CN108950158A - Eutectoid rail and hypereutectoid steel rail weld joint heat treatment method - Google Patents
Eutectoid rail and hypereutectoid steel rail weld joint heat treatment method Download PDFInfo
- Publication number
- CN108950158A CN108950158A CN201810946740.2A CN201810946740A CN108950158A CN 108950158 A CN108950158 A CN 108950158A CN 201810946740 A CN201810946740 A CN 201810946740A CN 108950158 A CN108950158 A CN 108950158A
- Authority
- CN
- China
- Prior art keywords
- rail
- cooling
- welding point
- eutectoid
- welding
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- 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
- C21D1/78—Combined heat-treatments not provided for above
-
- 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
-
- 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
- C21D2211/009—Pearlite
Landscapes
- 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 invention discloses a kind of eutectoid rail and hypereutectoid steel rail weld joint heat treatment method, are related to railway track manufacturing technology field, provide it is a kind of cost is relatively low and after handling welding point satisfactory mechanical property welding point heat treatment method.This method includes the following steps successively carried out: it is cooling that the welding point that temperature is 1000~1400 DEG C A, is carried out the first stage, and welding point surface temperature is made to be reduced to 570~640 DEG C, and the first stage is cooled to air-cooled, and cooling velocity is 3.0~5.0 DEG C/s；B, welding point is subjected to second stage cooling, welding point surface temperature is made to be reduced to 170~230 DEG C, second stage is cooled to the cooling carried out using imitative type cooling device, and cooling velocity is 1.5~2.5 DEG C/s；C, welding point is subjected to phase III cooling, welding point surface temperature is made to be reduced to 10~30 DEG C, the phase III is cooled to the cooling carried out using imitative type cooling device, and cooling velocity is 0.05~0.50 DEG C/s.
Description
Technical field
The present invention relates to railway track manufacturing technology fields more particularly to a kind of eutectoid rail to connect with hypereutectoid rail welding
Head heat treatment method.
Background technique
Currently, heavy haul railway route mostly uses eutectoid pearlite steel rail both at home and abroad, the phosphorus content of such rail usually exists
In 0.72~0.82% weight range, metallographic structure is pearlite, has obdurability matching good, comprehensive mechanical property index is suitable
The features such as middle.With the fast development of railway, high axle load heavy-haul line proposes requirements at the higher level to rail military service performance.Due to passing
The comprehensive mechanical property and welding performance of system pearlite steel rail have almost developed to the limit, and in this case, strength grade is higher,
The hypereutectoid rail for taking into account the comprehensive performances such as good abrasion resistance properties and contact fatigue comes into being, and the phosphorus content of such rail is logical
Often in 0.90~1.10% weight range, metallographic structure is pearlite+a small amount of secondary cementite.At this stage, rail is mobile dodges
Flush weld has become the online welding technique of mainstream rail at domestic and international construction of railways scene, and for strength grade and material not phase
With two kinds of rail, the difference between base material performance brings huge challenge to its welding.Meanwhile rail is made by Thermal Cycle
With rear, the quench-hardened case of welding region disappears and in the biggish soft area of weld seam two sides formation width, leads to weld seam and heat affecting
The hardness in area is lower than rail base material.Rail easily preferentially forms " saddle in the rail head tyre tread of welding point during route is on active service
Type " abrasion, not only increase wheel-rail impact, also seriously affect rail service life, or even jeopardize traffic safety.Thus, such as
The mechanical property what restores rail and reduces by welding is just able to the premise applied at rail.
Currently, analysing the report and documents and materials of rail welding and post weld heat treatment technical study together about hypereutectoid rail
It is also relatively fewer.CN201610909362.1 discloses a kind of hypereutectoid rail and PG4 heat treatment eutectoid pearlite steel rail welding
The post weld heat treatment method of connector, this method include that the steel rail weld joint to be cooled that welding obtains is carried out first to be cooled to
400 DEG C hereinafter, the first steel rail weld joint after cooling is then heated to 860~930 DEG C, then carries out second and are cooled to steel
The wheel tread temperature of rail welding point is 410~450 DEG C.It can be met using the xenogenesis steel rail weld joint that this method obtains domestic existing
In row railroad industry standard TB/T1632.2-2014 " rail welding part 2: Flash Butt Welding " for fatigue, stretch, impact with
And the test request of quiet curved test.But rail postwelding normalizing heat treatment process it has been related in foregoing invention, has needed using rail
PWHT equipment carries out local heating to steel rail weld joint, and not only operation and implementation process are complicated, but also high expensive.
Summary of the invention
The technical problem to be solved by the present invention is providing, a kind of cost is relatively low and welding point satisfactory mechanical property after handling
Eutectoid rail and hypereutectoid steel rail weld joint heat treatment method.
