CN106544933B - The method that a kind of pair of steel rail weld joint carries out post weld heat treatment - Google Patents
The method that a kind of pair of steel rail weld joint carries out post weld heat treatment Download PDFInfo
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- CN106544933B CN106544933B CN201610909362.1A CN201610909362A CN106544933B CN 106544933 B CN106544933 B CN 106544933B CN 201610909362 A CN201610909362 A CN 201610909362A CN 106544933 B CN106544933 B CN 106544933B
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- steel rail
- rail
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01B—PERMANENT WAY; PERMANENT-WAY TOOLS; MACHINES FOR MAKING RAILWAYS OF ALL KINDS
- E01B31/00—Working rails, sleepers, baseplates, or the like, in or on the line; Machines, tools, or auxiliary devices specially designed therefor
- E01B31/02—Working rail or other metal track components on the spot
-
- 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
- C21D9/50—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for welded joints
- C21D9/505—Cooling thereof
Abstract
The present invention relates to rail welding fields, disclose the method that a kind of pair of steel rail weld joint carries out post weld heat treatment.This method comprises: the steel rail weld joint to be cooled that welding obtains, which is carried out first, is cooled to 400 DEG C or less, then the first steel rail weld joint after cooling is heated to 860-930 DEG C, then carrying out the wheel tread temperature that second is cooled to steel rail weld joint is 410-450 DEG C；Wherein, the steel rail weld joint is 75kg/m hypereutectoid rail and pearlite steel rail welding point.Using method provided by the invention, post weld heat treatment is carried out to hypereutectoid rail and PG4 heat-treated rail welding point, the internal flaw of xenogenesis rail joint is few, welding quality stable, can be met the requirements by the test of fatigue test, stretching and impact test and quiet curved test.
Description
Technical field
The present invention relates to rail welding fields, and in particular, to a kind of pair of steel rail weld joint carries out post weld heat treatment
Method.
Background technique
Hypereutectoid rail is the new rail kind that developed in recent years, and the phosphorus content of hypereutectoid rail is generally in 0.90-
In the range of 1.0 weight %, microscopic structure is the line and staff control along brilliant secondary cementite+pearlite, at present in the world most
The top rail of high intensity (1350MPa) and hardness (400HB-420HB).The tissue of pearlite steel rail is pearlite, has generation
The pearlite steel rail of table is PG4 heat-treated rail.PG4 heat-treated rail (also known as U78CrV, abbreviation PG4 rail) carbon content exists
In the range of 0.72-0.82 weight %, microscopic structure is pearlitic structrure, and intensity is suitable with hypereutectoid rail, and hardness is slightly lower
20HB.The histological difference of both rail is larger, is two distinct types of high-strength heat-treated rail.Hypereutectoid rail and
PG4 heat-treated rail is mainly used in heavy haul railway anvil faced rail.The 25m that current railway both domestic and external is produced by steel mill
Or 100m scale rail, using the long rail string of base flash welding connection 250m or 500m, long rail string uses movement after transporting route
Flash welding, gas pressure welding or thermit welding process technology form gapless track, improve Track regularity and comfort, reduce wheel track punching
It hits, extends wheel track service life.The online 75kg/m pearlite PG4 heat-treated rail difficulty using mobile Flash Butt Welding big cross section
Greatly, if high-carbon that further will be different from microscopic structure, high intensity and high rigidity hypereutectoid rail welding, difficulty are bigger.
There is presently no the reports and text that are heat-treated after the welding and welding about hypereutectoid rail and PG4 heat-treated rail
Offer record.
Summary of the invention
The purpose of the present invention is overcome the deficiencies of the prior art and provide a kind of pair of steel rail weld joint to carry out post weld heat treatment
Method.
The martensite critical speed of the continuous cooling transformation of hypereutectoid rail is about 1.5 DEG C/s, and the company of pearlite steel rail
The martensite critical speed of continuous cooling transformation is about 1.0 DEG C/s.It was found by the inventors of the present invention that in hypereutectoid rail and PG4 heat
Process (including the heating and quickly for the post weld heat treatment of welding point that processing rail (one kind of pearlite steel rail) welding obtains
It is cooling) in, it is necessary to it is limited with the Critical cooling speed of pearlite steel rail, otherwise will generates the martensitic structure hardened, lead to connector
Early stage is broken.Simultaneously as because there is secondary cementite Intergranular precipitation in hypereutectoid rail, it is necessary to by austenite
Start to be quickly cooled down before starting to perlitic transformation, is quickly cooled down the precipitation that can inhibit secondary cementite, it is often more important that
Avoid secondary cementite along brilliant in netted precipitation.Based on above-mentioned discovery, inventor completes the present invention.
