RU2626252C2 - Method of obtaining metallic bargains in shape of polygon from thin band - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: cutting is carried out in two stages. In the first stage, preliminary incisions are made on the moving strip. In the second stage, by deforming the shear at the notches, the workpiece is separated from the strip. Two interlocking two-roll stands are used, the first of which carries out preliminary notches on the strip, and in the second one - a shift in the places of the notch.

EFFECT: expanded technological capabilities.

3 cl, 9 dwg, 2 ex

Description

The invention relates to sheet stamping, in particular to the production of metal blanks for sheet stamping.

A known method of producing metal blanks for sheet stamping, including plastic deformation of the ingot by forging (see, for example, patent 2288064 B21J 1/04 from 04.04.2005).

The main disadvantage of this method is the increased complexity of the process and large losses of metal with trim, eliminating the mass production of billets.

A known method of producing round blanks from a sheet or a roll, including multi-row cutting of blanks in a checkerboard pattern and cutting them with curly knives, partially repeating the contour of the blanks being cut, each subsequent cut with scissors is carried out after the sheet or knife is shifted halfway through the blanks (see, for example application 2011111230, B21D 28/00 of 02.24.2011).

The main disadvantage of the method is the technical impossibility of providing a strictly standardized displacement of the sheet or strip before each cut, which leads to increased metal losses during the implementation of the method.

There is a method of low-waste cutting of a blank from a card, including cutting a card from a sheet material in the form of a sheet, strip or a wide roll, the card can be square or rectangular, and subsequent cutting from this card with a punch of a blank with a cross section in the form of a regular or irregular polygon (see , for example, patent 2308343, B21D 28/02 from 07/18/2005).

The main disadvantage of this method is the increased cost due to its low productivity.

A known method of low-waste cutting of a workpiece from a thin tape, a wide roll or strip, including single-row or multi-row cutting of workpieces without side jumpers between two adjacent blanks from a strip (tape, wide roll). In this case, punching is carried out by a punch in the form of a regular or irregular polygon (see, for example, patent 2.295.414, B21D 28/06 of July 18, 2005).

A known method of producing blanks in the form of a polygon from a thin strip, including cutting blanks from a thin metal strip passing through two interconnected two-roll stands (see, for example, SU 1516187 A1, B21D 28/36; B26F 1/20 from 04/23/86). By the set of essential features, the known method for producing blanks in the form of a polygon from a thin strip is the closest analogue to the proposed method for producing metal blanks in the form of a polygon from a thin strip, therefore it is adopted as a prototype.

The fundamental difference of the proposed method is the application of the most effective, due to high productivity, method of processing metal by rolling. The aforementioned allows to completely eliminate the noted disadvantage of the known method.

These technical results are achieved due to the fact that in the method for producing blanks in the form of a polygon from a thin metal strip, including cutting blanks from a thin metal strip passing through two interconnected two-roll stands, according to the invention, preliminary cuts are made in the first stand with a depth ensuring the integrity of the strip, and in the second stand, the workpiece is separated by a shift in the places of preliminary cuts, while the strip with preliminary cuts under they undergo alternating plastic deformation of the bending of the incision sites by passing the strip through a three-roller bending installation. In this case, blanks in the form of a polygon are obtained by single-row and multi-row cutting, and preliminary cuts are made along the perimeter of the polygon. Moreover, square blanks are obtained by double-row cutting, preliminary cuts are made in the form of longitudinal and transverse cuts, shear deformation is carried out along longitudinal cuts, and a second stand with rolls of different diameters along their barrel is used.

The proposed method for producing metal blanks in the form of a polygon from a thin strip is illustrated in FIG. 1-9.

In FIG. 1-2 shows a General view of the installation that implements the proposed method (in Fig. 2 - view in plan); in FIG. 3 is a preliminary cut on the strip (enlarged view), in FIG. 4 - prefabricated with the strip and already separated from it, in FIG. 5-8 are examples of the outlines of individual types of blanks obtained and in FIG. 9 (in plan view) shows a strip with hexagonal blanks previously cut on it.

The implementation of the method comprises (Fig. 1 and 2) a two-roll stand with an upper roll 1 and a lower roll 2 and a two-roll stand with an upper roll 3 and a lower two-layer roll 4 and 5. A thin metal strip 6 is supplied to the welding unit 7 in an endless strip. Loop 8 compensates for the discrepancy between the speeds of the strip. Rolls 1 and 2 on the strip cause preliminary cuts 9 around the perimeter of the polygon. The installation 10 contains three bending rollers 11, at the exit from the two-roll stand 3-5, the obtained workpieces 12 enter the hopper 13. On the upper roll 1 there are fixed protrusions (knives) 14 for application on the strip of preliminary cuts 9. The produced workpieces may have the shape of a square 15 (Fig. 5), the correct 16 six- (Fig. 6) and eight- 17 (Fig. 7) polygons, the irregular (Fig. 8) octagon 18, and other polyhedral figures with different aspect ratios. The process of manufacturing blanks is carried out practically without loss to trim (for example, in the production of square 15) or have losses 19 (Fig. 9), the value of which depends on the aspect ratio of the resulting polygonal blanks.

