CN110172546A - Based on laser-induction heat source Rail Surface functionally gradient strengthening layer preparation method - Google Patents

Based on laser-induction heat source Rail Surface functionally gradient strengthening layer preparation method Download PDF

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CN110172546A
CN110172546A CN201910469216.5A CN201910469216A CN110172546A CN 110172546 A CN110172546 A CN 110172546A CN 201910469216 A CN201910469216 A CN 201910469216A CN 110172546 A CN110172546 A CN 110172546A
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laser
rail
induction
rail surface
heat source
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Inventor
杨志翔
王爱华
熊大辉
叶兵
吴文迪
吕威
李婷
宫卫华
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Wuhan Huagong Laser Engineering Co Ltd
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Wuhan Huagong Laser Engineering Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/06—Surface hardening
    • C21D1/09—Surface hardening by direct application of electrical or wave energy; by particle radiation
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/06—Surface hardening
    • C21D1/09—Surface hardening by direct application of electrical or wave energy; by particle radiation
    • C21D1/10—Surface hardening by direct application of electrical or wave energy; by particle radiation by electric induction
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/04—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rails
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/008—Martensite
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Articles (AREA)

Abstract

The present invention provides a kind of based on laser-induction heat source Rail Surface functionally gradient strengthening layer preparation method, includes the following steps: that laser and induction heating component 1) is arranged in the top of rail；2) when heating to Rail Surface, laser and induction heating component move at the same speed in the same direction, and induction heating component preheats Rail Surface, and laser is heated to austenitizing temperature to the Rail Surface of preheating；3) cooling rail is the functionally gradient strengthening layer for forming the distribution of interface hardness gradient.The invention combines the laser beam of high-energy and induction heat source, on the one hand the depth of laser action is improved, on the other hand the innovative interfacial structure for improving quenching layer and substrate, overcome conventional laser quenching bed boundary transition it is precipitous, the big disadvantage of brittleness increases the thickness of half martensite transition region, realize the transition of interface hardness gradient, and while improving depth of hardening and processing efficiency, quenching layer toughness is increased, realizes the Strengthening and Toughening processing of efficient Rail Surface.

