A method of manufacturing a solid-rolled railway wheels of continuously cast ingots

 

(57) Abstract:

The invention relates to ferrous metallurgy, in particular to the production of railway wheels. The method includes the production of a number of heats BOF steel, secondary treatment steel wheel with bringing amount (+1/4 MP) to a certain value, continuous casting into ingots, rolling wheels, heat treatment by heating the wheel to the temperature of thermal hardening, cooling for a certain period of time and leave. During secondary treatment amount (+1/4 MP) in the steel is brought to a constant value for all heats, equal 0,815 - 0,864. Heat treatment of different wheel heats are on a single mode of heat strengthening with a constant cooling time and vacation. At all stages of manufacturing solid-rolled railway wheels simultaneously use the ingots obtained from different heats. The technical result - reducing losses wheels, improving the reliability of the wheels, increasing the life of the wheels. 1 C.p. f-crystals, 3 tables.

By known methods [1, 2] solid-rolled wheels for railway transport are made using steel elements in a very wide range: carbon, from 0.20 to 0.94%, marginv steel these elements, and the process of manufacture of the wheels on the outside (cutting of ingots, heating of the workpieces under deformation, the deformation of the workpieces on machines and mill, isothermal exposure, heating under heat treatment, termouprochnenija, tempering, machining, movement of the workpieces and the wheels on the intermediate warehouses and shipping to the consumer) to organize exclusively float.

At domestic plants, in accordance with GOST 10791 [2] used wheeled steel grade 2 (primary) with a carbon content (C) 0,55 - 0,65% (mass fraction) and manganese (Mn) 0.50 to 0.90 percent. To ensure that required by this standard mechanical properties have different duration of cooling of the wheels when thermal hardening specific experienced by the sum (C+1/4 Mn). Such groups for wagon wheel set 6. All this leads to the complication of the organization float flow of wheels in the wheel shops, large losses wheels when slippage from the stream.

On the other hand there is a method of secondary treatment of the wheels [3], which provides the generation of narrow limits on the concentration of elements in steel, including carbon and manganese. So blowing the metal in the ladle argon in his paramasivan manganese) content items in carbon steel BOF steel.

As a prototype adopted a known method of manufacturing a solid-rolled railway wheels [4], which includes the production of crude steel, its secondary treatment, continuous casting, rolling wheels and their heat treatment. While smelting in the Converter and secondary treatment wheeled steel are the basic elements of carbon and manganese within: From = 0,55 - 0,65%, Mn = 0,50 - 0,90%. After continuous casting, the obtained ingots float passed in the wheel shop, where they perform as strongly float the following process steps: cutting of ingots to the original procurement, warehousing, heating the billet to a temperature of deformation, sediment and forging billets, rolling and calibration of the wheels, isothermal aging wheels in heated wells, cooling to a temperature of workshops and warehousing, inspection, measurement, repair, storage, machining, warehousing, heated wheels under heat treatment, termouprochnenija wheels (cooling of the rim water), leave the wheels in heated wells, storage, cooling to the temperature of the shop, inspection, measurement, testing, warehousing, shipment to the consumer.

It should be noted that in each plank only required for one - depending on the content in the wheel carbon steel and manganese, but rather the amount (+1/4 Mn), correctly set the duration of the cooling of the rim water during thermal hardening. This duration for wagon wheel diameter 957 mm ranges from 110 to 220 seconds.

In practice, to ensure the required mechanical properties of the metal wagon wheel, taken into account the following dependence of the cooling time of the rim of the content in carbon steel and manganese (table. 1).

The amount of carbon and manganese are determined in the following ranges (table. 2).

I.e. each heat with its chemical composition is subjected to thermal hardening separate cooling mode. Failure mode cooling leads to a reduced level of mechanical properties (if less than the required duration hardening) or to an increased level of residual stresses in wheels (if more than required, the duration of hardening).

Further, when used in carbon steel less 0,56 leave the wheels is carried out in two modes (table. 3).

In the process of manufacturing the wheels at all stages involved more than 1,000 people, managing almost all technological and transport is Riki and vacations in this case, the processing of group 6 wheels), warehousing wheels between the individual stages - all this leads to greater organizational difficulties, the use of additional staff, but most importantly - do not prevent rotation of the bottoms: a separate procurement and wheels fall for various reasons in other smelting and thermoproteus on incorrect cooling. This can have adverse effects on the railway, which is what happens in practice. In this regard, technology is foreseen to run at every production stage (heating, machining, etc.) wheels of this melting until then, will not be processed until the last wheel of this melting, not starting processing of the wheels of the other trunks. This constrains the performance plots, and therefore not performed. On the other hand, a separate wheel, behind on a separate stages from this thread melting (for example, when repairing before machining), later translated into the category of lost and sent to scrap. Such wheels on the same plant reaches 4-5 thousand pieces per year, and the losses are 10-15 billion rubles, I.e., using known techniques float the manufacture of the wheels causes a large Knymi wheels in operation.

The objective of the proposed invention is the provision of heat strengthening wheels of different trunks on a single mode of cooling, without float flow of the billets and wheels.

The problem is solved due to the fact that in the method of manufacturing a solid-rolled railway wheels of continuously cast ingots, including the production of a number of heats BOF steel, secondary treatment steel wheel with bringing amount (+1/4 Mn) to a certain value, continuous casting into ingots, rolling wheels, heat treatment by heating the wheel to the temperature of thermal hardening, cooling for a certain period of time and leave, in the process of secondary treatment amount (+1/4 Mn) in the steel is brought to a constant value for all heats, equal 0,815 - 0,864, and heat treatment of different wheel heats are on a single mode of heat strengthening with a constant cooling time and leave, at all stages of manufacture wheels simultaneously use the ingots obtained from different heats.

