SU1215852A1 - Method of centrifugal casting of bimetallic articles more than four metres long - Google Patents

Description

one.

The invention relates to foundry production, in particular, to centrifugal casting technology, and can be used in casting technology for bimetallic billets for barrels of milling rollers, rolls for rolling rolls, castors for casting rolls, caster rolls, etc.

The purpose of the invention is to improve the quality of bimetal goods.

When casting bimetallic products with a length of about 5.2 m in diameter. up to 300 mm and an outer layer thickness of 15 mm or more, the casting time of the second layer is one of the decisive factors of the quality of the weldability of the layers. Experience has shown that if the second layer is poured in less than 40 seconds, then the alloys are partially mixed, and the transition layer becomes significant. This means that the outer layer is that. is working at the mill, will have a reduced work resource.

If the beginning of the filling of the second layer after pouring the first one is more than 55 s, then the weldability of the two layers will be unsatisfactory.

It is known that the coefficient of gravity shows how much, once the melt is desired in the field of action of centrifugal forces:, P tx) V

 R..

where P is the density of the melt, g / cm; and) is the frequency of the form,

rad / s;

"9.81 cm / s is the acceleration of free fall;

K is the gravity coefficient.

V.

After pouring the outer layer, it is necessary to maintain the value of 5 a, since the radius r of the inner cavity decreases, which means also K. In order to keep centrifugal forces constant when pouring the second layer, it is necessary to increase the rotational speed lO to such values that the gravitational coefficient remains constant. If the gravity factor remains constant, the quality from LIZKI will be satisfactory, since all the entrances in the melt and the gases will be separated into the cavity under the action of centrifugal forces. VNIIPI Order 935 /

Branch ShSh Patent, Uzhgorod, Proektna St., 4

8522

Experience has shown that if the gutter is introduced to the full extent, it takes time and the second layer “has unsatisfactory welding

bridge with the first layer. When a gutter is inserted at 1/3, the weldability is satisfactory. In this case, the speed of the machine decreases when the second layer is cast.

0 When the second layer is poured, when the chute is injected by 1/3 and the rotation frequency of the mold is increased, the melt loosens the crust that was formed at the end of the floor.

A rotating non-cooled single-layer pipe and partial diffusion of fusi of molecules of the first and second layers occurs. In this case, the weldability between the layers is satisfactory.

0 The method is carried out as follows.

Pour into a pouring ladle-melt intended for the outer layer; . modify it; poured

five . In the second casting ladle the melt intended for the second layer; they include rotation of the mold and the machine is set to its initial position, i.e. in position when

0 entered the entire chute; the melt is poured into the gutter for the outer layer, and as soon as the metal begins to drain from the gutter, the machine runs; after the completion of pouring the first layer, the machine is installed in such a way that the chute is inserted only 1/3; after 40 s after pouring the first layer, the melt for the second layer is poured into the gutter and passage. tires include only when from the end of the Vits melt of the second layer. This usually occurs with a slight melt kick on the pallet. The speed of the machine in this case is almost three times less than when filling the second layer.

After the two-layer product has a tepypy less than 800 H, it is removed from the mold. The method makes it possible to cast high-quality bimetallic products with a length of 5.2 m on the LN-104m machine being reconstructed, which additionally contains a second casting ladle, provides increased productivity, eliminates the flux from the centrifugal casting technology. Circulation 757 Pbpisnoe

five

five

Claims (3)

I. METHOD FOR CENTRIFUGAL CASTING OF BIMETHALPIC PRODUCTS LONGER THAN MORE THAN FOUR METERS, including sequential casting of the outer and inner layers of the product, characterized in that "in order to improve the quality of bi-; metal products, the filling of the inner layer is carried out after 40-50 s after the completion of the filling of the 'outer layer. 2. The method according to π. 1, I distinguish -, u and i with the fact that the filling of the outer and inner layers is carried out with the same gravity coefficient. 3. The method according to PP. 1 and 2, which consists in the fact that, in order to increase the durability of the casting trough of the casting machine, the casting trough when pouring the inner layer is introduced by a value equal to 1/3 of the length of the mold. g>