SU986583A1 - Flux for centrifugal casting of carbon steels - Google Patents

Description

(54) FLUSH FOR CENTRIFUGAL CASTING.

one

The invention relates to the field of foundry production, in particular, to the technology of centrifugal casting of submerged fluxes from ugreyodistyl steel grades, including molds of centrifugal machines.

Known refining fluxes for centrifugal pour into the stream of liquid metal G13.

The disadvantage of fluxes is their low effectiveness against the formation of hot trenshn in castings.

The closest technical solution to the invention is flux compositions containing metal oxides and fluorides, which are used to protect the metal from secondary oxidation, metal refining from harmful impurities, non-metallic inclusions and gases, for example, during electroslag remelting 2.

However, these fluxes do not have a noticeable effect on the structure of the cast metal and, as a result, do not change its carbon steel.

plastic properties. The crack resistance of the steel is primarily caused by the ductility of the steel. Since carbonaceous at centrifugal "agglomerates to steel m with an increased tendency to. Formation of gyr chich cracked, in the production of large-sized casting of these steels (and above all the molds of centrifugal machines: there was a need to improve the plastic properties

10 Carbon Shrok became: her.

The aim of the invention is to create a fgpos for centrifugal casting of carbon steel, which enhances its crack resistance.

15

The goal set is: that the flux for centrifugal casting of carbon steel, including fluorides and metal oxides, additionally contains silico-metal with SEECHY20 calcium in a ratio of 3: 1 npi, the following ratio of components, weight. %:

Silikomishmetall in mixture

with silicocalcium 10-40 3. 98 Fluorides 20-65 Metal oxides The remaining Refining Flux is a mechanical mixture of a modifying additive and a slag forming component. The slag-forming flux component is pre-alloyed in a slag-melting furnace. Before dosing the flux into a rotating form, its components are dried at a temperature of 120-150 ° C, grinding in ball mills to a fraction of O, O5-0.3 mm and thoroughly mixed in the required proportions. Before pouring the metal into the mold, a flux is poured into the dispenser, which is placed above the chute of the casting device, which is metered into the jet of liquid metal during its pouring into the rotating mold. The ratio of the components of the slag-forming composition of flux fluids is selected by TaKravi so that the melting point of the flux is 1100-1250 ° С and it would have a high refining ability. Slag assimilates non-metallic inclusions, gas, by centrifugal forces, is cast onto the free surface of the casting and is evenly distributed along it. Silikomishmetall together with siliko calhum serves as an effective modifier of steel. The introduction of a silico-metal in mixture with a silicate in steel, together with slag-forming flux components, contributes to a more complete assimilation of its active elements and an increase in the efficiency of modification. The following grades can be used as a modifying additive: SIITMISH, SIMISH FSM, FSMI Ammish When the mixture of silica gel with silicon oxide in the flux is less than 10%, its effect on the structure and properties of the steel is insignificant, since the content of rare-earth elements in the mixture is up to 1-3%, and less than 0 are added to steel, OO5-O, O15%, which is not enough to change the composition of the inclusions. This amount of rare-earth metals is insufficient for the micro-alloying of the metal base and the grinding of the steel macrostructure. A content of more than 30% of silico-metal with silicocalcium in the flux is undesirable, since the rare-earth metals start to react with oxides of the mixture to form rare-earth oxides, which increase its melting temperature and increase the viscosity of the slag. 3 A 3: 1 ratio of silica-alumina metal and silicone calc is recognized as optimal for casting molds from low-alloyed and low-carbon steel grades. The ratio of silico-metal and silica-alumi less than 3: 1 leads to an increase in the amount of silica-gel in the refining flux, which, interacting with oxygen, burns, goes into the slag and increases its melting point and viscosity. If the ratio of silico-metal and silicocalcium is greater than 3: 1, then not only silicocalcium, but also silico-metallic, are consumed to deoxidize steel. The use of the proposed method of casting ingotting molds makes it possible to increase the plasticity of steel by 10 (20% and 30-4O% impact strength. Increasing these metal characteristics provides an increase in the crack resistance of the material at high temperatures and an increase in the quality of the workpieces. To increase the crack resistance of low carbon steel grades used to manufacture the molds of centrifugal machines, pilot billets were made from steel 20L and 15HL under various compositions flux and at a ratio of silico-metal and silicocalcium equal to 3: 1 (Table 1). Silicone-seemetal was used as SIITMISH, and silicocalcium - 1Q10. Steel was melted in an IST-O16 induction furnace. After the metal was melted and oxygenated in the furnace, manganese and silicon were used. and with aluminum in the ladle, it was poured into the mold with a diameter of 55 mm and a length of 600 mm. The refining flux was metered to the stream of liquid metal during casting in an amount of 2% of the weight of the cast metal. In order to insulate the inner surface and create a metal billet directed by KJJHO, after it was poured into the mold, kiln slag was poured in an amount ensuring that a slag layer of 4-5 mm was formed on the inner surface of the billet. Workpieces cast under a fluxing flux without the content of silico-metal and silicocalcium (composition 1 and No.-5 m

table), have ijo the outer surface of the crack. Mold billets cast under fysome with a silica-mix-tal content mixed with silicocalcium (composition N ° 2, 3, 4, and 6) with approximately the same S strength with compare billets with billets, have a higher ductility and 30-4% higher. impact strength. Increasing metal struc- tures provides the metal with high crack resistance and, as

as a result, the preparation of the workpiece is without cracks, TJfo allows to replace the manufacture of E 4 molds of forged metal molds by centrifugally cast. The expected economic effect on pre; According to the calculations of the replacement of forged metal production at the price, the cast iron will reduce their cost, and teasxe will reduce the cost of a ton of centrifugal casting by 10-15 rubles.

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9986583lO

Formula of gaining Silikomishmetapp in a mixture

Flux for centrifugal casting carbon-fluoride. , 20-65

diet., including fluorides and metal oxides Else

metal oxides that distinguish s sources of information

so that, in order to keep the cracks-taken into account in the examination

but the stability of steel, he additionally1. Yudin S. B, et al. Centrifugal

contains silikomishmetall in a mixture of draining, metallurgi, M., 1972, p., 229.

silica calcium in a ratio of 3: 1 at 2. Latash Yu.V., Medovar B.I. ElekleNuyushchem ratio of components, Yu troschlakovy remelting, Metallurgists, wt. %: .. 1970, p. 25

with silica calf. 10-40

Claims (1)

Claim The flux for centrifugal casting of yrnepofdistar steel, including fluorides and metal oxides, is distinguished by the fact that, in order to increase the crack resistance of steel, it additionally contains silicomishmetal mixed with silicopotassium in a ratio of 3: 1 in the following ratio of components, weight. %: Silikomishmetall mixed with silica dough 10-40 Fluorides 20–65 Metal Oxides · Else