SU1364392A1 - Mould for centrifugal casting of necked rolls - Google Patents

Abstract

The invention relates to a foundry industry, namely to molds for casting rolls by a centrifugal method. The purpose of the invention is to reduce roll breakage for blockages. This is achieved by making at the base of the form for the lower neck a roll of an annular conical groove, the maximum dia // 6 9 S 8 1 Srig 1 2 3 meter of which is 1.02-1.04 minimum diameter of the lower neck, and the angle of inclination of the side surface according to the formula about arctg x

Description

roll 3,

flasks (forms) 4 and 5 are installed

necks 6 and 7 rolls made

1.13

The invention relates to a foundry, namely, devices for casting rolls by centrifugal method.

The aim of the invention is to reduce the marriage of d &

FIG. 1 shows the form, general view; in fig. 2 - node I in figure 1

The form includes a housing 1 with an inserted sleeve 2, forming a barrel on both sides of which

dl out

molding mixture 8, and end caps 9 lined with graphite-chamotte inserts 10 and secured with locks 11. An annular conical cavity 12 located in the shape of 5 for the lower neck of the roll 7 at its base is intended to concentrate the remains of litter and molding sand. The maximum diameter of the conical cavity is 1. 02-1.04 minimum diameter of the lower neck, and the angle of inclination of the side surface of the cavity is determined by the formula

0 / arctg (3.2-4.0).

MKN.SH

where 1sh - the length of the lower neck, m; p / ((lssh minimum diameter of the lower neck, mm.

If the maximum diameter of the conical cavity, made in the form for the lower neck of the roll at its base, is less than 1.02 of the minimum diameter of the lower neck, then the litter and residues of the filling mixture do not fit and are retained in the cavity. As the maximum diameter of the conical cavity increases to more than 1.04 the minimum diameter of the lower neck, the thickness of the molding sand layer decreases and the volume of the cavity increases and, accordingly, the metal consumption increases.

When the angle of inclination of the side surface of the conical cavity is about arctg3,2

x- resulting from promin, w

longitudinal and transverse shrinkage of the stress roll billet leads to the formation of cracks or neck formation, with

1sh

arctg 4.0 angle

sor and residue ALMN .Y

CI molding sand is not retained in the cavity under the action of centrifugal forces and shifted by

the bottom surface of the lower neck to the barrel area, which leads to a marriage of blockages in the working layer of the molded

roll.

To avoid blockages in workers

Parts of the roll are rotated at the nominal frequency in the vertical position before pouring the melt. AT

the process of rotation of the form: with a nominal frequency after its assembly in a vertical position, final grinding of its elements takes place. Under the action of the force of gravity, the litter and remnants of the molding mixture are located in the region of the lower neck (at the bottom of the mold) and under the action of centrifugal forces are mixed to the periphery (into a conical cavity). With a decrease in the frequency of rotation of the mold below the nominal one, a shift of the residual mixture to the working area of the lower neck may occur. Completion of the rotation frequency more than the nominal is technologically inexpedient,

since it promotes the formation of cracks and blockages in the casting and causes the vibration of the centrifugal machine, which leads to its premature wear.

After the remnants of the mixture fall into the conical cavity, the rotating form is returned to the horizontal position and the melt is cast. The cavity with the remnants of the mixture is filled with liquid metal. Formed on the outer surface of the lower neck in the region of the cavity, blockages are removed by machining.

Feature sheet rolls

with a barrel diameter of 505 mm, a barrel length of 1470 mm, with a total length of 3640 mm and a weight of 3.3 tons. With a minimum

the meter of the lower neck d

“WH. Sh

- 450 mm

45

the maximum diameter of the annular conical cavity is within: (459-468) mm, and the angle of inclination of the lateral surface, determined by the formula

o / arctg (3,2-4,0), with a length of “nn.

50 is not. lower cervix 1 in. - 800 mm is in the range of 80-82. Litter and mold sand residues located at the bottom of the mold at its vertical position, upon reaching the nominal

55, the rotational frequencies are shifted to the periphery and concentrated in an annular conical cavity. The working surfaces of the barrel and the necks of the roll after removal of the casting were free from blockages.

Claims (1)

Invention Formula A form for centrifugal casting of rolling rolls with necks, containing a metal mold with an inserted sleeve to form a roll barrel, on both sides of which there are flasks for the roll necks and face crushers, characterized in that, in order to reduce the spoilage of rolls in the hem, at the base Flasks for the lower neck of the roll are made annular conical cavity, the maximum diameter of which is 1.02-1.04 minimum diameter of the lower neck, and the angle of inclination of the side surface of the cavity is determined by the formula 0 arctgO, 2-4.0) one mii-sh Where d min.sh and, - the length of the lower neck, m; - minimum diameter of the bottom necks, mm. Fg1g. 2