CA1205729A - Process for heat-treating rails - Google Patents
Process for heat-treating railsInfo
- Publication number
- CA1205729A CA1205729A CA000423018A CA423018A CA1205729A CA 1205729 A CA1205729 A CA 1205729A CA 000423018 A CA000423018 A CA 000423018A CA 423018 A CA423018 A CA 423018A CA 1205729 A CA1205729 A CA 1205729A
- Authority
- CA
- Canada
- Prior art keywords
- cooling medium
- rail
- process according
- cooling
- heat
- 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.)
- Expired
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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/04—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rails
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/56—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering characterised by the quenching agents
- C21D1/60—Aqueous agents
-
- 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
- C21D1/62—Quenching devices
- C21D1/63—Quenching devices for bath quenching
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
Abstract:
For heat-treating rails for achieving a high wear resistance, at least the rail head is, starting from a temperature lying within the austenite range, brought to a temperature at which perlitizing is completed by means of a cooling medium con-taining 20 to 60 % by volume of a polyglycol. This treatment is particularily concerned with steels containing 0.65 to 0.85 % C and 0.5 to 2.5 % Mn. A Vickers hardness HV30 between 340 and 380 is obtained.
For heat-treating rails for achieving a high wear resistance, at least the rail head is, starting from a temperature lying within the austenite range, brought to a temperature at which perlitizing is completed by means of a cooling medium con-taining 20 to 60 % by volume of a polyglycol. This treatment is particularily concerned with steels containing 0.65 to 0.85 % C and 0.5 to 2.5 % Mn. A Vickers hardness HV30 between 340 and 380 is obtained.
Description
12~S7~
The presenl invent:ion relates to a p-.-ocess for heat-trea~ing ralls of a stee] containin~ C, Si and ~In as well as alloying elements S by quenching the rail or at least the rail head bv cooling medium from a -temperature within -the austenite range down to a temperature at which perlitiæina is completed,-for obtaining a fine-perlitic structure. The appearance of the structure depends to a vast extent on the cooling conditions.
10 Formation of martensite must at any rate be prevented because this would result in making the rail brittle. It has proved that optimum wear properties of such rails can be obtained if cooling is performed such that a fine-perlitic structure is formed.
From German Auslegeschrift 24 39 338 it ha~ become known to quench such rails in hot water. On quenchin~ in hot w'ater a vapour skin is formed on the rail, the vapour skin reducing the cooling ra-l:e at those areas where this vapour skin is 20 formed, while at those areas where the hot ~ater immediately contacts the rail, coolinq is effected at a higher rate. In view of the formation of scale, the vapour skin is ununiformly formed bec~use the scale is split off at arbitrary areas during tlle coolir~a process. Thus, parts of 25 the rail or ~he rail head, respectively, are in contact with the vapour skin formed while other parts are immediately acted upon hy the hot water. Thus, ununiforrnities of the coolin~ rate result over the lenqth of the rail or in different parts of the ~urface of the r~il or of the rail 30 head, respectivelv. This negativelv affects the formation of a flne perlite structure and the wear properties of the r~il become ununiform at the different areas. In view of those areas of the rail which have ~ worse structure beinq ~ec.isive for the wear properties of the whole rail, no optimum wear 35 properties are obtained with such a process.
It is an ob~ect of the invention to make ~he fine-perlitic structure more uniform and thus to improve the wear proper-ties of the rail or of -the rail head.
ln the process of tlrle present invention rails of a steel containing 0.65 - 0.85 ~ C, ma*. 0.~0 ~ Si and 0.5 - 2.5 ~
Mn, remainder iron and unavoidahle contaminations are treated in a coo]ing medium con-t~ining water and a s~nthetic cooling meclium additive know per se, preferablv polyglycol, in an 10 amount of 20 - 60 ~, based on the whole cooling medium. By such an addition of a svnthetic coolin~ medium additive, a layer is formed on the rail or the rail head, respectively, which reduces the cool;ng rate. Such a layer is uniform and is not adversely affected by scale split-off, so that in this 15 manner uniform cooling ccnditions are obtained over the whole surface and over the whole length of the rail or the rail head, respectively.