Description

Based on laser-induction heat source Rail Surface functionally gradient strengthening layer preparation method
Technical field
The invention belongs to laser surface hardening processing technology fields, and in particular to a kind of based on laser-induction heat source steel Track surface functionally gradient strengthening layer preparation method.
Background technique
Laser quenching technology, also known as laser heat treatment or laser transformation hardening technique are to irradiate metal using laser beam Workpiece makes its skin temperature be higher than austenitizing temperature.It is thermally conductive by basis material itself after laser beam flying, make to swash Light heating region is quickly cooled down, and temperature drops to martensitic transformation temperature rapidly hereinafter, and forming martensitic structure in workpiece surface Hardened layer.Laser quenching cooling velocity is fast, does not need the cooling mediums such as water or oil, belongs to self-quench hardening technical process.
When traditional laser-quenching technique is strengthened for raceway surface, two problems are primarily present, a problem is surface Hardened layer hardness is excessively high, and interface hardness gradient is precipitous, and the requirement of rail is not achieved in anti-fatigue performance.General rail material Wearability and contacting fatigue resistance in order to balance, using the high-carbon steel of phosphorus content > 0.7%, rolled rail is pearlitic structrure (hardness 25-30HRC), Slack Quenching Rails are Soxhlet body tissue (hardness 35-38 HRC), and hardness is all relatively low.And rail table After the laser quenching of face, due to its cooling rate 2-3 order of magnitude higher than tradition quenching cooling rate, the quenching layer hardness of formation is very high, can To reach 60-67HRC, and it is very precipitous in quenching stratum boundary surface hardness transition.Although steel can be improved in the quenching layer of high rigidity The wear-resisting property of track surface, but biggish brittleness can be also generated simultaneously, especially in interface, the hardness and strength for quenching layer compare base Material is much higher, and when by identical stress, due to not having transition zone presence, the strain of two kinds of materials can not be coordinated, then In addition the influence of Vehicular vibration, hard crisp Laser Hardened Layer can crack because of rolling contact fatigue, and crackle can be along quench-hardened case Interface extends and eventually leads to hardened layer and falls off.
The processing efficiency and depth that another problem is laser quenching are all than relatively limited.Because laser quenching material surface Maximum temperature is limited by material melting point, cannot infinitely be improved, at the same the depth of heat effect by the laser action time and The limitation of material thermal conductivity causes the depth of Laser Hardened Layer generally than relatively limited.When taking the infusible critical-temperature in surface, The depth for quenching layer is related to laser scanning speed, and laser scanning speed is lower, and depth of hardening is bigger.Reduce quenching scanning speed Degree can sacrifice significantly the efficiency of processing to improve the depth of quenching, and will increase workpiece deformation and surface oxidation, therefore tradition swashs The layer depth that photoquenching technique obtains is generally within 2mm.The processing efficiency of laser quenching is by spot width and scanning speed Limitation, quenching processing efficiency are difficult more than 2m2Per hour.
At present there are ways to realize that rail laser quenching is strengthened, Chinese patent CN 105200198A discloses one kind Railway track laser surface intensified technique first quenches Rail Surface using laser, is then returned with laser to rail Fiery treatment process, formed tempered martensite, depth 0.8-1mm, hardness HRC35-50, can be improved rail antisticking, The performance of creep and conquassation, side grinding, wave mill.Chinese CN 104212965A discloses a kind of online laser broadband of Rail Surface and quenches The method of fire sprays one layer of light absorption paint (graphite particle+SiO in Rail Surface2Particle), it is then fast using optical fiber laser The Wheel Rail Contact surface of speed scanning rail, is formed with the band-like quenching area of certain intervals, and laser hardens layer tissue for martensite, shellfish The line and staff control of family name's body and retained austenite, improve anti-fatigue performance.Chinese patent CN 2474561Y discloses one kind The railway rail of laser surface remelting forms hardened layer with high energy laser beam consolidation Rail Surface, and hardened layer can be continuously Be also possible to discontinuous, wearability and toughness are excellent.Chinese patent CN 2496915Y discloses a kind of laser surface phase transformation The railway rail of hardening forms dotted, linear, curve-like, netted, planar hardening in Rail Surface with laser beam flying Layer has excellent wearability and toughness.Chinese patent CN 106893970A discloses a kind of use Laser carburizing intensive treatment The method of railway track configures suspension using carbon dust first, is then coated in Rail Surface, passes through Laser carburizing processing method Bionic coupling carburizing unit is prepared in rail surface, the carburizing unit of high rigidity is distributed according to certain rule, is able to bear more Big load improves the service life of rail.Chinese patent CN 101109034A discloses a kind of railway high speed heavy rail laser Quench hardening technique precoats SiO2Light absorption paint is to improve CO2The absorptivity of laser quickly scans rail table using rectangular light spot Face forms Laser Hardened Layer, improves the polishing machine of Rail Surface.