Specifically, the present invention provides the methods that a kind of pair of steel rail weld joint carries out post weld heat treatment, this method comprises:
The steel rail weld joint to be cooled that welding obtains is carried out first and is cooled to 400 DEG C hereinafter, the first rail after cooling is welded
Connector is heated to 860-930 DEG C, and then carrying out the wheel tread temperature that second is cooled to steel rail weld joint is 410-450 DEG C；Its
In, the steel rail weld joint is 75kg/m hypereutectoid rail and pearlite steel rail welding point.
Using method provided by the invention, hypereutectoid rail and PG4 heat-treated rail (one kind of pearlite steel rail) are welded
Connector is handled, and longitudinal hardness under connector tyre tread at 5mm reaches 90% or more hypereutectoid and PG4 heat-treated rail mother
Material performance, softening sector width control within 30mm, and the matching of connector obdurability is good.The internal flaw of xenogenesis rail joint
Few, welding quality stable can be met the requirements by the test of fatigue test, stretching and impact test and quiet curved test；It is different
The connector of kind of rail can continue through 15 flash welding connectors and drop hammer inspections, with preferable stability.
Other features and advantages of the present invention will the following detailed description will be given in the detailed implementation section.
Detailed description of the invention
The drawings are intended to provide a further understanding of the invention, and constitutes part of specification, with following tool
Body embodiment is used to explain the present invention together, but is not construed as limiting the invention.In the accompanying drawings:
Fig. 1 is the post weld heat treatment curve of the steel rail weld joint in embodiment 1；
Fig. 2 is the web of the rail low power sample after steel rail weld joint is air-cooled in embodiment 1；
Fig. 3 is web of the rail low power sample final after steel rail weld joint post weld heat treatment in embodiment 1；
Fig. 4 is vertical section hardness distribution at 5.0mm under tyre tread after steel rail weld joint is air-cooled in embodiment 1；
Fig. 5 is vertical section hardness distribution at 5.0mm under steel rail weld joint post weld heat treatment rear tread pattern in embodiment 1.
Specific embodiment
Detailed description of the preferred embodiments below.It should be understood that described herein specific
Embodiment is merely to illustrate and explain the present invention, and is not intended to restrict the invention.
The endpoint of disclosed range and any value are not limited to the accurate range or value herein, these ranges or
Value should be understood as comprising the value close to these ranges or value.For numberical range, between the endpoint value of each range, respectively
It can be combined with each other between the endpoint value of a range and individual point value, and individually between point value and obtain one or more
New numberical range, these numberical ranges should be considered as specific open herein.
In the present invention, in the absence of explanation to the contrary, described " steel rail weld joint " refers to be obtained after weld formation
Comprising weld seam and/or normalizing heat affected area in the region that interior length is about 100-120 millimeter, the center line in the region is two
The commissure of the rail welded together.In the present invention, described " room temperature " refers to 0-45 DEG C of temperature range.
The present invention provides a kind of methods of the post weld heat treatment of steel rail weld joint, this method comprises: welding is obtained
Steel rail weld joint to be cooled carry out first and be cooled to 400 DEG C hereinafter, the first steel rail weld joint after cooling is heated
To 860-930 DEG C, then carrying out the wheel tread temperature that second is cooled to steel rail weld joint is 410-450 DEG C；Wherein, the rail
Welding point is 75kg/m hypereutectoid rail and pearlite steel rail welding point.
In the present invention, the post weld heat treatment of the steel rail weld joint preferably carries out after convex completion in upset and pushing away.
Typically 1050-1200 DEG C of initial temperature for welding obtained steel rail weld joint to be cooled, i.e., the first cooling
Beginning temperature can be 1050-1200 DEG C.
In the present invention, the described first cooling mode can be natural cooling, and the natural cooling can be at room temperature
It carries out.
Under preferable case, the steel rail weld joint to be cooled that welding obtains is carried out first and is cooled to 280-360 DEG C, more
Preferably 290-330 DEG C；It is further preferred that the first steel rail weld joint after cooling is heated to 860-930 DEG C, then into
The wheel tread temperature that row second is cooled to steel rail weld joint is 430-450 DEG C.The temperature that second cooling process terminates is second
Cooling final cooling temperature.
It is described by first in the method for the post weld heat treatment of steel rail weld joint of the present invention under preferable case
Steel rail weld joint after cooling is heated to 870-925 DEG C, is further preferably heated to 880-920 DEG C.
It is described to be heated to welding point in the method for the post weld heat treatment of steel rail weld joint of the present invention
860-930 DEG C of method can there are many, present invention preferably employs Medium frequency inductions as shape electric heater and/or oxy-acetylene flame
As steel rail weld joint is heated to 860-930 DEG C by shape heater.
