SU1497242A1 - Method of producing solid-rolled railway wheels - Google Patents

Abstract

The invention relates to metallurgy, in particular to methods for the manufacture and heat treatment of railway wheels. The purpose of the invention is to increase the fatigue strength of the wheels while simplifying the process and reducing the complexity of finishing operations. The method includes rolling, thermal hardening of the rim, tempering the wheel, podstuzhivanie up to 200-220 ° C, plastic deformation of the places of transition of the disk in the rim and hub, cooling and cold deformation of the places of transition of the disk in the rim from the inside, and in the hub from the outer sides, penetration depth of 6-8% of the minimum disk thickness. The use of the method allows to increase fatigue strength, simplify the process of manufacturing wheels. 1 tab.

Description

The invention relates to the processing of metals by pressure, in particular to the wheel-rolling production, and can be used in workshops for the manufacture of railway wheels.

The purpose of the invention is to increase the fatigue strength of the wheels while simplifying the process and reducing the complexity of finishing operations.

The invention is illustrated by the following example.

In the wheel rolling shop, ingots of steel with a content of 0.58% C, 0.78% Mp, 0.39% Si were cut into blanks weighing 478 kg to make solid-rolled railway wheels with a diameter of

050 mm. After heating, the blanks were pressed down on the press with a force of 2,000 tons. Then the blank was precipitated in a ring and the central part was distilled with a punch on the press with a force of 5,000 tons. The blank prepared in this way was subjected to 10,000 tons molding in a press. dimensions of the hub and part of the disk. Rolling produced in a wheel rolling mill with a horizontal wheel. After the rim was calibrated and the disc was bent on the press with a force of 3,500 tons, the wheels were subjected to anti-friction treatment by

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isothermal aging in conveyor ovens at 650 ° C. After mechanical processing of the rim as a whole and the hubs on the outside of the wheel, they were tested in the workshop of experimental plants. The wheels were heated in an electric furnace to a temperature of 850 ° C for 1.5 h, intermittent cooling of the rim was carried out in the final machine with sprayers for 130 s at a water pressure of 5 atm.

Subsequently, the wheels were processed according to the following options: some of the wheels were subjected to tempering at 500 ° C for 1 jO h. Immediately after the release, the middle part of the wheel disc was oksazdali with compressed air at a specific flow rate of 0.2 (under normal conditions) for 420, 450, 510 and 540 seconds until the temperature reaches 230, 220, 200 and 90 ° C. (respectively options 1, 2, 3 and 4). When the indicated temperatures were reached, the place of transition of the disk into the rim from the outer and into the hub from the inner sides was subjected to pneumatic blasting treatment for 90 s with a fraction of 2-2.5 mm and air pressure 0.4 MPa. Subsequently, the wheels were cooled to the temperature of the workshop, after which all four variants were further subjected to pneumatic blasting treatment of the places where the disc passes into the rim from the inner and into the hub on the outer side for 90 s, fraction 2-2.5 microns and pressure of compressed air MPa: for option 1 and 2 - 0.4, for option Zi4-0.6, for option 5 - 0.3 for option 6 - 0.7, for option

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One wheel was subjected to pneumatic blasting treatment (time 90 s), air pressure 0.4 MPa, place of transition of the disk into the rim from the outer and into the hub from the inner side immediately after tempering. Further processing was carried out according to option 3 (option 8).

Two wheels immediately after tempering were subjected to cooling of the middle part of the disk for 510 seconds until the temperature reached 200 ° C. Subsequently, the wheels were cooled to the temperature of the workshop (variant 9) and one wheel was simultaneously subjected to pneumatic-modal blasting at all places where the disk went to the rim and hub from the outer and inner sides (variant 10).

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One wheel was machined according to variant .11 (a known method). For this, after tempering and cooling the wheel to the workshop temperature, the disk and the places of its transition into the rim and hub were subjected to cold plastic deformation by rolling the surface with a ball of 18 mm in diameter on a machine model KS 274 with a force of 800 kg and a feed rate of 0.3 mm / rev,

To determine the level and nature of the residual stresses in the wheels, a destructive method with a mechanical cutting of the templates, equipped with two component outlets of strain gages 2 PCB with a base of 10 mm, was used. Measurement of strain gauge deformations was determined with a digital strain gauge bridge DTM-5,

Ots; residual stresses in the rim were produced according to the method of international standard UIC812-3 by radially cutting the wheel and measuring the initial mm distance between fixed points on the rim on both sides of the cut. The standard requires that the distance be reduced to at least 1 mm.

