SU1507529A1 - Method of producing moulds for centrifugal casting - Google Patents

Abstract

The invention relates to foundry and can be used in the manufacture of centrifugal casting molds, mainly from liquid self-hardening mixtures. The purpose of the invention is to increase the durability of the mold by preventing it from cracking during rotation. After the mixture has cured, the resulting shrinkage gap between the flask and the mixture is filled with a non-wetting sand mixture in an amount equal to the volume of the gap, which prevents the form from cracking during its rotation.

Description

The invention relates to casting production, in particular, to methods for producing centrifugal casting molds, predominantly from liquid self-hardening mixtures (LSC).

The aim of the invention is to increase the durability of the mold by preventing its cracking during rotation.

 The invention uses the property of liquids - incompressibility. The fluid filling the shrinkage gap formed after the curing of the displace- ment | SI counteracts the centrifugal forces and, therefore, prevents the cracking of the mold.

If the volume of the liquid is less than the volume of the shrinkage gap, then the shape may crack when it rotates.

The increase in the volume of the liquid over the volume of the shrinkage gap leads to its increased consumption.

It is advisable to use sidkosti, not wetting the molding mixture, such as liquid paraffin or compounds based on it. If the liquid wets the molding mixture, due to its absorption with the mixture, the resulting shrinkage gap is not completely filled, which will lead to cracking of the form during rotation.

The method is carried out as follows.

Example. Made of CSH shape of the neck of the mill roll. Dimensions of the working cavity of the form: height 1800 mm; minimum diameter of 380 mm; maximum diameter 420 mm. Opoka - cylindrical, material - cast iron

SP Ch

JV Yu

with

3 1507529 СЧ-20 - outer diameter 900 mm; 800 mm inside diameter

The flask was installed on a submodel plate with the model and washed down with the CSH i, composition, wt.%: Quartz sand sand 94.6; ferrochrome slag 4.0; caustic soda solution 0,3; ground coal 1.4; liquid glass 4.0 DS-PAC 0.12. The moisture content of the mixture is 5.8%. Cure time of the mixture is 40 min. Shrinkage of the mixture of 0.6%.

Before pouring the mixture on the inner surface of the flask, a layer of molten and superheated to 80 ° C was applied.

The volume of the shrinkage gap was determined by the formula

Vi / irH (R - R V

.

J.

where Va is the volume of shrinkage gap, cm; H is the height of the gap, cm; R is the inner radius of the flask; CMJ R2 is the outer radius of the form (by mixture) with regard to shrinkage, see

The use of the proposed method makes it possible to increase the durability of centrifugal casting molds by paraffin, which formed after hardening-15 to prevent their cracking during distortion, a layer 1 mm thick. After whelping by 15-30%. The holders for curing the mixture to the flask were removed from the model and transferred to the preparation site. In a gas chamber dryer, the colored form is heated to 20,600 ° C. In this paraffin

Claims (1)

Invention Formula A method of making molds for centrifugal casting of predominantly from liquid self-hardening mixtures, comprising pouring the mixture in the flask at the mine. del and her vyerzhkha for curing get down to melted and filled the shrinkage gap. The volume of paraffin was adjusted to the required amount by feeding with liquid paraffin. The heated shaft neck shape is 25 in that the ka was assembled in a centrifugal mold to increase the durability of the molds along with other elements and rotated in a centrifugal machine with a frequent way of preventing its cracking during rotation, after holding for curing, the resulting shrinkage 350 rpm for 20 minutes The volume of the shrinkage gap is determined by the formula Vi / irH (R - R V . J. Va - the volume of shrinkage gap, cm; H is the height of the gap, cm; R is the inner radius of the flask; CMJ R2 is the outer radius of the form (by mixture) with regard to shrinkage, see The use of the proposed method allows increasing the durability of centrifugal casting molds by eliminating their cracking during rotation by 15-30%. Invention Formula The use of the proposed method allows increasing the durability of centrifugal casting molds by eliminating their cracking during rotation by 15-30%. A method of making molds for centrifugal casting of predominantly from liquid self-hardening mixtures, comprising pouring the mixture in the flask at the mine. del and her vyerzhkha for curing characterized in that, in order to increase the durability of the forms characterized in that, in order to increase the durability of the forms by preventing it from cracking during rotation, after holding for curing, the resulting shrinkage Thus, the rotation was stopped, the gap between the flask and the mixture was filled with the mold elements from the mold on the non-wetting sand mixture of the disassembly and their quality was examined. bone in an amount equal to the volume of the gap.