RU2302915C1 - Universal stand of planetary bar rolling mill - Google Patents

Abstract

FIELD: processes for rolling enlarged assortment of billets in bar rolling planetary mills with alternating reduction in two mutually normal planes.

SUBSTANCE: stand includes two pairs of retainers where drive rolling rolls arranged in mutually normal planes are mounted at shift of mutually normal pairs of rolls one relative to other. On barrel of each roll trapezoidal groove is formed; said groove has constant profile along circumference of roll and concave bottom whose cross section is in the form of part of circle or rectangle with rounded corners similar to cross section contour of ready article. Width of said groove along its bottom is no more than 0.21 of width of inlet cross section of billet. Rounding radius consists of 0.1 - 0.5 of width of outlet cross section of article. As grooves of all rolls are identical, rounded portions of article profile are formed alternatively by means of identical parts of grooves of mutually normal pairs of rolls.

EFFECT: possibility for producing round articles, square cross section products with rounded corners, enlarged assortment of products at high efficiency of universal stands of planetary rolling mills, elimination of cracking and backfins.

4 dwg, 1 ex

Description

The invention relates to the field of rolling production and relates to the improvement of the tool (rolls) of high-quality planetary mills for rolling with alternate compression in two mutually perpendicular planes.

A known stand of a planetary mill for rolling pipes and section metal, containing two sets of planetary rolls located one above the other, including separators with work rolls, while the work rolls are calibrated, with crimp sections of a variable profile and calibrating sections of a constant caliber profile [see, for example, SU 124398, 11/19/1960].

A disadvantage of the known system is that it is designed for rolling in one plane and does not have high productivity, while the manufacture of calibers of variable profile is a complex and time-consuming process.

Closest to the declared one is a universal stand of a planetary high-grade rolling mill, containing two pairs of separators with driven drive rolls fixed in them, placed in mutually perpendicular planes, with a displacement of mutually perpendicular roll pairs relative to each other. The work rolls of this stand are made with smooth barrels. The stand is designed for rolling square products. Obtaining products of other sections, for example round, requires subsequent additional compression in the stands of mills with rolls with calibers of the corresponding section [see, for example, RU 2100109, 12.27.1997].

This known device is characterized by high productivity and economy due to rolling with high hoods. Its disadvantages, however, include the impossibility of obtaining profiles other than square (in particular, round), despite the fact that the resulting square profile has sufficiently sharp angles (ribs), leading to uneven cooling and, as a result, damage to the tool during rolling in subsequent stands, to stall profile, the formation of sunsets and the appearance of cracks in the metal.

The objective of the invention is to expand the range of products due to the possibility of obtaining products of a round profile and profile in the form of a square with rounded corners, improving the quality of finished products by eliminating sunsets and cracking, combined with the high performance characteristic of universal stands of high-quality planetary rolling mills.

The problem is solved due to the fact that in a universal stand of a high-grade planetary rolling mill containing two pairs of separators with driven drive rolls fixed in them, placed in mutually perpendicular planes, with mutually perpendicular pairs of rolls offset relative to each other, in accordance with the invention on each barrel a trapezoidal stream made of rolls of a profile roll constant in circumference, with a concave bottom having a cross section in the form of a part of a circle or a rectangle with rounded angles identical to the cross-sectional shape of the finished product, with a width along the bottom of the stream not exceeding 0.21 of the width of the input section of the workpiece, and a radius of rounding of 0.1-0.5 of the width of the output section of the product, while the streams of all the rolls are made the same, for the formation of rounded sections of the product profile alternately identical sections of streams of mutually perpendicular pairs of rolls.

The implementation of the work rolls of the universal stand of a high-grade planetary rolling mill in the calibrated manner described above enables the formation of the same rounded part of the rolled profile in mutually perpendicular roll pairs, with overlapping this section of the workpiece by sections of two mutually perpendicular calibers made with the same radius of rounding, which eliminates the formation of sunsets in profile corners. The described stand makes it possible to roll products of a round profile, which is a consequence of the use of rolls whose streams are made with a maximum degree of rounding of the bottom profile (radius of rounding is 0.5 of the width of the output section of the product), that is, with a profile that is part of a circle.