Polygon-shaped blanks are obtained by single-row or multi-row cutting, and preliminary cuts are made along the perimeter of the polygon. Square blanks are obtained by double-row cutting, while preliminary cuts are made in the form of longitudinal and transverse cuts, shear deformation is carried out along longitudinal cuts, and a second stand with rolls of different diameters along their barrel is used.

A method of producing metal blanks in the form of a polygon from a thin strip is as follows.

A metal strip 6 of thickness h from a roll enters the polygon production line. At the entrance to the line in the installation 7 cut the front end of the strip and carry out its welding with the rear trimmed end of the previous strip.

In the process of performing these operations in installation 7, the production process in the line is carried out using metal from loop 8. When passing through the first two-roll stand with 1-2 knives 14 of the upper roll 1, preliminary cuts 9 are made along the perimeter of the polygon by pressing the upper roll 1 to the roll 2 s the force sufficient to introduce the knives 14 into the strip metal, with the formation on the strip of preliminary cuts 9 (Fig. 1-3) with a depth of h ₁ (Fig. 3), ensuring the integrity of the strip due to the abandonment of jumpers of thickness h ₂ (Fig. 3). Rolls 1 and 2 are used from steels of the type 9X, 9X2, 9XF, 60XH, etc., cutting knives 14 from hard alloy plates are fixed on the body of roll 1. Knives 14 are installed only on the upper roll 1, while the cutting edges of the knives 14 are formed on the surface body roll 1 shape of the manufactured workpieces 12 (Fig. 1, 2, 4 and 5-8) and others. The shape of the knives 14 and their location on the roll 1 (most often the roll 1 as a whole) change depending on the location of the preliminary cuts 9 on strip 6 (i.e., on the shape of the workpieces produced). Moreover, the roll 1 is replaced depending on the shape of the produced metal billets 12.

By the pressure of the upper roll 3 on the lower roll 4, shear deformation is realized in the strip and the workpiece is separated by shearing in the places of preliminary cuts. The specified separation of the workpiece is carried out due to the elastic layer 5 on the roll 4 and the vertical displacement of the notched section of thickness h _{2 of the} workpiece at the moment the workpiece passes the vertical plane of the axes of the rolls 3 and 4. In this case, shear deformation occurs in the layer of strip 6 of thickness h ₂ , the formation of metal blanks 12 falling into the hopper 13.

The combination of the described operations is necessary and sufficient for single-row production of polygons. But even in this case, plastic deformation of the section with a thickness h _{2 of the} preliminary notch 9 is necessary, which makes it possible to facilitate the separation of the strip 6 into blanks 12 by shifting in the places of the preliminary notch.

To implement these provisions, the strip 6 with preliminary notches 9 is subjected to alternating plastic deformation of the bending of the incisions by passing the strip through a three-roller bending installation 10 (Fig. 1 and 2). The installation 10 contains three rollers 11. The strip 6 with notches 9, passing through the rollers 11, experiences (more precisely its layer h ₂ in Fig. 3) plastic deformations of compression and tension, thereby facilitating the conditions necessary for the destruction of notches 9 located across the strip , when passing through a stand with rolls 3 and 4.

To facilitate the implementation of the shear operation in the longitudinal cuts 9 of the strip 6, an upper roll 3 with different diameters along the barrel length is used (see D ₁ and D ₂ in Fig. 2). The difference in diameters D ₁ and D _{2 is} assigned depending on the thickness h ₂ and the strip material, but usually their difference does not exceed 2-3 mm. The transition from the diameter D ₁ and D ₂ on the upper roll 3 coincides with the longitudinal notch 9 on the strip 6 (see Fig. 2). Naturally, in this case, in the installation design of FIG. 1 and 2 provide means that exclude the displacement of the strip 6 along the length of the barrel rolls 1-2 and 3-4 and 5.

The set of described operations and their implementation in the installation shown in FIG. 1 and 2 allow the production of the polygonal blanks shown in FIG. 5-8, and others with different aspect ratios that limit their outlines. In the manufacture of blanks from thin sheets according to the totality of the described operations, there is a loss of metal in the edge. These trimming losses depend on the shape (in plan) of the resulting workpiece and the aspect ratio of the polygon, covering (describing) the polygon, as well as the multiplicity of their production.