In order to solve the above problem the technical solution adopted is that: eutectoid rail and hypereutectoid steel rail weld joint heat treatment method
Including the following steps successively carried out:
A, the welding point that the temperature for forming eutectoid pearlite steel rail and hypereutectoid rail welding is 1000~1400 DEG C
First stage cooling is carried out, so that welding point surface temperature is reduced to 570~640 DEG C, the first stage is cooled in air natural
Cooling, cooling velocity is 3.0~5.0 DEG C/s；
B, that welding point is carried out second stage is cooling, and welding point surface temperature is made to be reduced to 170~230 DEG C, and second
Stage is cooled to the cooling carried out using imitative type cooling device, imitates type cooling device Welded Joints injection compressed air or water mist
Gaseous mixture, cooling velocity are 1.5~2.5 DEG C/s；
C, welding point is subjected to phase III cooling, so that welding point surface temperature is reduced to 10~30 DEG C, third rank
Section is cooled to the cooling carried out using imitative type cooling device, imitates type cooling device Welded Joints injection compressed air or water mist is mixed
Gas is closed, cooling velocity is 0.05~0.50 DEG C/s.
Further, imitating type cooling device apart from 20~50mm of welding point in step B；Cooling device is ejected
Compressed air or water mist gaseous mixture pressure be 0.40~0.80MPa.
Further, imitating type cooling device apart from 20~50mm of welding point in step C；Cooling device is ejected
Compressed air or water mist gaseous mixture pressure be 0.05~0.25MPa.
Further, welding point be by rail rail type it is identical, specification be 60~75kg/m eutectoid pearlite steel rail and
Hypereutectoid rail welds the connector to be formed by the mobile flash welder of rail.
The beneficial effects of the present invention are: (1) present invention is heat-treated using the welding waste heat of welding point, it is heat treated
It does not need to reheat in journey, therefore simplifies heat treatment process, and reduce cost.
(2) this method can by the martensitic structure percentage composition being likely to occur in rail joint metallographic structure control≤
In 3% range.Meanwhile it can make meeting corresponding eutectoid away from the rail joint longitudinal direction hardness in the region Weld pipe mill ± 10mm
± 30HV the range of pearlite steel rail and hypereutectoid rail base material average hardness (does not include the axis of a weld of decarburization, by rail
Welding high temperature influences, and Weld pipe mill decarburization simultaneously generates melting loss of elements, leads to lower hardness), and the softening of joint welding two sides
Sector width is below 15mm.Helped to improve rail during route is on active service due to welding region lower hardness using the present invention
Caused steel rail weld joint " saddle " abrasion, help to ensure that railway operation safety.
Detailed description of the invention
Fig. 1 is that the rail head of the steel rail weld joint under the conditions of the post weld heat treatment obtained using the method in embodiment 1 is stepped on
Longitudinal stiffening effect figure of 3~5mm position below face.
Fig. 2 is the rail head using the steel rail weld joint under the conditions of the obtained post weld heat treatment of method in embodiment 2
Longitudinal stiffening effect figure of 3~5mm position below tyre tread.
Fig. 3 is that the rail head of the steel rail weld joint using the obtained postwelding of method in comparative example 1 under the conditions of air-cooled is stepped on
Longitudinal stiffening effect figure of 3~5mm position below face.
Fig. 4 is the rail head using the steel rail weld joint under the conditions of the obtained post weld heat treatment of method in comparative example 2
Longitudinal stiffening effect figure of 3~5mm position below tyre tread.
Fig. 5 is the rail head using the steel rail weld joint under the conditions of the obtained post weld heat treatment of method in comparative example 3
Longitudinal stiffening effect figure of 3~5mm position below tyre tread.
Fig. 6 is each position of the present invention or position view.
Fig. 7 is the rail head tyre tread metallographic specimen sample position schematic diagram of rail joint of the invention.
Specific embodiment
The present invention is further described with reference to the accompanying drawings and detailed description.
Heretofore described welding point be by rail rail type it is identical, specification be 60~75kg/m eutectoid pearlite steel rail and
Hypereutectoid rail welds the connector to be formed by the mobile flash welder of rail.Welding point includes that weld seam and/or heat affected area exist
Interior length is the region of 70~100mm range, and the center in the region is weld seam.In the present invention, " room temperature " is 10~30
The temperature of DEG C range.
It is eutectoid pearlite steel rail at a in Fig. 6, is welding point at b, be hypereutectoid rail at c, is rail head tyre tread at d.
It is Weld pipe mill at e in Fig. 6 and Fig. 7.It is metallographic specimen sample position at f in Fig. 7.
The critical cooling rate about 0.7 of martensite transfor mation during eutectoid pearlite steel rail steel continuous cooling transformation~
1.5 DEG C/s, and the critical cooling rate about 1.8~3.0 of the martensite transfor mation during hypereutectoid steel rail steel continuous cooling transformation
℃/s.About 250 DEG C of eutectoid pearlite steel rail Ms temperature (start temperature that martensitic structure is formed), and hypereutectoid rail Ms temperature
About 190 DEG C.To avoid steel rail weld joint from the abnormal structures such as martensite occur, when the welding for analysing rail together to hypereutectoid rail
When connector carries out post weld heat treatment, the final cooling temperature during need to being quickly cooled down post weld heat treatment is controlled in eutectoid pearlite steel
It is more than rail Ms temperature.Meanwhile the cooling velocity in PWHT procedures must be relatively low with Critical cooling speed eutectoid pearlite
Rail steel is limited, and otherwise connector will cause premature fatigue to be broken due to the martensitic structure hardened.In the steel of some countries
It is carbon containing for certain high grades, height as provided in the rail welding standard AS1085.20-2012 of Australia in rail welding standard
The rail of amount and high alloy content goes out martensite in steel rail weld joint under the observation multiplying power of metallographic microscope 100x
Existing most serious region, the percentage composition of martensitic structure must not be higher than 5%, and otherwise connector will be due to the geneva largely hardened
Body tissue and cause premature fatigue to be broken, seriously affect railway operation safety.Therefore, the horse in strict control rail welding tissue
Family name's body content is most important for the stable operation of rail track.Further, since there is also few in hypereutectoid rail base material
The secondary cementite of amount must be in austenite to pearl to avoid secondary cementite during rail welding in netted Intergranular precipitation
Butt joint is implemented to be quickly cooled down before body of light transformation starts.
