RU2355502C1 - Manufacturing method of solid-rolled railway wheels - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to metal deformation process, particularly it relates to manufacturing methods of solid-rolled railway wheels made of round billets. It is implemented heating and deforming of round billets by means of settlement, moulding, mandrel of disk and wheel treads, wheel disk bending, calibration of wheel tread and broaching on rotary piercing mill with receiving of cartridge cases. There are separated mentioned cartridge cases in hot conditions for wheeled blank by means of operating tool rolling, steadily impressed into cartridge cases body.

EFFECT: it is increased level and reduced grade of metal mechanical anisotropy of tread, disc and wheel hub, it is improved its micro- and macrostructure, it is increased life time and reliability of wheels, and also it is reduced metal consumption.

1 dwg, 2 tbl, 1 ex

Description

The invention relates to the processing of metals by pressure, in particular to the manufacture of solid-rolled wheels from round ingots or continuously cast billets.

A known method of manufacturing wheels from continuously cast billets, including melting and casting steel, cooling the billets, separating them into initial billets by machining, in particular circular saws, heating them to the deformation temperature, draft, forming, rolling, bending the disk, calibrating the rim, flashing ( Japan, Sumitomo Kinzoku Koge; China, Maanshan; Germany, Bochum; Czech Republic, Bonatrans; Russia, NTMK, etc.) [1]. The disadvantages of this manufacturing method include a high expenditure coefficient of the metal, low quality of the micro- and macrostructure of the initial billets and wheels, especially the central part of the billet and, respectively, the wheel hub, low level and high degree of anisotropy of the physical and mechanical properties of the metal of the rim, disk, wheel hub, due to insufficient deformation study of the cast structure of the initial billets.

A known method of manufacturing wheels from round ingots, including heating the ingots to a deformation temperature by induction, followed by dividing them into initial billets by running round rollers during the rotation of the ingot for the profitable part (Italy, Lucchini) [2]. The specified method allows to reduce the consumption of metal, but does not lead to an increase in the quality of the wheels (level of mechanical properties, macro- and microstructure, degree of anisotropy of properties).

There is also known a method of manufacturing wheels from continuously cast billets, including draft billet with torsion (Japan, "Sumitomo Kinzoku Koge") [3]. Although this technology allows you to slightly reduce the anisotropy of properties, to improve macro- and microstructure, it also has a low level of physico-mechanical properties of the wheels, high metal consumption.

The closest technical solution, selected as a prototype, is a method of manufacturing wheels from ingots, including heating the ingots to a deformation temperature, flashing the ingot in the container, separating the ingots with separation of the bottom and head trim by rolling with the successive introduction of round discs into the body of the workpiece [4]. Although this technology allows you to improve the macrostructure of the wheel hubs and reduce metal consumption, it is characterized by a low level and a high degree of anisotropy of the physical and mechanical properties of the wheels.

The closest analogue of the claimed invention is a method for the manufacture of solid-rolled railway wheels from round ingots (SU 1318338 A1, B21H 1/04, 06/23/1987), 2 pp., / 5 /, which is characterized by the following features: a method of manufacturing solid-rolled railway wheels from round ingots , including heating the initial blanks for hot deformation and their hot deformation by upsetting, molding, rolling the disk and wheel rim, bending the wheel disc, calibrating the wheel rim and flashing. This technical solution has the same disadvantages as the above methods 1-4.

Thus, the well-known wheel manufacturing technologies closest to the proposed method, although they can partially solve the problems of reducing metal consumption and some quality improvement, are not dramatic and not complex.

The technological task of the invention is to develop a method for manufacturing wheels, ensuring minimum metal consumption during their manufacture, improve the quality of the macrostructure, increase the level of physico-mechanical properties of the wheels, reduce the anisotropy of the properties of the metal of the rim, disk, hub, and ultimately increase the operational properties of the wheels, including reliability and service life. Also significant is the task of reducing the cost of manufacturing wheels and preserving the processability.

The technological problem is ensured by the proposed method for manufacturing solid-rolled railway wheels from round billets, including the separation of round billets into initial billets, heating of the initial billets for hot deformation and then their hot deformation by upsetting, molding, rolling the wheel and wheel rim, bending the wheel rim and calibrating the wheel rim while heating round billets, their deformation and piercing on a screw rolling mill to produce sleeves and subsequent separation of the path m run-in with a working tool, progressively pressed into the body of the mentioned liners in the hot state on the wheel blanks, and after calibrating the wheel rim, they carry out the firmware.

The technological result for improving the micro- and macrostructure of the wheel is achieved by the fact that during flashing during screw rolling, the defects of the axial part are concentrated along the hole and during subsequent hot deformation operations are concentrated in the extrusion. The degree of spreading of axial defects of the initial continuously cast billets from the center of the wheel to the periphery (to the hub, disk) decreases many times. Due to deformation, the metal of the hub, disk and rim is significantly compacted. It occurs during screw rolling and a reduction in the size of non-metallic inclusions.

The technical result to increase the physico-mechanical properties (tensile strength and yield strength, elongation, relative narrowing, impact strength, fracture toughness, degree of anisotropy of the indicated properties of the rim, disk and hub in different directions: axial, radial, tangential) is achieved due to the deep deformation study of the metal of the initial billet during screw rolling and firmware. This is due to the fact that the method of screw rolling and firmware is characterized by a helicoidal outflow of metal (along a helix). Moreover, the degree of accumulated deformation is much higher than, for example, during forging or upsetting on presses. The stress-strain state is characterized by high shear deformations, as a result of which the degree of structure development, both in the center and at the periphery, is much higher in comparison with upsetting processes on presses. In addition, the presence of a working tool in the central zone (mandrel) along with the continuous rotational movement of the workpiece also contributes to the development in the central zone of the workpiece, which significantly improves the quality and properties of the hub. To achieve the optimum level of properties, rolling can be carried out both with an increase (for rise), and with a decrease in the diameter of the initial billet (for landing).