Under preferable case, in the method for the post weld heat treatment of steel rail weld joint of the present invention, by rail welding
Connector is heated to 860-930 DEG C of mode as the mode of tunneling boring heating.In the present invention, it is described using full face mode into
Row heating refers to being about that steel rail weld joint whole cross section within the scope of 100-120mm adds comprising the length including weld seam
The mode of heat.
Under preferable case, the present invention acquires the temperature signal of tyre tread using infrared measurement of temperature, when detecting that wheel tread temperature reaches
To after the signal of target temperature, heating power supply switch is automatically closed.The tyre tread refers to the contact portion of wheel and rail.
Under preferable case, in the method for the post weld heat treatment of steel rail weld joint of the present invention, described second is cold
But process can carry out immediately after the heating of previous stage terminates, can also after heating process terminates natural cooling
A period of time carries out again, but is to ensure that the initial temperature of the second cooling procedure not less than 830 DEG C.
Under preferable case, the described second cooling mode is air-cooled.It is described air-cooled including being welded using air-jet device to rail
The tyre tread heating region of connector is cooled down, and the distance of air nozzle to tyre tread can be 20-70mm, preferably 30-50mm, spray
The wind pressure of wind can be 0.15-0.5MPa, preferably 0.18-0.25MPa.
Under preferable case, the method also includes: after second is cooling, steel rail weld joint is naturally cooled into room
Temperature.Under preferable case, the pearlite steel rail can be PG4 heat-treated rail；Preferably, the 75kg/m hypereutectoid rail is
PG5 hypereutectoid rail.
It is further to note that the pearlite steel rail and hypereutectoid rail that are welded in the present invention are 75kg/m's
Specification.
Under preferable case, steel rail weld joint is welding point made of mobile Flash Butt Welding.
In the present invention, the mobile Flash Butt Welding includes dodging flat, pulsation, accelerating to burn, upset and pressure maintaining, wherein weldering
The total heat input connect can be 10-13MJ, and the total duration of welding can be 143-162s, and welding upset amount can be
15.5-18.5mm。
As long as although within the above range by total heat input of welding, duration and the control of welding upset amount,
But in order to reach better welding effect, it is preferable that total heat input of the welding is 11-12MJ, the mobile welding
Total duration be 149-156s, the welding upset amount be 16.5-17.5mm.
In the present invention, each stage during mobile Flash Butt Welding (including dodges flat, pulsation, accelerates to burn, upset and guarantor
Pressure) thermal weld stress amount, displacement and duration can change in a big way, as long as by total heat input of welding
Amount, duration and welding upset amount control are in range provided by the invention.Wherein, total heat input of welding is each
The total duration of the sum of a stage heat input, welding is the sum of each phase duration, and it is each that rail, which burns displacement,
The sum of the displacement in a stage.
In the present invention, the thermal weld stress amount for dodging the flat stage can be 2.2-2.9MJ, preferably 2.5-2.7MJ；Displacement
Amount can be 1.8-2.6mm, preferably 2-2.5mm；Duration is 28-32s, preferably 29-30s.
In the present invention, the thermal weld stress amount of pulsation phase can be 7.7-9.3MJ, preferably 8.1-8.6MJ；Displacement
Amount can be 9.5-11mm, preferably 10-10.5mm；Duration is 78-83s, preferably 80-82s.
In the present invention, accelerate to burn the thermal weld stress amount in stage be 0.1-0.7MJ, preferably 0.3-0.5MJ；
Displacement can be 9-13mm, preferably 10-12mm；Duration is 24-28s, preferably 25-27s.
In the present invention, the thermal weld stress amount in upset stage is no more than 0.2MJ, preferably more than 0.1MJ, more preferably
0.01-0.1MJ；Displacement can be 15.5-18.5mm, preferably 16.5-17.5mm；Electrification upset time is 0.3-0.6s,
Preferably 0.4-0.5s.
In the present invention, the dwell pressure of packing stage is 26-32t, preferably 28-30t；Duration is 13-18s,
Preferably 15-16s." t " refers to " ton ".
A kind of preferred embodiment according to the present invention, the thermal weld stress amount for dodging the flat stage is 2.5-2.7MJ, displacement
For 2-2.5mm, duration 29-30s；The thermal weld stress amount of pulsation phase is 8.1-8.6MJ, displacement 10-
10.5mm, duration 80-82s；Accelerating the thermal weld stress amount for burning the stage is 0.3-0.5MJ, displacement 10-
12mm, duration 25-27s；The thermal weld stress amount in upset stage is no more than 0.1MJ, displacement 16.5-17.5mm,
Electrification upset time is 0.4-0.5s；The dwell pressure of packing stage is 28-30t, duration 15-16s.
The present invention will be described in detail by way of examples below.
