar (melting range 1250 ° C) and silicate lump (temperature of 1089 ° C).

The fusible glium is a natural aluminosilicate material, having a composition, weight. %: silicon dioxide 42-48; alumina 15-20; Calcium window 15-20; iron oxide 3-6; magnesium oxide the rest. Comparatively, the temperature of the clay cladding (1050-1100 C) and its high (20-30 poise) viscosity at these temperatures also makes POSSIBLE and effective its irimeenne as part of the exothermic H-molten mixtures for casting became 11.

The content of components in exothermic mixtures is primarily due to the grade of casting of steels. The exothermic mixture of the invention with a higher content of fuel nigredieite is used for casting high-alloy steels, and with a low content of them - for casting low-alloyed and alloyed carbon steels. When the content of combustible is less than 15%, the sufficient amount of heat required for the melt molten of 1 placiferous components is not provided without the extraction of heat from the metal; when the content of nx is more than 25%, the amount of heat emitted by the heat generator is too high, which is not rational, since the cost of the mixtures increases significantly with an increase in the content of combustible materials. The content of solid oxidizing agents is due to the content of the combustible ingredient, which increases by increasing the content of the latter.

Exothermic smes with a high content of datolite (at the upper limit and closer to it) and ionized clay content (at the lower limit and closer to it) are used in the casting of boron-containing steels, as well as pipe and boiler steels, and carbon-bonded and carbon-growing products for manufacturing, products that are not quenched or require a depth of hardenability, as well as high-alloy steels, in which boron is introduced as a technological additive for new hot metal ductility.

Exothermic smes with a high content of low-melting glia (at the upper limit and closer to it) and low datolum (but at the lower limit and closer to it) are used for casting carbon steels and steels with different alloying styles, manufactured products that are hardened to a shallow depth.

The exothermic slag-forming mixture according to the invention is prepared from powder components of 0.5-1.5 mm fractions. The mixture is added in porous form, as well as in the form of granules and briquettes. When the mixture is used in a normal manner in vnde and in the form of briquettes, it is placed on the bottom of the SUB1P1. You before the start of casting. When using the mixture in the vnde granules, the latter can be fed to the metal mirror into the mold evenly during casting. Consumption s.mesi 3-3.5 kg / t of steel.

The invention is explained by the compositions of the mixtures, which are listed in the table.

Slags from exothermic mixtures No. 1-7 due to the absence of calcium fluoride and sodium oxide in them, which lead to the release of volatile compounds causing suntanization and varnishes when casting steel, which are not soothed, which allows to use the mixture according to the invention for casting steel under the slag in a vacuum (vacuum up to 10 mm Hg. Art.).

The exothermic mixtures listed in the table were also tested when casting the above steel grades into ingots weighing 0.5 tons. Tests have shown that the technological properties of the mixtures according to the invention are higher than the known mixture 2.

So, when casting iodine with mixtures nos. 1-7, the release of gaseous fluoride gas I1eni1 | is completely eliminated, while when casting iodine with known mixture 2, it is 0.11-0.2 mg / l, while 25% decrease the consumption of the mixture and the thickness of the slag crust on the walls of the mold, the silts have 3 times less adhesion to the walls of the narration. The latter greatly facilitates the cleaning of molds.

Due to the fact that datolite and fusible clay have a low cost of 45 rubles / ton and 5 rubles / ton, respectively, the cost of the exothermic mixture decreases by 20-25%. In addition, when using mixtures N ° 1-5, microalloying of boron steel during the casting process is provided.

Claims (2)

1.Avt. St. No. 212469, cl. In 22D 27/06, 1967. 2. Avt. St. LI 212468, CL In 22D 27/00, 1967 (prototyii).