RU2056198C1 - Method of making deep thin-wall cylindrical articles from polyhedral blanks - Google Patents

Abstract

FIELD: metal pressure forming. SUBSTANCE: method comprises steps of making a polyhedral blank by blanking it or by cutting from a rolled sheet; subjecting it to multitransition drawing according to combination schedule; at first pass performing a drawing operation with use of a cylindrical punch, having on its lateral surface flats, whose number is equal to a number of faces of the blank, with depth, equal to (0.1-0.25) of a gap between a die and the cylindrical surface of the punch, and over further passes - by the same punches; upon drawing orienting the blank or a semifinished product by apeces of its crowns towards to the flats for receiving after drawing the semifinished product, having a thickness of its wall, being variable along its perimeter; at the last operation performing a combination drawing with uniform gap along the perimeter of the blank. EFFECT: enhanced quality of articles. 1 cl, 2 dwg

Description

 The invention relates to the processing of metals by pressure, namely the manufacture of deep thin-walled cylindrical products from multifaceted workpieces.

To obtain deep cylindrical products, in most cases, a circle cut from a strip or tape is used as a blank, which is subsequently subjected to a multi-junction combined hood [1]
With a combined hood, the diameter of the workpiece or the semi-finished product and the wall thickness are simultaneously reduced. This allows for a smaller number of operations to obtain a deep thin-walled product. However, the use of a mug as a workpiece leads to increased consumption of metal.

To save metal, square or multifaceted workpieces are used. However, when such billets are drawn on a semi-finished product, “crown” irregularities appear along the edges, which increase the metal waste during trimming. This reduces the effect of saving metal from the use of multifaceted workpieces [2]
The objective of the invention is to save metal upon receipt of deep thin-walled cylindrical products from multifaceted workpieces.

 This is solved by the fact that in the known method for producing deep thin-walled cylindrical products from multifaceted workpieces, including the operation of cutting or cutting from a strip or tape of a multifaceted workpiece with a base in the form of a regular polygon and the subsequent multi-junction combined hood in which the final operation is carried out by a punch with a cylindrical side surface, all the drawing operations except the last are carried out by a punch, on the lateral cylindrical surface of which flats, by the number of lateral faces of the workpiece, with a depth equal to 0.1-0.25 of the gap between the die and the cylindrical surface of the punch, and in the first drawing operation, the workpiece relative to the punch is oriented so that the maximum gap between the flats of the punch and the matrix takes place in directions from the axis of the workpiece to the ribs of its side faces, and in subsequent drawing operations, the resulting semi-finished product with “crowns” is oriented so that the mentioned maximum clearance takes place in the directions from the semi-finished axis to the vertices m his "crown".

 With this method of combined drawing, metal is redistributed from the corner sections of the multifaceted workpiece to the middle of the sides, as well as from the formed “crowns” of the semi-finished product in the direction of the formation of depressions, so that in the last operation the product is obtained with an even edge in height.

 The recommended orientation of the punch with flats in directions from the axis of the workpiece to the ribs of its side faces was taken from the results of experiments and theoretical calculations, and the depth of the flats was established experimentally. The magnitude of the boundary values of the flatter depth interval depends on the relative thickness of the workpiece or semi-finished product. For a multifaceted workpiece, the relative thickness was determined as the ratio of the workpiece thickness t to the diagonal M of a regular polygon, which is the basis of the multifaceted workpiece. Moreover, the diagonal M is also the diameter of the circumscribed circle of the polygon.

= 100•t_мин/d_ср Установлено, что для относительных толщин в 2% целесообразно использовать пуансон с лысками глубиной С 0,10 от величины зазора Z_i между матрицей и цилиндрической поверхностью пуансона, а для относительных толщин более 3% глубиной С 0,25 от Z_i, где i номер перехода.For the semi-finished product, the relative thickness was determined as the ratio of the minimum wall thickness t _min to the average diameter d _cp ;

= 100 • t _min / d _cf. It was found that for relative thicknesses of 2% it is advisable to use a punch with flats with depth C 0.10 of the gap Z _i between the matrix and the cylindrical surface of the punch, and for relative thicknesses more than 3% with depth C 0, 25 from Z _i , where i is the transition number.

