CN2474561Y - Laser surface fused railway rail - Google Patents
Laser surface fused railway rail Download PDFInfo
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- CN2474561Y CN2474561Y CN 01219892 CN01219892U CN2474561Y CN 2474561 Y CN2474561 Y CN 2474561Y CN 01219892 CN01219892 CN 01219892 CN 01219892 U CN01219892 U CN 01219892U CN 2474561 Y CN2474561 Y CN 2474561Y
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- rail
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- transformation hardening
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Abstract
The utility model provides a laser surface melting steel rail, and comprises a laser melting layer, a phase-change hardening layer, a heat-affected layer, a steel rail body. The laser melting layer, the phase-change hardening layer and the heat-affected layer are all formed through laser beam illuminating surface materials of the melting steel rail, the phase-change hardening layer can exist under the laser melting layer, and the heat-affected layer is located between the phase-change hardening layer and the steel rail body. The laser melting layer of the steel rail surface can be processed as continuous or discontinuous layer by the laser beam, the shape of the laser melting layer can be point-like, straight line-like, curved line-like, reticular, planar form. The microcosmic tissue of the hardening layer of the laser surface melting steel rail is thin and dense, the abradability and toughness are all excellent.
Description
The utility model relates to a kind of railway rail, particularly relates to a kind of railway rail of laser surface remelting.
Rail is the important component part of railroad track.For adapting to the needs of national economy, speed, the load-carrying of railway improve constantly.China railways has surpassed 3,000 ten thousand ton kilometres by gross weight every year, and special section has reached 1.5-2 hundred million ton kilometres; Main line passenger vehicle speed will progressively be brought up to 140-160Km/h, and lorry speed will reach 80-85Km/h.Railway rail directly bears the effect repeatedly of train load, is the critical component that adapts to high-speed overload, strengthened rail structure, and the railway rail that research has excellent functional performance is a present railway system significant problem anxious to be solved.
The rail that the China railways main line uses at present is 50 types, 60 types, surpasses 60,000 kilometers, accounts for 90% of whole main lines.Homemade these two kinds of rail steel grades mainly are U71Mn and U74, are the common straightcarbon steel rail.Under present traffic condition, these two kinds of rail defects and failureses are serious day by day, exposed not long problem of bearing capacity deficiency, application life, and the superiority of heavy rail is not in full use.The hurt that rail in use occurs mainly is the rail head side grinding, and the ripple mill is peeled off and conquassation, and is the most serious with the side grinding hurt especially.Rail just need replacing about 1 year at present on the little curve on the busy circuit.
The main cause of rail defects and failures is the rolling contact fatigue that forms under the contact stress effect, and main hurt form is that the plasticity that plastic deformation of metal causes is peeled off.Be to solve the rail defects and failures problem, improve rail application life, both at home and abroad to the research of rail towards both direction: an approach is a heat treatment reinforcement, and the approach that heat treatment is strengthened is mainly walked by Japan and the United States, the Commonwealth of Independent States (CIS), and rail is carried out the total length Quenching Treatment; Another approach is an alloying, and some countries of West Europe mainly are the methods of taking the rail alloy strengthening.Common purpose is to improve the intensity and the abrasion resistance of steel rail material.China's rail has been done a large amount of tests and has been explored on these two approach.
The Ministry of Railways, Ministry of Metallurgical Industry unite and have manufactured experimently PD2 rail, PD3 rail and rare earth rail in recent years, and the rail of 12 countries such as import Japan is laid test for 800,000 tons.The Ministry of Railways is through thinking to the conclusion suggestions of a large amount of tests of domestic and international rail: the normal carbon rail wears no resistance, good toughness, and functional performance, weldability are good, do not have the brittle failure phenomenon, safety is after total length is quenched, but 0.5 times of life-saving should be widelyd popularize full quenching rail; The alloy rail abrasion resistance is good, but weldability is poor in using, and poor impact toughness has the brittle fracture phenomenon, and potential safety hazard is arranged, the further test of still needing.It is should be to extremely about 900 ℃ of the local electrical heating of rail head of rail on production line with double-frequency inductor that full length rail quenches, and keep a few minutes, water or air (generally using forced air-cooling) are chilled to about 600 ℃ then, and till this temperature range is incubated austenite and is transformed into bainite fully, cause transformation hardening, rail head of rail case hardness 280-400HV is about tensile strength 800MPa.
