SU1323226A1 - Method of producing bimetallic rolling mill rolls - Google Patents

Abstract

The invention relates to ferrous metallurgy and can be used in casting bimetallic rolled rolls of iron and steel. The purpose of the invention is to reduce energy consumption and increase the productivity of the process. The essence of the method lies in the fact that in a mold, outer cast iron is installed coaxially. roll shell and tubular consumable electrode, molten slag is fed into the mold, and the electrode is melted, and molten steel is poured into the mold, forming the core of the roll, while the lifting speed of the molten steel in the cavity of the outer shell is maintained at (1-10) m / c, and the ratio of the mass of the consumable electrode to the mass of molten steel is 0.02-0.2. The required level of heat content in the fusion zone of the bimetallic compound is provided mainly by the heat supplied to the casting mold of molten steel, melted, for example, in induction furnaces. The heat energy of electroslag remelting is an auxiliary source of heat content in the zone of descaling. The method allows to significantly reduce the consumption of electrode material, electricity consumption, as well as the cost of the production of mill rolls. 1 ill., 1 tab. (L with N9 SO yu

Description

The invention relates to ferrous metallurgy and can be used in the casting of bimetallic rolling rolls of iron and steel.

The aim of the invention is to reduce energy consumption and improve the performance of the process.

The drawing shows schematically a device for carrying out the singing of a dog.

The outer cast-iron sheath 1 of the roll is placed coaxially in the casting mold 2. In the lower part of the casting mold, the lower electrode 3 is installed, to which one of the wires from the power supply source of the electroslag process is connected. The second wire is connected to the consumable tubular electrode 4, which is also installed coaxially in the mold at 5-10 mm lower lower end surface of the outer sheath 2 of the roll. Molten steel 6 is supplied with a siphon through a casting channel 5 into the mold. Slag bath 7 rises in a mold and melts a melted steel, during electrical contact with a consumable electrode, locks the circuit and warms up to t 1600-1900 ° C through it. In this case, the consumable electrode melts with a linear velocity equal to the linear velocity of the melt lifting in the mold. The heat flux directed from the slag to the outer shell creates a melted layer 8 on the inner surface of the latter, which is fused with the steel.

After filling the roll sheath, the electrical circuit is interrupted.

The essence of the proposed method of manufacturing bimetallic rolls

mine in the mold of molten i steel, prepared, for example, in induction electric furnaces. Electroslag remelting heat energy

5, the thin-walled tubular electrode is an auxiliary source of heat content in the fusion zone.

Thus, when implementing the proposed method, the formation

0 the inside of the bimetallic roll is mainly due to the supplied molten steel, the consumption electrode is used in the proposed method only as a means

 5 replenishment of the heat content of the zone

fusing, the ratio of the mass of the consumable electrode to the mass of the casting melt, in the process of manufacturing the rolls is maintained at 0.02-0.2.

20 If the ratio of the mass of the consumable electrode to the mass of the casting melt is less than 0.02, then the heat to restore the heat content of the fusion zone of the bimetallic compound is insufficient. In this case, the non-fusion of the joined metals of the outer shell and the casting melt is observed and the manufacture of the bimetallic roll is excluded.

 If the ratio of the mass of the consumable electrode to the mass of the casting melt exceeds 0.2, then the consumption of the electrode and electricity will increase until it melts, which increases

35 the cost of production of bimetallic rolls, i.e. The inventive goal is not achieved. Molten steel is fed into the mold at a rate of lifting its surface in the area of the outer cast-iron sheath of the roll, equal to (1–10) m / s. This feed rate of expanded steel allows heat transfer

25

from the slag bath and the melt to the inner walls it consists in the fact that after the coaxially 5th surface of the outer shell.

installation in the casting mold of the outer cast-iron sheath of the roll and the tubular consumable electrode, feeding the liquid slag into the mold, melting the electrode; molten steel is fed into the casting mold at the speed of its rise in the cavity of the outer sheath (1-10) m: / s consumable electrode to the mass of molten steel, equal to 0.02-0.2. In this case, the necessary level of heat content in the fusion zone of the bimetallic compound is provided mainly due to the heat supply 50

5.5

heat it up a thin layer before melting, remove oxidation and contamination products from its surface into the slag bath and qualitatively alloy the metals being joined.

g

If molten steel is fed into at a rate of lifting its surface in the cavity of the outer shell of less than 1-10 m / s, this results in solidification of the melt in the channels of the gating system, which excludes the possibility of making a bimetallic roll by the proposed method.

mine in the mold of molten i steel, prepared, for example, in induction electric furnaces. Electroslag remelting heat energy

The thin-walled tubular electrode is an auxiliary source of heat content in the fusion zone.