Based on above-mentioned discovery, the present invention is as follows: eutectoid rail and hypereutectoid steel rail weld joint heat treatment method include according to
The following steps of secondary progress: A, the welding that the temperature that eutectoid rail and hypereutectoid rail welding are formed is 1000~1400 DEG C is connect
Head carries out first stage cooling, so that welding point surface temperature is reduced to 570~640 DEG C, the first stage is cooled in air certainly
So cooling, cooling velocity is 3.0~5.0 DEG C/s；B, welding point is subjected to second stage cooling, makes welding point surface temperature
170~230 DEG C are reduced to, second stage is cooled to the cooling carried out using imitative type cooling device, imitates type cooling device to welding
Connector sprays compressed air or water mist gaseous mixture, and cooling velocity is 1.5~2.5 DEG C/s；C, welding point is subjected to the phase III
It is cooling, so that welding point surface temperature is reduced to 10~30 DEG C, the phase III is cooled to carry out using imitative type cooling device cold
But, type cooling device Welded Joints injection compressed air or water mist gaseous mixture are imitated, cooling velocity is 0.05~0.50 DEG C/s.
The present invention realizes the PWHT procedures of rail using the welding waste heat of rail.For the obtained residual temperature of welding compared with
High rail joint implements postwelding and accelerates cooling, to reduce phase transition temperature of the connector rail head from austenite to perlitic transformation, from
And improve the hardness in austenite recrystallization area.Based on Principles of Metallography, rail joint is deposited under postwelding high temperature condition of fast cooling
In certain dynamic degree of supercooling, austenite under nonequilibrium condition is caused to move down to the phase transition temperature of perlitic transformation, and with mistake
The increase of cold degree, phase transition temperature gradually decrease.Thus, even if opening the relatively low second stage cooling of cold temperature, connector rail
Head remains to occur the structural transformation from austenite to pearlite.
In the present invention, the first stage is cooled to the natural cooling carried out in air, can be by adjusting experimental enviroment
Temperature (as used central air-conditioner temperature control) realizes the control to first stage cooling velocity.The stage be although it is air-cooled but at a temperature of
Reduction of speed degree is still faster the reason is that welding point is larger with Air Temperature Difference.
The cold temperature of opening of second cooling stage is 570~640 DEG C.In the present invention, the described second cooling end cold temperature
Degree is higher than the Ms (martensite start) point (Ms temperature) of hypereutectoid steel rail steel and eutectoid pearlite steel rail steel, second in the present invention
Cooling final cooling temperature is 170~230 DEG C.In step B, it is ensured that cooling velocity is 1.5~2.5 DEG C/s, be can be used such as lower section
Method: type cooling device is imitated apart from 20~50mm of welding point；Compressed air that cooling device is ejected or water mist gaseous mixture
Pressure is 0.40~0.80MPa.
When carrying out phase III cooling to rail joint, for the martensitic structure for avoiding connector from occurring hardening, the present invention
Selection is implemented with 0.05-0.50 DEG C of the cooling velocity lower than eutectoid pearlite steel rail steel martensite transfor mation Critical cooling speed/s butt joint
It cools down at a slow speed.Guarantee that following method can be used in 0.05-0.50 DEG C of cooling velocity/s: imitating type cooling device apart from welding point 20
~50mm；The pressure of compressed air or water mist gaseous mixture that cooling device is ejected is 0.05~0.25MPa.
It below will the present invention will be described in detail by specific embodiment.In following embodiment, hypereutectoid rail and altogether
Analysis pearlite steel rail is all produced by Pan Gang group.