The depth of work hardening was determined on the cut out templates by the X-ray method on the DRON-3M unit.

The measurement results are shown in the table.

The table also shows the data after processing by a known method (rolling, thermal hardening of the rim, tempering the wheel, cold plastic deformation of the transitions of the disk into the rim and the hub with a penetration depth of 10-30% of its minimum thickness).

From the table it can be seen that the proposed method for manufacturing solid-rolled railway wheels (variants 2 and 3) improves the fatigue strength of the wheels while simplifying the process and reducing finishing operations by creating an increased level of compressive residual stresses in the auxiliary part of the disk, while reducing the penetration depth deformation, as well as the reduction of additional operation to remove the rolled mill scale.

The output of the parameter of the phase of the suppressor for the proposed interval is the sublimation of the middle part of the disk to 230 ° C

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It does not cause the compression of the compression voltage HG in the primed part of the disk from the outside (option 1) The compression of the middle part of the disk ensures that the compressive residual stresses form in the external part of the disk, but it leads to a decrease in the value and proportion of compressive stresses in the rim is below the permissible limits, as evidenced by the residual stresses in the rim, 9 (option 4).

Reducing the depth of penetration over the proposed interval, the depth of penetration of the deformation 5% of the minimum thickness of the disk leads to a slight increase in the level of residual compressive stresses in the auxiliary part of the disk from the inside- (option 5). An increase in the penetration depth of deformation to 9 and 12% (respectively, variants 6 and 7) does not lead to a noticeable increase in residual compressive stresses in the priory part of the disk from the inside and further penetration of the deformation depth becomes inequivalent due to unreasonable costs. as the time spent on machining the wheel, taking into account the installation and tilting on the wall of the COP 274, on average is 12-14 minutes. With a wheel rolling capacity of 2,000 wheels per day, 14-16 expensive machines will be required.

Changing the sequence of the pneumatic blasting stages at the places where the disc goes to the rim from the outer and to the inner side before the operation immediately after tempering (option 8) and carrying out this treatment after cooling the wheel (option 10) leads to the formation of small compressive stresses in these areas. .

Processing the wheels according to a known method (variant 9) leads to the formation of compressive residual stresses on the inner side of the disc from the inside, but it forms tensile residual stresses on the outer part of the disc, which adversely affects the fatigue strength of the wheel.

Processing wheels by a known method (variant 11) leads to the formation of residual compressive pressure 7242

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The results are on both wheel ststrompm.

However, in a npibol is a dangerous place where the disc enters the rim from the inside

hand, the level of residual compressive stresses is lower than the level of the proposed method. In addition, processing according to a known method requires an additional finishing operation for removing in some places a millboard scale, which increases the cost of such a process.

Thus, the proposed method for manufacturing rolled railway wheels enhances fatigue strength by creating a disc with an inner and aprons on the outer side that has increased relative to the known level of residual compressive stresses, while simplifying the process of deformation. from 10-30% to 6-8% of the minimum thickness of the wheel disk. The technical effect of this method is to reduce the finishing removal operation in some places of the rolled-in scale.

Claims (1)

Invention Formula The method of manufacturing solid-rolled 35 railway wheels, including rolling, thermal hardening of the rim and with the subsequent release of the whole wheel and cold plastic deformation of its elements in areas of 40 disc strokes into the rim and hub, characterized in that, in order to test fatigue strength of the wheels while simplifying the process and reducing labor input from 45 finishing operations, after the termination at the tempering temperature, the middle part of the disc is pressed and 200 t at this temperature, the surface50 plastic deformation of the places of transition of the disk into the rim from the outside and into the hub from the inside, cool the wheel to room temperature, and cold plastic deformation 5g exposes the places where the disc enters the rim from the inner and into the hub from the outer side with a fraction with a penetration depth within 6–8% of the minimum disc thickness. Compose V.Rusanenko Editor M.Npdo.puzhenko Tehred M.Hodanich Proofreader V.Girn to Order 4408/30 Circulation 530 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and publishing plant Patent, Uzhgorod, st. Gagarin, 101 Subscription