SU996063A1 - Bimetallic casting production method - Google Patents

Description

(54) METHOD OF MANUFACTURING BIMETALLIC CASTINGS

one

The invention relates to foundry and can be used to make critical castings with special properties.

The closest to the invention to the technical essence and the achieved result is a method of manufacturing castings on melted models, including the manufacture of a casting model and a gating system model by pressing in (mold I of a thermoplastic material in a mold, connecting the casting model with a casting system model molding with refractory material and heating.

; However, the known method does not allow to obtain high-quality bimetallic composite castings from metal that are not optically cast alloys 20 due to the difference in their physical properties (melting point, etc.). Simultaneously J pouring two metals in either alternate fill leads to

cue of heterogeneous properties of castings by volume, loss of mechanical characteristics of raw materials, as well as to the appearance of a marriage due to casting failure.

Surface alloying of castings leads to distortion of geometrical parameters and cannot be a method of manufacturing parts with an alloy ratio of about 1: 1.

The purpose of the invention is to increase labor productivity and improve the quality of castings.

Claims (2)

The goal is achieved in that according to the method of manufacturing bimetallic castings, including the manufacture of a casting model and a model of a gating system by pressing a thermoplastic material into the pressfor IV, connecting the casting model with a model of the gating system, forming a refractory material and heating the mold, before pressing in the model compositions are introduced metallic powders, more refractory - in the casting model, and less refractory - in the model composition of the gating system, and the heating of the mold leads to temperatures 1.10-1.25 melting point material powder gating system. Alumina is used as a refractory material during molding. The drawing shows the casting mold assembly. The proposed method makes it possible to produce castings of various configurations, radios with thin cavities due to the high compliance of the thermoplastic base of model masses. The cavities of the castings can be filled with easily removable water-soluble rods at the stage of making the casting model. The introduction of metal powders in an amount of up to 8 5–9 O wt.% Practically does not complicate the process of pressing models. After the model is connected with the model of the gating system, a molding is made. The proposed method allows the molding of refractory powders without binders. When heated, the plasticizer is removed into the mold and then burns out. When the melting point of the powder material entering the model composition of the gating system is reached, the powder melts and fills the pores of the casting, forming a bimetallic composite casting with uniformly distributed components. The proposed method allows eliminating the operations of melting metal in the furnace and pouring the mold by combining the operation of melting the metal with calcining the mold. Heating the mold to a temperature of 1 D O1, 25 of the melting temperature of the material of the runner system is not necessary to create a good flowability metal when filling the pores of the model casting. Less than 1.10 of the melting point, the fluidity is low, and more than 1.25 of the melting point — evaporation of the metal and intense oxidation begins. Example. A bimetal casting of a valve plate of copper and iron was made. Iron powder in the amount of 80% was introduced into the model composition of the casting on the basis of paraffin before pressing. & 54 Copper powder was introduced into the model composition of the gating system in the amount of 85%. The casting model 1, soldered to the model of the Gating system 2, was stirred in graphite support 4 and molded with aluminum oxide 3. To preserve the density and heat insulation, the mold was covered with asbestos 5. The temperature control was performed using an induction unit inductor LPZ-67U to 1200s, gradually raising the temperature, periodically turning on the generator for 15 minutes. The results of comparative experiments have shown that it is not possible to obtain high-quality iron-copper casting of the valve plate type using known methods. Using the proposed method provides an economic effect of about 60 rubles. on tons of usable castings, increases productivity, improves the quality of castings. Formula from. 1. A method of making bimetallic castings, including making a model of a casting and a model of a gating system by pressing a thermoplastic material into a mold, connecting the model of casting with a model of a gating system, forming a refractory material and heating the mold, characterized in and improving the quality of castings; before pressing, metal powders are introduced into the model compositions, more refractory - into the casting model, and less refractory - into the model composition the heating system, and the heating of the mold is carried out to a temperature of 1.10-1.25 of the melting point of the powder material. gating system. 2. The method according to claim 1, which is based on the fact that aluminum oxide is used as a refractory material during molding. Sources of information are taken into account during the examination 1. A. Lipnitsky and M. Morozov B. Handbook of Worker Tleyteyschik. L., Mechanical Engineering, 1976, p. ZO5-ZO8. five