The method of hardening steel wheels
(57) Abstract:The invention relates to metallurgy, and in particular to methods of hardening steel castings and rolled wheels. The technical result of the present invention is to improve the operational stability. The method of hardening steel wheels, including heat treatment of the rim and its reinforcement by the stiffening elements having a hardness exceeding the hardness of the material in which they are performed. The stiffening elements are in the form of tracks, with tracks that encircle the surface profile of skating wheels, perform open and shift places rupture paths between a ratio of the section height track width 1 corresponds to 3-5. 1 Il. The invention relates to metallurgy, and in particular to methods of hardening of cast steel wheels and solid wheels.There is a method of hardening steel wheels , including heat treatment of the surface profile of the riding wheel and its reinforcement by the stiffening elements having a hardness exceeding the hardness of the material in which they are performed. Reinforcement of the surface layer is produced by performing the holes, the walls of which oblada performed separately plots the hardness is insufficient connects the volume of the metal and the formation of the Bicycle wheel during operation is offset from the metal surface layer. Another disadvantage is that when poor-quality laser processing holes occur plots with an internal voltage different from the voltage of an adjacent parcel and the voltage of the metal surface layer skating wheels, and in the presence of metal defects, such as voids, delamination, etc. may damage the wheels. And also, dynamic impacts arising from the movement on the rail joints, switches and other local stiffeners leads to chipping of metal and as a consequence of damage to the wheels. And all this leads to lower operating resistance of the wheel.The aim of the present invention is to improve the operational stability of the wheel.This objective is achieved in that in the method of hardening steel wheels, including heat treatment of the surface profile of the riding wheel and its reinforcement by the stiffening elements having a hardness exceeding the hardness of the material in which they are performed, the stiffening elements are in the form of tracks, with tracks that encircle the surface profile of skating wheels, perform open and shift places rupture paths between a ratio of the height of the CE is strasti perform in tracks, with tracks that encircle the surface profile of skating wheels, perform open and offset locations tear tracks between themselves and the ratio of the section height track width corresponds to 1 to 3 to 5, allows you to link the amount of the metal roll surface sufficient to eliminate its movement in the form of rent and to reduce the contact area of the tread surface of the wheel with the rail and the brake pads and eventually to increase the operational stability of the wheel.In Fig. 1 is a diagram of the complete method.On the surface 1 Catania wheel 2 is made track 3 rigidity, hardness exceeding the hardness of the material in which they are performed. The ratio of the height h of section 4 lanes 3 and width L corresponds to 1 to 3 to 5. Track 3, encircling surface 1 profile Catania wheel 2, is made open and offset 5 divide paths between them.The method of hardening steel wheels 2 implemented as follows. In accordance with the chemical composition of the metal wheel 2 select a certain power of the laser radiation. A focused laser beam is directed perpendicular to the processing surface 1 wheel 2 while rotating the residual for heating and education track 3 stiffness ratio of the height h of the cross-section to its width L=1 to 3 5. This ratio is optimal for phase transitions of metal and forming a reinforcing tracks with hardness exceeding the hardness of the material in which it is made. Obtained in a stable form section 4 of hardened layer has a smooth transition from high hardness on the surface of the section to the original hardness of the metal in any radial direction. The transition from one track 3 produced by another smooth on and off the laser light source. In the case of performing tracks 3, encircling the rolling surface of the wheel 2, they are open and offset locations of the gap 5 track 5 between them.Test method produced the reinforcement of the pair of wheels with a diameter of 970 mm gas laser power of 1.4 kW. Made track stiffness wide cross-section of 4.5 - 5 mm and a height of 1.2 mm, field tests have shown that when the mileage 56000 km Bicycle wheelset was 0. At the same time control the raw wheelset with such de mileage showed the car surface = 0,9 mmThe implementation of this method allows to obtain a significant economic effect; since the reinforcement 240 wheelset economic effect of colournote profile skating wheels and reinforcement stiffeners, having a hardness exceeding the hardness of the material, in which the stiffening elements are made, characterized in that the stiffening elements made in the form of tracks, with tracks that encircle the surface profile of skating wheels, perform open and shift places rupture paths between a ratio of the section height track width 1 corresponds to 3-5.
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