However laser quenching reinforcement technique disclosed above, there is also following problems: (1) needing to come using light absorption paint The depth of laser quenching is improved, and the coating operation of light absorption paint is comparatively laborious, is unfavorable for realizing the processing of automation；(2) do not have There is the interface problem for solving quenching area and substrate, all hardening of rails intensifying methods are all to directly heat rail table with laser Face generates the marquench layer of high rigidity, and this quenching layer and substrate interface are very narrow, and hardness transition is precipitous, to quenching layer Fatigue behaviour is harmful.
Traditional laser-quenching technique, regardless of whether addition light absorption paint, is all directly to be thermally formed quenching layer with laser, Its cooling procedure be by the thermally conductive cooling of substrate itself, cooling rate quickly, much larger than the Critical cooling speed that martensite is formed, therefore surface layer The region of austenitizing can form martensite, and the half martensite area of interface is generally very narrow, cause hardness in interface meeting It mutates, or even only needs the depth of 0.1mm, hardness is just reduced to 300HV from 800HV.In interface, the mechanics of two layers of material Performance difference is excessive, will lead to the uncoordinated of strain, and the stress in interface is concentrated, and the fatigue resistance for quenching layer is influenced Energy.
Summary of the invention
The purpose of the present invention is overcome the Rail Surface martensite excessive high hardness of existing laser-quenching technique processing, brittleness mistake Greatly, hardness transition is precipitous at quenching bed boundary, influences the problem of quenching the anti-fatigue performance of layer.
For this purpose, the present invention provides a kind of based on laser-induction heat source Rail Surface functionally gradient strengthening layer preparation side Method includes the following steps:
1) laser and induction heating component are set in the top of rail, and induction heating component is located at the laser of laser transmitting The front in beam scanning direction；
2) when heating to Rail Surface, laser and induction heating component move at the same speed in the same direction, by induction heating component to steel Track surface is preheated, and laser is heated to austenitizing temperature to the Rail Surface of preheating；
3) after Rail Surface is cooled to martensitic transformation temperature or less, that is, the functionally gradient for forming the distribution of interface hardness gradient is strengthened Layer.
Further, induction heating component setting is in front of the laser scans direction at 10~50mm.
Further, the induction heating component includes medium frequency induction power supply and induction coil, the induction coil shape It is identical as rail head of rail tyre tread outer profile, and it is parallel to rail upper surface, induction coil and rail upper surface 5~10mm of spacing, Induction coil is 50~400mm along the length of rail length direction.
Further, the induction coil is coiled into spiral by hollow copper tubing, and cooling water is connected with inside it, outside installation There is magnetizer.
Further, the induction heating component is 3~10mm, heating temperature 100 to the heat penetration that rail preheats ~500 DEG C.
Further, the induction heating component is greater than the heat penetration of laser to the heat penetration that rail preheats.
Further, the functionally gradient strengthening layer is horizontal by quenching layer after the cooling of induction heating component warm-up control rail Section sequentially forms full martensitic regions and half martensite area along its layer depth direction, the hardness of full martensitic regions 650~900HV it Between, half martensite area hardness is between 350~600HV.
Further, the scanning speed of the laser is 4~20mm/s, and the power of laser is 600~12000W, is swashed The laser beam spot width of light device transmitting is 10~50mm.
Further, the laser is the direct output laser of semiconductor, semiconductor optical fibre transmission laser or optical fiber Laser.
In the present invention, preposition induction heating component is used to preheat as auxiliary thermal source to Rail Surface, Ke Yizeng Add the depth of interaction of laser, it is only necessary to which lower laser power can allow the tissue of deeper to obtain austenitizing, to increase Add the depth of depth of hardening and strengthening layer.And induction preheating depth is greater than the depth of laser heating, and amount of residual heat may be used also To reduce the cooling temperature gradient of austenitizing layer, quenching stress and deformation are reduced.It quenches layer bottom cooling rate and is lower than the geneva bodily form At Critical cooling speed, quench layer cross-section covering weave and martensite+troostite line and staff control be transitioned by the full martensitic structure on surface, With the increase of layer depth, martensite content is gradually decreased, and troostite content gradually increases, and is finally transitioned into matrix structure, is realized The gradient transition of interface hardness.By adjusting different induction preheating temperatures, the content of adjustable interface martensite changes The slope for becoming transition region hardness curve, to obtain the functionally gradient strengthening layer of different hardness distribution gradient.Preheating is incuded simultaneously Amount of residual heat can be produced from drawing effect, further increase quenching layer toughness.
Compared with prior art, beneficial effects of the present invention:
It is provided by the invention it is this based on laser-induction heat source Rail Surface functionally gradient strengthening layer preparation method by high-energy Laser beam and induction auxiliary thermal source combine, on the one hand improve the depth of laser action, it is on the other hand innovative to improve The interfacial structure of quenching layer and substrate, overcomes that conventional laser quenching bed boundary transition is precipitous, and the big disadvantage of brittleness increases The thickness of half martensite transition region realizes the transition of interface hardness gradient, and is improving the same of depth of hardening and processing efficiency When, quenching layer toughness is increased, the Strengthening and Toughening processing of efficient Rail Surface is realized.
