SU1703335A1 - Method of manufacturing bimetallic strips for electrical devices - Google Patents

Abstract

The invention relates to metallurgical production, namely the production of multilayer tapes for electrical devices. The goal is to improve the quality of bimetallic tapes by improving the adhesion of the layers with a total coating thickness of 5 ... 30%. For this, when preparing the components for cladding, the ratio of the yield strengths of the outer copper billet to the inner steel 1.0 ... 0.4 is provided. The rolling process is carried out with the rear tension of the steel billet and the forward tension of the bimetal. The ratio of the projection of the arc of contact of the metal with the roller and the average thickness of the tape is 6.5 ... 6.0. The adhesion strength of the layers is high with a total coating thickness of 5 ... 30%. 1 tab.

Description

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The invention relates to metallurgical production, in particular to the production of multilayer tapes of low carbon steels and copper or its alloys for electrical devices in rolling mills,

The aim of the invention is to improve the quality of bimetallic tapes by improving the adhesion of the layers with a total coating thickness of 5 ... 30%.

The method of obtaining bimetallic ribbons for electrical devices made of low carbon steel clad with copper or its alloys includes preparation of blanks for cladding, co-rolling with cold rolling at least 55% in one pass, intermediate heat treatment, calibration rolling and final annealing. In preparation for cladding, the ratio of the yield strength of the outer (copper) and

inner (steel) billets in the range of 1.0-1.4, and joint cold rolling is carried out with the deformation zone parameter l / hc 6.5-9.0, where I is the horizontal projection of the arc, in which the roll is in contact with the rolled metal ; hc - arithmetic average between the thickness of the package at the entrance of the metal in the rolls and at the exit from them.

To determine the range of the effect of these parameters on the adhesion strength of the layers, experimental studies were conducted, the results of which are shown in the table. A heat-treated tape of 11kp steel with a yield strength of 7CT 248-256 MPa was taken as the basis for cladding, and the cladding was made with L90 brass (the yield strength using heat treatment and cold deformation varied in the E range of cgm 126-403 MPa). Parameter

mm b

vl

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with

SA) CJ SL

I / he was changed from within 5.4 to 10.0 by changing the thickness of the blanks. The total thickness of the coating was provided within 24–30% of the thickness of the steel base.

As a criterion for the strength of adhesion of layers, we used the value of the relative deformation of a multilayer preform, in which the adhesion strength of the layers was not less than the strength of the weakest component (brass). Joint cold rolling (cladding) was carried out at an quarto 400/1000 x 500 industrial mill.

As can be seen from the table, strong adhesion of the layers during their joint cold deformation with the degree from 55% is achieved while ensuring the ratio of the yield strength of copper (brass) to the yield strength of the steel base in the range 1.0-1.4 while ensuring the deformation parameter I / he in the range of 6.5-9.0.

Thus, the goal is achieved with cold cladding with a degree of reduction of at least 55%, the ratio of the yield strength of copper and its alloys to the yield strength of the steel base in the range of 1.0-1.4 and ensuring the deformation parameter in the range of 6.5. -9.0.

Example. PlakiR bimetal was produced on an industrial four-roll mill 400/1000 x 500 with a reduction of 57%. The cladding force was 6150 kN, the back tension of the steel base was 60 MPa, the tompac was 30 MPa, and the forward tension of the bimetal was 30 MPa. The yield strength of the steel base and the tampak L90, respectively, was 282 and 370 MPa. The ratio of the projection of the arc of contact of the metal with the roller and the average thickness of the tape was l / hc 7.2

The effect of the mechanical properties of the workpiece and the parameters of the deformation zone on the adhesion strength of bimetal layers

(measured on non-rolled pieces). At the same time, a strong connection of components with a cladding layer thickness of 11: 12% per side (i.e., a total coating thickness of 23% of the steel base thickness) was obtained.

The use of the proposed method will make it possible to replace with bimetal the copper or its alloys currently used for the manufacture of electrical devices, save up to 70% of copper while maintaining the service properties of the products. The expected economic effect of 43,000 rubles.

Claims (1)

The invention The method of obtaining bimetallic tapes for electrical devices of low carbon steel clad with copper or its alloys, including preparing the components of the header for cladding, co-rolling with at least 55% reduction in one pass, intermediate heat treatment, calibration rolling and final annealing, different the fact that, in order to improve the quality of bimetallic tapes by improving the adhesion strength of the layers with a total coating thickness of 5 ... 30%, during the preparation those leaving to cladding provide the ratio of yield strengths of the outer (copper) billet to the inner (steel) range 1.0 .., 1.4, and joint cold rolling is carried out at the ratio l / hc 6.5 ... 9.0 where I is the horizontal projection of the arc along which the roll is in contact with the rolled metal; hc is the erifetic average between the thickness of the package at the entrance of the metal to the rolls and at the exit from them, Table continuation