Embodiment 1
Specification connects for the upset during the mobile Flash Butt Welding of rail completion of 68kg/m and after pushing away tumor to what welding obtained
Head carries out post weld heat treatment.Firstly, the residual temperature that welding is obtained is cooling fast with the first of 4.8 DEG C/s in 1100 DEG C of rail joint
Degree carries out first stage cooling so that the rail head skin temperature of rail joint is down to 630 DEG C, then makes rail joint with 2.0 DEG C/s
The second cooling velocity to carry out second stage cooling the rail head skin temperature of rail joint is down to 220 DEG C, finally make rail
Connector carries out phase III cooling with the third cooling velocity of 0.4 DEG C/s the rail head skin temperature of rail joint is down to 25 DEG C
Room temperature, to obtain the steel rail weld joint of the invention through post weld heat treatment.In PWHT procedures, first is cooled to
The natural cooling carried out in air, second cools down and rail head of rail is used to imitate type cooling device to compress in third cooling procedure
Air or water mist gaseous mixture cool down the rail head tyre tread of rail joint and rail head side as cooling medium, cooling device away from
From rail head of rail tyre tread 40mm.In second cooling procedure, the compressed air of cooling device injection or the gas pressure of water mist gaseous mixture
Power is 0.60MPa.In third cooling procedure, the compressed air of cooling device injection or the gas pressure of water mist gaseous mixture are
0.20MPa.Rail head of rail wheel tread temperature is monitored using infrared radiation thermometer.
The rail joint through post weld heat treatment that the present embodiment is obtained is machined to longitudinal hardness specimens.It is hard using cloth dimension
Degree meter position 4mm below rail head of rail tyre tread (Laizhou, Shandong city testing machine head factory, model HBV-30A), using 2mm between measuring point
Away from longitudinal Vickers hardness detection is carried out to hardness specimens, two sides are symmetrically arranged measuring point to the left and right centered on weld seam.Vickers hardness
The method of inspection is carried out referring to GB/T 4340.1-2009 " Vickers Hardness Test part 1: test method ", is marked using HV
Ruler.Hardness Surveillance data are shown in Table 1, and the distributed effect of connector longitudinal direction hardness is as shown in Figure 1.
Table 1:
By table 1 and Fig. 1 it is found that for steel rail weld joint processed by the invention, away from the region Weld pipe mill ± 10mm
Interior rail joint longitudinal direction hardness meets corresponding eutectoid pearlite steel rail and hypereutectoid rail base material average hardness respectively
± 30HV range (does not include the axis of a weld of decarburization: being influenced by rail welding high temperature, Weld pipe mill decarburization simultaneously generates first biscuiting
Damage, leads to lower hardness).The softening sector width of joint welding eutectoid pearlite steel rail side is 8.6mm, hypereutectoid rail side
Softening sector width be 6.4mm, the softening sector width of joint welding two sides is below 15mm.
The sampling referring to shown in Fig. 7, by GB/T 13298-2015 " the metal microstructure method of inspection " to rail joint metallographic
Sample carries out microstructure examination, carries out etch to rail joint metallographic specimen using 3% nital, is come using Germany
Card MeF3 optical microscopy observes rail joint metallographic structure.Inspection result shows: welding point eutectoid rail side
Heat affected area in there is a small amount of martensitic structure.In the case where the 100x of metallographic microscope observes multiplying power, for martensite group
Existing most serious region is woven, through counting, the percentage composition of martensitic structure is 1.5%.Meanwhile welding point hypereutectoid rail
The metallographic structure of side is normal, does not occur the abnormal structures such as martensite, bainite.
Embodiment 2
Specification connects for the upset during the mobile Flash Butt Welding of rail completion of 60kg/m and after pushing away tumor to what welding obtained
Head carries out post weld heat treatment.Firstly, the residual temperature that welding is obtained is cooling fast with the first of 4.2 DEG C/s in 1000 DEG C of rail joint
Degree carries out first stage cooling so that the rail head skin temperature of rail joint is down to 620 DEG C, then makes rail joint with 2.3 DEG C/s
The second cooling velocity to carry out second stage cooling the rail head skin temperature of rail joint is down to 185 DEG C, finally make rail
Connector carries out phase III cooling with the third cooling velocity of 0.10 DEG C/s the rail head skin temperature of rail joint is down to 25
DEG C room temperature, to obtain the heterogeneous material steel rail weld joint of the invention through post weld heat treatment.In PWHT procedures,
First is cooled to the natural cooling carried out in air；Second is cooling in third cooling procedure, and it is cold to imitate type using rail head of rail
But device cools down the rail head tyre tread of rail joint and rail head side using water mist gaseous mixture as cooling medium, cooling device
Apart from rail head of rail tyre tread 40mm；In second cooling procedure, the gas pressure of the water mist gaseous mixture of cooling device injection is
0.66MPa；In third cooling procedure, the gas pressure of the water mist gaseous mixture of cooling device injection is 0.09MPa.Using infrared survey
Warm instrument monitors rail head of rail wheel tread temperature.
The rail joint through post weld heat treatment that the present embodiment is obtained is machined to longitudinal hardness specimens.It is hard using cloth dimension
Degree meter position 4mm below rail head of rail tyre tread (Laizhou, Shandong city testing machine head factory, model HBV-30A), using 2mm between measuring point
Away from longitudinal Vickers hardness detection is carried out to hardness specimens, two sides are symmetrically arranged measuring point to the left and right centered on weld seam.Vickers hardness
The method of inspection is carried out referring to GB/T 4340.1-2009 " Vickers Hardness Test part 1: test method ", is marked using HV
Ruler.Hardness Surveillance data are shown in Table 2, and the distributed effect of connector longitudinal direction hardness is as shown in Figure 2.