 Using a punch with flats according to the number of faces of a regular polygon results in a semi-finished product whose inner surface is faceted, the minimum thickness coinciding with the direction of the normal drawn to the middle of the base side of the polyhedral workpiece, and the maximum in the directions from the workpiece axis to the edges of its side faces. The unevenness of the thickness along the perimeter of the semifinished product leads to the fact that with a combined hood, the height of the semifinished product increases most strongly in the direction of the generatrix, which coincides with the minimum clearance between the punch and the matrix, i.e., in the direction of the formation of a cavity when drawing a multifaceted workpiece by a known method. As a result of this, the "crown" of the semi-finished product will decrease.

 At subsequent transitions of the combined extraction of the semi-finished product in areas with a minimum wall thickness, a concentration of circumferential compressive stresses occurs, causing significant plastic deformations, which leads to redistribution of the metal. As a result of such a redistribution, a semifinished product with a smooth edge without “crowns” is obtained. In the final operation, the unevenness of the thickness, if necessary, is eliminated by using a punch with a cylindrical side surface.

 Thus, a multi-junction combined hood with a periodically varying gap around the perimeter according to the number of side faces of the workpiece makes it possible to obtain a product with a flat edge, which leads to significant metal savings.

 In FIG. 1 and 2 are two projections of the punch; figure 3 the sequence of obtaining a hollow product with a straight edge without "crowns".

= 100

•100 2,1%
Чтобы при заданной относительной толщине заготовки не наблюдалось складкообразования на первой операции комбинированной вытяжки используем пуансон (фиг. 2), имеющий цилиндрическую поверхность 1 и четыре лыски 2 глубиной С 0,1 Z₁, где Z зазор между матрицей и цилиндрической поверхностью 1 пуансона.PRI me R. Consider the technology of combined drawing of a square billet with a side a of 100 mm, a diagonal of M 141 mm and a thickness of t 3.0 mm. Determine the relative thickness of the workpiece

= 100

• 100 2.1%
So that at a given relative thickness of the workpiece, no folding occurs during the first operation of the combined drawing, we use a punch (Fig. 2) having a cylindrical surface 1 and four flats 2 with a depth of 0.1 0.1 Z ₁ , where Z is the gap between the matrix and the cylindrical surface 1 of the punch.

Suppose that in the first operation, the hood is drawn through a matrix with a diameter d _{M1 of} 60 mm and a wall thinning coefficient m _{t1 of} 0.70. The gap between the cylindrical surface of the punch and the die is Z ₁ m _t1 · t 0.70 x 3.0 2.10 mm, therefore the diameter of the punch is d _n1 d _m1 2Z ₁ 60 2 x 2.1 55.80 mm. Four flats with a depth of C ₁ 0.10 x Z ₁ 0.1 x 2.1 0.21 mm are made on the punch.

-1

= 0,25

-1

≈ 4 мм
На втором переходе (операции) заготовкой является полуфабрикат, у которого имеется заданная периодическая разнотолщинность по периметру. Максимальная толщина стенки равна t_max1 Z₁ + +C₁ 2,10 + 0,21 2,31 мм. Минимальная толщина равна t_min1 Z₁ 2,10 мм. Определим относительную толщину полуфабриката t₁ t_min1 · 100/d_cp1 2,10 x 100/57,90 3,7% Примем коэффициент уменьшения диаметра на втором переходе (операции) равным 0,80, а коэффициент утонения стенки m_t20,70. Тогда рабочий диаметр матрицы равен d_м2 d_cp1 ·m_d2 57,90 x 0,80 46,30 мм. Определим зазор между матрицей и цилиндрической поверхностью пуансона Z₂ m_t2 х х t_max1 0,70 x 2,31 1,62 мм. Следовательно, диаметр пуансона равен d_п2 d_м2 2Z₂46,3 2 x 1,62 43,1 мм.Before drawing, the square blank 3 (Fig. 3, a) is oriented in the matrix relative to the flats of the punch in such a way that in the direction from the axis of the blank to the edges of its side faces, the gap between the punch and the matrix would be maximum (Fig. 3, b). In the process of combined drawing, metal will be redistributed both in the circumferential and in the radial direction, and the height of the “crown” 6 will decrease by:
H 0.25

