A method of manufacturing a solid-rolled railway wheels
(57) Abstract:The invention relates to metallurgy, in particular to the technology of solid-rolled railway wheels. The objective of the invention is to provide a method of manufacturing a solid-rolled railway wheels that reduce energy consumption in the process by reducing the duration of isothermal aging. The technical result is achieved by the fact that after the hot plastic deformation produce cooling below ANDr170 - 320oC and after cooling to equalize the temperature carry out heating to a temperature of austenization are determined, the exposure at this temperature, thermal hardening and tempering, and the operation vacation combined with the operation of isothermal holding at the duration of the last not less than 3 h, and austenitization produced at temperatures above ANDC340 - 100oC. The invention relates to metallurgy, in particular to the technology of solid-rolled railway wheels.A known method of manufacturing a solid-rolled railway wheels , including a hot plastic deformation, podstugivaniya after Def is the temperature of 600 650oC, cooling to the temperature of the shop, machining, hardening and tempering.There is also known a method of manufacture of railway wheels, aimed at reducing placeofpublication . The method involves performing additional operations after plastic deformation before isothermal exposure. The essence of this operation is as follows: the wheel after rolling is cooled to 450 - 500oC, then heated to AU3+ /30 - 40o/ and make the shutter speed to ensure phase transformations and then cooled to a temperature of isothermal aging. Reducing placeofpublication is achieved by recrystallization of steel, reducing the grain size of austenite, in comparison with the grain size of austenite after rolling, and increase the mobility of atomic hydrogen.A disadvantage of the process according to the method of  is the duration and intensity, together with the intermediate cooling to a temperature of workshops between operations isothermal soaking and heating for hardening does not provide continuity of isothermal exposure that does not guarantee the absence of placenow.The lack of technology p the termination of hot deformation before isothermal exposure. The number of technological operations under this scenario technology increases, moreover, is not ensured continuity of the process of isothermal aging, because after isothermal aging product is cooled to the temperature of the shop.As a prototype adopted a method of manufacturing a rail wheel factory ZD in the Czech Republic . After hot plastic deformation produce isothermal exposure for 4 hours at a temperature of 600oC, heated to the quenching temperature, the hardening, tempering and machined wheels.The disadvantage of this technology is the prototype high energy intensity of the process.The objective of the invention is to provide a method of manufacturing a solid-rolled railway wheels that reduce energy consumption and process by reducing the duration of isothermal aging.The technical result is achieved by the fact that after the hot plastic deformation produce cooling below Ar170 - 320oC and after cooling to equalize the temperature carry out heating to a temperature of austenitization, exposure at this temperature, tedliashvili last not less than 3 hours, and austenitization produced at temperatures above Ac340 - 100oC. Cooling after hot elastic deformation below Ar170 - 320oC /400 - 650oC/ allows austenite-pearlitic transformation in minimal time under conditions of industrial use. Subsequent heating above Ac340 - 100oC and holding at that temperature /820 - 880oC/ allow to grind grain in the process of transformation of pearlite to austenite and to prepare the structure to thermal hardening. Limiting the heating temperature in the range 820 - 880oC is connected with the necessity of forming in the steel value austenitic grain before thermal hardening 7 - 8 points.Increase the duration of the operation vacation, combined with isothermal exposure, with 2 to 3 hours in combination with grain sizes 7 - 8 points and continuity of the process of isothermal exposure allows you to achieve a residual hydrogen concentration at the level of 2 cm3/100 g of metal.Thus, the proposed method reduces the number of technological operations by consolidating operations isothermal aging and leave, while ensuring the continuity of technological leave combined with isothermal aging.For industrial sampling method were selected ingot billet of open-hearth steel of the following composition: carbon-0.6, manganese 0,72, silicon 0,24. The content of impurities was within GOST 10791-89. The billet was heated to a temperature of 1250oC for five hours, and then deformed by the press wheel and the mill. After hot plastic deformation of the workpiece was cooled on an operating pipeline to 420oC /Ar1= 300oC/ and made the shutter speed to equalize the temperature of the elements of the wheel. Then the wheel was heated to a temperature of 840oC /Ac3- 60oC/ and after holding at this temperature produced intermittent quenching rim for 130 sec. Operation vacation combined with