Table 2:
By table 2 and Fig. 2 it is found that for steel rail weld joint processed by the invention, away from the region Weld pipe mill ± 10mm
Interior rail joint longitudinal direction hardness meets corresponding eutectoid pearlite steel rail and hypereutectoid rail base material average hardness respectively
± 30HV range (does not include the axis of a weld of decarburization: being influenced by rail welding high temperature, Weld pipe mill decarburization simultaneously generates first biscuiting
Damage, leads to lower hardness).The softening sector width of joint welding eutectoid pearlite steel rail side is 7.0mm, hypereutectoid rail side
Softening sector width be 6.5mm, the softening sector width of joint welding two sides is below 15mm.
The sampling referring to shown in Fig. 7, by GB/T 13298-2015 " the metal microstructure method of inspection " to rail joint metallographic
Sample carries out microstructure examination, carries out etch to rail joint metallographic specimen using 3% nital, is come using Germany
Card MeF3 optical microscopy observes rail joint metallographic structure.Inspection result shows connector hypereutectoid rail and eutectoid
Occurs different degrees of martensitic structure in the welding heat affected zone of pearlite steel rail.It is observed in the 100x of metallographic microscope
Under multiplying power, for the most serious region that martensitic structure in connector occurs, through counting, the martensitic structure hundred of eutectoid rail side
Dividing content is 2.8%, and the martensitic structure percentage composition of hypereutectoid rail side is 1.5%.The horse of steel rail weld joint two sides
Family name's body tissue percentage composition is respectively less than 3.0%, helps to ensure that railway operation safety.
Comparative example 1
Specification is for the upset during the mobile Flash Butt Welding of rail completion of 68kg/m and after pushing away tumor, by residual temperature at 1100 DEG C
Rail joint Direct Air-Cooled to room temperature (about 25 DEG C), to obtain the steel rail weld joint under the conditions of air-cooled (natural cooling).
Rail joint under the conditions of the postwelding for taking this comparative example to obtain is air-cooled is processed into longitudinal hardness specimens.It is hard using cloth dimension
Degree meter position 5mm below rail head of rail tyre tread (Laizhou, Shandong city testing machine head factory, model HBV-30A), using 2mm between measuring point
Away from longitudinal Vickers hardness detection is carried out to hardness specimens, two sides are symmetrically arranged measuring point to the left and right centered on weld seam.Vickers hardness
The method of inspection is carried out referring to GB/T 4340.1-2009 " Vickers Hardness Test part 1: test method ", is marked using HV
Ruler.Hardness Surveillance data are shown in Table 3, and the distributed effect of connector longitudinal direction hardness is as shown in Figure 3.
Table 3:
By table 3 and Fig. 3 it is found that for not connect using the rail welding of post weld heat treatment method provided by the invention processing
Head, compared with the rail base material hardness of weld seam two sides, entire welding region is rendered as soft state.Away from Weld pipe mill ± 10mm
It is average that rail joint longitudinal direction hardness in region is not able to satisfy corresponding eutectoid pearlite steel rail and hypereutectoid rail base material
± 30HV the range of hardness (does not include the axis of a weld of decarburization: being influenced by rail welding high temperature, Weld pipe mill decarburization simultaneously generates
Melting loss of elements leads to lower hardness).The softening sector width of joint welding eutectoid pearlite steel rail side is 17.0mm, hypereutectoid
The softening sector width of rail side is 18.0mm.The welding point obtained by the comparative example is easily preferential during route is on active service
It forms that rail head of rail tyre tread is low collapses in the softened zone of steel rail weld joint, influences Track regularity and traffic safety.
The sampling referring to shown in Fig. 7, by GB/T 13298-2015 " the metal microstructure method of inspection " to rail joint metallographic
Sample carries out microstructure examination, carries out etch to rail joint metallographic specimen using 3% nital, is come using Germany
Card MeF3 optical microscopy observes rail joint metallographic structure.Inspection result shows that welding point metallographic structure is normal,
The abnormal structures such as martensite-free, bainite.
Comparative example 2
Specification connects for the upset during the mobile Flash Butt Welding of rail completion of 75kg/m and after pushing away tumor to what welding obtained
Head carries out post weld heat treatment.Firstly, the residual temperature that welding is obtained is cooling fast with the first of 4.0 DEG C/s in 1050 DEG C of rail joint
Degree carries out first stage cooling so that the rail head skin temperature of rail joint is down to 620 DEG C, then makes rail joint with 2.2 DEG C/s
The second cooling velocity to carry out second stage cooling the rail head skin temperature of rail joint is down to 160 DEG C, finally make rail
Connector carries out phase III cooling with the third cooling velocity of 0.10 DEG C/s the rail head skin temperature of rail joint is down to 25
DEG C room temperature, to obtain the heterogeneous material steel rail weld joint of the invention through post weld heat treatment.In PWHT procedures,
First is cooled to the natural cooling carried out in air；Second is cooling in third cooling procedure, and it is cold to imitate type using rail head of rail
But device cools down the rail head tyre tread of rail joint and rail head side using compressed air as cooling medium, cooling device away from
From rail head of rail tyre tread 40mm；In second cooling procedure, the gas pressure of the compressed air of cooling device injection is 0.65MPa；
In third cooling procedure, the gas pressure of the compressed air of cooling device injection is 0.09MPa.Steel is monitored using infrared radiation thermometer
Rail rail head wheel tread temperature.