For example, in the production of square (Fig. 5) and rectangular blanks, there are practically no marked metal losses to the edge. In the production of preforms in the form of a hexagon in two rows, the loss to the edge is made up of the sections indicated by number 19 in FIG. 9.

Example 1. On the line for producing metal billets (Figs. 1 and 2), square billets of 100 × 100 mm are produced from a hot-rolled strip of mild steel with a width of B = 100 mm and a thickness of h = 2.0 mm by single-row cutting of the billets. The lateral edges of the strip 6 are pre-processed and subsequently become the edge of the finished square blanks 12.

The blank production line contains a two-roll stand with rolls 1 and 2 of steel 9X2 with a diameter of 200 mm. Six cutting knives 14 with a cutting edge 1.5 mm high are fixed on the upper roll 1. Knives are made of steel grade 60XHM.

In the process of one revolution of the roll 1 on the strip 6 form six preliminary cuts 9 with a depth of h ₁ = 15 mm with the remaining jumper with a thickness of h ₂ = 0.5 mm (Fig. 3).

The strip 6 with these preliminary cuts 9 enters the installation 10, equipped with three rollers with a diameter of 200 mm, where the jumpers with a thickness of h ₂ = 0.5 mm are subjected to plastic bending, covering a depth of about 0.15 mm on each side of the thickness of the bridge. Thus, after installation 10, the strip 6 with notches 9, in which the jumpers with a thickness of h ₂ = 0.5 mm, are subjected to the specified plastic deformation, enters the two-roll stand with rolls 3, 5 and 4.

When the strip passes through this stand, due to the presence on the lower roll 4 of layer 5 of superhard elastic rubber, this jumper with a thickness of h ₂ finally breaks (due to shear deformation) into individual square billets 100 × 100 mm 2.0 mm thick. The resulting workpieces 12 are subsequently processed in a separate hopper with sand (or shot), which smooths out the roughness formed by breaking the strip 6 along the notches 9.

Example 2. In the production line described in example 1, the production of square 100 × 100 mm blanks 12 in two rows is carried out using the techniques and equipment specified in example 1 (see Figs. 1 and 2, which are shown). In this case, the cutting knives 14 on the upper roll 1 are arranged as shown in FIG. 2.

As a result, longitudinal and transverse cuts 9 shown in FIG. 2. In the device 10, the strip 6 with notches 9 is subjected to the processing described in Example 1. In a two-roll stand with rolls 3 and 4, the left and right (top view) sections of the strip with notches 9 are passed through a stand with rolls 3 and 4, in which the diameter of the roll along the length of its barrel has two values: D ₁ and D ₂ , with D ₁ ≠ D ₂ . The transition between D ₁ and D ₂ passes through the center of the longitudinal notches 9. Due to the difference | D ₁ -D ₂ | of the order of 2-3 mm, a longitudinal shift of the strip occurs along the longitudinal part of the notch 9. At the exit from the cage, by analogy with Example 1, workpieces 12 from strip 6 enter the hopper 13 as shown in FIG. 2. An integral part of the production, as in example 1, is the processing of the obtained blanks in a separate hopper with sand or shot.

The proposed method for producing metal blanks in the form of a polygon from a thin strip naturally does not provide an ideal outline for the separation of the strip (their faces) in the places of shear, which in most cases the subsequent use of blanks is not necessary. If necessary, to eliminate roughness in the places of movement of the workpieces along their perimeter, the workpieces are subjected, as indicated, to substantial additional processing in bunkers with sand (or shot).

Thus, a method has been developed for the mass production of metal billets in the form of a polygon from a thin strip, the basis of which is the use of elements of rolling production, which is the most productive method of processing metals.

Claims (3)

1. A method of producing blanks in the form of a polygon from a thin metal strip, comprising cutting blanks from a thin metal strip passing through two interconnected two-roll stands, characterized in that preliminary cuts are made in the first stand with a depth that ensures the integrity of the strip, and in the second stand they carry out separation of the workpiece by shear in the places of preliminary incisions, while the strip with preliminary incisions is subjected to alternating plastic deformation of the bending of the incisions by passing the strip through a three roller bending installation. 2. The method according to p. 1, characterized in that the blanks in the form of a polygon receive a single-row or multi-row cutting, and preliminary cuts are performed around the perimeter of the polygon. 3. The method according to p. 1, characterized in that the square blanks are obtained by double-row cutting, preliminary cuts are made in the form of longitudinal and transverse cuts, shear deformation is carried out along longitudinal cuts, and a second stand with rolls of different diameters along their barrel is used.

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