The present invention is described in further details below with reference to attached drawing.
Detailed description of the invention
Fig. 1 is preposition induction heating component preheating auxiliary laser quenching structure schematic diagram in the present invention；
Fig. 2 is the quench-hardened case microhardness distribution figure for not having induction to obtain in the embodiment of the present invention when preheating；
Fig. 3 is the functionally gradient strengthening layer microhardness distribution figure obtained when 200 DEG C of preheatings in the embodiment of the present invention；
Fig. 4 is the functionally gradient strengthening layer micro-organization chart obtained when 300 DEG C of preheatings in the embodiment of the present invention；
Fig. 5 is the functionally gradient strengthening layer microhardness distribution figure obtained when 300 DEG C of preheatings in the embodiment of the present invention.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete Site preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts all other Embodiment shall fall within the protection scope of the present invention.
Present embodiments provide it is a kind of based on laser-induction heat source Rail Surface functionally gradient strengthening layer preparation method, Include the following steps:
(1) laser and induction heating component are set in the top of rail, and induction heating component is located at swashing for laser transmitting At 10~50mm of front of light beam scanning direction.
Wherein, the induction heating component includes medium frequency induction power supply and induction coil, the induction coil shape and steel Rail rail head tyre tread outer profile is identical, and is parallel to rail upper surface, induction coil and rail upper surface 5~10mm of spacing, induction Coil is 50~400mm along the length of rail length direction.Specifically, the induction coil is coiled into spiral by hollow copper tubing, And cooling water is connected with inside it, outside is equipped with magnetizer.
(2) when heating to Rail Surface, laser and induction heating component move at the same speed in the same direction, induction heating component conduct Auxiliary thermal source first preheats Rail Surface, and the laser beam of laser transmitting is carried out as Rail Surface of the main heat source to preheating Rail Surface is heated to austenitizing temperature by laser quenching.
Specifically, the heat penetration that the induction heating component preheats rail is 3~10mm, heating temperature is 100~ 500 DEG C, by adjusting different induction preheating temperatures, it is bent to change transition region hardness for the content of adjustable interface martensite The slope of line, to obtain the functionally gradient strengthening layer of different hardness distribution gradient.The suitable induction preheating of selection as needed Temperature, quenching floor cross section sequentially forms full martensitic regions and half martensite area along its layer depth direction after controllable rail is cooling, It is increased with induction preheating temperature, laser action depth deepens, full martensitic regions narrow, half martensite area broadens, and preheating temperature is got over The gradient of height, the hardness transition of strengthening layer to substrate is gentler, and the hardness of full martensitic regions is between 650~900HV, half geneva Body area hardness is between 350~600HV.Optimization, the induction heating component is greater than laser to the heat penetration that rail preheats The heat penetration of device, amount of residual heat can also reduce the cooling temperature gradient of austenitizing layer, reduce quenching stress and deformation； The amount of residual heat for incuding preheating simultaneously can be produced from drawing effect, further increase the toughness of quenching layer.
And after use feeling should preheat, laser power needs corresponding reduction, and it is different according to induction preheating temperature, compared to not When having induction to preheat, laser power reduces by 5~50%, and induction preheating temperature is higher, and laser power reduces more.The present embodiment In, the scanning speed of the laser is 4~20mm/s, and the power of laser is 600~12000W, the laser of laser transmitting Beam spot width is 10~50mm；The laser can be the direct output laser of semiconductor, semiconductor optical fibre transmission laser Device or optical fiber laser.
(3) Rail Surface is cooled to martensitic transformation temperature hereinafter, quenching the cross-section covering weave of layer by the full martensite on surface Tissue is transitioned into martensite+troostite line and staff control and is formed when quenching layer bottom cooling rate is lower than the Critical cooling speed that martensite is formed The line and staff control of martensite and troostite, with the increase of layer depth, from quenching layer to substrate, martensite content is gradually reduced, and is bent Family name's body content gradually increases, and is finally transitioned into matrix structure, realizes the gradient transition of interface hardness, that is, forms interface hardness ladder The functionally gradient strengthening layer of degree decline distribution, to increase, Rail Surface is wear-resistant and anti-fatigue performance.
Below by specific embodiment to provided by the invention this based on laser-induction heat source Rail Surface function ladder Strengthening layer preparation method is spent to further illustrate.
Embodiment 1:
The present embodiment carries out laser quenching to U71Mn Rail Surface using semiconductor optical fibre transmission laser.Wherein, laser facula Width 35mm, laser power 5600W, laser scanning speed v=15mm/s, preposition 200 DEG C of induction preheating temperature, laser power phase 11% is reduced than no induction preheating.
