SU1301554A1 - Method of producing sectional hollow centrifugally-cast billet - Google Patents

Abstract

The invention relates to metallurgy and makes it possible to obtain centrifugally cast billets with core external and internal surfaces with minimal expenditure on them. manufacture and amount of liquid metal. This is achieved by the fact that a liquid coolant is supplied to the mold before the metal is poured, and around certain molds a rotating electromagnetic field is created at a speed of 1.1-2.1 speeds of rotation of the mold. The direction of rotation of the floor coincides with the direction of rotation of the mold. In this case, the liquid cooler takes the form adequate to the external profile surface of the workpiece, after which the liquid metal is poured into the mold. The inner surface of the metal takes the profile form under the action of forces similar to the forces in the formation of the profile of the liquid cooler. When the metal solidifies, the required floor profile is formed. I (L ate 4

Description

The invention relates to the field of metallurgy and can be used in the production of castings by the centrifugal method.

The aim of the invention is to increase the utilization rate of the metal and reduce the labor intensity of manufacturing the part.

The proposed method for obtaining the profile hollow dent-bitumen casting head: the outer diameter of the middle barrel

600 mm, internal - 150 mm, on each side of the middle barrel there is one more barrel with an outer diameter of 380 mm and an inner 75 mm. Overall 5 length of the workpiece 3700 mm, the length of the extreme barrels of 600 mm. The inner diameter of the mold 810 mm, length 3700 mm

The process of manufacturing a blank for this configuration is as follows.

Preliminary, the required amount of liquid metal cooler is determined from the difference in the volumes of the mold and the future cast billet. An artificial lead alloy with bismuth (Pb 56%, Bi 44%) is used as a liquid metal cooler (liquid substrate). For this case, 1.0 t of packing is required includes pouring the metal into the mold and forming the workpiece.

Before pouring the metal into the mold, a liquid cooler is supplied, and around certain molds, a rotating electromagnetic field is created around the mold, the speed of which is 1.1-2.1 of the speed of rotation of the mold, and the direction coincides with the direction of rotation of the mold.

In this case, in the area where a rotating electromagnetic field is created, the liquid cooler rotates at a speed that is greater in the rest of the mold. As a result of this, the pressure created by the centrifugal forces will be different on different parts of the mold. After equalizing the pressures, the liquid cooler will take on a profile that is adequate to the external encircled alloy. In addition, the tops of the workpiece are determined. The speed-rotation of the mold and the

Reducing the rate of rotation of the coolant cooler to create

25

The customer less than 1.1 speeds of rotation of the mold loses meaning, since both speeds approach each other to a synchronous one that does not give an additional effect.

Increasing the speed of rotation of the cooler more than 2.1 speeds of rotation of the mold leads to the fact that the heat transfer fluid from the section will flow into the adjacent ones, which will make it impossible to obtain a given profile.

After the preset profile of the liquid cooler has been formed, a liquid metal is poured into the mold, which is distributed along the length of the mold in accordance with the speeds of rotation of the mold and the electromagnetic field. At the same time, the limits of advancement of steel are limited by the shape given by the liquid cooler, the density of which must exceed the density of the metal being poured.

After solidification of the metal crust to a thickness of 50-60 mm, the rotational speeds of the mold and the electromagnetic field are changed to a value that ensures the formation of the inner surface of the poured metal. In accordance with the specified profile, the metal is then cooled until solidified.

Example. Obtaining a billet of steel grade 38XNZMFA weighing 6.0 tons for the subsequent manufacture of the shaft.

The billet has the following dimensions of 600 mm, the inner one — 150 mm, on each side of the middle barrel there is one more barrel with an outer diameter of 380 mm and an inner diameter of 75 mm. The total length of the workpiece is 3700 mm, the length of the outer barrels of 600 mm. The inner diameter of the mold is 810 mm, length is 3700 mm.

The process of manufacturing a blank of a given configuration is carried out as follows.

Preliminary, the required amount of liquid metal cooler is determined from the difference in the volumes of the mold and the future cast billet. An artificial lead alloy with bismuth (Pb 56%, Bi 44%) is used as a liquid metal cooler (liquid substrate). For this case, 1.0 tonnes is required.

alloy. In addition, the speed-rotation of the mold is determined and

His required form.

For this case, the speed of rotation of the mold before pouring metal into it is 315 rpm, and the speed of rotation of the electromagnetic field in the area of the mold corresponding to the smaller outer diameter of the cooking 2500 mm long is equal to

380 rpm, in the remaining parts the rotation speed of the cooler is not increased.

After the metal is poured, the rotational speed of the mold should be 520 rpm, and the electromagnetic field on the specified section e - 850 rpm.

After the rotational modes of the mold and the electromagnetic field are established, the billet is cast, for which a liquid cooler (having a melting point of 125 ° C) in an amount of 1.0 tons is poured into a mold heated to 150 ° C at a speed of 315 rpm. connect the winding of the electromagnet covering the mold to a power source with a frequency of

0.1 Hz, while setting the rotational speed of the electromagnetic field to 380 rpm. After exiting the mode, the electromagnetic field accelerates the coolant to a speed of 380 rpm only in the area of the mold, which is covered by the electromagnet, until the pressure equalizes over the length of the mold, forming a form from the cooler that is adequate to the external required surface of the workpiece.

After forming the cooler of the required form, 6.5 tons of 38KHNZMFA liquid steel with temperature is poured into it.

The liquid steel is distributed along the length of the mold in accordance with the speeds of rotation of the mold and the electromagnetic field, while

advancement of steel is limited to for-20 but cast billets with different

 7, Og / cm3, f After casting steel

mine, given by a liquid cooler having a density, is substantially

( with.

 10 g / cm3).

and solidifying the crust to a thickness of 50-60 mm, which corresponds to a solidification time of 5 minutes, change the rotational speeds of the mold and the electromagnetic field, respectively, to 520 and 850 rpm to form a core internal channel of the workpiece in accordance with the specified dimensions and complete freezing of the metal and then disconnecting the electromagnet winding from the power source. Then, molten fluorspar is poured into the central cavity of the preform, under the action of heat of which a certain layer of the inner surface of the preform, contaminated non-editor H1 Egorov

Compiled by N.R.Mashova Tehred L.Serdyukova

Corr Sub

1178/12 Circulation 741

VNIIPI USSR State Committee

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

Production and printing company, Uzhgorod, st. Project, 4

metal inclusions, dilutes, after which the internal cavity is flushed with a neutral gas at a pressure of 3 atm, resulting in a liquid

the mixture from the central cavity is blown into the previously prepared slag. Thus, a clean and smooth surface of the internal cavity of the workpiece is created, excluding the occurrence of stress concentrators in it.

After purging the central cavity of the billet, the mold is stopped, the cooler is discharged from it, and the cast billet is removed.

Thus, in one cylindrical mold, changing the amount of the cooler, the speed of rotation of the mold and the electromagnetic field,

profile of external and internal surfaces.

Claims (1)

Invention Formula The method of obtaining a hollow centrifugally molded preform, including pouring metal into a mold and forming a blank, so that, in order to increase the utilization rate of the metal and reduce the complexity of manufacturing the part, before pouring the metal into the ingot mold, a liquid cooler, and around certain molds create a rotating electromagnetic field, the speed of which is 1.1-2.1 speeds of rotation of the mold, and the direction coincides with the direction of rotation of the mold. Proofreader S. Cherni Subscription