RU2056199C1 - Blank for drawing cylindrical semifinished product - Google Patents

Abstract

FIELD: metal working. SUBSTANCE: method comprises steps of using a blank for drawing a cylindrical semifinished product, being in the form of a polyhedron, having as a base a regular polyhedron. At a side of the base the blank has thinned portions in the form of cylindrical chutes, oriented along a normal relative to middles of polyhedron sides. A dead end of each chute is spaced from an axis of the blank by a distance, equal to a mean radius of a cylindrical part of the semifinished product. A side of an open edge the chute has a bottom, in a plan view being protruded over a side of the polyhedron as a segment. Values of radius of the cylindrical surface of the chute R, a depth of the chute C, a radius of the segment R and a height of the segment X are restricted by next ranges: R=(0.7-1.7)M, where M - a large diagonal of the polyhedron; C= (0.1-0.25)S, where S - a thickness of the blank; R = 0,4- 0,8 R, where, R - a mean radius of the blank cylindrical portion of the semifinished product; X=(0.085-0.17)x (d-2d - 2R), where d - a diameter of a circle, inscribed to the polyhedron. EFFECT: enhanced quality of semifinished products with use of such initial blank. 1 cl, 2 dwg

Description

 The invention relates to the processing of metals by pressure, namely the use of a workpiece for drawing cylindrical products.

In the manufacture of cylindrical hollow products using the drawing operation, in most cases a circle is cut out of sheet metal, the diameter of which is determined depending on the size of the finished part [1]
The disadvantage of using such a workpiece is a significant waste of metal upon receipt, associated with irrational cutting of a strip or tape when cutting.

 Known square billet with fillets in the corner sections [2] The use of such a billet reduces metal waste during cutting, but the product is obtained with uneven crown edges. This requires an increase in height allowance for cropping.

 Also known is a square blank without rounding in the corner sections [3] which is adopted as a prototype. Its advantage is to obtain a hollow cylindrical product greater by 12-15% of height than when using a mug or square billet with fillets in the corner sections. This is due to the influence of the angular sections of the square billet, which, when drawn, are “hard” zones that change the kinematics of the flow of material in the flange of the billet when drawn so that part of the metal flows from the corner sections to the middle of the sides. As a result, the height of the semi-finished product increases. The disadvantages of such a workpiece include the formation of unevenness-crowns at the edges of the part, which requires an increase in height allowance for trimming.

 The objective of the invention is to save metal when drawing products from multifaceted workpieces.

To solve this problem, a workpiece is used to draw a cylindrical semi-finished product in the form of a polyhedron having a regular polygon in the base, according to the invention, thinning in the form of cylindrical grooves oriented along the normal to the midpoints of the sides of the polygon is made on the base side, the blind end of each groove is removed from the axis of the workpiece at a distance equal to the average radius of the cylindrical part of the semi-finished product, from the side of the open edge, the bottom of the trough in the plan is made protruding above the sides th segment in the form of a polygon, the values of the radius of the cylindrical surface of the trough R, the depth of the trough C, the radius R _c and the segment X segment height limited to the following intervals:
R 0.7-1.7M, where M is the largest diagonal of the polygon;
C 0.1-0.25 S, where S is the thickness of the workpiece;
R _c 0.4-0.8 R _cp , where R _{cp is the} average radius of the cylindrical part of the semi-finished product;
X (0,085-0,17) x (d 2R _cp ), where d is the diameter of the circle inscribed in the polygon.

к диагонали М правильного многоугольника, являющегося основанием многогранной заготовки в процентах

100S/M. Под коэффициентом вытяжки понимается отношение среднего диаметра (или радиуса R_cp) цилиндрического участка полуфабриката после вытяжки к диаметру (радиусу) окружности, вписанной в многоугольник m 2R_cp/d.The above ratios are taken from experiments on the extraction of multifaceted workpieces. For example, the shape and dimensions of the groove, the protruding section and the tendency of the workpiece to fold form depend on the size of the radius of the groove R. The same effect is exerted by the depth of the gutter C. From the given range of values of the radius R and the depth of the gutter C, values are selected depending on two factors: the relative thickness of the workpiece and the drawing coefficient. The relative thickness refers to the ratio of the thickness of the workpiece

to the diagonal M of the regular polygon, which is the basis of the polyhedral workpiece in percent

100S / M. Under the coefficient of drawing refers to the ratio of the average diameter (or radius R _cp ) of the cylindrical section of the semi-finished product after drawing to the diameter (radius) of a circle inscribed in the polygon m 2R _cp / d.

So, with a relative thickness of 1%, the radius of the cylindrical surface of the groove R 1.3 of the diagonal M is recommended; 2% RM; 3% and above R 0.7 M. The depth of the groove C is selected depending on the drawing coefficient m. If m ≅ 0.55, it is recommended that the depth of the gutter be C 0.1 S, and with a drawing coefficient m ≥ 0.85 C 0.25 the thickness of the workpiece S. The gutters in the workpiece are made, for example, by upsetting using a punch whose end has convex protrusions mirroring the size of the gutters. After precipitation in the direction of the middle of the sides, thinning is formed in the workpiece in the form of gutters, while the blind end of the gutter is separated from the center of the workpiece by a distance equal to the average radius of the cylindrical part of the semi-finished product, and from the side of the open edge, the bottom of the gutter extends above the polygon side in the form of a segment with a radius of 0, 4-0.8 from the average radius of the cylindrical part of the semi-finished product R _cp . The height of the segment is X (0.085-0.17) x (d 2R _cp ).

