RU2074038C1 - Method of making hollow metallic tanks - Google Patents

Abstract

FIELD: production of hollow thin-wall articles from high strength, difficult-to-form steels and alloys. SUBSTANCE: method comprises steps of non-uniformly heating flange portion of blank in radial direction up to temperature of hot deforming and stage-by-stage drawing of said blank; at first drawing operation making semifinished product whose height consists at least 1.2-1.5 of its diameter without thinning initial material and deforming at rate of 20-40 mm/s; performing second and further drawing operations at thinning wall at least by 18-20% and at rate of 20-60 mm/s; during all drawing operations sustaining temperature in zone of part cutting equal at least to 0.8 of upper limit of temperature range of hot deforming of material to be formed; reducing necking portion after drawing operations at rate 4-7 mm/s. EFFECT: enhanced quality of articles, their increased capacity, enlarged manufacturing possibilities, lowered cost price due to realization of optimal temperature rate modes of deforming in combination with first drawing operation without thinning and second drawing operation at predetermined thinning of walls. 4 cl, 11 dwg, 2 tbl

Description

 The invention relates to the processing of metals by pressure and can be used for the manufacture of hollow thin-walled products from high-strength hardly deformable steels and alloys.

A known method of manufacturing a hollow metal containers, including the manufacture of a semi-finished product in the form of a glass with a spherical bottom by drawing a sheet blank between the punch and the die and then crimping the blank [1]
The disadvantage of this method is the low quality of the products due to the significant (up to 20% or more) thinning of the wall, limited technological capabilities for producing products of large capacity (height not exceeding 2.5-3 diameters), the inability to obtain products from high-strength, difficult to deform structural materials (high-strength steels, titanium and aluminum alloys).

There is also a known method of manufacturing hollow forgings such as ball vessels, in which a cylindrical billet heated to forging temperature is mounted on a stamp and deformed in two stages, provided that a non-uniform temperature field is created in the billet [2]
In the known method, stage-by-stage settlement (rather than drawing) of the workpiece is carried out, the nature of the temperature distribution over the workpiece is not set, the influence of the speed and degree of deformation on the quality and parameters of the resulting products is not taken into account. This method is limited in application, does not solve the problem of manufacturing products such as large-capacity containers (with a height of at least 2.5-3 diameters) from high-strength steels and alloys.

The closest in technical essence to the proposed solution is a method of drawing with heating, including clamping the flange part of the workpiece between the die and the clamping ring, uneven heating in the radial direction of the flange part to the temperature of hot deformation by passing electric current through it and stage-by-stage deformation by applying a drawing force to the central blank area. At each stage, the workpiece is deformed to the moment corresponding to the lower boundary of the temperature range of the hot deformation of the workpiece material [3]
The disadvantages of this method are:
1. The difficulty of determining the stopping time of the drawing process at each stage due to the difficulty of determining the boundary of the lower temperature range of the optimal deformation. This requires very sensitive recording equipment (the complexity of die tooling).

2. Each of the heating zones, wherein the flange is blocked from the lower limit of the temperature range of hot working a formed material (T _n) of hot deformation temperature range to the upper limit _(T) requires additional power consumption, increase cycle several hoods (2-5) times .

 3. The need to return (after drawing each part) to the initial temperature difference between the workpiece flange and the hauling rib, for which, after each drawing, the stamp must be cooled and re-heated. As a result, the stamping time is increased.

4. Heating of the working areas of the stamp, not participating in the subsequent stages of drawing to temperatures exceeding T _in , which negatively affects the resistance of the stamping tooling.

 5. As the flange moves to the waist rib from stage to stage, the temperature difference between the part flange and the waist rib decreases, which negatively affects the quality of the products (local thinning in the zone of the waist rib, flange detachment) and the degree of deformation.

 The purpose of the invention is improving the quality of products, increasing their capacity, expanding technological capabilities, reducing costs due to the implementation of optimal temperature and speed deformation modes in combination with the absence of thinning in the first operation of the hood and with the specified thinning in the second operation.

