RU2283715C1 - Method for making forged pieces with square or rectangular cross section - Google Patents

Abstract

FIELD: plastic working of metals, namely processes for making forged products with square or rectangular cross section in forging presses.

SUBSTANCE: method comprises steps of preliminary radial forging of ingot; further final forging of formed blank. Preliminary forging is performed with use of four strikers in four-striker forging apparatus of forging press while providing additional macro-shears of metal in cross plane of blank and with deformation degree no less than 7% at each squeezing. At process next relation is satisfied: F = (1.1 - 3.0)F₁ where F and F₁ - surface area of forged piece respectively. Final forging is performed with use of two strikers in forging press for forming forged piece with desired cross section.

EFFECT: improved quality of metal, simplified forging process.

2 ex, 1 tbl

Description

The invention relates to the field of metal forming, and in particular to methods for manufacturing forgings of square and rectangular cross-section on forging presses.

A known method of forging workpieces in a four-sided forging device, comprising compressing a workpiece of square cross-section along the ribs in the radial direction in two mutually perpendicular planes with the formation on each subsequent pass forgings of square cross section, the central axis of which is offset from the central axis of the workpiece of the previous pass, with a tangential shift the direction of one of two pairs of oppositely located edges of the workpiece [1].

This forging method allows to obtain forgings with high quality metal.

The disadvantage of this forging method is the inability to obtain forgings of square or rectangular cross section in a wide range of sizes with one set of strikers. In the manufacture, using such a device, forgings of square or rectangular cross-section of different sizes requires several sets of strikers, which makes the process more expensive.

There is also a known method of manufacturing forgings of various cross-sections, including square and rectangular, including radial forging of an ingot with four dies on a radial crimping machine (ROM) and subsequent final forging of the billet obtained by two dies on the forging press with the formation of forgings of the required cross section [2] .

The known method of forging provides forgings of square and rectangular cross-section in a wide range of sizes using only one set of strikers on the ROM and one set of strikers on the forging press.

The disadvantages of this method is the low metal quality of the obtained forgings, as well as the need to use ROM in its implementation, which relates to expensive and unique equipment.

The basis of the invention is the task, by changing the technology of obtaining the workpiece, to provide improved metal quality and simplification of the process.

The problem is achieved in that in the method of manufacturing forgings of square or rectangular cross-section, including preliminary radial forging of the ingot with four strikers and subsequent final forging of the billet with two strikers on the forging press with the formation of forgings of square or rectangular cross-section, the new is that the preliminary radial the forging of the ingot is carried out in a four-side forging device on the forging press with additional macroshifts of metal in p peppermint plane of the workpiece and the deformation degree of not less than 7% per unit compression, thus maintaining the relationship:

F = (1.1-3.0) F ₁ ,

where F, F ₁ - the cross-sectional area of the workpiece obtained after preliminary forging and forging, respectively.

A patented method of manufacturing forgings is as follows.

The ingot heated to the forging temperature is first forged on the forging press in a four-sided forging device with additional macroshifts of the metal in the transverse plane of the workpiece and a degree of deformation ε of at least 7% with each single compression, until a round or square cross-section is obtained.

In the forging process, they maintain the ratio:

F = (1.1-3.0) F ₁ ,

where F, F ₁ - the cross-sectional area of the workpiece obtained after preliminary forging and forging, respectively.

The resulting billet is also forged on the forging press with two strikers until a forging of square or rectangular cross section with the required dimensions is obtained.

When the degree of deformation ε <7% (for each single reduction), the required study of the metal structure and, therefore, its quality are not ensured.

With the ratio F / A ₁ <1.1, it is impossible to obtain a forging of square or rectangular cross section of the required dimensions forged by two strikers from a round cross-section blank.

When the ratio F / F ₁ > 3.0, the productivity of the whole process is significantly reduced, since the time for the formation of forgings from the workpiece is significantly increased.

Example 1. An ingot of circular cross section made of R6M5FZ steel, having an average diameter of 370 mm, was heated to a temperature of 1150 ° C and preliminary radial forging was carried out in a four-side forging device using a 5MN hydraulic forging press. The degree of deformation at each single compression was 10-18%. The ingot was forged in a four-side forging device up to a diameter of 90 mm. The resulting billet with a diameter of 90 mm was forged on the same press with a force of 5 MN by two flat strikers for forging of a square cross section with a side of a square of 70 mm (with rounded ribs), with the ratio F / F ₁ = 1.6.

Similar forgings were obtained by the prototype method. Samples were taken from the obtained forgings to study the quality of the metal.

Tests of the method were carried out with other values of the parameters ε and F / F ₁ (table.)

Analysis of the data given in the table shows that the quality of the forgings obtained by the patented method (estimated by the carbide inhomogeneity score) is higher than the quality of the forgings obtained in a known manner.

No. p / p ε,% F / F ₁ , single Carbide heterogeneity score Note one 5-6 1,6 5 2 7-8 1,6 four 3 10-18 1,6 four four 10-18 1.05 four Marriage for the size of the finished forgings 5 10-18 3.0 four 6 10-18 3,5 four Decreased process performance 7 (famous) - - 5

Compared with the prototype method, in the implementation of which ROM is used, the patented method is much simpler, since the whole process is carried out on the press.

Example 2. An ingot weighing 5.5 tons of steel 5 HNM, having an average cross-sectional size of 580 mm, was heated to a temperature of 1180 ° C and forged on a press with a force of 20 MN in a four-gang forging device to a workpiece diameter of 300 mm. The obtained billet was forged with two flat dies on a second press with a force of 20 MN for forging a square cross section with a square side of 200 mm.

For comparison, an 5.5-ton ingot made of steel 5 HNM was forged with two flat dies according to the technology adopted by Tyazhpressmash for forgings of square cross section with a square side of 200 mm.

Comparison of the forging results showed that in the manufacture of forgings according to the patented method, the productivity of the process increased by 1.8 times compared with the technology adopted at the factory.

Thus, the patented method of manufacturing forgings provides an increase in the quality of the metal (reduction of carbide heterogeneity by 1 point) and simplification of the process compared to the prototype method. Compared with the traditional method of manufacturing forgings of square and rectangular cross-section on presses, the proposed method allows to increase the productivity of the process by 1.8 times.

Information sources

1. USSR author's certificate No. 1639860, MKI B 21 J 1/04, 1989

2. Forging on radial crimping machines. V.A. Tyurin, V.A. Lazorkin, I.A. Pospelov, etc. Under the general. ed. V.A. Tyurina. - M.: Mechanical Engineering, 1990, p.217-218.

Claims (1)

A method of manufacturing forgings of square or rectangular cross-section, including preliminary radial forging of the ingot by four strikers and subsequent final forging of the billet obtained by two strikers on the forging press with the formation of forgings of square or rectangular cross-section, characterized in that the preliminary radial forging of the ingot is carried out in a four-billet forging device on forging press with additional macroshifts of metal in the transverse plane of the workpiece and the degree of def at least 7% for each single compression, while maintaining the following ratio: F = (1.1-3.0) F ₁ , where F, F ₁ - the cross-sectional area of the workpiece obtained after preliminary forging, and forgings, respectively.