isothermal aging and produced at a temperature of 830oC for 3 hours.The hydrogen content in the rim of the experimental wheels, processed by the proposed method was 1.5 - 2 cm3/100 g of metal.For comparison technology prototype was made several wheels of the workpieces with the same chemical composition. The initial hydrogen content was identical, as the metal is selected EACA plastic deformation produced isothermal exposure for 4 hours at a temperature of 600oC, and the duration of the vacation was 2 hours. The size of the actual grain of the wheels arrived at the isothermal exposure, was 2 - 3 points. When the grain size, the mobility of atomic hydrogen is much lower than the proposed method, in which the isothermal aging is carried out at the value of the real grain 7 - 8 points.The analysis of the residual hydrogen content in the wheels handled by the technology of the prototype was 2 - 2.5 cm3/100 g of metal. The total duration of the operations of the heating technology of the prototype, including isothermal exposure, heated to the quenching temperature and tempering was 7 hours, at the same time, according to the proposed method, by reducing the operation isothermal exposure in the operation of heating for hardening this time was 4 hours.Thus, the proposed method reduces the number of technological operations by combining the operations of isothermal aging and tempering at a residual content of hydrogen in steel 1.5 - 2 cm3/100 gSources of information
1. Instruction manual for the production of solid-rolled wheels and centers, T K-95 Vyksa 1995
A method of manufacturing a solid-rolled railway wheels, comprising the sequential deformation in forging-rolling line, cooling after hot plastic deformation to a temperature below Ar1, shutter speed, heating to a temperature of austenization are determined, thermal hardening and tempering, characterized in that the cooling after the end of the plastic deformation lead to Ar1- (70 - 320)oC with exposure to equalize the temperature of the wheel elements, when heated to a temperature of austenization are determined exercise restraint, and during thermal hardening conduct isothermal exposure, combined with a vacation.
FIELD: heat treatment of parts made in form of bodies of revolution from metal materials; cooling of monoblock wheels, tires, wheel discs and similar discs and rings such as railway wheels and tram wheels, gear wheels and sprockets.
SUBSTANCE: first, scale is removed from one and the same device by one and the same method to improve its mechanical properties and then mechanical properties are determined and reproduced through complex cooling performed in functional zone; cooling processes are different for different sections; parts are cooled at control or adjustment in "on-line" mode due to spraying or blowing-off by one cooling medium.
EFFECT: enhanced efficiency.
27 cl, 2 dwg
SUBSTANCE: invention relates to thermal treatment field. For providing of solidity not less than 300 HB on depth not less than 50 mm from surface of volution wheel tread, exclusions during the process of cooling of formation of hardening structures and providing of maximal drop of residual voltage, solid-rolled wheels made of steel with carbon content no less than 0.60 wt % is heated till the austenitising temperature and intensively cooled, at that during the cooling process from the moment of the beginning for 50-100 seconds it is implemented increasing of cooling intensity of comb roll surface and side surfaces of crown by all height from 0 till value 2-3 W/(cm2·s), then it is cooled during 40-300 sec with constant refrigeration rate of specified wheel face equal to value 2-3 W/(cm2·s) for providing of strengthening in all crown volume.
EFFECT: providing of material strengthening.
2 dwg, 3 tbl
SUBSTANCE: wheel pair is installed and fixed in rotating facility. Matte coating eliminating reflection of laser beam is applied on surface subject to treatment with CO2-laser. Focusing system is adjusted so, that diametre of laser radiation spot corresponds to a chosen mode. Required rates of wheel pair rotation and laser beam transfer are set by means of program controlled device. Compressed air blows off a flare of products of combustion into exhaust ventilation; laser treatment is carried out under a chosen mode to obtaining geometry of paths of laser strengthening eliminating melting zones of thermal effect and mutual overlapping of laser strengthening paths.
EFFECT: increased wear resistance of roll surface and crest of wheel pair due to increased hardness and due to obtaining high dispersed structure of strengthened zone.
SUBSTANCE: plasma surface hardening is performed by plasma generator with work gas flow converter that has slit-like outlet. Flow converter face surface is made to fit processed part shape. In processing, slit-like outlet is located at α=30-60° to generatrix of converter face surface. Processing is performed with overlap of processing strip, overlap length making l≥h·-tgα, where h is the processing strip width.
EFFECT: notably reduced extension strain, higher efficiency of surface hardening.
2 cl, 2 dwg
FIELD: machine building.