 This goal is achieved by the fact that in the method of manufacturing hollow metal containers, including uneven heating of the flange part of the workpiece in the radial direction to the temperature of hot deformation, phased extraction by applying a drawing force to the central zone of the workpiece, deformation of the workpiece to the moment corresponding to the lower boundary of the hot deformation temperature range material of the workpiece, the first operation of drawing is carried out to obtain a semi-finished product with a height of at least 1.2-1.5 of its diameter without y thinning of the initial thickness of the material, and the second and subsequent drawing operations are carried out with a wall thinning of at least 18-20%. The drawing is carried out with the optimum degree and speed of deformation, while not the first drawing operation is obtained by a semi-finished product of certain dimensions (height not less than 1.2-1, 5 of its diameter, without reducing the initial thickness of the material in all sections).

The semi-finished product of the indicated geometric parameters, in contrast to the prototype, has a stock of technological capabilities that allows for subsequent repeated reforming (drawing) both with thinning and without thinning the wall of the part, depending on Tu on the product. Thus, it becomes possible to obtain products that are significantly larger and larger in size and performance than the prototype. In turn, the proposed method of deformation, in contrast to the prototype, allows, on the one hand, to maintain the specified temperature regime, which helps to improve quality by eliminating the possible overheating of the stamped material and its local thinning, reducing costs by reducing power consumption and simplifying the design of the die tooling, reducing the cycle by 2-5 times, increasing the durability of die tooling by lowering the operating temperature and, on the other hand, reducing the negative effect of the strain rate plastic and strength properties of the stamped material. Clearly marked, in contrast to the prototype, the boundaries of the temperature range of the heating (T _in -T _n ) in the radial direction of the workpiece and their preservation during deformation allow to maximize the use of the ductility resource of the stamped material and the positive effect of deformed heating, which, in turn, allows you to deform the wall or neck of the product due to the flange zone of the workpiece with minimal or no thinning of the material in a dangerous section of the workpiece (the top of the hemisphere). Wall sinking of 18-20% incorporated in subsequent drawing operations allows for a controlled additional set of walls due to its thickness, while the minimum thickness remaining after all forming operations does not go beyond the limits of thinning allowed by the technical specifications for the product. Thinning equal to 18-20% at the same time provides a set of material (thickness, neck length) when crimping the neck, sufficient for trimming the end and threading under the fitting, according to the requirements of GOST.

In FIG. 1 shows a stamp for a first drawing operation, section “AA” of FIG. 2, in FIG. 2 the same top view (punch conventionally not shown), in FIG. 3 is a diagram of connecting transformers to a matrix; FIG. 4 a stamp for a second drawing operation, in FIG. 5 the same top view (punch conventionally not shown), in FIG. 6 device for crimping the neck, in FIG. 7 prefabricated in the form of a glass with a spherical bottom, obtained by drawing from a flat billet, in FIG. 8 prefabricated in the form of a glass obtained in the second operation of the hood, in FIG. 9 the product obtained by the proposed method, in FIG. 10 the dependence of ductility εψ = log (F ₀ / F ₁ ) (F ₀ (F ₁ ) the cross-sectional area of the sample before and after the test) of the OTCH-1-L 2.0 titanium alloy on temperature, in FIG. 11 the nature of the change in the initial thickness of the workpiece after drawing in the stamp of the first operation.

 The stamp of the first operation of the hood contains the punch 1, the pressure ring 2, the matrix 3. The pressure ring 2 and the matrix 3 (Fig. 1, 2) on the outer contour have symmetrically arranged protrusions 4, to which the electrical contacts are connected via screws 5. Through the rack 7, the matrix 3 is rigidly connected to the base 8. Between the rack 7 and the matrix 3 there is a thermally insulating gasket 9. On the base 8 there are hydraulic cylinders 10, which are connected through the rod 11, the lever 12 and the brackets 13, 14 to the clamping ring 2. The electrical contacts 6 to the matrix 3 are connected in series Alternating between "plus-minus". The number of electrical contacts is at least four. The power supply of each pair of opposite contacts is carried out from two autonomous sources 15, 16 (Fig. 3), the voltages of which are in phase. For uniform heating of the matrix 3 and the clamping ring 2 in the tangential direction, the equality of voltage drops per unit length of the distance between the electrical contacts is created. This is achieved by the symmetrical arrangement of the protrusions 4 on the matrix 3.