At present, the development of rail forward heavy-duty, on main trunk railway, 50,60 shaped steel rails are popularized, and the whole fatigue of rail relaxes to some extent; Along with the development of high speed, heavy duty, the rolling contact fatigue of rail is serious day by day; On the whole, the hurt of rail destruction is to be controlled by the contact fatigue of running surface of wheeltrack at present, so the intensity and the hardness that further improve the rail surface have very great economic implications.The scope that full length rail quenches is under the rail head of rail surface in the certain depth, if only require to quench or further improve intensity and hardness at running surface of wheeltrack, the full length rail quenching technology is difficult to accomplish.Say technically, utilize modern surface engineering technology,, improve surface and surface interior intensity and the hardness of certain depth scope down,, can do obtaining with the hurt that opposing contact fatigue causes rail only in the running surface of wheeltrack selective hardening; And compare from the advance of technology and economic feasibility, the high power laser process technology is present optimal selection.
Utilize laser processing technology, can produce the laser transformation hardening rail, but hardness, intensity and the degree of depth of laser phase-transformation hardening rail hardening layer are subjected to the restriction that rail base material tissue and surface must not consolidations; The crackle that the rail contact fatigue hurt produces and the rapid expansion of crackle, the laser transformation hardening rail can not be eliminated and suppress; And the laser surface remelting technology provides this possibility, can eliminate the surface fatigue crackle, suppresses cracks can spread, increases hardened layer hardness, intensity and the degree of depth.
The purpose that this adaptation is novel, be on the basis of homemade normal carbon rail, utilize the high power laser process technology, a kind of laser surface remelting rail is provided, to obtain than full quenching rail and laser phase-transformation hardening rail higher surface strength, hardness, the mobility of maintenance and longer application life, to adapt to the requirements at the higher level of railway transportation to rail.
The utility model is achieved in that
A kind of railway rail of laser surface remelting comprises: rail surface (1), consolidation layer (2), transformation hardening layer (3), heat affected layer (4), rail matrix (5), rail head (6), the web of the rail (7), the flange of rail (8), abrasion profile (9), wherein, rail head (6), the web of the rail (7), the flange of rail (8) physical dimension is all identical with present homemade rail, and the material of rail matrix (5) is identical with present homemade rail, is common straightcarbon steel.Consolidation layer (2), transformation hardening layer (3) form by laser beam irradiation rail surface in surperficial certain depth of rail head (6) and scope.Between rail surface (1) and transformation hardening layer (3) is the consolidation layer, between transformation hardening layer (3) and rail matrix (5) heat affected layer (4) is arranged.Consolidation layer (2), transformation hardening layer (3) have identical chemical composition with rail matrix (5).Consolidation layer (2), transformation hardening layer (3) have certain spatial form in rail head (6), can be continuous or discontinuous.Consolidation layer (2), transformation hardening layer (3) have certain flat shape on rail head (6), can be netted, point-like, and linearity, curve-like, plane.Consolidation layer (2), transformation hardening layer (3) have specific heterogeneous microstructure in rail head (6), this specific heterogeneous microstructure has specific physical behavior and characteristic.
Advantage of the present utility model is: the principal character of laser surface remelting rail is to produce consolidation layer (2), transformation hardening layer (3) with laser beam in rail surface certain depth and scope.Consolidation layer (2), transformation hardening layer (3) have identical chemical composition and different microstructures with rail matrix (5), and excellent physical characteristics is also arranged.The laser surface remelting rail does not change the physical dimension of existing rail, does not change the production technology of existing rail.The laser surface remelting rail is only local under rail head (6) running surface of wheeltrack to carry out the consolidation reinforcement with laser beam.Utilize laser equipment, the laser melting rail can be produced on the plant produced line, also can carry out laser melting to existing rail on the spot in orbit and strengthen.Like this, when laser surface remelting rail hardening layer wearing and tearing on the track or fatigue failure, just can utilize laser equipment to form new fusing hardening layer again on the rail surface.Laser surface remelting rail abrasion resistance is good, and toughness is good, can increase by 1 times by gross weight than common rail, is a kind of means uniqueness, cost economic, the new rail of excellent performance.
Below in conjunction with accompanying drawing the utility model laser surface remelting rail is described in detail:
Fig. 1 is the utility model laser surface remelting rail schematic cross-sectional view.
Fig. 2 is the utility model laser surface remelting rail plan view.
Fig. 3 is the utility model laser surface remelting rail side view.
With reference to Fig. 1, Fig. 2, Fig. 3, label (5) is the normal carbon rail, label (6) is a rail head of rail, label (7) is the rail web of the rail, label (8) is the rail flange of rail, label (9) is the real surface profile of rail head (6) after wheel track rubs for a long time, and label (2), (3) are for going up consolidation layer, transformation hardening layer of formation with laser beam at rail head (6), and label (4) is the heat affected layer between transformation hardening layer (3) and rail matrix.