In following embodiment, the hypereutectoid rail is PG5 hypereutectoid rail, and pearlite steel rail is PG4 heat-treated rail；
PG5 hypereutectoid rail and PG4 heat-treated rail are the product of Pan Gang group；Room temperature indicates 25 DEG C；
Mobile steel rail flash welding machine model YHG-1200TH, power 240kVA, forging force 1200kN.Welding point drops hammer
Inspection, hardness, fatigue test, tension test and it is quiet it is curved test according to TB/T 1632.1-2014, TB/T 1632.2-2014 with
And AS1085.20-2012 standard is detected.
Embodiment 1
The method that the embodiment is used to illustrate the post weld heat treatment of steel rail weld joint provided by the invention
The PG5 hypereutectoid rail of 75kg/m and PG4 heat-treated rail are welded using mobile steel rail flash welding machine, dodged
The thermal weld stress amount in flat stage is 2.5MJ, displacement 2.1mm, duration 29s；The thermal weld stress of pulsation phase
Amount is 8.4MJ, displacement 10.2mm, duration 81.2s；Accelerating the thermal weld stress amount for burning the stage is 0.4MJ, position
Shifting amount is 11.6mm, duration 26.1s；The thermal weld stress amount in upset stage is 0.1MJ, displacement 16.9mm, band
Electric upset time is 0.4s；The dwell pressure of packing stage is 28.6t, duration 15.5s.Welding total heat input be
11.4MJ, duration 152.2s, it is 40.8mm that rail, which burns displacement, and welding upset amount is 16.9mm.Welding result is
It is qualified.Specific data are listed in Table 1 below.
After the completion of upset is with pushing away convex, the steel rail weld joint that above-mentioned welding is obtained carries out post weld heat treatment.Steel first
Rail welding point to 300 DEG C, heats welding point extremely using intermediate frequency power supply tunneling boring by 1100 DEG C of natural coolings (first is cooling)
Rail head weld seam tyre tread peak temperature is 900 DEG C, and the signal after infrared radiation thermometer automatic collection wheel tread temperature to temperature is simultaneously automatically closed immediately
Heating power supply switch.Then start (second is cooling) air-cooled to tyre tread spray wind at 850 DEG C, air-cooled heating is accelerated using air-jet device
Welding point tyre tread heating region after to temperature, air nozzle spray wind wind pressure 0.22MPa apart from tyre tread 40mm.Using infrared measurement of temperature
Instrument automatic collection and monitoring wheel tread temperature, when weld seam wheel tread temperature is air-cooled be down to final cooling temperature be 430 DEG C when, be automatically closed air-cooled
Device, avoids hypereutectoid rail from the martensitic structure of high hardenability occur, and subsequent welding point carries out cooled to room temperature.
Fig. 1 is the post weld heat treatment curve of the steel rail weld joint in the present embodiment, which is obtained by infrared radiation thermometer.
Fig. 2 is the web of the rail low power sample after steel rail weld joint is air-cooled in the present embodiment, and Fig. 3 is rail welding in the present embodiment
Final web of the rail low power sample after connector post weld heat treatment, Fig. 2 and Fig. 3 are the images that sample macroscopic view camera is shot, with weld seam
Center on the basis of, wherein left side be PG4 heat-treated rail, right side be PG5 hypereutectoid rail.
Fig. 4 is vertical section hardness distribution at 5.0mm under tyre tread after steel rail weld joint is air-cooled in the present embodiment.Fig. 5
It is vertical section hardness distribution at 5.0mm under steel rail weld joint post weld heat treatment rear tread pattern in the present embodiment.Hardness distribution
It is tested by interval of 2mm, obtained number using cloth dimension hardometer (Laizhou, Shandong city testing machine head factory, model HBV-30A)
According to using EXCLE to map.
Figure 4, it is seen that the side PG4 softening sector width is 16mm, it is 28mm that the side PG5, which softens sector width, is met
Soften the requirement that sector width is less than 30mm in AS1085.20-2012 standard.
From figure 5 it can be seen that quality of weld joint is stablized, longitudinal hardness under connector tyre tread at 5mm reach 90% with
On PG5 hypereutectoid rail and PG4 heat-treated rail base material performance, it is 20mm that the side PG4, which softens sector width, and the side PG5 softened zone is wide
Degree is 25mm, meets and softens the requirement that sector width is less than 30mm in AS1085.20-2012 standard.
Rail after the welding that the present embodiment obtains can achieve continuous 15 mobile sudden strains of a muscle of TB/T1632.2 standard requirements
The final purpose that flush weld connector passes through inspection of dropping hammer.Wherein, the 1st continuous amount of deflection of hammer is 8.2mm, and the 2nd continuous amount of deflection of hammer is
15.0mm。
Fatigue test, stretching and the impact test of steel rail weld joint, the result of quiet curved test are listed in table 2,3 and of table respectively
In table 4.