 The stamp of the second operation (Fig. 4, 5) of the hood contains a hollow punch 17, a matrix 18 covering the punch, a sleeve 19, a ring 20, on the inner surface of which a heater 21 is installed. Inside the hollow punch 17 there is a tube 22 for supplying a cooler. An annular channel 23 is provided for cooling the constriction rib of the matrix 18. The matrix 18 is connected to the base 24 by the struts 25.

 The device for crimping the neck (Fig. 6) contains a matrix 27 mounted on the holder 26, a spring-loaded ejector 28, a support 29, a base 30. An inductor 31 is used to heat the matrix 27. The blank is indicated at 32 in the drawings.

 The method is as follows.

In the initial position, the clamping ring 2 is raised relative to the matrix 3. The blank 32 is placed in the gap between the matrix 3 and the clamping ring 2. The hydraulic cylinders 10 are turned on and through the rod 11, the lever 12 is pressed by the clamping ring 2 to the matrix 3. When turning on the power sources 15 and 16, the heating current flows along the clamping ring 2, the matrix 3 and the workpiece 32. The latter are heated to a predetermined temperature. In this case, the peripheral zone (flange) of the workpiece 32 is heated to a temperature of T _in for a given material, and the zone of the waist rib to T _n . The required temperature difference is achieved either by changing the magnitude of the voltage drop between the contacts, or by changing the heating time. The predetermined nature of the temperature distribution is maintained automatically, for which, using potentiometers (not shown in the drawing), the temperature is constantly recorded on the flange and the hauling rib. Since the stamp in the radial direction is heated unevenly, the flange of the workpiece 32, moving towards the center of the stamp, falls into the zone of ever lower temperatures. An unsteady heat flux passes through the blank 32, at which the temperatures of different zones change in time and in coordinates according to a very complex and practically uncontrollable law. The temperature interval T _in -T _n established at the beginning of deformation, which ensures the necessary ductility of the material being stamped, is violated. This change occurs the more intensively, the lower the speed of movement of the flange (deformation rate), the larger the diameter of the workpiece in relation to the diameter of the product and the smaller the thickness of the workpiece. An increase in the rate of deformation can reduce heat loss, however, starting from some speeds, the resistance to deformation increases and the ductility of the material decreases. At high temperatures, this pattern is enhanced. So, for example, with an increase in the deformation rate from 10 to 100 mm / min, the deformation resistance (σ _0.1 ) of the OTCH-1 alloy at a temperature of 600 ^o C increases from 12 kg / mm to 24 kg / mm, and the ductility decreases to 30% Therefore, the workpiece is deformed in a predetermined range of strain rates, providing optimal temperature conditions for this material. The size of the initial preform is taken so that after drawing get a semi-finished product with a height of H ₁ equal to 1.2-1.5 diameter D ₁ semi-factory (Fig. 7). Furthermore, the thickness of the semi-finished product S _min (0.97-0.98) S (S is the thickness of the original workpiece).

где m коэффициент вытяжки первой операции, который определяется по формуле m d/D;
m_ут. коэффициент утонения;
F_н(F_к) площадь поперечного сечения до и после деформации, мм;
Z_н(Z_к) толщина стенки до и после деформации, мм;
d диаметр изделия;
D диаметр заготовки.In the second operation of the hood, the semi-finished product (preform 32) obtained in the first operation, together with the sleeve 19, is heated in a separate heating device (not shown) to a temperature of T _in . The heated preform, together with the sleeve, is mounted in the ring 20 on the die 18. A punch 17 is connected to the preform 32 until it contacts the bottom of the preform. The bottom zone of the billet is cooled to a temperature T _n , after which the billet 32 is drawn through the die 18. The sleeve 19 in this case plays the role of not only a coolant, but also a fold holder (clamp). The time of baking this zone of the workpiece during the period of contact with the cold punch and the matrix and the deformation rate are set so that the temperature on the wall of the workpiece (in the cutting area) remains at the level of (0.8-0.9) T _c . Conservation temperature _T also facilitates the heater 21 disposed on the inner surface of the sleeve 19. In the second drawing operation is also carried out the principle of the combined extracts, which combines the two types of deformation and diameter reduction hoods decrease in wall thickness. The degree of deformation, determined by a simultaneous change in the diameter and wall thickness of the semi-finished product is determined by the known ratio (see V. P. Romanovsky "Handbook of cold stamping", 1977, p. 162)