It under the conditions of prior art, is preheated without using preposition induction, Direct Laser quenching using same process parameter, needs The laser power of 6300W, quench-hardened case microhardness distribution are as shown in Figure 2.As shown in Figure 2, case depth 0.8mm, hardness Reach 800HV or more.At 0.8~0.9mm of surface, for the interface for quenching layer and substrate, microhardness is reduced rapidly, from 800HV is reduced to 260HV, and the difference in material properties of interface two sides is excessive, causes to will appear not assisting for strain when bearing load It adjusts, accelerates the generation of Interface Crack.
And the present embodiment is this specific based on laser-induction heat source Rail Surface functionally gradient strengthening layer preparation method Realization process use form shown in FIG. 1, the region to be processed of Rail Surface is cleared up first, remove surface greasy dirt and Rusty stain；Then induction coil is laid on rail, apart from Rail Surface 5mm；Laser defocusing amount is adjusted again, adjusts spot width Laser beam to 35mm, laser transmitting is aligned at the 10mm of induction coil rear.When starting processing, induction coil is first turned on, Induction coil and laser start to travel forward at the same speed with 15mm/s speed sync simultaneously, control the power of induction heating, guarantee Rail is just heated to 200 DEG C by preheating and when reaching laser beam irradiation area.Add when the rail of preheating reaches laser beam When thermal potential is set, laser goes out light according to 5800W setting power, carries out laser quenching to Rail Surface.After Rail Surface is cooling, Form the functionally gradient strengthening layer of hardness gradient distribution in interface as shown in Figure 3.
From the figure 3, it may be seen that it is aobvious that the strengthening layer surface layer of acquisition forms full martensite after the present embodiment is using 200 DEG C of induction preheatings Micro-assembly robot, case depth 0.6mm, hardness reach 800HV, interfaces transition layer depth 0.6mm, and hardness declines in gradient.Laser Depth of interaction reaches 1.2mm, compared to no preheating in the case where improve 50%.The Malpighian layer of high surface hardness can be improved The wearability of Rail Surface, interface hardness gradient decline, forms a transition zone, reduces interface two layers of material performance It mismatches, to reduce the spreading rate of Interface Crack.
Embodiment 2:
The present embodiment carries out laser quenching to U75V Rail Surface using semiconductor optical fibre transmission laser.Wherein, laser heats Using 20mm width laser hot spot, 3000W laser power, 15mm/s laser scanning speed, preposition 300 DEG C of induction preheating temperature, Laser power, which is compared, reduces by 25% without preheating.
It under the conditions of prior art, is preheated without using preposition induction, Direct Laser quenching needs the laser function using 4000W Rate, quench-hardened case microhardness distribution are as shown in Figure 2.Hardened layer and substrate mutate in interface hardness, to the tired of quenching layer Labor performance is unfavorable.
The specific implementation process and embodiment 1 of the present embodiment are similarly.
After the present embodiment is using 300 DEG C of induction preheatings, the strengthening layer microscopic structure of acquisition is as shown in figure 4, microhardness point Cloth is as shown in Figure 5.It can be seen that, surface layer obtains full martensitic microstructure, and hardness reaches 800HV, from table from microscopic structure Layer starts, and hardness declines in gradient.Bottom obtains tiny troostitic structures, and entire laser action depth reaches 1.3mm, compares 62.5% is improved in the case where not preheating.Preheating temperature improves, and the hardness transition between strengthening layer and substrate is gentler, It further reduced the mismatch of quenching thermal stress and interface performance.Rail Surface can be improved in the Malpighian layer of high surface hardness Wearability, interface hardness gradient can reduce the spreading rate of Interface Crack.The functionally gradient prepared using this method is strong Changing layer can be improved the wearability and contacting fatigue resistance of Rail Surface.
Embodiment 3:
The present embodiment carries out laser quenching to U75V Rail Surface using semiconductor optical fibre transmission laser.Wherein, laser heats Using 20mm width laser hot spot, 4000W laser power, 18mm/s laser scanning speed, preposition 300 DEG C of induction preheating temperature, Scanning speed, which is compared, improves 20% without preheating.
It under the conditions of prior art, is preheated without using preposition induction, Direct Laser quenching, using the laser power of 4000W, only 15mm/s scanning speed can be reached, case depth 0.8mm, quench-hardened case microhardness distribution is as shown in Figure 2.Hardened layer and substrate It mutates in interface hardness, it is unfavorable to the fatigue behaviour of quenching layer.
The specific implementation process and embodiment 1 of the present embodiment are similarly.
It after the present embodiment is using 300 DEG C of induction preheatings, keeps laser power constant, is equally obtaining 0.8mm depth-hardened In the case where layer, 18mm/s is can be improved in scanning speed, improves 20%.Microscopic structure surface layer obtains complete micro- group of martensite It knits, hardness reaches 800HV, and since surface layer, hardness declines in gradient, and bottom obtains tiny troostitic structures.With embodiment 2 It compares, Malpighian layer and troostite layer depth shoal, and total depth and without using front preheating process when are consistent, but processing efficiency Improve 20%.The wearability of Rail Surface can be improved in the Malpighian layer of high surface hardness, and interface hardness gradient can reduce The spreading rate of Interface Crack.The wearability of Rail Surface can be improved using functionally gradient strengthening layer prepared by this method and resist Contact fatigue property.
The foregoing examples are only illustrative of the present invention, does not constitute the limitation to protection scope of the present invention, all It is within being all belonged to the scope of protection of the present invention with the same or similar design of the present invention.

Claims (9)

1. based on laser-induction heat source Rail Surface functionally gradient strengthening layer preparation method, which is characterized in that including walking as follows It is rapid:
1) laser and induction heating component are set in the top of rail, and induction heating component is located at the laser of laser transmitting The front in beam scanning direction；
2) when heating to Rail Surface, laser and induction heating component move at the same speed in the same direction, by induction heating component to steel Track surface is preheated, and laser is heated to austenitizing temperature to the Rail Surface of preheating；
3) after Rail Surface is cooled to martensitic transformation temperature or less, that is, the functionally gradient for forming the distribution of interface hardness gradient is strengthened Layer.
2. special as described in claim 1 based on laser-induction heat source Rail Surface functionally gradient strengthening layer preparation method Sign is: induction heating component setting is in front of the laser scans direction at 10~50mm.
3. special as described in claim 1 based on laser-induction heat source Rail Surface functionally gradient strengthening layer preparation method Sign is: the induction heating component includes medium frequency induction power supply and induction coil, the induction coil shape and rail head of rail Tyre tread outer profile is identical, and is parallel to rail upper surface, induction coil and rail upper surface 5~10mm of spacing, induction coil edge The length of rail length direction is 50~400mm.
4. special as claimed in claim 3 based on laser-induction heat source Rail Surface functionally gradient strengthening layer preparation method Sign is: the induction coil is coiled into spiral by hollow copper tubing, and cooling water is connected with inside it, and outside is equipped with magnetizer.
5. special as described in claim 1 based on laser-induction heat source Rail Surface functionally gradient strengthening layer preparation method Sign is: the induction heating component is 3~10mm to the heat penetration that rail preheats, and heating temperature is 100~500 DEG C.
6. special as claimed in claim 5 based on laser-induction heat source Rail Surface functionally gradient strengthening layer preparation method Sign is: the induction heating component is greater than the heat penetration of laser to the heat penetration that rail preheats.
7. special as claimed in claim 5 based on laser-induction heat source Rail Surface functionally gradient strengthening layer preparation method Sign is: the functionally gradient strengthening layer is by quenching layer cross section after the cooling of induction heating component warm-up control rail along its layer Deep direction sequentially forms full martensitic regions and half martensite area, and the hardness of full martensitic regions is between 650~900HV, half geneva Body area hardness is between 350~600HV.
8. special as described in claim 1 based on laser-induction heat source Rail Surface functionally gradient strengthening layer preparation method Sign is: the scanning speed of the laser is 4~20mm/s, and the power of laser is 600~12000W, laser transmitting Laser beam spot width is 10~50mm.
9. special as claimed in claim 8 based on laser-induction heat source Rail Surface functionally gradient strengthening layer preparation method Sign is: the laser is the direct output laser of semiconductor, semiconductor optical fibre transmission laser or optical fiber laser.
CN201910469216.5A 2019-05-31 2019-05-31 Based on laser-induction heat source Rail Surface functionally gradient strengthening layer preparation method Pending CN110172546A (en)

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Cited By (3)

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CN110670063A (en) * 2019-09-29 2020-01-10 东南大学 Cladding equipment and method for carrying out online repair on surface of steel rail
CN112149333A (en) * 2020-09-28 2020-12-29 上海交通大学 Optimization method for parameters of bearing raceway laser-induction composite quenching process
CN116065001A (en) * 2023-04-04 2023-05-05 浙江工业大学 Device and method for preparing and regulating strengthening and toughening complex phase structure on surface of medium-high carbon steel

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CN108456879A (en) * 2018-01-23 2018-08-28 华中科技大学 A kind of method of laser-auxiliary thermal source high efficiency composition cladding and hardening rail

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