Table 1
Embodiment 2
The method that the embodiment is used to illustrate the post weld heat treatment of steel rail weld joint provided by the invention
The PG5 hypereutectoid rail of 75kg/m and PG4 heat-treated rail are welded using mobile steel rail flash welding machine, dodged
The thermal weld stress amount in flat stage is 2.6MJ, displacement 2mm, duration 29s；The thermal weld stress amount of pulsation phase
For 8.1MJ, displacement 10mm, duration 80s；The thermal weld stress amount for accelerating to burn the stage is 0.3MJ, and displacement is
12mm, duration 27s；The thermal weld stress amount in upset stage is 0.08MJ, displacement 17.5mm, charges upset time
For 0.45s；The dwell pressure of packing stage is 30t, duration 15s.Total heat input of welding is 11.08MJ, is continued
Time is 151.45s, and it is 41.5mm that rail, which burns displacement, and welding upset amount is 17.5mm.Short-circuit impedance is 113.515 μ Ω.
Welding result is qualification.
After the completion of upset is with pushing away convex, the steel rail weld joint that above-mentioned welding is obtained carries out post weld heat treatment.Steel first
Rail welding point to 290 DEG C, heats welding point extremely using intermediate frequency power supply tunneling boring by 1080 DEG C of natural coolings (first is cooling)
Rail head weld seam tyre tread peak temperature is 890 DEG C, and the signal after infrared radiation thermometer automatic collection wheel tread temperature to temperature is simultaneously automatically closed immediately
Heating power supply switch.Then start (second is cooling) air-cooled to tyre tread spray wind at 840 DEG C, air-cooled heating is accelerated using air-jet device
Welding point tyre tread heating region after to temperature, air nozzle spray wind wind pressure 0.18MPa apart from tyre tread 30mm.Using infrared measurement of temperature
Instrument automatic collection and monitoring wheel tread temperature, when weld seam wheel tread temperature is air-cooled be down to final cooling temperature be 450 DEG C when, be automatically closed air-cooled
Device, avoids hypereutectoid rail from the martensitic structure of high hardenability occur, and subsequent welding point carries out cooled to room temperature.
The steel rail weld joint quality that the present embodiment obtains is stablized, and longitudinal hardness under connector tyre tread at 5mm reaches 90%
Above PG5 hypereutectoid rail and PG4 heat-treated rail base material performance, softening sector width control within 20mm.After welding
Rail can achieve the final mesh that continuous 15 mobile flash welding connectors of TB/T1632.2 standard requirements pass through inspection of dropping hammer
's.
Fatigue test, stretching and the impact test of steel rail weld joint, the result of quiet curved test are listed in table 2,3 and of table respectively
In table 4.
Embodiment 3
The method that the embodiment is used to illustrate the post weld heat treatment of steel rail weld joint provided by the invention
The PG5 hypereutectoid rail of 75kg/m and PG4 heat-treated rail are welded using mobile steel rail flash welding machine, dodged
The thermal weld stress amount in flat stage is 2.7MJ, displacement 2.5mm, duration 30s；The thermal weld stress of pulsation phase
Amount is 8.6MJ, displacement 10.5mm, duration 82s；Accelerating the thermal weld stress amount for burning the stage is 0.5MJ, displacement
Amount is 10mm, duration 25s；The thermal weld stress amount in upset stage is 0.07MJ, displacement 16.5mm, charges upset
Time is 0.5s；The dwell pressure of packing stage is 28t, duration 16s.Total heat input of welding is 11.87MJ, is held
The continuous time is 153.5s, and it is 39.5mm that rail, which burns displacement, and welding upset amount is 16.5mm.Short-circuit impedance is 111.8491 μ
Ω.Welding result is qualification.
After the completion of upset is with pushing away convex, the steel rail weld joint that above-mentioned welding is obtained carries out post weld heat treatment.Steel first
Rail welding point to 330 DEG C, heats welding point extremely using intermediate frequency power supply tunneling boring by 1150 DEG C of natural coolings (first is cooling)
Rail head weld seam tyre tread peak temperature is 880 DEG C, and the signal after infrared radiation thermometer automatic collection wheel tread temperature to temperature is simultaneously automatically closed immediately
Heating power supply switch.Then start (second is cooling) air-cooled to tyre tread spray wind at 830 DEG C, air-cooled heating is accelerated using air-jet device
Welding point tyre tread heating region after to temperature, air nozzle spray wind wind pressure 0.25MPa apart from tyre tread 50mm.Using infrared measurement of temperature
Instrument automatic collection and monitoring wheel tread temperature, when weld seam wheel tread temperature is air-cooled be down to final cooling temperature be 440 DEG C when, be automatically closed air-cooled
Device, avoids hypereutectoid rail from the martensitic structure of high hardenability occur, and subsequent welding point carries out cooled to room temperature.