The technical result of reducing the consumption of metal is achieved by eliminating waste in the form of chips during the separation of the casings obtained after screw rolling by rolling discs. The introduction of these disks progressively into the body of a heated preform can be carried out both during rotation of the preform, during rotation of the disks around a stationary preform, and during rotation of the preform and disks. The extrusion mass will significantly decrease due to the possibility of a local concentration of defects in the axial zone of the workpieces in it when healing the holes of the stitched workpiece during deformation.

An example implementation of the method

To implement the proposed method, 6 round cone-free seven-workpiece ingots of evacuated wheel steel, smelted and cast in the conditions of OAO Vyksa Metallurgical Plant, were selected. The diameter of the ingots is 475 mm. After removing the profitable part, three ingots were sent for heating and deformation with firmware on a screw rolling mill. The chemical composition of steel ingots is given in table 1.

The ingots were heated and screw-rolled in the conditions of Chelyabinsk Pipe-Rolling Plant OJSC. Wheel steel ingots were heated in an oven to a temperature of 1180 ° C. Next, the ingots were transported to the piercing mill.

The firmware was carried out in a two-roll helical rolling mill. As the guiding tool used guide rollers. The diameter of the work rolls in the pinch was 900 mm, the diameter of the rollers was 450 mm. The feed angle was 10 °. An ingot with an initial diameter of 475 mm was flashed with 10.5% compression. In this case, the distance between the rollers in the pinch was 425 mm, and the distance between the rollers was set to 480 mm (ovalization coefficient - 1.13). The diameter of the mandrel was 95 mm, and its extension beyond the pinch was 30 mm.

The resulting liners with a size of 430 × 165 mm were sent to the machine for separation into wheel blanks with three disks, simultaneously pressed into the body of the liner. The separation tool consists of three disks with a thickness of 20 mm and a diameter of 550 mm, located at an angle of 120 ° and rolling around a stationary workpiece.

The initial blanks from the three remaining ingots were obtained in the process of cutting them on the saws. Cutting width 11 mm.

Wheels with a diameter of 957 mm according to GOST 10791-2004, GOST 9036-88 in the conditions of OAO Vyksa Steel Works according to the existing technology were made from the obtained (experimental and comparative) billets.

The billets were heated in circular furnaces with a rotary hearth of ⌀ 30 m in series: in furnace No. 1 - to a temperature of 1000-1050 ° C for 3 hours, in furnace No. 2 - to a temperature of 1240-1260 ° C for 3 hours 15 minutes. The deformation was carried out according to the following scheme: preliminary draft on the press with an effort of 2000 tp sediment with acceleration of the central part in the calibration ring on a press with a force of 5000 tp, molding on a press with a force of 10,000 tf, rolling of a disk and a rim on a rolling mill, disk bending, calibration of a rim and flashing on a press with a force of 3500 tf At the end of the hot plastic deformation, the obtained draft wheels cooled to a temperature of 450-600 ° C, after which anti-flock treatment was carried out in conveyor furnaces at a temperature of 600-650 ° C for 3.5 hours.

The wheels that cooled after this treatment were quenched in annular rotary hearth furnaces for 2 hours to a temperature of 830-850 ° C and subjected to vertical intermittent quenching. The rim hardening time is 160 seconds, the water pressure in front of the sprayers is 0.9-1.1 kgf / cm ² . After quenching, the wheels were tempered in conveyor furnaces at a temperature of 500 ° C.

Test specimens were cut from the wheels obtained from the rim in the radial, axial and tangential directions, from the disk in the radial and tangential directions, from the hub in the axial and tangential directions. The test results are presented in table 2.

A comparative analysis of the properties of the wheels shows that preliminary hot deformation with firmware significantly increases the level of plastic and viscous characteristics of the disk, rim, hub, and sharply reduces the anisotropy of properties (see drawing).

Literature

1. Technical catalogs of Sumitomo Kinzoku Koge, Maanshan, Bochum, Bonatrans, and NTMK firms.

2. Technical catalog of the company "Luccini".

3. Technical catalog of Sumitomo Kinzoku Koge.

4. The project of the launch complex of the wheel rolling shop of Vyksa Metallurgical Plant No. DD-46987, Dnepropetrovsk, Ukrgipromez, July 1969

Table 1
The chemical composition of steel Items FROM Mn Si S P Cr Ni Cu The content of elements, wt.% 0.63 0.77 0.35 0.014 0.019 0.08 0,03 0,07

table 2
Mechanical test results Wheel element Test direction Mechanical properties Tensile strength σ _in kgf / mm ² Elongation δ,% Relative narrowing, Ψ,% Impact strength KCU (at + 20 ° С), J / cm ² Impact strength KCU (at -60 ° C), J / cm ² Fracture toughness K ₁ s, MPa · m ^1/2 rim tangential

-

axial

-

radial

-

disk tangential

- radial

- hub tangential

- - axial

- - Note: the numerator indicates the properties of the wheels made by the claimed method, in the denominator - the technology of the prototype.

Claims (1)

A method of manufacturing solid-rolled railway wheels from round billets, comprising dividing round billets into initial billets, heating the initial billets for hot deformation and then hot deforming them by upsetting, molding, rolling the wheel and wheel rim, bending the wheel disc and calibrating the wheel rim, characterized in that they carry out the heating of round billets, their deformation and piercing on a helical rolling mill with obtaining sleeves and subsequent separation with a working tool, progressively pressing hot into the body of the aforementioned sleeves, on the wheel blanks, and after calibrating the wheel rim, they carry out the firmware.