Rail joint under the conditions of the postwelding for taking this comparative example to obtain is air-cooled is processed into longitudinal hardness specimens.It is hard using cloth dimension
Degree meter position 4mm below rail head of rail tyre tread (Laizhou, Shandong city testing machine head factory, model HBV-30A), using 2mm between measuring point
Away from longitudinal Vickers hardness detection is carried out to hardness specimens, two sides are symmetrically arranged measuring point to the left and right centered on weld seam.Vickers hardness
The method of inspection is carried out referring to GB/T 4340.1-2009 " Vickers Hardness Test part 1: test method ", is marked using HV
Ruler.Hardness Surveillance data are shown in Table 4, and the distributed effect of connector longitudinal direction hardness is as shown in Figure 4.
Table 4:
By table 4 and Fig. 4 it is found that for not connect using the rail welding of post weld heat treatment method provided by the invention processing
The softening sector width of head, obtained connector eutectoid rail side is 9mm, and the softening sector width of hypereutectoid rail side is
8.2mm.Joint welding eutectoid pearlite steel rail side hardness is higher, and the hardness away from the position Weld pipe mill 2mm reaches 480HV, surpasses
Eutectoid pearlite steel rail base material average hardness 40HV out.
The sampling referring to shown in Fig. 7, by GB/T 13298-2015 " the metal microstructure method of inspection " to rail joint metallographic
Sample carries out microstructure examination, carries out etch to rail joint metallographic specimen using 3% nital, is come using Germany
Card MeF3 optical microscopy observes rail joint metallographic structure.Inspection result shows connector hypereutectoid rail and eutectoid
Occurs different degrees of martensitic structure in the welding heat affected zone of pearlite steel rail.It is observed in the 100x of metallographic microscope
Under multiplying power, for the most serious region that martensitic structure in connector occurs, through counting, the martensitic structure hundred of eutectoid rail side
Dividing content is 11%, and the martensitic structure percentage composition of hypereutectoid rail side is 7%.The martensite of steel rail weld joint two sides
Organizing percentage composition has been more than 5%, is unfavorable for railway operation safety.
Comparative example 3
Specification connects for the upset during the mobile Flash Butt Welding of rail completion of 68kg/m and after pushing away tumor to what welding obtained
Head carries out post weld heat treatment.Firstly, the residual temperature that welding is obtained is cooling fast with the first of 4.2 DEG C/s in 1050 DEG C of rail joint
Degree carries out first stage cooling so that the rail head skin temperature of rail joint is down to 600 DEG C, then makes rail joint with 2.2 DEG C/s
The second cooling velocity to carry out second stage cooling the rail head skin temperature of rail joint is down to 180 DEG C, finally make rail
Connector carries out phase III cooling with the third cooling velocity of 2.5 DEG C/s the rail head skin temperature of rail joint is down to 25 DEG C
Room temperature, to obtain the heterogeneous material steel rail weld joint of the invention through post weld heat treatment.In PWHT procedures, the
One is cooled to the natural cooling carried out in air；Second is cooling in third cooling procedure, and it is cooling to imitate type using rail head of rail
Device cools down the rail head tyre tread of rail joint and rail head side using compressed air as cooling medium, cooling device distance
Rail head of rail tyre tread 40mm；In second cooling procedure, the gas pressure of the compressed air of cooling device injection is 0.65MPa；The
In three cooling procedures, the gas pressure of the compressed air of cooling device injection is 0.80MPa.Rail is monitored using infrared radiation thermometer
Rail head wheel tread temperature.
Rail joint under the conditions of the postwelding for taking this comparative example to obtain is air-cooled is processed into longitudinal hardness specimens.It is hard using cloth dimension
Degree meter position 4mm below rail head of rail tyre tread (Laizhou, Shandong city testing machine head factory, model HBV-30A), using 2mm between measuring point
Away from longitudinal Vickers hardness detection is carried out to hardness specimens, two sides are symmetrically arranged measuring point to the left and right centered on weld seam.Vickers hardness
The method of inspection is carried out referring to GB/T4340.1-2009 " Vickers Hardness Test part 1: test method ", using HV scale.
Hardness Surveillance data are shown in Table 5, and the distributed effect of connector longitudinal direction hardness is as shown in Figure 5.
Table 5:
By table 5 and Fig. 5 it is found that for not connect using the rail welding of post weld heat treatment method provided by the invention processing
The softening sector width of head, obtained connector eutectoid rail side is 8.5mm, and the softening sector width of hypereutectoid rail side is
8.7mm.The hardness of welding point eutectoid pearlite steel rail side is higher, exceeds altogether away from the hardness at weld seam 2mm, 4mm, 6mm
Analyse pearlite steel rail base material average hardness 30HV or more.