The synthetic coolinq medium additive, preferably polvglycol 20 (or polyetherglycol), is, according to the invention, used in an amount of 20 - 60 % based on the whole cooling medium.
~ithin these limits a unifor~ result with respect to wear resistance could be obtained with rail steels containing 0.65 to 0.85 ~ C, maximum 0.8 ~ Si and 0.5 - 2.5 ~ Mn, remainder 25 iron and unavoidable contaminations. The cooling medium can he sprayed onto the rail or the rail head, respectively.
However, the rail or at least the rail head is conveniently dipped in a manner known per se into the cooling medium because in this manner the film of the syn-thetic antifreezing 30 compound added can be formed more easily and in a more uniform manner.
~ccording to the invention, the heat-treatment can, in a manner known per se, be effected startinq from the rolling 35 heat so that the rollina heat is made use of and any subsequent expensive heating operation can be avoided.
'~.,:,;
I " 0~ .~
. ., Accord;.nq to -the invention the cooling medium has preferably such a composi.tion that a coolinq rate of 0.2 - 6 C per second is obtai.ned in the temperature range between 800 and 500 C. The cooling rates required fox a fine-perlitic structure are known for the various compositions of the rail and are comprised by the indicated range of 0.2 to 6 C per second. ~hen using a greater amount of the synthetic antifreezing compound, based on the whole cooling medium, a thicker film of the antifreezing agent or cooling medium 10 additive added is formed on the rail or the rail head, respectively, and the cooling rate becomes smaller than with a smaller amount of synthetic antifreezing compound or cooling medium additive added. The coolin~ rate can he varied within the range of 0.2 to fi C by selecting the amount of 15 cooling medium additive added under consideration of the composition of the rai.l steel within the above indicated limits of 0.65 to 0.85 ~ C, max. 0.80 ~ Si and 0.5 - 2.5 Mn.
20 Steels containing 1.2 to 1.3 ~ by weight manganese and 0.7 to 0.75 ~ by weight carbon can with particular advantage be treated according to the invention within the limits of 20 to 50 ~ by weight of the s~nthetic cooling medium additive if the addition of coo].inq medium additive is increased with 25 increasing content in manganese and is reduced with increasing content in carbon. Within these predetermined limits of cooling medium additive added and within the indicated ranges for the content in manganese and the content in carbon, constant values for the wear resistance could be 30 obtained, thereby achieving a Vickers hardness HV30 within the rail head of`between 340 and 380. For thi.s purpose, the coolinq bath temperature is in an advantaqeous manner maintained at 40 to 60 C, particular]v 50 ~C, thereby recyclinq or aqitating, respectivel~.~, the bath. These 35 measures provide for a uniform temperature treatment and, ..,
The presenl invent:ion relates to a p-.-ocess for heat-trea~ing ralls of a stee] containin~ C, Si and ~In as well as alloying elements S by quenching the rail or at least the rail head bv cooling medium from a -temperature within -the austenite range down to a temperature at which perlitiæina is completed,-for obtaining a fine-perlitic structure. The appearance of the structure depends to a vast extent on the cooling conditions.
10 Formation of martensite must at any rate be prevented because this would result in making the rail brittle. It has proved that optimum wear properties of such rails can be obtained if cooling is performed such that a fine-perlitic structure is formed.
From German Auslegeschrift 24 39 338 it ha~ become known to quench such rails in hot water. On quenchin~ in hot w'ater a vapour skin is formed on the rail, the vapour skin reducing the cooling ra-l:e at those areas where this vapour skin is 20 formed, while at those areas where the hot ~ater immediately contacts the rail, coolinq is effected at a higher rate. In view of the formation of scale, the vapour skin is ununiformly formed bec~use the scale is split off at arbitrary areas during tlle coolir~a process. Thus, parts of 25 the rail or ~he rail head, respectively, are in contact with the vapour skin formed while other parts are immediately acted upon hy the hot water. Thus, ununiforrnities of the coolin~ rate result over the lenqth of the rail or in different parts of the ~urface of the r~il or of the rail 30 head, respectivelv. This negativelv affects the formation of a flne perlite structure and the wear properties of the r~il become ununiform at the different areas. In view of those areas of the rail which have ~ worse structure beinq ~ec.isive for the wear properties of the whole rail, no optimum wear 35 properties are obtained with such a process.
It is an ob~ect of the invention to make ~he fine-perlitic structure more uniform and thus to improve the wear proper-ties of the rail or of -the rail head.
ln the process of tlrle present invention rails of a steel containing 0.65 - 0.85 ~ C, ma*. 0.~0 ~ Si and 0.5 - 2.5 ~
Mn, remainder iron and unavoidahle contaminations are treated in a coo]ing medium con-t~ining water and a s~nthetic cooling meclium additive know per se, preferablv polyglycol, in an 10 amount of 20 - 60 ~, based on the whole cooling medium. By such an addition of a svnthetic coolin~ medium additive, a layer is formed on the rail or the rail head, respectively, which reduces the cool;ng rate. Such a layer is uniform and is not adversely affected by scale split-off, so that in this 15 manner uniform cooling ccnditions are obtained over the whole surface and over the whole length of the rail or the rail head, respectively.
The synthetic coolinq medium additive, preferably polvglycol 20 (or polyetherglycol), is, according to the invention, used in an amount of 20 - 60 % based on the whole cooling medium.
~ithin these limits a unifor~ result with respect to wear resistance could be obtained with rail steels containing 0.65 to 0.85 ~ C, maximum 0.8 ~ Si and 0.5 - 2.5 ~ Mn, remainder 25 iron and unavoidable contaminations. The cooling medium can he sprayed onto the rail or the rail head, respectively.
However, the rail or at least the rail head is conveniently dipped in a manner known per se into the cooling medium because in this manner the film of the syn-thetic antifreezing 30 compound added can be formed more easily and in a more uniform manner.
~ccording to the invention, the heat-treatment can, in a manner known per se, be effected startinq from the rolling 35 heat so that the rollina heat is made use of and any subsequent expensive heating operation can be avoided.
'~.,:,;
I " 0~ .~
. ., Accord;.nq to -the invention the cooling medium has preferably such a composi.tion that a coolinq rate of 0.2 - 6 C per second is obtai.ned in the temperature range between 800 and 500 C. The cooling rates required fox a fine-perlitic structure are known for the various compositions of the rail and are comprised by the indicated range of 0.2 to 6 C per second. ~hen using a greater amount of the synthetic antifreezing compound, based on the whole cooling medium, a thicker film of the antifreezing agent or cooling medium 10 additive added is formed on the rail or the rail head, respectively, and the cooling rate becomes smaller than with a smaller amount of synthetic antifreezing compound or cooling medium additive added. The coolin~ rate can he varied within the range of 0.2 to fi C by selecting the amount of 15 cooling medium additive added under consideration of the composition of the rai.l steel within the above indicated limits of 0.65 to 0.85 ~ C, max. 0.80 ~ Si and 0.5 - 2.5 Mn.
20 Steels containing 1.2 to 1.3 ~ by weight manganese and 0.7 to 0.75 ~ by weight carbon can with particular advantage be treated according to the invention within the limits of 20 to 50 ~ by weight of the s~nthetic cooling medium additive if the addition of coo].inq medium additive is increased with 25 increasing content in manganese and is reduced with increasing content in carbon. Within these predetermined limits of cooling medium additive added and within the indicated ranges for the content in manganese and the content in carbon, constant values for the wear resistance could be 30 obtained, thereby achieving a Vickers hardness HV30 within the rail head of`between 340 and 380. For thi.s purpose, the coolinq bath temperature is in an advantaqeous manner maintained at 40 to 60 C, particular]v 50 ~C, thereby recyclinq or aqitating, respectivel~.~, the bath. These 35 measures provide for a uniform temperature treatment and, ..,
2~1 therewith, for uniform results over the whole cross section of the rail hea~l and over the whole surfac~ of the rail head.
It is also ~ossihle to improve the ~ear properties of the rail by correspondingly allo~inq the rail steel, for e~ample by using a Cr-Mn-alloy. Thls results, however, in addition to the hic~her cost.s of such a s-teel, in draw-backs with respect to the we]dabilitv of the rail, hecause with such allovs the cooling rate must be kept low even after a weldinq operation 10 in order to preven-t t'he formation of martensite.
Fig. 1 shows a diagramm and Fi~. 2 shows a section through a rail head, Fig. 3 shows a diaqramm of the wear resistance in dependence on the Vickers hardness alld Fig. 4 shows the 15 dependence of the improvement of the wear resistance from the manganese content and the carbon content, with the proportion of the cooling medium additi~7e being predetermined.
In the representation of Fiq. ~ showina a section through a 20 railhead, samples are determinded in different di~stances from the surface b of the rail head along the so-called hardness trace indicated by the arrow a.
In Fig. 1 the Vickers hardness HV30 is shown on the ordinate.
'25 On the abscissa there are indicated the distances of the measurements from the top surface or the runninq surface b, respectively, of a rail head. Curve c shows a measurement of rails treated according to the inventive proce~ss and having a fine-perlitic structure. A rai] of a rail steel was chosen 30 whlch contained 0.72 ~ C, 0.30 ~ Si and 1.~7 % Mn, remainder iron and unavoidahle contaminations. Curve d show~s the varying hardness a],onq the hardness trace a for a rail of similar composition, the head of which was ~uenched in hot water. A comparison of the curve c and d shows that the 35 values of the Vickers hardness are hiqher for the treatment according to the invention than is the case with curve d, and .~
. . .
' .' :
5~
that, above ali, also the c~ecrease in hardness in-dependence on the distance from the top surface _ of the rail head is sma]ler. I~ is believed that the reason for -this is that the fine-per]itic struc-ture is more uniformely Eormed.
Fig. 3 shows a diagramm in which the wear resistance B, expressed in M/cm2, is plotted on the ordinate. The abscissa shows the Vickers hardness I~V30, as measured in the marginal area of the rail head. The curve e shows the course of the 10 wear resistance in comparison to the Vickers hardness. The range el is the range within which the wear resistance and the Vickers hardness is encountered for rails heat-treated according to the inventive process. The known values, which are obtained by known processes, are substantially below the 15 range el. Thus, the ranqes e2, e3 and e4 show the strength values obtained up till now for various rail steel qualities, the ranges e3 and e4 applying to different standard qualitites of rail steels and the range e2 applying to a chromium-manganese rail steel.
In the representation of Fig. ~ the manganese content in ~ by - weight is, beginning with 1.1 % by weight, plotted on the ordlnate. On the abszissa is plotted the carbon content in percent by weight, beginning with 0.65 % by weight. The 25 rectangle f shown in this diagram delimits the range of steels having a carbon content of 0 7 to 0.75 % by weight and a manganese content of 1.2 to 1.3 % by weight. With steels of a medium carbon content and of a medium manganese content within this range, it h~s been shown that a proportion of 30 30 ~ by volume of a polyglycol as the cooling medium additive provides the best results. For this case, the straight line g corresponds to a proportion of 3n % bv volllme of a polyglycol within the cooling medium. With the manganese content remaining constant, the proportion of cooling medium additive 35 must be reduced with increasing carbon content for obtaining equal results. Converselv, the proportion of cooling medium adclitive must be increased with increasing manganese content and with the carbon content remaininq constant for again achieving equal results, the straight lines h and i re-presenting the upper and the lower lirnit, respectively, for the proportion of coolinq medium additive added, nanlely 20 ~
by volume and 50 % bv volume. ~lhen passi~g below the lower limit of 20 % by volume of coolinq medium additive added, too high a cooling rate would result ror the mentioned steels, thus increasing for too great an extent the tendency of the 10 rail head to become distorted. Conversely, trespassing the upper limit of 50 % by volume of cooling medium additive added would, for steels with a composition within the indicated range, result in the formation of a thicker laver.
Such formation of a ]aver results in an non-uniform distri-15 bution of the concentration of the cooling medium additivewithin the cooling medium, and an uncontrolled reduction of the proportion of the cooling medium additive added would result in non-uniformities in the local distribution of the cooling rate. Furthermore, a depletion of the coolinq medium 20 in cooling medium additive would result in leavina the area within which the best results with res~ect to increasing the wear resistance are obtained. From -this diaaram, for each individual steel corresponding in its composition to the rectanqle f r an optimum proportion of the cooling medium 25 additive within the coolinq medium can be deri~ed with which particularly good and uniform results are obtained with respect to the wear resi.stance of the rail steels. ~lith these experiments, the temperature of the coolinq medium was ; constantly kept at 50 C and the bath was continuously 30 agitated. The dippinq depth of the rail head was 40 mm in all cases. With an optimum composition o~ the coolinq medium a fine-perlitic structure could in any case he obtained within the mar~inaJ layers of the rail head.
It is also ~ossihle to improve the ~ear properties of the rail by correspondingly allo~inq the rail steel, for e~ample by using a Cr-Mn-alloy. Thls results, however, in addition to the hic~her cost.s of such a s-teel, in draw-backs with respect to the we]dabilitv of the rail, hecause with such allovs the cooling rate must be kept low even after a weldinq operation 10 in order to preven-t t'he formation of martensite.
Fig. 1 shows a diagramm and Fi~. 2 shows a section through a rail head, Fig. 3 shows a diaqramm of the wear resistance in dependence on the Vickers hardness alld Fig. 4 shows the 15 dependence of the improvement of the wear resistance from the manganese content and the carbon content, with the proportion of the cooling medium additi~7e being predetermined.
In the representation of Fiq. ~ showina a section through a 20 railhead, samples are determinded in different di~stances from the surface b of the rail head along the so-called hardness trace indicated by the arrow a.
In Fig. 1 the Vickers hardness HV30 is shown on the ordinate.
'25 On the abscissa there are indicated the distances of the measurements from the top surface or the runninq surface b, respectively, of a rail head. Curve c shows a measurement of rails treated according to the inventive proce~ss and having a fine-perlitic structure. A rai] of a rail steel was chosen 30 whlch contained 0.72 ~ C, 0.30 ~ Si and 1.~7 % Mn, remainder iron and unavoidahle contaminations. Curve d show~s the varying hardness a],onq the hardness trace a for a rail of similar composition, the head of which was ~uenched in hot water. A comparison of the curve c and d shows that the 35 values of the Vickers hardness are hiqher for the treatment according to the invention than is the case with curve d, and .~
. . .
' .' :
5~
that, above ali, also the c~ecrease in hardness in-dependence on the distance from the top surface _ of the rail head is sma]ler. I~ is believed that the reason for -this is that the fine-per]itic struc-ture is more uniformely Eormed.
Fig. 3 shows a diagramm in which the wear resistance B, expressed in M/cm2, is plotted on the ordinate. The abscissa shows the Vickers hardness I~V30, as measured in the marginal area of the rail head. The curve e shows the course of the 10 wear resistance in comparison to the Vickers hardness. The range el is the range within which the wear resistance and the Vickers hardness is encountered for rails heat-treated according to the inventive process. The known values, which are obtained by known processes, are substantially below the 15 range el. Thus, the ranqes e2, e3 and e4 show the strength values obtained up till now for various rail steel qualities, the ranges e3 and e4 applying to different standard qualitites of rail steels and the range e2 applying to a chromium-manganese rail steel.