The steel rail weld joint quality that the present embodiment obtains is stablized, and longitudinal hardness under connector tyre tread at 5mm reaches 90%
Above PG5 hypereutectoid rail and PG4 heat-treated rail base material performance, softening sector width control within 20mm.After welding
Rail can achieve the final mesh that continuous 15 mobile flash welding connectors of TB/T1632.2 standard requirements pass through inspection of dropping hammer
's.
Fatigue test, stretching and the impact test of steel rail weld joint, the result of quiet curved test are listed in table 2,3 and of table respectively
In table 4.
Embodiment 4
The method that the embodiment is used to illustrate the post weld heat treatment of steel rail weld joint provided by the invention
The PG5 hypereutectoid rail of 75kg/m and PG4 heat-treated rail are welded using mobile steel rail flash welding machine, dodged
The thermal weld stress amount in flat stage is 2.4MJ, displacement 2.6mm, duration 28s；The thermal weld stress of pulsation phase
Amount is 8.8MJ, displacement 9.8mm, duration 83s；Accelerating the thermal weld stress amount for burning the stage is 0.55MJ, displacement
Amount is 9.5mm, duration 24.5s；The thermal weld stress amount in upset stage is 0.05MJ, displacement 16mm, electrification top
The forging time is 0.35s；The dwell pressure of packing stage is 31t, duration 17s.Total heat input of welding is 11.8MJ,
Duration is 152.85s, and it is 37.9mm that rail, which burns displacement, and welding upset amount is 16mm.Short-circuit impedance is 112.4885 μ
Ω.Welding result is qualification.
After the completion of upset is with pushing away convex, the steel rail weld joint that above-mentioned welding is obtained carries out post weld heat treatment.Steel first
Rail welding point to 280 DEG C, heats welding point extremely using intermediate frequency power supply tunneling boring by 1120 DEG C of natural coolings (first is cooling)
Rail head weld seam tyre tread peak temperature is 910 DEG C, and the signal after infrared radiation thermometer automatic collection wheel tread temperature to temperature is simultaneously automatically closed immediately
Heating power supply switch.Then start (second is cooling) air-cooled to tyre tread spray wind at 860 DEG C, air-cooled heating is accelerated using air-jet device
Welding point tyre tread heating region after to temperature, for air nozzle apart from tyre tread 55mm, spray wind wind pressure is 0.3MPa.Using infrared measurement of temperature
Instrument automatic collection and monitoring wheel tread temperature, when weld seam wheel tread temperature is air-cooled be down to final cooling temperature be 425 DEG C when, be automatically closed air-cooled
Device, avoids hypereutectoid rail from the martensitic structure of high hardenability occur, and subsequent welding point carries out cooled to room temperature.
The steel rail weld joint quality that the present embodiment obtains is stablized, and longitudinal hardness under connector tyre tread at 5mm reaches 90%
Above PG5 hypereutectoid rail and PG4 heat-treated rail base material performance, softening sector width control within 20mm.After welding
Rail can achieve the final mesh that continuous 15 mobile flash welding connectors of TB/T1632.2 standard requirements pass through inspection of dropping hammer
's.
Fatigue test, stretching and the impact test of steel rail weld joint, the result of quiet curved test are listed in table 2,3 and of table respectively
In table 4.
Embodiment 5
The method that the embodiment is used to illustrate the post weld heat treatment of steel rail weld joint provided by the invention
The PG5 hypereutectoid rail of 75kg/m and PG4 heat-treated rail are welded using mobile steel rail flash welding machine, dodged
The thermal weld stress amount in flat stage is 2.8MJ, displacement 1.8mm, duration 31s；The thermal weld stress of pulsation phase
Amount is 8MJ, displacement 10.8mm, duration 79s；Accelerating the thermal weld stress amount for burning the stage is 0.25MJ, displacement
Amount is 12.5mm, duration 27.5s；The thermal weld stress amount in upset stage is 0.06MJ, displacement 18mm, electrification top
The forging time is 0.55s；The dwell pressure of packing stage is 27.5t, duration 14s.Welding total heat input be
11.11MJ, duration 152.05s, it is 43.1mm that rail, which burns displacement, and welding upset amount is 18mm.Short-circuit impedance is
110.9004μΩ.Welding result is qualification.
After the completion of upset is with pushing away convex, the steel rail weld joint that above-mentioned welding is obtained carries out post weld heat treatment.Steel first
Rail welding point to 340 DEG C, heats welding point extremely using intermediate frequency power supply tunneling boring by 1110 DEG C of natural coolings (first is cooling)
Rail head weld seam tyre tread peak temperature is 870 DEG C, and the signal after infrared radiation thermometer automatic collection wheel tread temperature to temperature is simultaneously automatically closed immediately
Heating power supply switch.Then start (second is cooling) air-cooled to tyre tread spray wind at 865 DEG C, air-cooled heating is accelerated using air-jet device
Welding point tyre tread heating region after to temperature, air nozzle spray wind wind pressure 0.15MPa apart from tyre tread 25mm.Using infrared measurement of temperature
Instrument automatic collection and monitoring wheel tread temperature, when weld seam wheel tread temperature is air-cooled be down to final cooling temperature be 420 DEG C when, be automatically closed air-cooled
Device, avoids hypereutectoid rail from the martensitic structure of high hardenability occur, and subsequent welding point carries out cooled to room temperature.
The steel rail weld joint quality that the present embodiment obtains is stablized, and longitudinal hardness under connector tyre tread at 5mm reaches 90%
Above PG5 hypereutectoid rail and PG4 heat-treated rail base material performance, softening sector width control within 20mm.After welding
Rail can achieve the final mesh that continuous 15 mobile flash welding connectors of TB/T1632.2 standard requirements pass through inspection of dropping hammer
's.
Fatigue test, stretching and the impact test of steel rail weld joint, the result of quiet curved test are listed in table 2,3 and of table respectively
In table 4.
Table 2
| Parameter | Embodiment 1 | Embodiment 2 | Embodiment 3 | Embodiment 4 | Embodiment 5 |
| The 1st continuous amount of deflection (mm) of hammer | 8.2 | 7.5 | 7.9 | 7.2 | 7.0 |
| The 2nd continuous amount of deflection (mm) of hammer | 15.0 | 14.8 | 15.5 | 14.9 | 14.8 |
| Times of fatigue (ten thousand times) | > 201.2 | > 201.1 | > 202.1 | > 200.9 | > 201 |
Table 3
| Parameter | Embodiment 1 | Embodiment 2 | Embodiment 3 | Embodiment 4 | Embodiment 5 |
| Rp0.2(MPa) | 731 | 676 | 750 | 690 | 735 |
| Rm(MPa) | 1039 | 1043 | 1150 | 1080 | 1050 |
| A (%) | 8.4 | 12.6 | 7.5 | 9.0 | 8.5 |
| Z (%) | 43.1 | 37 | 36.0 | 37.0 | 37.5 |
| AKU(J) | 14.36 | 15 | 15.5 | 14.5 | 16.0 |
Note: Rp0.2 indicates that stress when Non-proportional extension rate is 0.2%, Rm indicate tensile strength, and A indicates elongation of having no progeny
Rate, Z indicate the contraction percentage of area, AKUIndicate impact absorbing energy.It is measured according to the defined method of TB/T1632.2 standard, with
Upper parameter value is average value.Rm >=980MPa, A >=6.0%, AKU>=6.5J is qualification.
Table 4
Note: quiet curved test is with reference to document AS1085.20-2012, rail bottom minimum stress 900MPa, i.e. F >=1850kN
It is constantly qualification；Being broken minimum amount of deflection 75kg/m rail minimum value is 13.3mm, that is, is met the requirements.In addition, in TB/T1632.2-
In 2014,75kg/m rail rail head compression F >=1850kN is constantly qualified.There is zero defect for fracture, if in test process
In do not break, then break after artificial opening to carry out the observation of fracture.
Comparative example 1
The comparative example is used to illustrate the method and rail of the mobile Flash Butt Welding of the mobile rail of reference
The PG5 hypereutectoid rail of 75kg/m and PG4 heat-treated rail are welded using mobile steel rail flash welding machine, dodged
The thermal weld stress amount in flat stage is 3MJ, displacement 2.8mm, duration 35s；The thermal weld stress amount of pulsation phase
For 9.4MJ, displacement 10.2mm, duration 81.2s；Accelerating the thermal weld stress amount for burning the stage is 0.8MJ, displacement
Amount is 11.6mm, duration 28s；The thermal weld stress amount in upset stage is 0.3MJ, displacement 19mm, charges upset
Time is 1s；The dwell pressure of packing stage is 28.6t, duration 20s.Total heat input of welding is 13.5MJ, is held
The continuous time is 165.2s, and it is 43.6mm that rail, which burns displacement, and welding upset amount is 19mm.
After the completion of upset is with pushing away convex, the steel rail weld joint that above-mentioned welding is obtained carries out post weld heat treatment.Steel first
Rail welding point to 290 DEG C, heats welding point extremely using intermediate frequency power supply tunneling boring by 1080 DEG C of natural coolings (first is cooling)
Rail head weld seam tyre tread peak temperature is 890 DEG C, and the signal after infrared radiation thermometer automatic collection wheel tread temperature to temperature is simultaneously automatically closed immediately
Heating power supply switch.Then start (second is cooling) air-cooled to tyre tread spray wind at 840 DEG C, air-cooled heating is accelerated using air-jet device
Welding point tyre tread heating region after to temperature, air nozzle spray wind wind pressure 0.18MPa apart from tyre tread 30mm.Using infrared measurement of temperature
Instrument automatic collection and monitoring wheel tread temperature, when weld seam wheel tread temperature is air-cooled be down to final cooling temperature be 390 DEG C when, be automatically closed air-cooled
Device, subsequent welding point carry out cooled to room temperature.