where m is the coefficient of extraction of the first operation, which is determined by the formula md / D;
m _ut coefficient of thinning;
F _n (F _to ) the cross-sectional area before and after deformation, mm;
Z _n (Z _k ) wall thickness before and after deformation, mm;
d product diameter;
D is the diameter of the workpiece.

The degree of deformation E is calculated based on the geometric parameters of the product and the permissible degree of deformation of the stamped material. In this operation, the hoods receive a semi-finished product (Fig. 8) with a height of H ₂ equal to 2-3 of its diameter D ₂ with a thinning of at least 18-20% (S _min 0,8S).

Then, the neck is crimped. The workpiece 32 is placed in the support 29. The matrix 27 heated to the required temperature using the inductor 31 is brought to the end face of the workpiece. The end face of the workpiece is introduced into the cylindrical cavity 33 of the matrix 27. The end area of the workpiece is heated to a temperature T _in , after which, by moving the matrix 27, it is deformed, first giving this zone the shape of a cone, and then, as the matrix moves, the shape of a cylinder. Thus, get the body of the cylinder with a compressed neck. In the process of deformation, by reducing the diameter of the workpiece, a thickening (set) of semi-finished machines in the neck area is carried out. After reaching the specified length and neck thickness, the matrix 27 is retracted from the support 29 and the workpiece 32 is pushed out of the matrix by the ejector 28.

Далее определяли диаметр полуфабриката на первой операции вытяжки из соотношения:

Из условия постоянства объемов было установлено, что для получения на второй операции вытяжки полуфабриката длиной 180 мм, диаметром 70 мм и толщиной 1,6 мм, на первой операции необходимо получить полуфабрикат диаметром 90 мм, толщиной 2 мм, длиной не менее 112 мм, что составляет 1,2-1,5 диаметра полуфабриката D. При этом процесс вытяжки должен быть осуществлен без утонения исходной толщины материала. В этом случае коэффициент вытяжки на первой операции m d_E/D 90/230 0,4, что и было реализовано методом вытяжки с дифференцированным нагревом заготовок в радиальном направлении.An example of the implementation of a technical solution. The method was tested in the manufacture of cases of small-capacity cylinders (0.4 liters) for gases at a pressure of 9.8 MPa (100 kgf / cm). The shape and geometric parameters of the housings were taken in accordance with GOST 949-73 (form) and GOST 9909-81 (thread) and are shown in FIG. 9. The cylinders were made of the titanium alloy OTCH-1-L 2.0, aluminum alloy AMg-6-L 2.5 and St. 3-L 2.0. Experimentally, by crimping a tube billet with a diameter of 70 mm made of HGSF 30 ductile steel in the delivery state, it was found that to obtain a cylinder body with a length of 165 mm, an outer diameter of 70 mm, with a neck with a diameter of 29 mm, a length of 20 mm, with a wall thickness in the neck 5 mm, the initial length of the semi-finished product (glass with a spherical bottom) should be at least 180 mm. The diameter of the initial sheet blank for such a semi-finished product is 230 mm. To obtain a semi-finished product of the indicated dimensions from a workpiece with a diameter of 230 mm for one drawing operation, it is necessary to create conditions under which the drawing coefficient md ₁ / D (d _{1 the} diameter of the workpiece after the first drawing operation, D is the diameter of the initial workpiece) is 0.30, which for the indicated grades materials are practically impracticable. In order to save energy and reduce the cost of dies, the task was to obtain a semi-finished product for crimping with a minimum number of drawing operations 2. According to the requirement of GOST 949-73, the minimum wall thickness of a cylinder made of a material of a thickness of 2 mm is allowed at least 1.6 mm. Knowing this, from the ratio (1) we determined the degree of deformation in the second drawing operation:

Next, the diameter of the semi-finished product in the first operation of the hood was determined from the ratio:

From the condition of constant volumes, it was found that in order to obtain in the second operation, the semi-finished product is 180 mm long, 70 mm in diameter and 1.6 mm thick, in the first operation, it is necessary to obtain a semi-finished product with a diameter of 90 mm, 2 mm thick, at least 112 mm long, which is 1.2-1.5 of the diameter of the semi-finished product D. In this case, the drawing process should be carried out without thinning the original thickness of the material. In this case, the extraction coefficient in the first operation md _E / D 90/230 0.4, which was realized by the extraction method with differentially heating the workpieces in the radial direction.

The first drawing operation was carried out in a stamp having an armhole of a matrix with a diameter of 90 mm. The matrix and pressure ring were made of EI 961 heat-resistant steel and heated by passing current, for which two pairs of electrical contacts were connected to the matrix, alternating alternately plus or minus as shown in FIG. 3. The stamp was heated from two transformers TKP-150. Used current industrial frequency. The voltage on the primary winding of the transformer was 380 V, on the secondary from 12 to 36 V. The temperature on the workpiece flange and the hauling rib was recorded and maintained using thermocouples and KSP-3 devices (not shown). By varying the voltage between the contacts (switching the transformer breakers) and the heating time, we sought to establish the necessary temperature in the area of the workpiece cutoff and on the flange. These temperatures corresponded to the upper T _in and lower T _{n the} limits of permissible heating of the stamped material. For a titanium alloy, T _in and T _n were selected according to the dependence εψ = f (T) (Fig. 10), taking into account the VIAM instructions for this material. The interval T _in -T _n for AMg-6 and Art. 3 were selected from TU per material. The dependence graph shows that, starting from 400 ^o C, the ductility of the OTCH-1 alloy increases sharply and reaches a maximum at temperatures from 650 ^o C to 700 ^o C. Heating above this temperature leads to intense interaction of titanium to embrittlement and loss of plastic properties. Thus, the upper optimal heating interval T _in equal to 600 ^o -700 ^o C and the lower T _n equal to 400 ^o C were selected. To maintain T _in the range from 600 ^o C to 700 ^o C it was necessary to set such a deformation rate, in which the pre-cut, passing the zone of the tensile rib, would not be less than 600 ^o C. In order to determine the optimal deformation rate, studies were carried out to cool the heated thin-sheet preform (thickness 1.0-2.5 mm) from the OTCH-1 alloy in contact with cold and heated to different temperatures plate. The measurement data are presented in table 1.

Вытяжку осуществляли на гидравлическом прессе PVE-160 с регулируемой скоростью перемещения ползуна пресса. При скоростях деформирования меньше 20 мм/сек наблюдался отрыв фланцевой зоны, либо трещины по стенке полуфабриката из-за охлаждения материала при подходе к перетяжному ребру. При скоростях деформирования больше 40 мм/сек происходило разрушение заготовки в полюсе полусферы по причине упрочнения и снижения пластичности материала в этой зоне. При соблюдении указанных температурно-скоростных режимов получали полуфабрикаты с габаритами не менее указанного в табл.2. Изменение исходной толщины заготовки из титанового сплава ОТЧ-1-Л 2,0 представлено на фиг. 11, из которого видно, что утонение не превышает 2%
Из фиг. 11 видно, что утонение, равное 2-3% наблюдается в локальных, не связанных между собой зонах, является характерной особенностью листового проката и не влияет на последующие операции вытяжки и эксплуатационные характеристики изделия.From table 1 it is seen that when a workpiece is heated to 700 ^o C with a plate heated to 400 ^o C (the temperature of the drawing edge of the matrix), the cooling time to a temperature of 600 ^o C depends on the thickness of the workpiece and ranges from 3 to 6 seconds. For a material 2 mm thick, this time is 5 seconds. Knowing the radius of the workpiece in the first operation of drawing and taking without a large error the radius equal to the value of the stroke of the punch, we determined the minimum speed of movement (strain rate) of the flange zone of the workpiece:

