SU1217506A1 - Method of producing band and foil from aluminium and its alloys - Google Patents

Description

metallurgy, in particular, to the production of aluminum tapes and foils, intended for the manufacture from them by stamping with an extractor of various parts, mainly perforated plates of heat exchangers of automobile radiators.

The purpose of the invention is to increase the strength and ductility of the material in the carbonized state.

The method consists in the fact that cold rolling is carried out with a total stretch of 30-90 at a temperature of the last two or three passes of 50 ° C.

On a 0.1 mm thick foil made of aluminum grades A5, A6, these rolling modes provide dg 170-200 MPa and 8 3-6%, i.e. The optimum set of mechanical properties required for a radiator foil.

The increased plasticity characteristics of aluminum tapes and foils, i rolled with a stretch of 30-90, are due to the intense dispersion of the deformed microstructure and the increase in the total length of the grain boundaries, which has a positive effect on the inhibition of the development and propagation of microcracks in the metal during its subsequent reformation . In addition, with these extrusions, the process of dynamic return is activated, associated with the redistribution and partial annihilation of dislocations, the intensification of their cross slip, which leads to the formation of a pronounced subgrain (cellular) structure. In this case, the dislocation density within the subgrains is reduced, the boundaries themselves become narrower due to the resorption of coarse dislocation clusters in them, the subgrains have a size of about 1-2 µm and relatively small misorientation angles. Such a structure is fairly homogeneous with a significant number of mobile dislocations, which facilitates the flow of uniform plastic deformation in the bulk of the metal and leads to an increase in the plasticity indices.

does not exceed 1-2%. This is due to the decrease in the number of grains and the total length of their boundaries in the cross section of the scientific research institute of metal, as well as the imperfection of the deformed cellular substructure, in which the cell boundaries are wide coil dislocation clusters and difficult

10 the flow of uniform plastic deformation in the macro-volume metal. When stamping radiator plates of such a material with low ductility, cracks and breaks will appear,

15 in connection with which it cannot be used for the indicated purposes.

An increase in the total stretching during rolling of more than 90 is accompanied by a decrease in plasticity indices,

20 which is caused by the increase in the misorientation angles of subgrains and, for this reason, the difficulty of passing dislocations through high-angle boundaries. In this case, the elongation

25 foils with a thickness of 0.1 mm does not exceed 2-2.5%, which leads to the possibility of the appearance of cracks when stamping radiator plates. In addition, excessive hardening of the metal accompanies 30 with an increase in the tensile strength of more than 200 MPa, which leads to a large overload of equipment for the stamping of perforated plates.

Maintaining the temperature of the rolled metal in

35

40

45

50

the last two or three passes at the level of 50-100 C in combination with the total stretch of 30-90 provides a sufficiently high level of plasticity of the welded aluminum, mini radiator tapes and foils and the necessary optimum strength value equal to 170–200 MPa and achieved as a result partial weakening when returning to the specified temperature range.

At a temperature of less than 50 ° C, the return process is retarded, resulting in an excessively high strength of the welded metal J 120-230 MPa. This not only leads to certain difficulties in rolling, but also causes

large equipment overload for the reduction of the total exhaust during the pro-55 stamping of the radiator plates and the backing of less than 30 is accompanied by the possibility of its malfunctioning decrease in plasticity of breakdowns. An increase in temperature and relative lengthening of the temperature of more than 100 ° C is accompanied by

does not exceed 1-2%. This is due to the decrease in the number of grains and the total length of their boundaries in the metal cross section, as well as the imperfection of the deformed cellular substructure, in which the cell boundaries are wide coil dislocation clusters and difficult

flow of uniform plastic deformation in the macro-volume of the metal. When stamping radiator plates from such a material with low ductility, cracks and breaks will appear,

in connection with which, it cannot be used for the indicated purposes.

An increase in the total stretching during rolling of more than 90 is accompanied by a decrease in plasticity indices,

this is due to the increase in the misorientation angles of subgrains and, for this reason, the difficulty of passing dislocations through high-angle boundaries. In this case, the elongation

foil with a thickness of 0.1 mm does not exceed 2-2.5%, which leads to the possibility of the appearance of cracks when stamping plates of radiators. In addition, excessive hardening of the metal is accompanied by an increase in the tensile strength of more than 200 MPa, which leads to a large overload of equipment for the stamping of perforated plates.

Maintaining the temperature of the rolled metal in

the last two or three passes at the level of 50-100 C in combination with the total stretch of 30-90 provides a sufficiently high level of plasticity of the welded aluminum radiator tapes and foils and the necessary optimum strength strength value equal to 170–200 MPa and achieved due to partial softening when returning in the indicated temperature range.

At a temperature of less than 50 ° C, the return process is retarded, resulting in an excessively high strength of the welded metal J 120-230 MPa. This not only leads to certain difficulties in rolling, but also causes

a significant drop in the plasticity characteristics, while the relative elongation of the foil with a thickness of .0.1 mm is reduced to -1.5-2.5%. This is due to the formation of a polygonized substructure and a significant decrease in the number of mobile dislocations, which makes it difficult for uniform plastic deformation to occur in the bulk of the metal. In addition, at such elevated temperatures, an excessive softening of the material can occur. All this makes it impossible to use it to obtain radiator plates of the required quality.

Comparative data on the results of tests of aluminum tapes and foils made by the proposed and known methods are presented in the table.

Example. The manufacture of radiator foils from aluminum of the A5 grade with a thickness of 0.1 mm is carried out as follows.

The starting material is hot rolled coil with a thickness of 6 mm, having a recrystallized Co structure with an average grain size of about 80 µm. After trimming the edges, the billet is rolled cold to a thickness of 0.45 mm on a five-needle continuous mill.

After trimming the edges, on a longitudinal cutting, the rolled foil billet with dimensions of 0.45–1530 mm rolls a quarter / 280 / 850x1850 mm quarter in a cold mill in three passes

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according to the scheme 0.45-0.28-0.17-0.1 + 0.008 mm, i.e. the total stretching from hot-capped hp to the final size of the foil thickness is 5 et 60.

The actual temperature of the rolled metal due to the deformation heating is about 60-9 ° C and decreases with decreasing

no foil thickness. Between passes natural cooling (coiling) of the rolls to a temperature of no more than 30-50 ° C is performed.

After the final rolling and cooling of the coils, the foil is cut to the required dimensions of pge width with the acceptance of metal into the spools with an inner diameter of about 150 mm. The mechanical properties of the foil obtained during the testing for constriction are d 180-190 MPa, S 4 4.5%, t, e, have a high level and meet the requirements imposed by aluminum radiator foil with a thickness of 0.1 mm Stamping perforated plates of such foil provides the required quality.

The use of aluminum foil obtained by the proposed method for the manufacture of perforated plates of new types of precast radiators for passenger cars makes it possible to significantly reduce the laboriousness of the process, replace scarce and expensive materials, and improve some radiator operating parameters.

Table continuation

Claims (1)

METHOD FOR PRODUCING TAPES AND FOILS FROM ALUMINUM AND ITS ALLOYS, including hot and cold rolling, characterized in that, in order to increase the strength and ductility of the material in the cured state, cold rolling is carried out with a total hood of 30-90 at a temperature of the last two to three passageways 50-100 ° C.