It is homemade model U74, U71Mn that rail (5) uses main steel grade at present, and its main component is C, Mn, Si.The little curved steel rail of violent abrasion, the result of wheel-rail friction motion forms actual surface such as profile (9) on rail head.On the composition basis of U71Mn, increase C content, reduce Mn content, forming a kind of homemade new rail kind is PD2.On the composition basis of U71Mn, adjust C, Mn, Si content, increase V element simultaneously, forming a kind of homemade new rail kind is PD3, is called for short the vanadium rail.On the composition basis of U71Mn, adjust C, Mn, Si content, increase Nb, Re element, forming a kind of homemade new rail kind is the BNbRe rail, is called for short the rare earth rail.U71Mn, PD2 are the normal carbon rail, and PD3 is the vanadium alloy rail, and RNbRe is the rare earth alloy rail.Facts have proved in a large number that both at home and abroad normal carbon rail good toughness wears no resistance; The alloy rail abrasion resistance is good, poor toughness.Rail (5) in use damages the abrasion control of scrapping mainly by rail head (6), when rail head (6) wears away the state of profile (9), the web of the rail (7), the flange of rail (8) but operate as normal still.For increasing abrasion resistance, on whole section, use alloy steel, not only increase cost, the more important thing is the fragility that has increased rail head (6), the web of the rail (7), the flange of rail (8), reduced toughness.Full length rail quenches, and form quench hardened case in the suitable degree of depth of rail's end portion, and at the discontiguous position of wheel track, quench hardened case is actual to be useless; On the contrary, excessive quench hardened case will increase the fragility of rail.And the utility model provides a kind of like this rail, utilizes laser technology to go up the part at rail (5) and to produce the good laser melting hardened layer of anti-wear performance as required.Rail (5) will give processing before laser melting.For improving the efficient of laser treatment, light absorbent is given with methods such as brushing, sprayings put on rail (5) surface; Adjust the distance on laser optical head lens and rail (5) surface, make rail (5) surface be in nearly burnt a distance, make laser power density greater than 6*10
6W/cm
2; LASER HEATING speed is 10
4-10
8℃/s, heating-up temperature is greater than 1200 ℃ of vapourizing temperatures that also must not surpass the rail base material; Can reach 10 from cooling speed
4-10
6℃/s; Case depth can reach 1-2mm.Laser melting power density and sweep speed are very big to consolidation layer microstructure and physical parameters impact; Laser power density is medium, and speed is slower, and dissolve than large tracts of land on the rail surface, coarse, and darker transformation hardening layer is arranged under the ablation zone; Increase power density, speed is medium, and surface roughness descends, and the transformation hardening layer is not obvious under the ablation zone, and heat affected layer is arranged; Laser power density is very high, and speed is very fast, and surperficial firing rate, cooling velocity are exceedingly fast, and the ablation zone smooth surface is smooth, and the rail surface can obtain the not only thin but also hard glaze layer of one deck, and the consolidation district organizes crystal grain superfine, even can obtain amorphous state.
Laser surface remelting rail hardening layer (2,3) has unique microstructure.Laser melting rail surface melting layer is an eutectic structure, and is very fine and closely woven, mainly is made of martensite and cementite, and hardness is up to 1100HV; The transformation hardening floor is the dendrite district, is organized as spline-simulating martensite, thick a little martensite and retained austenite, the about 920HV-980HV of hardness; Undertissue is thin brilliant martensite and retained austenite again; Rail matrix again is a pearlite, the about 280HV of hardness.
Laser melting rail hardening layer (2,3) has specific space structures and flat shape.For overcoming the fragility of steel in the laser melting rail, prevent that hardened layer position crackle from producing, development, laser melting rail hardening layer (2,3) can be processed into various flat shapes, point-like as shown in Figure 2, shown in Figure 3 is netted.The hardened layer edge that like this can abrasion resistance is good, fragility is arranged is solid to wear no resistance but in the rail matrix (5) of good toughness, the crackle that has stoped thermal stress to produce effectively, the cracks can spread that has prevented hardened layer (2,3) with come off, and don't reduce the abrasion resistance of hardened layer (2,3).According to actual needs, hardened layer (2,3) can be processed into point-like, linearity (comprising parallel lines, horizontal line, oblique line), and curve-like, plane.