 A positive effect is achieved due to the fact that when drawing in the gutter formation area, a concentration of compressive stresses arises in the circumferential direction, which contributes to a more intensive flow of metal from the corner sections ("hard zones") to the middle of the sides. As a result of this, the height of the semi-finished product is increased by 10-20% more than in the prototype with the same dimensions of the workpiece. The shape of the open edge of the gutter also contributes to an increase in height and a decrease in crown formation. This leads to metal savings both when cutting along the height of the semi-finished product, and when receiving a workpiece due to the rational cutting of a strip or tape when cutting or cutting.

 Figure 1 shows a square billet; figure 2 hexagonal workpiece.

The square blank (Fig. 1) has four thinned sections 1 made in the form of grooves oriented normal to the middle of the sides of the square. The blank end of the groove 2 is spaced from the center of the workpiece at a distance equal to the average radius of the cylindrical part of the semi-finished product R _cp , and from the side of the open edge of the workpiece, the bottom of the groove projects above the side of the polygon 4 in the form of a segment 3 with a radius of (0.4-0.8) R _cp . The depth of the groove 1 is equal to C 0.1-0.25 of the thickness of the workpiece, and the height of the segment 3 varies within X (0,085-0,17) x (d 2R _cp ). Similar forms of gutters are made on a hexagonal workpiece (figure 2), only their number increases to six.

0,25 x 3,14 x 10000 7854 мм².PRI me R. It is necessary to obtain a semi-finished product with a diameter of 58 mm, a height of 30 mm, a bottom thickness of 3 mm and with a radius of transition of the bottom to the wall of 3 mm. Using the methodology for calculating the size of the workpiece (1), we obtain a circle diameter of 100 mm and a thickness of 3 mm. To obtain a semi-finished product with the given dimensions, one extraction operation is required. Find the average diameter of the semi-finished product after drawing d _cp d _l S 58 3 55 mm. We calculate the hood coefficient md _cp / d 55/100 0.55. The area of the round workpiece is equal to

0.25 x 3.14 x 10000 7854 mm ² .

 According to the equality of the area of the circle and the square blank, we determine the size of the latter.

= 0,5•100

89 мм.a 0.5 • D

= 0.5 • 100

89 mm.

100S/M 3 x 100 126 2,4%
В соответствии с этими факторами определяем размеры желоба 1 (фиг.1). Принимаем радиус цилиндрической поверхности желоба R 0,9 M 0,9 x 126 113 мм, глубину желоба С 0,15 S 0,15 x 3 0,45 мм. Глухой торец желоба должен располагаться от центра заготовки на расстоянии, равном среднему радиусу цилиндрической части полуфабриката, т.е. на расстоянии R_cp 0,5 x 55 27,5 мм. Для получения желобов данных размеров изготавливается кольцевой пуансон, внутренний диаметр которого равен среднему диаметру цилиндрической части полуфабриката, т.е. 55 мм, а внешний должен быть не меньше диаметра вписанной в многоугольник окружности с добавлением размеров сегмента 3 по высоте, равной Х 0,115 х (d 2R_cp) 0,115 x 34 3,91 мм.As a result of using a square billet, the drawing coefficient will change, which will be equal to: md _cp / D ₃ 55: 890.62. The relative thickness of the square billet is equal to:

100S / M 3 x 100 126 2.4%
In accordance with these factors, we determine the size of the gutter 1 (figure 1). We take the radius of the cylindrical surface of the gutter R 0.9 M 0.9 x 126 113 mm, the depth of the gutter C 0.15 S 0.15 x 3 0.45 mm. The blind end of the gutter should be located from the center of the workpiece at a distance equal to the average radius of the cylindrical part of the semi-finished product, i.e. at a distance of R _cp 0.5 x 55 27.5 mm. To obtain gutters of these sizes, an annular punch is made, the inner diameter of which is equal to the average diameter of the cylindrical part of the semi-finished product, i.e. 55 mm, and the outer one should be not less than the diameter of the circle inscribed in the polygon with the addition of the dimensions of segment 3 in height equal to X 0.115 x (d 2R _cp ) 0.115 x 34 3.91 mm.

 Thus, the outer diameter of the annular punch should be at least 89 + 2 X 89 + 7.82 96.92 mm. At the working ends of the punch in two diametrical directions, bulges are made with a radius of R 113 mm and a height of C 0.45 mm. After precipitation, a square blank is obtained in accordance with the required calculations. It can be seen from the example that significant metal savings are achieved compared to using a round billet, which is more than 30%, and about 20% compared to the prototype

Claims (1)

Billet for drawing a cylindrical semi-finished product in the form of a polyhedron having a regular polygon at the base, characterized in that it has thinning in the form of cylindrical troughs oriented along the normals to the midpoints of the sides of the polygon, the blind end of each trough is remote from the axis of the workpiece equal to the average radius of the cylindrical part of the semi-finished product, from the side of the open edge the bottom of the gutter in the plan is made protruding above the side of the polygon in the form of a segment, The values of the radius of the cylindrical surface of the groove R, the depth of the groove C, the radius of the segment R _c and the height of the segment X are limited by the following intervals
R = 0.7 - 1.7 M,
where M is the largest diagonal of the polygon;
C = 0.1 - 0.25S,
where S is the thickness of the workpiece;
R _s = 0.4 - 0.8 R _{s p} ,
where R _{with p} is the average radius of the cylindrical part of the semi-finished product;
X = (0.085 ^o C 0.17) • (d - 2R _{s p} ),
where d is the diameter of the circle inscribed in the polygon.

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