The sampling referring to shown in Fig. 7, by GB/T 13298-2015 " the metal microstructure method of inspection " to rail joint metallographic
Sample carries out microstructure examination, carries out etch to rail joint metallographic specimen using 3% nital, is come using Germany
Card MeF3 optical microscopy observes rail joint metallographic structure.Inspection result shows connector hypereutectoid rail and eutectoid
Occurs different degrees of martensite in the welding heat affected zone of pearlite steel rail.Multiplying power is observed in the 100x of metallographic microscope
Under, for the most serious region that martensitic structure in connector occurs, through counting, the martensitic structure percentage of connector eutectoid rail contains
Amount reaches 15%, and the martensitic structure percentage composition of connector hypereutectoid rail reaches 10%.The martensitic structure hundred of connector two sides
Point content has been more than 5%, is unfavorable for railway operation safety.
By welding point rail head tyre tread longitudinal direction hardness of the comparison diagram 1 into Fig. 5 and welding joint softened sector width it can be seen that
Pearlite steel rail welding point is analysed for hypereutectoid rail using post weld heat treatment method provided by the invention together and implements postwelding
Heat treatment can make meeting corresponding eutectoid pearly-lustre respectively away from the rail joint longitudinal direction hardness in the region Weld pipe mill ± 10mm
± 30HV the range of body rail and hypereutectoid rail base material average hardness (does not include the axis of a weld of decarburization: by rail welding
High temperature influences, and Weld pipe mill decarburization simultaneously generates melting loss of elements, leads to lower hardness), and the softened zone of joint welding two sides is wide
Degree is below 15mm.Meanwhile, it is capable to which the martensitic structure percentage composition being likely to occur in rail joint metallographic structure control is existed
In≤3% range, railway operation safety is advantageously ensured that.
Claims (4)
1. eutectoid rail and hypereutectoid steel rail weld joint heat treatment method, it is characterised in that: including the following step successively carried out
It is rapid:
A, the welding point that the temperature that eutectoid pearlite steel rail and hypereutectoid rail welding are formed is 1000~1400 DEG C is carried out
First stage is cooling, and welding point surface temperature is made to be reduced to 570~640 DEG C, and the first stage is cooled to natural cooling in air,
Cooling velocity is 3.0~5.0 DEG C/s；
B, welding point is subjected to second stage cooling, so that welding point surface temperature is reduced to 170~230 DEG C, second stage
It is cooled to the cooling carried out using imitative type cooling device, imitates type cooling device Welded Joints injection compressed air or water mist mixing
Gas, cooling velocity are 1.5~2.5 DEG C/s；
C, welding point is subjected to phase III cooling, so that welding point surface temperature is reduced to 10~30 DEG C, the phase III is cold
But it is the cooling carried out using imitative type cooling device, imitates type cooling device Welded Joints injection compressed air or water mist mixing
Gas, cooling velocity are 0.05~0.50 DEG C/s.
2. eutectoid rail according to claim 1 and hypereutectoid steel rail weld joint heat treatment method, it is characterised in that: step
In rapid B, type cooling device is imitated apart from 20~50mm of welding point；The compressed air or water mist gaseous mixture that cooling device is ejected
Pressure be 0.40~0.80MPa.
3. eutectoid rail according to claim 1 and hypereutectoid steel rail weld joint heat treatment method, it is characterised in that: step
In rapid C, type cooling device is imitated apart from 20~50mm of welding point；The compressed air or water mist gaseous mixture that cooling device is ejected
Pressure be 0.05~0.25MPa.
4. eutectoid rail according to claim 1 and hypereutectoid steel rail weld joint heat treatment method, it is characterised in that: weldering
For connector to be identical by rail rail type, it is mobile that the eutectoid pearlite steel rail and hypereutectoid rail that specification is 60~75kg/m pass through rail
Flash welder welds the connector to be formed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810946740.2A CN108950158B (en) | 2018-08-20 | 2018-08-20 | Heat treatment method for weld joint of eutectoid steel rail and hypereutectoid steel rail |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810946740.2A CN108950158B (en) | 2018-08-20 | 2018-08-20 | Heat treatment method for weld joint of eutectoid steel rail and hypereutectoid steel rail |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108950158A true CN108950158A (en) | 2018-12-07 |
| CN108950158B CN108950158B (en) | 2020-07-21 |
Family
ID=64470810
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810946740.2A Active CN108950158B (en) | 2018-08-20 | 2018-08-20 | Heat treatment method for weld joint of eutectoid steel rail and hypereutectoid steel rail |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108950158B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110358906A (en) * | 2019-08-23 | 2019-10-22 | 攀钢集团攀枝花钢铁研究院有限公司 | The heat treatment method of steel rail weld joint |
| CN110438327A (en) * | 2019-09-09 | 2019-11-12 | 攀钢集团攀枝花钢铁研究院有限公司 | Hypo eutectoid steel rail weld joint heat treatment method |
| CN112359179A (en) * | 2020-10-23 | 2021-02-12 | 攀钢集团攀枝花钢铁研究院有限公司 | Steel rail postweld heat treatment construction method |
| CN113414480A (en) * | 2021-07-23 | 2021-09-21 | 攀钢集团攀枝花钢铁研究院有限公司 | Method for eliminating overburning defect of mobile flash welding head of hypereutectoid steel rail of 75kg/m |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4375995A (en) * | 1978-05-12 | 1983-03-08 | Nippon Steel Corporation | Method for manufacturing high strength rail of excellent weldability |
| CN1648263A (en) * | 2004-01-30 | 2005-08-03 | 哈尔滨铁路工务器材有限公司 | Heat treatment process after full length quenching steel rail welding |
| CN104862466A (en) * | 2015-06-11 | 2015-08-26 | 攀钢集团攀枝花钢铁研究院有限公司 | Method for postweld heat treatment on hyper-eutectoid steel rail welding connector |
| CN106544933A (en) * | 2016-10-19 | 2017-03-29 | 攀钢集团攀枝花钢铁研究院有限公司 | A kind of method that post weld heat treatment is carried out to steel rail weld joint |
-
2018
- 2018-08-20 CN CN201810946740.2A patent/CN108950158B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4375995A (en) * | 1978-05-12 | 1983-03-08 | Nippon Steel Corporation | Method for manufacturing high strength rail of excellent weldability |
| CN1648263A (en) * | 2004-01-30 | 2005-08-03 | 哈尔滨铁路工务器材有限公司 | Heat treatment process after full length quenching steel rail welding |
| CN104862466A (en) * | 2015-06-11 | 2015-08-26 | 攀钢集团攀枝花钢铁研究院有限公司 | Method for postweld heat treatment on hyper-eutectoid steel rail welding connector |
| CN106544933A (en) * | 2016-10-19 | 2017-03-29 | 攀钢集团攀枝花钢铁研究院有限公司 | A kind of method that post weld heat treatment is carried out to steel rail weld joint |
Non-Patent Citations (1)
| Title |
|---|
| 马鸿涛: "攀钢U75V钢轨焊后热处理工艺探讨", 《设备管理与维修》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110358906A (en) * | 2019-08-23 | 2019-10-22 | 攀钢集团攀枝花钢铁研究院有限公司 | The heat treatment method of steel rail weld joint |
| CN110438327A (en) * | 2019-09-09 | 2019-11-12 | 攀钢集团攀枝花钢铁研究院有限公司 | Hypo eutectoid steel rail weld joint heat treatment method |
| CN112359179A (en) * | 2020-10-23 | 2021-02-12 | 攀钢集团攀枝花钢铁研究院有限公司 | Steel rail postweld heat treatment construction method |
| CN113414480A (en) * | 2021-07-23 | 2021-09-21 | 攀钢集团攀枝花钢铁研究院有限公司 | Method for eliminating overburning defect of mobile flash welding head of hypereutectoid steel rail of 75kg/m |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108950158B (en) | 2020-07-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108504848A (en) | The heat treatment method of WELDING JOINT | |
| CN108754114A (en) | The heat treatment method of steel rail weld joint | |
| CN108950158A (en) | Eutectoid rail and hypereutectoid steel rail weld joint heat treatment method | |
| CN108823394A (en) | Post-Welding Heattreatment of Rail method | |
| CN110016546A (en) | Construction method for the heat treatment of bainite rail postwelding connector | |
| CN108796202A (en) | The heat treatment method of heterogeneous material steel rail weld joint | |
| CN110358906A (en) | The heat treatment method of steel rail weld joint | |
| CN108660306A (en) | The post weld heat treatment method of hypereutectoid steel rail and eutectoid steel steel rail weld joint | |
| CN106544933B (en) | The method that a kind of pair of steel rail weld joint carries out post weld heat treatment | |
| CN110358905A (en) | The heat treatment method of steel rail weld joint | |
| CN109355481A (en) | Groove-shape rail flash welding connector post weld heat treatment method | |
| CN106334863B (en) | A kind of method and rail carrying out mobile Flash Butt Welding to 75kg/m hypereutectoid rail and pearlite steel rail | |
| CN109055708A (en) | A kind of eutectoid rail and hypereutectoid steel rail weld joint heat treatment method | |
| CN110016544A (en) | Construction method for the heat treatment of bainite rail postwelding connector | |
| CN109022750A (en) | The post weld heat treatment method of rail | |
| CN110331274A (en) | Bainite rail post weld heat treatment method | |
| CN108570550A (en) | Heat treatment type bainite rail welding point post weld heat treatment method | |
| CN112251587B (en) | Heat treatment method for welded joint of bainite steel rail and eutectoid pearlite steel rail | |
| CN110331275A (en) | Bainite rail post weld heat treatment method | |
| CN109207708A (en) | A kind of bainite rail welding point and the post weld heat treatment method for controlling bainite rail welding point " white piece " tissue | |
| CN110438326A (en) | Hypo eutectoid Post-Welding Heattreatment of Rail method | |
| AU2021215140B2 (en) | POST-WELD HEAT TREATMENT METHOD FOR 1,300MPa-LEVEL LOW-ALLOY HEAT TREATED STEEL RAIL | |
| CN113621881B (en) | Method for improving low-temperature toughness of medium-carbon steel rail welded joint | |
| CN110042218A (en) | Construction method for the heat treatment of bainite rail postwelding connector | |
| CN110438327A (en) | Hypo eutectoid steel rail weld joint heat treatment method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |