RU2470730C1 - Female die for multiport tube and hollow section pressing - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to production of tubes and hollows sections from aluminium, magnesium and titanium alloys to be used in aerospace engineering, etc. Multiport die comprises even number of supports, body, plug-in bushes to shape product outer contour, replaceable needles to shape product inner channel.

EFFECT: equal wall thickness, reduced pressing force.

Description

The present invention relates to the field of metal forming and can be used to obtain pipes and hollow profiles from aluminum, magnesium and titanium alloys used in aerospace and other industries.

A device for pressing products, taken as a prototype, consisting of an eight-channel matrix, where the needles are located symmetrically relative to the axis around the perimeter of the outer contour and are fixed in consoles facing their span in the direction from the center of the matrix to its periphery (German Patent No. 898883, 1955 .).

The disadvantages of this design are:

1. When pressing a hollow product, the metal stream line in the region where the matrix is located in the container is directed toward the center of the matrix, and the metal flow bends the needle in the same direction, which leads to an increased difference.

2. The consoles occupy the central part of the matrix, and the needles are located at considerable distances from the center, i.e. in places of difficult metal flow during the pressing process, which leads to an increase in the pressing force.

A known matrix, taken as an analogue, consisting of a matrix holder installed in the needle holder body having one centrally located channel expanding towards the matrix holder, while the needles are symmetrically relative to the axis around the perimeter of the outer contour of the needle holder so that the metal access to the welding chamber formed in the channel behind the needle between the matrix holder and the needle holder, occurs on one side of the needle from the center of the matrix (Copyright certificate No. 301201. - “Discoveries, inventions, industrial samples, trademarks ”, 1971, No. 14, p.26).

The disadvantage of the design of the matrix of the analogue is the withdrawal of the needles away from the center of the matrix during pressing due to the unilateral impact of the metal flow on the needles, which leads to increased difference.

A matrix design is proposed for multi-channel pressing of pipes and hollow sections, including an even number of consoles; housing; removable sleeves, forming the outer contour of the product and interchangeable needles, forming the shape of the internal channel of the product, pairwise fixed in consoles that are part of the matrix body, located diametrically and symmetrically relative to the axis of the matrix and facing their span to the center of the matrix, while the needles are fixed in position parallel to the axis matrix by positioning near the center of the matrix in the area corresponding to the least resistance of the metal, with equal distance from the center of the matrix to the extreme inner point Console largest pockets for diffusion welding metal defined product wall thickness. The thickness of the pocket is in the range from 3 to 5 wall thicknesses of the product.

Metal enters into the space formed between the consoles from the center of the matrix and in the expiration zone during pressing compensates the force on the needle from the side of the pocket, deflecting it to the center of the matrix, fixing the position of the needle parallel to the axis of the matrix. As a result, the difference is significantly reduced.

The pressed products are close to the center of the matrix, therefore, to the line of least resistance during pressing, which leads to a reduction in energy costs for the implementation of the deformation, a reduction in the pressing force and, as a result, an increase in the process productivity.

The productivity of the process increases in proportion to the number of matrix points.

The technical result is a reduction in the difference between the pressed products, a decrease in the pressing force and an increase in the productivity of the process.

Figure 1 shows a general view of this matrix.

The matrix consists of an even number of consoles 1, diametrically and symmetrically located relative to the axis of the matrix, interchangeable needles 2, forming the shape of an internal channel, housing 3, in which removable sleeves 4 are located, forming the outer contour of the product.

For a given pipe or profile size, it is only necessary to complete the matrix with needles and bushings when each pair corresponds to one type of product of the same size.

The device operates as follows. When pressing products from a continuous billet (ingot), the consoles separate the metal flows and connect them in pockets 5, where diffusion welding takes place. The process is continued until a press residue is formed, which is removed before pressing the next workpiece, after which the pressing cycle is resumed.

Using the proposed matrix, a pilot batch of especially thin-walled profiles of the cipher PS 890-68 was manufactured in the amount of 87 kg.

Pressing was carried out on a press with a force of 1250 tf from a container ⌀ 150 mm through a two-point matrix. The dimensions of the billet for pressing, mm: ⌀ 145 × 300. Alloy AMg2. The cross-sectional area of the product is 0.62 cm ² .

The volume of the workpiece is 4951.39 cm ³ . The mass of the workpiece is 13.27 kg.

The value of the press balance as a percentage of the ingot is:

,

,

where h _{ave. ost} - the height of the press residue equal to: h _{ave. ost} = h _gr +10 mm (h _gr - height of the ridge, mm),

l _zag - the length of the workpiece, mm

The yield is 85%.

From the blank 2 products were obtained with a length of 30 m by mass:

m _ed = m _{1 pm} (l _ed -h _{ave. ost} ) · 2,

where m _{1 lm} - mass of 1 running meter, kg,

l _ed - product length, taking into account the press balance, m

m _ed = 0.16 (30-0.045); 2 = 4.79 kg; 2 = 9.58 kg.

When pressing on a press with a force of 750 ton-force according to traditional technology, a workpiece with dimensions of mm was used through a single-point matrix, mm: ⌀ 90 × 200. The value of the press balance as a percentage of the ingot is:

The yield is 67.5%.

From the workpiece received 1 product with a length of 7 m mass:

m _ed = 0.16 (7-0.065) = 1.11 kg.

Thus, productivity is increased by 8.6 times, yield increased by 17.5%.

Actual pressing parameters: hood µ = 142, pressing temperature 460 ° C, flow rate 8 m / min.

Product quality

As a result of the experiments, a press product with one weld was obtained, which increased the reliability of the product in designs. Figure 2 shows the macrostructure of the cross section of the pressed profile PS 890-68. As can be seen in the photo, the structure of the profile is homogeneous, no traces of the weld are visible, no delamination.

The resulting products have a reduced difference. The thickness t _min is 1.22 mm in diameter and 1.30 mm across the canvas (Fig. 3). The manufactured batch of profiles fully meets the requirements of technical specifications for increased accuracy (Fig. 4) and is delivered to the customer.

Claims (1)

A matrix for multi-channel pressing of pipes and hollow profiles, including a housing, consoles, bushings and needles, forming the shape of the internal channel of the products, characterized in that the needles are pairwise fixed in diametrically opposite consoles, made as part of the matrix body and facing their spans to the center of the matrix, while the needles fixed in the consoles are fixed in position parallel to the axis of the matrix due to their location near the center of the matrix in the area corresponding to the least resistance to metal flow, while distance from the center of the matrix to the innermost point equal to the console pocket for diffusion bonding metal flows defined wall thickness of the article.

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