SUBSTANCE: metal surface strengthening is carried out by means of low temperature plasma arc of direct action. As plasma generating gas there is used argon, mixture of argon with helium, and mixture of argon with carbon containing gases. Also, heating is performed with magnetic oscillation of arc with triangle shape of voltage pulse, scanning amplitude 20-45 mm and distance of treatment 10-30 mm. A strengthened surface layer consists of several sub-layers: at depth of 0.2-0.8 mm - structure of martensite with inclusions of upper bainite, - from 0.8 to 1.8 mm - trosto-martensite structure, - from 1.8 to 2.5 mm - sorbitic-martensite structure, - from 2.5 to 3 mm - sorbite, - over 3 mm - ferrite-pearlite structure of basic metal.
EFFECT: raised efficiency of strengthening process, 3 times increased wear resistance of strengthened working zone of wheel, 3 times reduced probability of development of hydrogen metal brittleness and tendency to brittle fracture.
2 cl, 1 tbl
SUBSTANCE: cooling of working layer of rim during the first 180 sec is performed at discrete increase in flow rate of cooler of 0.0005 to 0.02 l/(cm2/s) by 0.0001 l(cm2/s) every 15-30 sec and the next 120 sec at constant flow rate of cooler to 0.5 l/(cm2/s), and cooling of end surface of rim on the ridge side is performed with air with flow rate of 0.5 m3/(cm2/s); then, wheel is cooled in the air and tempering is performed.
EFFECT: high application properties of railroad wheels owing to improving wear resistance of working layer of wheel rim and mechanical properties of wheel disc; heating to austenisation temperature and differentiated cooling of working layer of rim and its face on the ridge side is performed during 300 s.
1 ex, 2 tbl
SUBSTANCE: hardening is performed at 810-850°C. Tempering is performed at 450-500°C. Then, plasma treatment with plasmotron with energy density of 106-108 W·m-2 is performed. Nitrogen is used as plasma-forming gas. Plasma treatment of tread contact surface and wheel flange surface is performed. Transformer of working flow of plasma-forming gas, which is profiled as to shape of treated surface, is used. Wheel is rotated during treatment about its axis at certain speed. Wheel rotation speed is determined as per ratio n=K·(1/Dw), where n - speed of wheel rotation about its axis, rpm; K - empirical coefficient equal to 20-2000 revolutions·mm/min; Dw - diameter of treated wheel, mm.
EFFECT: increasing strength and thickness of reinforced layer; improving quality and efficiency of plasma strengthening process; simplifying the process diagram of strengthening plasma treatment.
2 dwg, 1 ex
SUBSTANCE: first, wheel is heated for formation of austenite in all sections of a rim and a disk. Then, wheel is cooled for formation of bainite/martensite microstructure in the disk section. Wheel is cooled for formation of bainite/martensite microstructure in the rim inner section. Wheel is cooled for formation of bainite/martensite microstructure in the rim outer section.
EFFECT: providing required mechanical properties of steel and increasing wheel service life.
10 cl, 7 dwg, 1 tbl
FIELD: process engineering.
SUBSTANCE: invention relates to thermomechanical processing of parts and can be used for surface hardening of friction working surfaces of rails and rolling stock wheels. Particularly, it relates to surface hardening of wearing surfaces of parts, primarily, rolling surfaces and railway mounted axle flanges. Strips with modified structure are produced that feature mechanical properties other than those of mother metal. Note here that said strips vary in width and depth over the wheel flange circle.
EFFECT: higher wear resistance, longer wheel life.
1 tbl, 7 dwg, 1 ex
FIELD: process engineering.
SUBSTANCE: invention relates to metallurgy, particularly, to heat treatment of binding bands. Railway bands made of steel containing the components that follow are subjected to heat treatment: C 0.65-0.75 wt %, Mn 0.6-0.9 wt %, Si 0.22-0.45 wt %, Cr 0.2-0.6 wt % and V 0.01-0.03 wt %. Band is heated to austenising temperature and subjected to controlled cooling nu liquid coolant or air-water mix, surface cooling being performed by water with controlled flow rate: 0.00035 l/(cm2·s) for up to 120 s, 0.00075 l/(cm2·s) for 121-150 s, 0.00115 l/(cm2·s) for 151-180 s, 0.00155 l/(cm2·s) for 181-210 s, 0.002 l/(cm2·s) for 211-300 s. Note here that side surface in the band inner diameter is air cooled with flow rate of 0.0003 m3/(cm2·s) with subsequent holding in air and tempering.
EFFECT: higher wear resistance of working play, contraction strains in working ply to 50-60 mm depth from rolling surface.
5 tbl, 1 ex