The width of the stream, measured at the bottom, does not exceed 0.21 of the width of the input section of the rolled billet. The choice of the width of the stream within these limits provides a stable position of the roll in the deformation section, optimal conditions for filling the caliber with metal. When performing a caliber of greater width, the formation of acute profile angles is possible. This limit value has been established experimentally and is optimal for specific conditions of metal deformation in a universal planetary stand. The declared rolling stand is intended for deformation of workpieces, the cross-sectional width of which is in the range of about 120-60 mm. This can be the side of a square blank or the diameter of a round. The width (side or diameter) of finished products (square or round) rolled on this equipment is 25-8 mm. The radius of the rounded parts of the stream, it is advisable to choose from a range of 0.1-0.5 of the width of the output section of the finished product. The maximum value of this range (0.5) corresponds to the rolling of the product, the cross-sectional shape of which is close to a circle, the minimum (0.1) - to the rolling of the product having a cross-section in the form of a square with the smallest technologically feasible rounding of corners. The intermediate values of the radius of rounding of the stream, selected in this range, mean rolling products with different degrees of rounding of the angles of the cross section (ribs).

Figure 1 presents a conditionally deployed system of rolls of a high-grade planetary mill, occupying positions 1, 2, 3 in the process of moving in a circular orbit, in figure 2 - view along arrow A in figure 1, figure 3 - view along arrow B in figure 1, figure 4 is a view along arrow C in figure 1.

Both pairs of work rolls 1 and 2 are located in the bores of the separators (not shown in the drawing), they are driven through the end gear, which engages the wheel with the internal tooth (sun gear), and when rolling alternately compress metal 3 in two mutually perpendicular planes . The pairs of drive roll separators 1 and 2 are arranged in mutually perpendicular planes and are offset from each other in the direction of the rolling axis. In the deformation zone, in the gap between two adjacent pairs of rolls of the first pair of separators, rolls are installed in the second pair of separators, rotated 90 ° relative to the first. A trapezoidal stream of a profile roll constant in circumference is made on the barrel of each of the rolls: the radius of the roll corresponding to one or another part of the stream does not change along the length of the barrel. The bottom of the stream is concave (deepened), in the cross section the portion of the bottom of the stream has the form of a part of a circle or rectangle with rounded corners identical to the cross-sectional shape of the finished product. It is these, bottom, sections of streams in rolls located in the deformation zone that form part of the caliber, which forms a given product profile.

The streams of all the rolls are made of the same configuration and size, since the dimensions of the gauges (the solution between the rolls) decrease during the rolling process due to the convergence of the work rolls as they move in a circular orbit. The metal in the gauge gradually moves from the zone of inclined side sections to the central zone formed by the bottom parts of the streams, where the finished product profile is formed.

As a result of the alternating deformation of the metal in mutually perpendicular planes with the inclined faces of the trapezoidal streams forming the corresponding gauges, the central parts of the gauges are sequentially filled with the whole mass of metal, the workpiece takes the form of a finished product. During rolling, the workpiece is crimped by the side wall 4 simultaneously by pairs of rolls on both sides. In this case, the side walls 4 at the final stage of rolling do not participate in the formation of the profile. The rounded part of the finished profile is formed by the outlets of 5 mutually perpendicular pairs of rolls 1 and 2. Performing radius curves of streams with the same radius in mutually perpendicular pairs ensures the accuracy of the formation of the same part of the profile with different calibers, eliminates the formation of sharp corners and sunsets on the surface of the finished profile and resulting this defects.

Similarly, a circular cross-section of the profile can be obtained.

Example.

In the universal stand of the planetary mill, rolls with trapezoidal streams are installed, the bottom of which has the shape of a rectangle with rounded corners, with a radius of rounding of 0.5 mm. A round billet with a diameter of 100 mm was rolled. A product was obtained with a square cross-section with a side of 20 mm without cracks and sunsets.

This example shows the possibility of obtaining defect-free long products under the condition of high productivity inherent in the rolling process in a universal planetary stand.

Claims (1)

A universal stand of a high-grade planetary rolling mill, containing two pairs of separators with driven drive rolls fixed in them, placed in mutually perpendicular planes with offset of mutually perpendicular roll pairs relative to each other, characterized in that a trapezoidal stream of a constant roll circumference is made on the barrel of each roll a profile with a concave bottom having a cross section in the form of a part of a circle or a rectangle with rounded corners identical to the shape of the cross section the finished product, with a width along the bottom of the stream not exceeding 0.21 of the width of the input section of the workpiece, and a radius of curvature of 0.1-0.5 of the width of the output section of the product, while the streams of all the rolls are made the same to form rounded sections of the product profile alternately identical sections of streams of mutually perpendicular pairs of rolls.

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