Thus, when implementing the proposed method, the formation

the inner part of the bimetallic roll is mainly due to the supplied molten steel, the consumption electrode is used in the proposed method only as a means

replenishment of the heat content of the zone

fusing, the ratio of the mass of the consumable electrode to the mass of the casting melt, in the process of manufacturing the rolls is maintained at 0.02-0.2.

If the ratio of the mass of the consumable electrode to the mass of the casting melt is less than 0.02, then the heat to restore the heat content of the fusion zone of the bimetallic compound is insufficient. In this case, the non-fusion of the joined metals of the outer shell and the casting melt is observed and the manufacture of the bimetallic roll is excluded.

If the ratio of the mass of the consumable electrode to the mass of the casting melt exceeds 0.2, then the consumption of the electrode and electricity will increase until it melts, which increases

the cost of production of bimetallic rolls, i.e. The inventive goal is not achieved. Molten steel is fed into the mold at a rate of lifting its surface in the cavity of the outer cast-iron roll shell equal to (1-10) m / s. This feed rate of expanded steel allows heat transfer

0

,five

heat it up a thin layer before melting, remove oxidation and contamination products from its surface into the slag bath and qualitatively alloy the metals being joined.

g

If molten steel is fed into at a rate of lifting its surface in the cavity of the outer shell of less than 1-10 m / s, this results in solidification of the melt in the channels of the gating system, which excludes the possibility of making a bimetallic roll by the proposed method.

If molten steel is fed at a rate of rise of its surface in the mold cavity more than 10 m / s, then heat transfer through the slag-metal interface to the fusion zone of metals does not occur to the required degree, which leads to non-fusion in the zone of their connection, which also excludes the ability to manufacture high-quality bimetallic roll.

The optimal rate of lifting the surface of the melt in the cavity of the outer shell is determined by the formula:

V 4 -ICT

D,

m / s

R

where d

wed

I - welding current. BUT;

- average diameter of the tubular

electrode, m;

- wall thickness of the tubular electrode, m

Molten steel is supplied to the casting mold from the top through the cavity of the tubular electrode or from the bottom using a siphon. The molten steel is poured into the mold before the liquid slag is supplied to it, or simultaneously with it or after the liquid slag is supplied.

Example. The proposed method produced bimetallic mill rolls. The outer shells of the rolls were pre-cast from wear-resistant cast iron ICH28bH2N4L, and the core - from steel ZOL. Tubular consumable electrodes were made of steel 55. The slag had the following composition,%: CaF, 60; CaO 20; A1g.0z 20.

An outer shell with a temperature of 700 C and a consumable tubular electrode, which protruded on Zyu and below the end of the shell, were installed in the mold.

Molten steel with a temperature of 1580 ° C through a gating system

filed in the lower part of the form with a linear rate of rise of the surface of the alloy (25-35) -10 m / s. At the same time, slag was poured into the mold from the top and voltage was applied to the tubular electrode.

Upon contact of the electro-slag bath with the electrode, an electroslag process was initiated. After that, the feed rate of the molten steel was reduced to (1-10) -10 m / s.

The dimensions of the castings, the parameters of the process of manufacturing bimetallic

rolls and the results are shown in the table.

As can be seen from the tables, the method of manufacturing bimetallic rolls in comparison with the prototype allows reducing the consumption of electrode material by a factor of time, energy consumption by a factor, and increasing the productivity of the process of producing mill rolls by more than

-20 times

Claims (1)

Invention Formula A method of manufacturing bimetallic rolling rolls of iron and steel, comprising a coaxial installation in a casting mold of a cast iron outer sheath of a roll and a tubular consumable electrode, feeding into the casting the shape of the liquid slag, the melting of the electrode, characterized in that, in order to reduce power consumption and increase the productivity of the process, after installation the consumable electrode into the casting mold serves molten steel with the speed of its rise in the cavity of the outer shell (1-10) 10 3 m / s and at the mass ratio of consumable  electrode to the mass of molten steel, equal to 0.02-0.2. 100 230 Prototype 100. 230,400 0.25 2500 40 0.5 3000 40 0.15 Casting failed due to solidification of the melt in the gating system 2660 8000 12-10 T44.6 132.2 130.1 129.4 Non-fusion of foundry hot melt and roll shell 72 229