SU1131594A1 - Method of obtaining bimetallic castings from iron-base alloys - Google Patents

Abstract

1. METHOD OF OBTAINING SMETALLIC CASTINGS FROM IRON BASED ALLOYS, see the preliminary imposition on the surface of a solid base of metal foil before placing it in a mold, setting it in a mold, casting an iron-based alloy and cooling the castings, about a tl and h So that, in order to increase the strength of the joint of the casting layers, before applying a metal foil, flu is applied to the surface of a solid base, and after applying a metal foil, it is pressed under a pressure of 5-30 MPa temperature of 50100 ° C above the melting point of the flux. 2. The way according to. Clause 1, characterized in that an aluminum sheet with a thickness of 0.3-1.0 mm is used as a metal foil, and a mixture of halides as a flux.

Description

00

ate

4 The invention relates to mechanical engineering, in particular, to the manufacture of bimetallic parts by casting. There is a known method for producing bimetallic castings, which includes installing a heated solid base in a casting mold and pouring a liquid metal. On a solid base L. However, this will not always get a quality base. weldability at the boundary between the metal of the base and the cast alloy. The closest to the proposed technical essence and the achievable result is a method of obtaining bimetallic castings from iron-based alloys, including preliminary imposition of metal foil on the surface of a solid base, heating the solid base by placing it in a casting mold, installing it into a mold, pouring in the form of an alloy based on iron and cooling castings. When such inserts are poured, the folia gus melts, forming a solid solution with iron and a transitional, diffusion layer between the metal to be poured and the metal of the insert 2. The disadvantage of this method is that the strength of the connection of the casting layers is not high due to the uneven fit of the metal mold to the surface of the solid base, and has retained the pores between the foil and the surface of the solid base. In addition, the imposition of metallic foil and its retention is possible only on horizontal surfaces of a solid base. On inclined and, moreover, vertical planes, the foil will not be relieved, which will not ensure the quality of the connection of the casting layers on these surfaces. The purpose of the invention is to increase the strength of the connection of the casting layers. The goal is achieved by the method of producing bimetallic castings from alloys based on iron, which includes the preliminary imposition of a metal foil on the surface of a solid base, heating a solid base before placing it in a casting mold, pouring an iron-based alloy into the mold and Cooling the castings before applying the metal foil to the surface of the solid base 942 causes flux to be applied, and after applying the metal foil, it is pressed under a pressure of 5-30 MPa at a temperature 50-100 ° C above the melting point of the flux, and aluminum sheet is used as the metal foil 0.3–1.0 mm thick, and a mixture of halides as a flux. An increase in the strength of the joint of the casting layers during the pressing of the metal foil ensures that it fits snugly to the surface of the solid substrate. In addition, an intermediate layer of flux cleans the surfaces of the foil and the solid substrate from oxide compounds, which increases the adhesive strength of the coating between these surfaces. The application of pressure when pressing up to 30 MPa-like and the use of foil with a thickness of less than 0.3 mm can lead to disruption of the metal foil continuity, its warping or breaking, which reduces the strength of the connection of the casting layers. A pressure of less than 5 MPa does not ensure that the metal foil fits snugly to the surface of the solid substrate. Increase foil thickness in excess of 1.0 mm. leads to increased pressing forces. In addition, a large-thickness metal foil may not be completely melted when zingivaya metal or it will ensure the formation of intermetallic phases in the diffusion transition layer after crystallization. In both cases, the bonding strength of the casting layers is reduced. Using the specified temperature range of the process provides high-quality adhesive adhesion of the metal foil to the surface of the solid substrate. The decrease in temperature does not ensure the activity of the flux deposited on the surface of the base, maintaining the flux in a liquid state for the duration of the entire process. Increasing the heating temperature can lead to melting of the metal foil and disruption of its continuity. Example. A solid 10 mm thick plate is prepared from steel 40X. A layer is applied to one of the side surfaces of the plate.

31

flux 34A GOST 1521-68 (34% KACI, 29-35% LiCI, 9-11% NaF, 8-12% ZnCi), a solid base with flux is heated to 470-520 ° C. In so doing, the flux melts and wets the surface of the base with a thin layer. Excess applied flux is allowed to drain, for which the plate is placed in a vertical position. The heated solid base with a layer of flux is placed under the press, metal foil AD1 GOST 21631-76 is applied and pressed. Then remove the base, again heated before and placed in a mold on the vertical side of its surface; The casting was carried out with steel 5HNM at 1580-160b ° C. In the process of pouring and subsequent crystallization, the layer of aluminum foil melts, ensuring the formation of diffusion zones and a firm connection of the casting layers. After cooling, the castings are cut out of them. Impact samples, the deposited metal layer being 1/3 of the thickness of the entire sample, and metallographic examinations and mechanical tests are carried out.

Way

944

The test results are presented in the table.

Met allographic analysis shows that the samples obtained have a continuous diffusion zone over the entire surface of the joint between the solid base and the metal being poured.

The strength of the bonding of the layers is determined by the magnitude of the impact strength determined on non-notched samples.

The proposed method can be applied for the manufacture of bimetallic billets of forging dies, injection molding molds, etc., tooling and cutting tools, as well as yifrochnenie surface castings wear-resistant inserts. The efficiency of the process is provided by saving expensive and scarce materials and alloying elements, as well as by reducing the amount (%) of castings resulting from the detachment of the wear-resistant insert from the cast metal. The economic effect in the manufacture of 1000 pieces of bimetallic billet cutting tool will be 250 rubles.

Luce

500 600

500 500 500 500 500 500

2.6 2.8

0.6 3.0

0.1

15 15 13 t5 15 15

3.7 0.3 5.7 0.6 6.8 1.0

6.1 1.3 5.8, 5 0.8

500

7 500

8 500

9 500

10 11 12 13 14J 500 500 420 470 520 15 16 600

17 without flux)

Brand 34A flux according to GOST 1521-68.

In samples without flux, the temperature of heating a solid base before placing it in a mold (600 C).

Table continuation

3.2 3.4

2.5 A, 5

5 7.4

30 7.2

35

45 6.3 4.4

15 5.7

15 6.9

15 6.2

15 6,1

15

Claims (2)

1. METHOD FOR PRODUCING BIME- TALLIC ALLOY CASTING ON THE BASIS OF IRON, including preliminary application of a metal foil to the surface of the solid base before placing it in the mold, installation in the mold, casting into the form of an alloy based on iron and cooling of the castings, characterized in that, in order to increase the strength of the layers castings, before applying a metal foil, a flux is applied to the surface of a solid base, and after applying a metal foil, it is pressed under pressure 5-30 MPa at a temperature of 50,000 ° C above the melting point of the flux. 2. The method according to. p 1, l and m of h and - _e. w w I and D with the fact that the metal foil kachestveV # ispolzuyutI aluminum sheet 0.3-1.0 mm thick, II and as a flux in the mixture galogenidov.I