The extract was carried out on a PVE-160 hydraulic press with an adjustable speed of movement of the press slider. At strain rates of less than 20 mm / s, a separation of the flange zone or cracks along the semifinished product wall was observed due to cooling of the material when approaching the tensile rib. At strain rates greater than 40 mm / s, the workpiece was destroyed in the hemisphere pole due to hardening and a decrease in the ductility of the material in this zone. Subject to the indicated temperature and speed conditions, semi-finished products with dimensions not less than those indicated in Table 2 were obtained. A change in the initial thickness of the OTCH-1-L 2.0 titanium alloy preform is shown in FIG. 11, which shows that thinning does not exceed 2%
From FIG. 11 shows that thinning equal to 2-3% is observed in local, not interconnected areas, is a characteristic feature of sheet metal and does not affect subsequent drawing operations and product performance.

Для заготовки толщиной 2 мм эта скорость была равна 30 мм/сек. Вытяжку осуществляли на гидравлическом прессе П 6330 с регулируемой скоростью перемещения ползуна пресса.Осуществляли два вида вытяжки:
без утонения стенки изделия;
с утонением стенки изделия на 20% (с 2 до 1,6 мм).After drawing in the stamp of the first operation and cutting along the end face, the semi-finished products were subjected to drawing in the stamp of the second operation (Fig. 4, 5). The preform alloy TSS-1-A with 2.0 skladkoderzhatelem uniformly heated in a muffle furnace to _T equal to 700 ^o C. After heating the preform with skladkoderzhatelem placed into the sleeve 19 and allowed to extract the time zone podstuzhivaniya preform contacting the matrix ( the transition zone of the hemisphere into the wall) to T _n equal to 400 ^o C. The exposure time was 2 seconds. During this time, the temperature on the workpiece flange in the cutting area decreased to 650 ^o C, which did not have a significant effect on the ductility of the stamped material (Fig. 10). Thus, a temperature drop T _in -T _{n of} 650 ^o 400 ^o 250 ^o C. was created. Next, the workpiece was deformed at a speed that ensures that the temperature at the edge of the part remains at the moment of passing through the drawing edge of the matrix of at least 600 ^o C. In accordance with table 1, this time for different thicknesses was different and ranged from 2 to 5 seconds. For a thickness of 2 mm 3 seconds. Knowing the height of the semi-finished product, the minimum strain rate was determined:

For a workpiece with a thickness of 2 mm, this speed was 30 mm / s. The hood was drawn on a P 6330 hydraulic press with an adjustable speed of the slide of the press. Two types of hood were carried out:
without thinning the product wall;
with thinning the product wall by 20% (from 2 to 1.6 mm).

In the first case, high-quality, without breaking, folds and ovality parts were obtained with a diameter of 70 mm, a length of 150 mm, and a thickness of 2 mm. In this case, the drawing coefficient md ₂ / D (d _{2 the} diameter of the semi-finished product obtained in the second drawing operation) was 0.7-0.8, which corresponded to the drawing of highly plastic materials and characterized the process as stable and stable. However, the length of the semi-finished product obtained by drawing without thinning was not enough to obtain a cylinder body (165 mm) in accordance with GOST 949-73. Therefore, a combined hood was used, in which the semi-finished product was reshaped from a diameter of 90 mm to a diameter of 70 mm while reducing the wall from 2 mm to 1.6 mm (thinning 20%). For this, the gap between the die and the punch was accordingly reduced. A semifinished product was obtained with a length of 180 mm and a wall thickness of 1.6 mm, from which the container body was crimped in accordance with GOST 949-73 (Fig. 9). Similar parts at the same strain rates were obtained from aluminum alloy AMg-6-L 2.5 and st. 3-L 2.0. At lower deformation rates, with both drawing methods, more intensive cooling of the flange zone of the workpiece was observed, leading to a decrease in height, the appearance of radial cracks and ellipse in the area of the cutoff of the part. Thus, high-speed deformation modes were established in the first drawing operation V ₁ equal to from 20 to 40 mm / s and the second drawing operation V ₂ equal to from 20 to 60 mm / s.