The laser surface remelting rail can be in plant produced, and also available laser car is produced in orbit on the spot.Plant produced laser surface remelting rail needs the laser Digit Control Machine Tool, and this lathe is by carbon dioxide gas laser, light-conducting system, and Digit Control Machine Tool is formed.Laser processing parameter such as laser spot diameter, speed of related movement, laser power density will conscientiously be tested definite.Laser facula can be circle, and rectangle is linear.The laser car is produced the laser melting rail on the spot, can eliminate the rail surface fatigue crackle that causes because of wheel Rail Contact Stresses; According to freight volume and rail defects and failures situation, available laser car carries out periodic laser melting to online rail; Same one steel rail can repeatedly form the laser melting hardened layer; Can prolong the online active time of rail greatly like this, change situation in rail application life, give full play to the advantage that heavy rail itself has by the contact fatigue control of rail surface.
The laser surface remelting rail has unique physical characteristic.According to the difference of the hardened layer (2,3) that designs, the tensile strength of laser surface remelting rail hardening layer (2,3) can surpass 1100MPa, and hardness can surpass more than the 1100HV, be a kind of super intensified abrasion-proof rail; And can be according to rail surface abrasion situation, the repair cycle of choose reasonable laser melting rail and the processing parameter of laser surface remelting will prolong the gross weight of passing through of the time limit of the online military service of rail and rail greatly.The laser surface remelting rail is applicable to state's railway network, urban light rail, subway, the main trunk railway of local railway and in-dustrial line, especially high-speed overload, fortune coal special line and little curve.
Claims (6)
1. laser surface remelting rail, comprise: rail surface (1), consolidation layer (2), transformation hardening layer (3), heat affected layer (4), rail matrix (5), it is characterized in that, consolidation layer (2) forms with laser beam irradiation consolidation rail surface (1) material, can there be transformation hardening layer (3) below the consolidation layer (2), have heat affected layer (4) between transformation hardening layer (3) and rail matrix (5), consolidation layer (2), transformation hardening layer (3) and heat affected layer (4) have different heterogeneous microstructures and physical characteristic with rail matrix (5).
2. laser surface remelting rail according to claim 1 is characterized in that, consolidation layer (2), transformation hardening layer (3) and heat affected layer (4) can be continuous or discontinuous in rail matrix (5).
3. laser surface remelting rail according to claim 1 is characterized in that, consolidation layer (2) can be a point-like on rail surface (1), linearity, and curve-like, netted, plane.
4. laser surface remelting rail according to claim 1 is characterized in that, consolidation layer (2), transformation hardening layer (3) and heat affected layer (4) in rail's end portion (5) running surface of wheeltrack scope, degree of depth 0.1-2mm.
5. laser surface remelting rail according to claim 1 is characterized in that, consolidation layer (2), transformation hardening layer (3) and heat affected layer (4) in rail's end portion (5) running surface of wheeltrack scope, degree of depth 2-5mm.
6. laser surface remelting rail according to claim 1, it is characterized in that consolidation layer (2), transformation hardening layer (3) and heat affected layer (4) can according to the crackle on rail surface and the abrasion situation be periodically shone consolidation with laser beam and periodically form.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01219892 CN2474561Y (en) | 2001-04-23 | 2001-04-23 | Laser surface fused railway rail |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01219892 CN2474561Y (en) | 2001-04-23 | 2001-04-23 | Laser surface fused railway rail |
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| Publication Number | Publication Date |
|---|---|
| CN2474561Y true CN2474561Y (en) | 2002-01-30 |
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ID=33637606
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 01219892 Expired - Fee Related CN2474561Y (en) | 2001-04-23 | 2001-04-23 | Laser surface fused railway rail |
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| Country | Link |
|---|---|
| CN (1) | CN2474561Y (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110344048A (en) * | 2019-07-17 | 2019-10-18 | 株洲辉锐增材制造技术有限公司 | Laser cladding layer of high manganese steel frog and preparation method thereof and high manganese steel frog |
| CN117535664A (en) * | 2023-12-01 | 2024-02-09 | 河北钨泰固机械设备有限公司 | Double-frequency induction heating composite laser cladding method and equipment thereof |
-
2001
- 2001-04-23 CN CN 01219892 patent/CN2474561Y/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110344048A (en) * | 2019-07-17 | 2019-10-18 | 株洲辉锐增材制造技术有限公司 | Laser cladding layer of high manganese steel frog and preparation method thereof and high manganese steel frog |
| CN110344048B (en) * | 2019-07-17 | 2021-06-22 | 株洲辉锐增材制造技术有限公司 | Laser cladding layer of high manganese steel frog, preparation method of laser cladding layer and high manganese steel frog |
| CN117535664A (en) * | 2023-12-01 | 2024-02-09 | 河北钨泰固机械设备有限公司 | Double-frequency induction heating composite laser cladding method and equipment thereof |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |