RU2630158C1 - Method for preparation of blank for screw rolling - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method includes cutting the blank of required length from a semi-finished rolled stock by rollers. The semi-finished rolled stock rotates around its axis during cutting. The rollers with a cutting edge enter into contact with the blank in two points lying diametrically opposite on its surface when the semi-finished rolled stock is rotating. The rollers move progressively towards each other penetrating into the blank, while the rollers rotate about their axis due to contact with the blank. The cutting is carried out twice, first at a distance of 15-20 mm from the end of the semi-finished rolled stock, and then the second time, while a place for the second cutting is selected at a distance equal to the length of the blank for screw rolling, counting from the place of the first cutting.

EFFECT: optimising shape of the ends of blanks by reducing end shrinkage during subsequent rolling.

5 dwg

Description

The invention relates to the field of metal forming, in particular to the preparation of a workpiece for screw rolling, and can be used in the production of seamless pipes using helical rolling mills in order to reduce end tension.

A known method of producing stepped shafts (No. 500866, USSR, published 01/30/1976). The method has the following disadvantages: the invention can be used in transverse rolling, rather than screw, a two-stage rolling scheme is used.

There is a method of improving the quality of rolled shafts (No. 564911, USSR, published July 15, 1977). The disadvantage of this method is the need for special cooling.

There is a method of preparing a workpiece for firmware and subsequent rolling in a twin roll screw rolling mill (RU 2533612 C2, published on November 20, 2014). The disadvantage of this method is the need for drilling the workpiece and significant restrictions on the shape and size of the workpiece.

There is a method of preparing a workpiece for screw rolling by compressing the end face of the workpiece (article "FEM modeling and optimization of a new method of compression of a continuously cast billet", Ferrous metals magazine, No. 11 (983), 2013, pp. 26-30). The method has the following disadvantages: the optimal calibrations of the crimping strikers are not completely determined, the experimental rolling was carried out only for plasticine blanks, the need for using grease was revealed.

A known method of producing parts from a bar by wedge rolling (BY 2564 C1, published 12/30/1998). The disadvantage of this method is the need to use a large number of additional equipment of complex design.

The technical result of the invention is to improve the quality of the end surface obtained by screw rolling round in cross section of the product by reducing the end weight.

The technical result is achieved by the fact that the tackle is subjected to cutting.

When cutting, the tackle rotates around its axis, while the contact with the workpiece at two points lying diametrically opposite on its surface includes rollers with a cutting edge, the rollers move forward towards each other, penetrating into the workpiece, while the rollers rotate due to contact with the workpiece around its axis, while cutting is carried out twice, first at a distance of 15-20 mm from the end of the tackle, and then a second time, while the place for the second cutting is selected at a distance equal to the length of the workpiece for screw rolling, counting I'm from the place of the first cutting.

After cutting, the ends take the form of a cone.

During screw rolling, the metal flow in the surface layers of the workpiece is much more intense than on the axis of the workpiece. If the billet for rolling had smooth ends, then a weight would be obtained, which must be cut off, thereby increasing the consumption of metal. However, the presence of cones at the ends of the workpiece will minimize the effect of the difference in the intensity of the flow of metal on the surface and in the axial zone and will lead to the appearance of a weight much smaller or will allow you to get absolutely flat ends without any weight.

The invention is illustrated by drawings, where in FIG. 1-4 shows the stages of the process of cutting the workpiece with rollers. In FIG. 1 shows how the rollers are brought into contact with the workpiece; FIG. 2 - the beginning of cutting due to the movement of the rollers towards each other. FIG. 3 shows the middle of the cutting process, FIG. 4 - end of the cutting process.

Using the proposed method does not require changes in the technology of screw rolling and equipment for its implementation.

Using the invention will provide a reduction in metal consumption in the manufacture of products by screw rolling and will improve the surface quality of the end face of the resulting workpieces.

An example of the use of the proposed method are experiments conducted on the installation for cutting with rollers, Department of OMD NUST "MISiS". Workpieces made of VT6 titanium alloy were subjected to cutting. The samples had a circular cross section with a diameter of 30 and 40 mm. Used rollers with a cutting edge angle of 50, 60, 70 and 80 degrees. The cutting site was heated to a temperature of 1050 ° C (Fig. 1-4). After cutting, the billets with a conical end were rolled in a three-roll mill and the weights were compared with the weights of the flat-end billets rolled in the same three-roll mill. It was found that the weight when rolling a workpiece with a conical end is less (Fig. 2).

Claims (1)

A method of producing a round billet in cross section for rolling in a helical rolling mill, comprising cutting the billet of the required length from the tack, characterized in that when cutting the tack, they rotate around its axis, at the contact points at two billets located diametrically opposite on its surface rollers with a cutting edge are introduced into the workpiece, which move translationally towards each other and are introduced into the workpiece, ensuring the rotation of the rollers around its axis due to their contact with the workpiece, is cutting the workpiece is performed twice, first at a distance of 15-20 mm from the end tackle, and then at a distance from the first cutting places equal to the length of the workpiece under the rolling screw.

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