In the representation of Fig. ~ the manganese content in ~ by - weight is, beginning with 1.1 % by weight, plotted on the ordlnate. On the abszissa is plotted the carbon content in percent by weight, beginning with 0.65 % by weight. The 25 rectangle f shown in this diagram delimits the range of steels having a carbon content of 0 7 to 0.75 % by weight and a manganese content of 1.2 to 1.3 % by weight. With steels of a medium carbon content and of a medium manganese content within this range, it h~s been shown that a proportion of 30 30 ~ by volume of a polyglycol as the cooling medium additive provides the best results. For this case, the straight line g corresponds to a proportion of 3n % bv volllme of a polyglycol within the cooling medium. With the manganese content remaining constant, the proportion of cooling medium additive 35 must be reduced with increasing carbon content for obtaining equal results. Converselv, the proportion of cooling medium adclitive must be increased with increasing manganese content and with the carbon content remaininq constant for again achieving equal results, the straight lines h and i re-presenting the upper and the lower lirnit, respectively, for the proportion of coolinq medium additive added, nanlely 20 ~
by volume and 50 % bv volume. ~lhen passi~g below the lower limit of 20 % by volume of coolinq medium additive added, too high a cooling rate would result ror the mentioned steels, thus increasing for too great an extent the tendency of the 10 rail head to become distorted. Conversely, trespassing the upper limit of 50 % by volume of cooling medium additive added would, for steels with a composition within the indicated range, result in the formation of a thicker laver.
Such formation of a ]aver results in an non-uniform distri-15 bution of the concentration of the cooling medium additivewithin the cooling medium, and an uncontrolled reduction of the proportion of the cooling medium additive added would result in non-uniformities in the local distribution of the cooling rate. Furthermore, a depletion of the coolinq medium 20 in cooling medium additive would result in leavina the area within which the best results with res~ect to increasing the wear resistance are obtained. From -this diaaram, for each individual steel corresponding in its composition to the rectanqle f r an optimum proportion of the cooling medium 25 additive within the coolinq medium can be deri~ed with which particularly good and uniform results are obtained with respect to the wear resi.stance of the rail steels. ~lith these experiments, the temperature of the coolinq medium was ; constantly kept at 50 C and the bath was continuously 30 agitated. The dippinq depth of the rail head was 40 mm in all cases. With an optimum composition o~ the coolinq medium a fine-perlitic structure could in any case he obtained within the mar~inaJ layers of the rail head.
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for heat-treating a rail by quench-ing at least the rail head by means of a cooling medium from a temperature lying in the austenite range down to a tempera-ture at which perlitizing is completed for achieving a fine-perlitic structure, said rail being made of a steel contain-ing 0.65-0.85% C, max. 0.80% Si and 0.5-2.5% Mn, remainder iron and unavoidable impurities, and said cooling medium containing water and a synthetic cooling medium additive in an amount of 20-60%, based on the total cooling medium.
2. A process according to claim 1, in which the whole rail is treated.
3. A process according to claim 1, in which the additive is polyglycol.
4. A process according to claim 1, 2 or 3, in which at least the rail head is dipped into the cooling medium.
5. A process according to claim 1, 2 or 3, in which the heat-treatment is effected starting from the roll-ing heat.
6. A process according to claim 1, 2 or 3, in which the cooling medium has a composition such that in the temperature range between 800 and 500°C a cooling rate of 0.2-6°C/sec results.
7. A process according to claim 1, 2 or 3, in which for steels containing 1.20 to 1.30% by weight manganese and 0.70 to 0.75% by weight carbon the addition of synthetic cooling medium additive is, within the limits of 20 to 50%
by volume, increased with increasing content in manganese and reduced with increasing content in carbon.
by volume, increased with increasing content in manganese and reduced with increasing content in carbon.
8. A process according to claim 1, 2 or 3, in which the temperature of the cooling medium is maintained at 40 to 60°C in a cooling bath which is recirculated or agita-ted.