-1

= 0.25

-1

≈ 4 mm
At the second transition (operation), the billet is a semi-finished product, which has a given periodic perimeter thickness difference. The maximum wall thickness is t _max1 Z ₁ + + C ₁ 2.10 + 0.21 2.31 mm. The minimum thickness is t _min1 Z ₁ 2.10 mm. We determine the relative thickness of the semi-finished product t ₁ t _min1 · 100 / d _cp1 2.10 x 100 / 57.90 3.7%. Let us take the coefficient of reduction in diameter at the second transition (operation) equal to 0.80, and the coefficient of thinning of the wall m _t2 0.70 . Then the working diameter of the matrix is d _m2 d _cp1 · m _d2 57.90 x 0.80 46.30 mm. Define the gap between the matrix and the cylindrical surface of the punch Z ₂ m _t2 x x t _max1 0.70 x 2.31 1.62 mm. Therefore, the diameter of the punch is d _p2 d _m2 2Z ₂ 46.3 2 x 1.62 43.1 mm.

Four flats are also made on the punch, the depth of which is calculated by the expression:
C ₂ 0.25 x Z ₂ 0.25 x 1.62 0.40 mm.

H

-1

-1

Таким образом, в результате двух операций комбинированной вытяжки высота "коронок" в сумме уменьшилась на 16 мм, т.е. "корончатость" практически исчезла, так как при комбинированной вытяжке по известному способу она равнялась 18 мм. Однако полученный полуфабрикат получил заданную периодическую разнотолщинность стенки по периметру. Максимальная толщина стенки оказалась равной t_max2 Z₂ + C₂ 2,02 мм, а минимальная t_min2 Z₂ 1,62 мм. Для ее устранения и получения изделия в соответствии с чертежом последнюю операцию комбинированной вытяжки проводят обычным пуансоном.When drawing the semi-finished product is oriented by the tops of the "crowns" so that the maximum clearance between the punch and the matrix takes place in the direction from the axis of the semi-finished product to the vertices of its "crowns" (Fig. 3, b). As a result of the combined drawing, an additional redistribution of the metal occurs again in both the circumferential and radial directions. The height of the "crowns" 6 will decrease by:

H

-1

-1

Thus, as a result of two operations of combined drawing, the height of the “crowns” in the total decreased by 16 mm, i.e. the "crown" has practically disappeared, since with a combined hood according to the known method, it was 18 mm. However, the resulting semi-finished product received a predetermined periodic wall thickness along the perimeter. The maximum wall thickness was t _max2 Z ₂ + C ₂ 2.02 mm, and the minimum t _min2 Z ₂ 1.62 mm. To eliminate it and obtain the product in accordance with the drawing, the last operation of the combined hood is carried out by a conventional punch.

In accordance with the drawing, a matrix with a diameter of d _m3 35 mm is used, and to obtain a product with a wall thickness of t ₃ 1.5 mm, a cylindrical punch with a diameter of d _p3 d _m3 2t ₃ 32 mm is used. In the process of combined drawing, at the stage of reducing the diameter of the semi-finished product, the wall thicknesses will be aligned around the perimeter until the metal enters the hole in the matrix, therefore, at the thinning stage, the inlet part of the semi-finished product will have the same wall thickness around the perimeter and as a result of the drawing, a flat edge will remain in the product.

 The experiments performed are close to the calculated ones.

 From the considered example, it can be seen that with a three-transition (three-operation) technological process of combined drawing of a square billet, significant metal savings of up to 30% are possible.

 The invention can be used not only for the manufacture of round in terms of products, as described in the example, but also in the manufacture of axisymmetric not round in terms of hollow products.

Claims (1)

 METHOD FOR PRODUCING DEEP THIN-WALLED CYLINDRICAL ARTICLES FROM MULTIPLAYED Billets, which includes cutting or cutting operations from a strip or tape of a multifaceted workpiece with a base in the form of a regular polygon and a subsequent multi-junction combined hood, in which the final operation is performed by hoods, with the exception of the latter, are carried out by punches, on the lateral cylindrical surface of which flats are made for to the side faces of the workpiece with a depth equal to 0.1 - 0.25 of the gap between the die and the cylindrical surface of the punch, and in the first drawing operation, the workpiece relative to the punch is oriented so that the maximum gap between the flats of the punch and the matrix takes place in the directions from the axis of the workpiece to edges of its lateral faces, and in subsequent drawing operations, the resulting semi-finished product with “crowns” is oriented so that the aforementioned maximum clearance takes place in the directions from the axis of the semi-finished product to the tops of its “crowns”.

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