Rail after welding drops hammer not over continuous 15 mobile flash welding connectors of TB/T1632.2 standard requirements
It examines, fracture when the 4th is dropped hammer.
It can be seen that from the result of embodiment using method provided by the invention, to hypereutectoid rail and PG4 heat- treated steel
Rail welding point carries out post weld heat treatment, and the internal flaw of xenogenesis rail joint is few, welding quality stable, can be tried by fatigue
It tests, stretch and the test of impact test and quiet curved test is met the requirements；The connector of xenogenesis rail can continue through 15 sudden strains of a muscle
Flush weld connector drops hammer inspection, has preferable stability.And the comparative example 1 of technical solution of the present invention is not used, the steel after welding
Rail can not be examined by dropping hammer, and be unsatisfactory for requiring.
The preferred embodiment of the present invention has been described above in detail, still, during present invention is not limited to the embodiments described above
Detail within the scope of the technical concept of the present invention can be with various simple variants of the technical solution of the present invention are made, this
A little simple variants all belong to the scope of protection of the present invention.
It is further to note that specific technical features described in the above specific embodiments, in not lance
In the case where shield, it can be combined in any appropriate way.In order to avoid unnecessary repetition, the present invention to it is various can
No further explanation will be given for the combination of energy.
In addition, various embodiments of the present invention can be combined randomly, as long as it is without prejudice to originally
The thought of invention, it should also be regarded as the disclosure of the present invention.
Claims (13)
1. the method that a kind of pair of steel rail weld joint carries out post weld heat treatment, which is characterized in that this method comprises: welding is obtained
Steel rail weld joint to be cooled carry out first and be cooled to 400 DEG C hereinafter, the first steel rail weld joint after cooling is heated
To 860-930 DEG C, it is the mode of tunneling boring heating by the mode that steel rail weld joint is heated to 860-930 DEG C, then carries out the
Two wheel tread temperatures for being cooled to steel rail weld joint are 410-450 DEG C, and the second cooling initial temperature is not less than 830 DEG C；Wherein,
The steel rail weld joint is 75kg/m hypereutectoid rail and pearlite steel rail welding point, and steel rail weld joint is mobile flash of light
The welding point being welded, the pearlite steel rail are PG4 heat-treated rail, and the 75kg/m hypereutectoid rail is PG5 mistake
Eutectoid rail during post weld heat treatment, is limited with the Critical cooling speed of pearlite steel rail.
2. according to the method described in claim 1, wherein, the described first cooling mode is natural cooling.
3. according to the method described in claim 1, wherein, it is cold that the steel rail weld joint to be cooled that welding is obtained carries out first
But to 280-360 DEG C.
4. according to the method described in claim 3, wherein, it is cold that the steel rail weld joint to be cooled that welding is obtained carries out first
But to 290-330 DEG C.
5. according to the method described in claim 4, wherein, the first steel rail weld joint after cooling is heated to 860-930 DEG C,
Then carrying out the wheel tread temperature that second is cooled to steel rail weld joint is 430-450 DEG C.
6. according to the method described in claim 5, wherein, the first steel rail weld joint after cooling is heated to 870-925 DEG C.
7. according to the method described in claim 6, wherein, the first steel rail weld joint after cooling is heated to 880-920 DEG C.
8. according to the method described in claim 1, wherein, using Medium frequency induction as shape electric heater and/or oxy-acetylene flame picture
Steel rail weld joint is heated to 860-930 DEG C by shape heater.
9. according to the method described in claim 1, wherein, the described second cooling mode is air-cooled.
10. according to the method described in claim 9, wherein, it is described it is air-cooled include using air-jet device to steel rail weld joint
Tyre tread heating region is cooled down, and the distance of air nozzle to tyre tread is 20-70mm；The wind pressure for spraying wind is 0.15-0.5MPa.
11. according to the method described in claim 10, wherein, it is described it is air-cooled include using air-jet device to steel rail weld joint
Tyre tread heating region is cooled down, and the distance of air nozzle to tyre tread is 30-50mm；The wind pressure for spraying wind is 0.18-0.25MPa.
12. method described in any one of -11 according to claim 1, wherein the rail welding to be cooled welded connects
The initial temperature of head is 1050-1200 DEG C.
13. according to the method for claim 12, wherein the method also includes: after second is cooling, by rail welding
Connector cooled to room temperature.
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