Оптимальный скоростной интервал деформирования для разных толщин составлял от 4 до 6 мм/сек. При скоростях деформирования более указанного наблюдалось образование складок и радиальных трещин в зоне обжима из-за недостаточного прогрева, в процессе перемещения матрицы, этих зон. При меньших скоростях деформирования наблюдалось бочкообразование или складка в окружном направлении в зоне опоры 30, обусловленные высоким разупрочнением материала в этой зоне. Аналогичным образом была устанолвлена скорость деформирования для сплава АМг-6-Л 2,5 и ст. 3-Л 2,0, которая составила от 3 до 4 мм/сек и от 5 мм/сек до 6 мм/сек соответственно. При указанных температурно-скоростных режимах деформирования получали корпуса баллонов диаметром 70 мм, длиной 170 мм, толщиной в зоне стенки 1,6 мм и в зоне горловины 5 мм.After drawing in the stamp of the second operation and trimming the workpiece, they were crimped on a UVTU-40 machine (installation of forming control rods) according to the scheme shown in FIG. 6. When crimping the neck with heating, along with the destruction of the deformable zone in the form of cracks in the radial direction, a loss of wall stability (barrel formation or crease in the circumferential direction) was observed in the force transfer zone. The main condition ensuring the preservation of the original form is the temperature difference and the strain rate. When crimping blanks from the OTCH-1 alloy, the matrix was heated to a temperature of 700 ^o C (T _in ). After introducing the end face of the workpiece into the cylindrical zone of the matrix (pos. 33 of Fig. 6), an exposure time of 10 seconds was given. During this time, the end face of the preform was also heated to 700 ^o C. It was experimentally established that to obtain the neck of the required size (Fig. 9), the length of the deformable zone of the initial preform (die stroke) is 50 mm. To maintain a stable temperature (700 ^o C) mode of deformation, the speed of movement of the matrix V ₃ must be equal to:

The optimal strain rate interval for different thicknesses was from 4 to 6 mm / s. At deformation rates higher than the indicated one, the formation of folds and radial cracks in the crimping zone was observed due to insufficient heating during the movement of the matrix of these zones. At lower deformation rates, barrel formation or a crease in the circumferential direction in the region of the support 30 was observed, due to the high softening of the material in this zone. In a similar way, the deformation rate for the alloy AMg-6-L 2.5 and st. 3-L 2.0, which was from 3 to 4 mm / s and from 5 mm / s to 6 mm / s, respectively. Under the indicated temperature-speed deformation modes, cylinder bodies were obtained with a diameter of 70 mm, a length of 170 mm, a thickness in the wall zone of 1.6 mm and a neck area of 5 mm.

 The combination of temperature and speed deformation modes used in combination with the absence of thinning in the first drawing operation and with a predetermined (not beyond the scope of GOST requirements) thinning in the second operation made it possible to obtain products in the form of cylinder bodies from hardly deformable and low-plastic, high-strength materials, which significantly expanded technological and operational capabilities. Products are obtained with a minimum number of drawing operations (two), with a minimum consumption of material and energy resources. The proposed method significantly reduces the manufacturing cycle of the cylinder bodies. The use of expensive and scarce rolling mills is excluded. The quality of the products increases, since they do not have welds that require stripping operations, leak tests, and x-rays.

Claims (3)

1. A method of manufacturing a hollow metal containers, including uneven heating of the flange part of the workpiece in the radial direction to the temperature of hot deformation, a phased hood, characterized in that the first operation of the hood is carried out to obtain a semi-finished product with a height of at least 1.2 1.5 of its diameter without thinning the original the thickness of the material, and the second and subsequent drawing operations are carried out with a wall thinning of at least 18 - 20%
2. The method according to claim 1, characterized in that in the first operation of the hood, the deformation is carried out at a speed of 20 to 40 mm / s, in the second and subsequent operations at a speed of 20 to 60 mm / s.  3. The method according to claims 1 and 2, characterized in that in all drawing operations, the temperature at the edge of the part is supported by at least 0.8 of the upper limit of the temperature range of the hot deformation of the stamped material.  4. The method according to PP.1 to 3, characterized in that after drawing, the neck is crimped at a speed of 4-6 mm / s.

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