SU1426458A3 - Method of manufacturing blank in the shape of strip from aluminium alloy for production of articles by deep drawing and by drawing with thinning of walls - Google Patents

Abstract

This invention relates to methods for producing blanks in the form of strips by continuously casting an aluminum-magnesium-manganese system from an aluminum-alloy alloy suitable for the manufacture of products of deep-drawn and thinned walls, such as cylinders, etc. The aim of the invention is to increase anti-creep properties and reduce festo formation. The method involves casting an alloy based on aluminum containing, in wt.%: Magnesium 0.8-1.2, manganese 1.0-1.5, copper up to 0.25, zinc up to 0.25, silicon up to 0.3, iron to 0.7 and chromium 0.11-0.66, in the form of a strip with a thickness of 6.35-12.7 mm, its homogenization at 572- 610 C for 10-40 hours and subsequent cold rolling in three stages. The first stage is carried out with a compression of 66-75%, the second - with a compression of 10-25% and the third - with a compression of 66-88%. Between the first and second rolling stages, annealing is carried out at 232-260 ° C for 1-4 hours, followed by heating at 426 ° C for 2-3 hours. After the second rolling stage, annealing is performed at 260 ° C for 1 hour, followed by heating for 1 2 hours. 27 tab. WITH GS Oft) 4 cl 00

Description

The invention relates to a method of production by continuously casting a strip of aluminum alloy suitable for use in the manufacture of products by deep drawing and drawing with wall thinning, for example cylinders, etc.

The aim of the invention is to increase the anti-scoring properties, reduce the festo formation and increase the strength of the agib.

During the homogenization, to obtain a product from an aluminum sheet, the web made by continuous casting is heated to 510-621 s (preferably to 538-593 s) for about 10-25 hours. The homogenization operation is carried out at about 593 C for at least 10h

If the cast aluminum sheet is heated to the homogenization temperature in coils, they must be heated slowly over a 2-H h time to exclude the initial melting of the alloy. Optimum heating under homogeneity

0

"

five

but

five

The embodiment of a continuously cast aluminum rolled strip is that the temperature of the web is raised from ambient to 538 ° C for 5 hours, from 538 to 566 ° C for 3 hours and from 566 to 5 hours.

The web is homogenized at 593 t ± for 20 h.

The study of photomicrographs of an aluminum alloy of the 3004 grade, homogenized by the proposed method, shows that the secondary elements in the aluminum alloy (Mn, Fe, Si) are agglomerated, changing shape and increasing in size. As a result, intermetallic particles are formed, approaching the global shape and having a size of 1-3 MK, which ensure the resistance of the cast strip to tearing during strong machining during the manufacture of two-piece cans by stretching with wall thinning.

The temperature of homogenization, the size of intermetallic particles and the degree of scoring are given in table.1.

b l and c a 1

482-510 0.5 - 1.0 Moderate 537 - 565 0.7 - 1.2 Limit 570 - 594 1.0 - 3.0 No

50

20 h at the specified temperature.

On an aluminum sheet, homogenous — up to 25.4 mm (usually 6.35 - teemed at 510-621 ° С, not in dishes and - 12.7 mm), the first cold is subjected to digging while drawing with thinning. the walls of the bowl formed from the sheet, however, after drawing, it has an unacceptably high film formation, which is removed after cold rolling with an intermediate recrystallization annealing.

After obtaining a billet of aluminum alloy by continuous casting of the strip and homogenization in accordance with the specified parameters, the cooled strip is thick

55

rolling to reduce thickness by about 25% (preferably 50-75%). Then the cold rolled sheet is heated to the reduction temperature, i.e. to a temperature at which it softens without forming a new granular structure (for an aluminum alloy of the 3004 grade, the reduction temperature is in the range of about 149-288 seconds, the optimum temperature is in the range of about 176-260 ° C) for about 2-6 hours ( preferably in the range of 218-246 C for 2-4 hours)

up to 25.4 mm (usually 6.35 - 12.7 mm) is subjected to the first cold

rolling to reduce thickness by about 25% (preferably 50-75%). Then the cold rolled sheet is heated to the reduction temperature, i.e. to a temperature at which it softens without forming a new granular structure (for an aluminum alloy of the 3004 grade, the reduction temperature is in the range of about 149-288 seconds, the optimum temperature is in the range of about 176-260 ° C) for about 2-6 hours ( preferably in the range of 218-246 C for 2-4 hours).

After heating the web to the temperature of recovery, it is cooled to ambient temperature and subjected to second cold rolling to reduce the thickness in general by 10% (preferably by 10-25%).

After the second stage of cold rolling, the temperature of the cold rolled sheet rises to the recrystallization temperature, while the grain is granular. the structure varies from elongated to equiaxed.

Heating to the recrystallization temperature is carried out at 315-482 ° C for about 1-4 hours (preferably within 371-427 ° C for about 2-3 hours).

After heating to a recrystallization temperature for a specified time, the recrystallized web is cooled to ambient temperature and then cold rolled to approximately 50% reduction in thickness (preferably 60-90%) to a final thickness determined by the requirements for the container, for example 0.3 mm - 0.35 mm, and the degree of hardness HI 9.

In order to optimally reduce the formation of festo, the aluminum sheet after the second cold rolling is heated a second time to the recovery temperature, followed by heating to the recrystallization temperature. The second reduction heating is carried out at 232-288 ° C for about 0.5-3 hours (preferably at about 246-274 ° C for 0.75-1.25 hours).

When carrying out the second heating to the reduction temperature, the web can be cooled to room temperature between the second heating stage to the recovery temperature and the recrystallization stage. Preferably, the heating for recrystallization is carried out without prior cooling to room temperature by direct heating from a heating temperature to a recrystallization temperature.

In order to achieve consistency in the results of reducing the festoon formation mainly after the homogenization stage, according to the proposed method, the web is cooled in a controlled and sequential manner, i.e. with a cooling rate of not more than 24 s / h. Cooling method is barely

Next: in the temperature range 593-cooling is carried out with an optimal average speed of 10 C / h, in the range of 485-399 ° C - at a speed of 24 C / h, and in the range of 399-190 C - with a speed of 1.1 l / h.

An aluminum alloy containing 0.1-0.4% by weight of chromium is used. The can, formed from the improved chromium alloy 3004 in the manufacture of two parts, obtained by stretching and thinning the walls, has better buckling strength, i.e. 5 ability to withstand high internal pressure without inverting the bottom.

Improved chromium aluminum alloy contains, wt%: magnesium about 0.5-1.5; manganese 0.5-1.5; iron 0.1-1.0; silicon 0.1-0.5; zinc to 0.25; copper to 0.25; chromium 0.1-0.4; aluminum and random elements and the rest.

five

0

five

0

five

0

five

In order to manufacture a sheet molded from a chromium-improved aluminum alloy 3004, it is important that it has the structure obtained after reduction during cold rolling with at least 50% of the material in the recrystallized state. The sheet in this state has a tensile strength of the order of 40000-45000 pounds per square inch and the total elongation measured on length specimens by caliber, 2 inches (50.8 mm), 1.5% or more. The ultimate tensile strength of the sheet material has been found to be 40000-45000 psi when such a sheet is subjected to stretching and wall thinning to produce a two-part beverage container for the purpose of correlating with buckling strength of the order of at least 98 psi.

In order to achieve the required ultimate tensile strength, which is characteristic of a sheet made from a continuous strip of a cast improved alloy according to the proposed method, it is necessary to strictly follow the specified chromium content in the alloy and to limit the treatment.

To obtain a chromium-enhanced aluminum alloy-sheet material by casting aluminum strips and alloying elements

is loaded into a smelter, from which a stream of metal is fed to an installation for casting strips, where a thin strip of 25.4 mm or less thick is cured (preferably about 6.35-12.7 mm thick). The cast strip is processed to obtain a sheet without sticking a meta face that has low festoon formation and high strength using homogenization and cold rolling and annealing modes in accordance with the proposed method.

A cast aluminum strip of 305 x 915 mm in size, 11.9 mm thick is placed in a furnace with a nitrogen atmosphere, quickly brought to the required temperature and maintained for 10-40 hours at homogenization temperatures varying from 590 to 610 ° C. from the oven and cooled to an appropriate temperature by blowing with cold compressed air to the strips.

The homogenization conditions applied during the series of heats are given in Table 3.

Table 3

610 594 590 593

30 35 40 10

Example 1. A series of aluminum alloys obtained by refractory casting, containing various components, including those that are part of the aluminum alloy 3004, manufactured according to the specifications of the Aluminum Association, are used in the manufacture of can body cases, obtained by drawing and thinning the walls.

The compositions of the alloys are given in table. 2.1.

The cooled strips are rolled in successive passes using a production mill to. as long as the band doesn’t reduce g with up to varying degrees of thickness of the order of 66-75%, i.e. up to 4.06-3.05 mm.

The reduced thickness strips are heated to the first reduction temperature, at which the strips are placed in a furnace, preheated to 232 seconds, and held for 3 hours, after which the strips are removed from the furnace and cooled to room temperature. After heat treatment to the temperature of the first cold rolling / settling, the strip is subjected to second cold rolling through successive passes through a pair of squeeze rolls until the thickness

The Q band does not decrease by 10-25% (i.e., 3.05 mm).

After the second cold rolling, the strip is subjected to secondary recovery.

extreme heating at 260 ° C for 55

1 h and then annealed at a recrystallization temperature of 426 ° C for 2 h.

Modes of cold rolling and intermediate annealing are given in table 4.

Table4

breaking up (Tables 5 and 6) and comparing these data with those presented in Table 7 shows that the aluminum strip, processed in accordance with cycles 1 and 2 of cold rolling and annealing, has a smaller festoon formation.

Example 2. The procedure of example 1 is repeated, but reproducing

The bands homogenized, as indicated in table 8, are cooled in accordance with the regimes given in tarl.9.

Table 9

45 At 190 ° C, the oven is turned off and the strips are allowed to cool to room temperature. The cooled strip is subjected to cold rolling and annealing GI, as in example 1.

50 The conditions of cold rolling and annealing are given in Table 10. (The Cj mode corresponds to a known method).

eleven

2044

250I

Not

4272

4272

4273

The conditions of heating and cooling when processing a coil strip on each

The cooled and recrystallized strips are subjected to a reduction in thickness. 0.33 mm - 0.37 mm.

The bands are examined under a scanning electron microscope in backscatter mode. The size of the intermetallic particle was found to be in the range of 1-3 microns, i.e., tearing was not observed, the strips were stretched with wall thinning to make cans.

The test results on the festoon formation of strips of alloys whose composition is indicated in Table 2 are presented in Table 12 (cycl.Z), 13 (cycle 4), 14 (cycle 5) and 15 (cycle 6). (Each re 1426458

12

t and in l and II and 10

260

Not

I No

Not

4272

Not

the stages of reduction and recrystallization are listed in Table 11.

T a

the result of the feston test is the average of three tests).

Table 12

13 Table 13

The results of tests on festoon-55 temperature homogenization formation on aluminum strips, 570-593 ° С. In order to achieve homogenization, the strips subjected to a comparative Cs cycle are reproducing conditions of cold rolling and annealing, representing and cooling at 10–15 tons of ruled into a table, 16. the length of the strip is approximately 12.7 mm thick,

J426458

14 Table 16

obtained by non-virgin casting, which is subjected to heating and cooling. The time and temperature of heating and cooling are given in Table 18.

Table 18

The bands, homogenized according to the conditions specified in Table 7, are cooled according to Table 1. 1 9 mode.

Each stage of reduction and recrystallization is carried out under conditions.

The cooled strips are rolled in successive passes on an industrial rolling mill to varying degrees of thickness in the range of 66-75% (4.064 - 3 mm).

In the first cycles of cold rolling and heating to the temperature of recovery or recrystallization of the strip

of reduced thickness (66–72%) is heated to the temperature of the first reduction, during which the strips are heated in a furnace to 232 ° C and held at this temperature for

3h After the first treatment, consisting in cold rolling and heating to the recuperation temperature, the strips are subjected to a second compression by passing the sequence through a pair of squeeze rolls to reduce the strip thickness by 10-25% (3 mm).

After the second cold reduction, the strips are heated to a temperature of 260 ° C of the second reduction.

operating in the processing of coil strips, which are listed in Table. 21,

The strips are then cooled to room temperature and strengthened by passing successively through the rolling mill until the strip is compressed by about 88% in thickness (to 0.33-0.37 mm).

The bands are examined under a raster electron microscope in the mode of reverse distance. The size of the intermetallic particle was found to be 1-3 microns, therefore, when the strips were stretched to thin the walls to make cans, tearing was not observed.

To determine the level of festoon formation during stretching of the strips, round billets with a diameter of 55.88 mm are cut from the reinforced hardness band HI 9 and deep shallow bowls with a diameter of 32.5 mm are prepared by deep drawing with a 30% reduction in diameter. For deep drawing a tool is used which provides approximately 3.5%.

C B

3.12 42.3 4.33 41.1

thirty

positive gap (0,0127 mm) between the walls of the punch and the matrix. In the test2 (festoon formation, which reproduces the stretching stage in the can manufacturing process, a gap between the punch and the stamp by 5% or less and a diameter reduction by 39% are required. To obtain a cup without fracture and wrinkling during each test, adjust the speed first stretching operation and pressure to secure the preform.

The test results on the festoon formation in the strips of alloys shown in Table 17, which were subjected to homogenization and cold rolling and annealing, according to Table 18 and Table 20, are presented in Table 22 (alloy V), 23

 (alloy A) and 24 (alloy Aj), (each result of the festoon formation test represents the average of three tests).

35

44.5 2.3 43.1 2.2

ten

J426458

20 Continued tabl. 22

AT

5.99

The mechanical properties of the bands hardened to the degree of hardness HI9, determined by the ASTM test method, E-8 using 50.8 mm long samples (each mechanical test result is the average of six tests, three measured in the longitudinal direction and three in the transverse direction ) are presented in table.

Table 25

39.0

41.2

2.0

Continued table. 25

39.8 40.5

40.6 41.3 42.7

42.3

97.0

98.5

99.0

100.0

101.0

102.0

Longitudinal flexural strength, measured for a sheet with a thickness of 0.0135 (0.333 mm) or adjustable for ca-.

at 1 psi for measuring 0.000l (0.0025 mm).

From Table 22 it can be seen that the addition of 0.11% by weight of chromium to the aluminum alloy 3004 will improve tensile strength and,

Thus, the appropriate buckling strength without adversely affecting the formability of the sheet for a can of this alloy, for example p 4, make strips

cast aluminum alloys for use in the manufacture of casings of cans obtained by stretching and weighting of walls. The compositions of the alloys are given in table. 26

Copper is introduced into alloys to reproduce scrap aluminum cans, which contains 0.1-0.2 wt.% Copper.

Aluminum alloys are produced by continuous casting using a Hunter-type casting machine with twin rollers, to make a sheet with a thickness of 6.6 mm, which can be welded into. rolls weighing 5,000 pounds. The rolls are cooled to room temperature within 48 hours. The cooled rolls are placed in an oven and homogenized in a nitrogen atmosphere. The rolls are heated to 576 4.3 seconds for 12 hours and kept at this temperature for 16 hours. The rolls are then cooled in an oven to 93.3 ° C for 32 hours. The cooled rolls are removed from the furnace and cooled to room temperature. 48 hours

The coil strips cooled to room temperature are subjected to the first treatment consisting in cold rolling and heating to the recovery temperature, the cooled strips are rolled in successive caliber on the rolling equipment until the thickness of the strip of each coil decreases by 83-85% ( 1.12-1.49 mm).

Thick rolled strip

heated to the temperature of the first reduction, for this the coils are placed in the oven and heated to 232 C for 4 hours, kept at this temperature for 44, then the coils are left in the oven to cool to 149 C for 9 hours. oven and cool for 48 hours to room temperature.

During the first cold rolling and heating to the recuperation temperature, the coils are subjected to the second cold rolling by passing successively through a pair of squeeze rolls to reduce the strip thickness by 25% (0.99 - 1.11 mm).

After the second cold rolling, the rolls are again placed in the furnace and heated to the second reduction temperature by increasing the furnace temperature to 260 ° C for 3.5 hours and then kept at this temperature for 1.5 hours. The rolls are annealed at the recrystallization temperature. ovens for 6 hours and hold at this temperature for 3 hours. The coils are cooled in an oven to 149 ° C for 14 hours and then removed from the oven and cooled to room temperature for 48 hours.

The recrystallized riots are rolled to a decrease in thickness of about 65-67%, i.e. to 0,331 mm.

Aluminum cans for beverages in an industrial plant for deep drawing and wall thinning are made in two parts from reinforced strip. About 5,000 cans were made from each riot. Festonification 2,0-2,6%. Banks are tested for buckling strength, i.e. the ability of the cans to withstand high internal pressure without continued bending.

The buckling strength is measured by applying pressure inside a can obtained by deep drawing and stretching with thinning of the walls, and then gradually increasing the pressure until deformation and buckling of the bottom, i.e. buckling. The pressure at which the bottom begins to bend, is the buckling strength. In order for the can to be applied, it must have a tensile strength of

25

buckling of at least 90 pounds / kb.inch.

The average longitudinal bending strength of cans manufactured from alloys VI-VII1 is given in Table. 27.

Table 27

Claims (1)

Invention Formula A method of manufacturing a billet in the form of a strip of aluminum alloy for the manufacture of products by deep drawing and drawing with wall thinning, including continuous casting 1426458 26 an alloy based on aluminum, containing 0.8–1.3 wt.% magnesium, 1.0– 1.5 wt.% manganese, up to 0.25 wt.% zinc, up to 0.25 wt.% copper, up to 0.3 wt.% silicon and up to 0.7 wt.% iron, in the form of a strip with a thickness of 6.35–12.7 mm, homogenization at 572-510 ° C, followed by cold rolling in several stages to final thickness and intermediate annealing, characterized in that; in order to increase anti-seize properties and reduce festoon formation, in the alloy additionally introduces 0.11-0.26 wt.% of chromium, homogenization is carried out for 10-40 hours, cold rolling is carried out in three stages with a decrease in thickness in the first stage on 66-75%, in the second - 10-25% and in the third - 66-88%, intermediate annealing after the first stage is carried out at 232-260 ° C for 1-4 hours, followed by heating at 426 ° C for 2-3 hours, and annealing after the second stage is carried out for 1 hour with subsequent heating at 426 ° C for 2 hours.