9. A process according to claim 1, 2 or 3, in which the temperature of the cooling medium is maintained at 50°C in a cooling bath which is recirculated or agitated,
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ATA931-82 | 1982-03-09 | ||
| AT0093182A AT375402B (en) | 1982-03-09 | 1982-03-09 | METHOD FOR HEAT-TREATING RAILS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1205729A true CA1205729A (en) | 1986-06-10 |
Family
ID=3503141
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000423018A Expired CA1205729A (en) | 1982-03-09 | 1983-03-07 | Process for heat-treating rails |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0088746B1 (en) |
| JP (1) | JPS58221229A (en) |
| AT (1) | AT375402B (en) |
| CA (1) | CA1205729A (en) |
| DE (1) | DE3370972D1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6406569B1 (en) * | 1992-07-15 | 2002-06-18 | Voest-Alpine Schienen Gmbh | Procedure for the thermal treatment of rails |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62161917A (en) * | 1986-01-09 | 1987-07-17 | Nippon Steel Corp | Manufacture of head end-heattreated rail excellent in resistance to damage and wear |
| JPS63203724A (en) * | 1987-02-19 | 1988-08-23 | Nkk Corp | Method for hardening rail |
| DE4003363C1 (en) * | 1990-02-05 | 1991-03-28 | Voest-Alpine Industrieanlagenbau Ges.M.B.H., Linz, At | Hardening rails from rolling temp. - using appts. with manipulator engaging rail from exit roller table with support arms positioned pivotably on each side |
| AT401359B (en) * | 1991-04-05 | 1996-08-26 | Vae Ag | METHOD FOR PRODUCING A HEART PIECE |
| EP0685566B2 (en) * | 1993-12-20 | 2013-06-05 | Nippon Steel & Sumitomo Metal Corporation | Rail of high abrasion resistance and high tenacity having pearlite metallographic structure and method of manufacturing the same |
| DE19621017C1 (en) * | 1996-05-24 | 1998-01-08 | Butzbacher Weichenbau Gmbh | Process for the production of a track superstructure and track superstructure |
| AT409268B (en) * | 2000-05-29 | 2002-07-25 | Voest Alpine Schienen Gmbh & C | METHOD AND DEVICE FOR HARDENING RAILS |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1242660B (en) * | 1963-06-29 | 1967-06-22 | Union Carbide Corp | Quenching medium for quenching heat-treated metal |
| DE1802273A1 (en) * | 1968-01-18 | 1969-08-07 | Zentralinstitut Fuer Fertigung | Quenching means for austenitic steels |
| DE2439338C2 (en) * | 1974-08-16 | 1980-08-28 | Fried. Krupp, Huettenwerke Ag, 4630 Bochum | Process for the heat treatment of rails from the rolling heat |
| US4087290A (en) * | 1975-07-03 | 1978-05-02 | E. F. Houghton & Co. | Process for the controlled cooling of ferrous metal |
| BE854834A (en) * | 1977-05-18 | 1977-09-16 | Centre Rech Metallurgique | PROCESS FOR MANUFACTURING RAILS WITH IMPROVED CHARACTERISTICS |
-
1982
- 1982-03-09 AT AT0093182A patent/AT375402B/en not_active IP Right Cessation
-
1983
- 1983-02-22 EP EP19830890026 patent/EP0088746B1/en not_active Expired
- 1983-02-22 DE DE8383890026T patent/DE3370972D1/en not_active Expired
- 1983-03-07 CA CA000423018A patent/CA1205729A/en not_active Expired
- 1983-03-09 JP JP3889983A patent/JPS58221229A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6406569B1 (en) * | 1992-07-15 | 2002-06-18 | Voest-Alpine Schienen Gmbh | Procedure for the thermal treatment of rails |
| US6547897B2 (en) | 1992-07-15 | 2003-04-15 | Voest-Alpine Schienen Gmbh | Procedure for the thermal treatment of rails |
Also Published As
| Publication number | Publication date |
|---|---|
| AT375402B (en) | 1984-08-10 |
| EP0088746A1 (en) | 1983-09-14 |
| DE3370972D1 (en) | 1987-05-21 |
| JPS58221229A (en) | 1983-12-22 |
| EP0088746B1 (en) | 1987-04-15 |
| ATA93182A (en) | 1983-12-15 |
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