The accepted amount (0,815-0,864) corresponds to the chemical composition of steel with a high content of carbon and manganese in the valid range of their regulatory requirements that provides the highest sweepline binget closer to the acceptable level 93 kgf/mm2and when the content in carbon steel 0.65% manganese 0,90% - closer to 113 kgf/mm2. If you consider that the increase in strength of steel wheel 1 kgf/mm2provides extra driving wheels in operation up to 1%, the effectiveness of the proposed method will be about 800,000 miles additional mileage.

Distinctive features of the proposed method in comparison with the prototype are: driving wheels of steel during secondary treatment to a constant amount (+1/4 Mn) for all heats, the implementation of heat treatment of different wheel heats on a single mode of heat strengthening with a constant cooling time and vacation, bringing the wheels of steel in the process of secondary treatment to the value sum (C+1/4 Mn) equal to 0,815 - 0,864, simultaneous use at all stages of manufacture wheels ingots obtained from different heats.

The process sequence of the proposed method. During secondary treatment produced in the Converter wheel steel is subjected to adjustment on the carbon content to a level of precision of 0.02% additive lump carbonaceous materials being used in resivour in pieces during the release of melt from the Converter. The mass of material to be calculated so that the content of manganese was at the lower limit or lower limit. Then after averaging the composition of the metal selected sample in which the concentration of essential elements, and then in the bucket add the required number of alloys and carry out the averaging of the composition of the metal. The amount of carbon and manganese not beyond one selected group of steel, for example, 0,815 - 0,864.

After continuous casting of metal ingots with a diameter of 430 mm last sent in wheel shop, where they are cut on a rotary saws on the original piece weight of 473 kg While the weights of the workpiece does not exceed 7 kg

The original piece different heats, but the chemical composition falling within one of the carbon equivalent is heated to a temperature deformation, and then subjected to upsetting, punching, rolling, calibration and isothermal aging. Chilled to the temperature of the workshop on intermediate stock wheels mechanically handle on the rim and the hub, and then heated to a temperature of thermal hardening, is cooled at a uniform regime for all laminated bottoms and subjected to vacation also single yavlyaetsya stringent requirements, ie Pets their entanglement between them, because it is the quality of the wheels has no effect.

Using the proposed method of manufacturing a solid-rolled railway wheels reduces the losses of the wheels in the process of their manufacture 4-5 thousand units per year by narrowing the limits of the content in the wheel carbon steel and manganese and bring to a constant amount (+1/4 Mn) for all heats.

Provides improved reliability wheels in operation through the use of a single mode of heat strengthening and tempering wheels and exceptions thereby hardening of the wheels on the invalid modes.

Enhances the life of the wheels in operation for about 20% through the use of elevated amounts (0,815-0,864).

Simplifies the organization of the flow of wheels in the wheel shop in the manufacturing process due to their processing at different conversions at different amounts of the bottoms.

Example. In the manufacture of solid-rolled railway wheels 957 mm, weight 392 kg steel was melted in a Converter with a capacity of 300 tons with subsequent secondary treatment with increasing carbon content up to level 0,63 - 0,65% pulverized carbonaceous powders through the submersible is nverter in the tundish with the provision of carbon equivalent, equal (0,815-0,864). Received concast way ingots with a diameter of 430 mm cut piece on a rotary saws, cold cutting on initial billet length 420 mm, which was then heated in the annular furnace to a temperature of 1280oC. the Heated billet was two systems on the press force 3000 ie, up to a height of 125 mm, stamp the hub and the portion of the disk in the press with force 7000 ie, rolled rim and another part of the disk on the mill, grooved wheel on the press force 3000 ie, then lowered the temperature of the wheels up to 600oC and at this temperature was carried out by isothermal aging in air for 3 hours. Then the wheels in a cold condition mechanically processed (rim and the hub) on the vertical lathe, was heated to a temperature of 880oC and Thermopanel by cooling the rim with water for 110 sec. And cooled according to this mode, all melting or parts thereof, had time to walk along the stream to thermal separation. After quenching wheel was placed in vacation wells, where it was kept for 3 hours at a temperature of 500oC. This was the final process operation. At each polling processing were subjected to 4 heats, with stragglers from the bottoms of the wheels are not condemned. As a result, these 4 swimming trunks was sales sections, rose of throughput by 12% (no need waiting behind their bottoms wheels on a separate shop areas), increased the level of strength of the metal rims of the wheels from 93 to 112 kgf/mm2(this led to the increase in the lifetime of their operation 19%), increased reliability wheels in service - excluded the impact of the reversal of the bottoms of the wheels on the wrong mode, heat strengthening.

1. A method of manufacturing a solid-rolled railway wheels of continuously cast ingots, including the production of a number of heats BOF steel, secondary treatment steel wheel with bringing the sum (C+1/4 Mn), where C is the mass fraction of carbon steel, %; Mn - manganese, % up to a certain value, continuous casting into ingots, rolling wheels, heat treatment by heating the wheel to the temperature of thermal hardening, cooling for a certain period of time and leave, characterized in that in the process of secondary treatment amount (C+1/4 Mn) in the steel is brought to a constant value for all heats, equal 0,815 - 0,864, and heat treatment of different wheel heats are on a single mode of heat strengthening with a constant cooling time and vacation.

2. The method according to p. 1, characterized in that at all studiowork.

 

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