SU1661241A1 - Method of making rolled slabs of aluminium - Google Patents

Abstract

The invention relates to metallurgy, in particular, to the technology of manufacturing aluminum semi-finished products, mainly sheets, tapes and foils. The aim of the invention is to increase the plasticity and reduce the anisotropy of properties in the longitudinal and transverse directions. The method involves heating the aluminum billet in the deformation zone, based on the ratio T _p = 167.3 Σ ° ^{, 17} ± 2 ° C, where Σ is the sum of impurities in aluminum, wt.%, Rolling in 5 to 8 passes with a rolling speed, defined the ratio of V _pr = 0,01N ° ^, ° ⁷ @ ^- ° ^{, 3} ± 0,001 m / s, where N is the number of the passage

ε is the degree of deformation. At the same time, the temperature of the rolls is maintained equal to T _p + (10 - 20) ° C, and after each pass the billet is cooled to 80 - 100 ° C. 2 ill., 2 tab.

Description

The invention relates to the field of metallurgy, namely to the technology of manufacturing aluminum semi-finished products, mainly sheets, tapes and foils.

The aim of the invention is to increase the plasticity and reduce the anisotropy of properties in the longitudinal and transverse directions.

When processed under the action of thermal cycles (heating to tp and cooling to 80-100 ° C), plastic deformation in each passage is accompanied by complete or partial relaxation of the structure, namely polygonization and recrystallization, which leads to grinding of the microstructure and elimination grain along the rolling direction). Such processing allows the formation of a texture of aluminum semi-finished products with non-pronounced orientations (111) and (200) along the rolling direction. Cooling in the pauses between the aisles is not

gives rise to a collective recrystallization and softens the metal, as evidenced by studies carried out with an electron microscope and an X-ray texture diffractor.

Rolling, consisting of less than 5 or more than 8 passes, in these specific conditions does not allow to achieve the desired level of properties, which is due to the incompleteness in the first case and the suppression of ongoing relaxation processes in the second. The cooling of the peal between passages below 80 ° C and heating above 100 ° C does not allow the metal to be heated to a predetermined temperature in the subsequent pass, which leads to non-optimal properties. The roll temperatures below tp + 10 ° C and above tp + 20 ° C are not optimal for the same reasons as in the previous case, since the heat content of the workpiece in each particular variant (depending on the purity

w

AND

ON (

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aluminum) should be regulated.

Thus, an increase in the dislocation density with simultaneous polygonization and partial recrystallization leads to an increase in ceoncte (in this case plasticity) and a decrease in anisotropy.

The invention is illustrated by the following examples:

Example. Processing of workpieces of 25x50x100 mm in size from aluminum of the A8 grade (total of impurities Ј 0.2%) is carried out according to the proposed and known methods. In this case, the heating temperature of the blanks in the deformation zone is found from the ratio

Vp 167.3Ј0 Tr + 2 ° C, which is equal to 125 ° C.

Figure 1 shows the temperatures to which the blanks are heated depending on the purity of the aluminum.

According to the proposed method, the deformation of the blanks is carried out by rolling in 5-8 passes with a rolling speed determined from the ratio

Vnp 0.01n ° 07Ј) 3 ± 0.001 m / s.

The rolling speed in each pass is set in accordance with FIG. 2 (the shaded part) and Table 1, in which the rolling speed in each pass is given.

The temperature of the rolls in the passages set 135-145 ° C. After each pass, cooling to 80-100 ° C is carried out. Processing modes and mechanical properties are given in table 2.

The advantage of the proposed method for producing semi-finished products in comparison with the known one is that it allows to increase the mechanical properties, in particular plasticity, by 20-30% and, in addition, to reduce the anisotropy of the properties, OB о, 2 and б by 10, 20 and 40%, respectively (Table 2).

Claims (1)

Invention Formula A method of manufacturing flat rolled aluminum, which includes multi-pass rolling at elevated temperature, characterized in that, in order to increase plasticity and reduce anisotropy of properties in the transverse and longitudinal directions, rolling is carried out in 5-8 passes with a speed Vnp 0, 001 m / c, where n is the passage number; Ј - the degree of deformation per pass with the heating of the workpiece in each pass to tp 167.3 17 + 2 ° С where .- is the sum of impurities in aluminum, wt,%, followed by cooling it to 80-100 ° C, while the temperature of the rolls is maintained at tp + (10-20) 0C. Note. The numerator shows the properties of aluminum grade A8 along the rolling axis, in the denominator, across the axis. Table 1 Table 2 t, s 150 130 110 100 / one ABOUT 0.1 Vnp.M / c 0.10 0.02 ABOUT 7x Lx 0.2 0.3 OA 0.5 FIG. one eight