HRP950386A2 - Process and apparatus for heat-treating shaped rolled pieces - Google Patents
Process and apparatus for heat-treating shaped rolled pieces Download PDFInfo
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- HRP950386A2 HRP950386A2 HRA1431/94A HRP950386A HRP950386A2 HR P950386 A2 HRP950386 A2 HR P950386A2 HR P950386 A HRP950386 A HR P950386A HR P950386 A2 HRP950386 A2 HR P950386A2
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- cooling
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- 238000000034 method Methods 0.000 title claims abstract description 32
- 230000008569 process Effects 0.000 title claims description 11
- 238000001816 cooling Methods 0.000 claims abstract description 133
- 239000000463 material Substances 0.000 claims abstract description 34
- 238000002360 preparation method Methods 0.000 claims description 52
- 238000007654 immersion Methods 0.000 claims description 19
- 230000009466 transformation Effects 0.000 claims description 18
- 239000000110 cooling liquid Substances 0.000 claims description 16
- 229910001562 pearlite Inorganic materials 0.000 claims description 14
- 238000005452 bending Methods 0.000 claims description 13
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 11
- 238000010438 heat treatment Methods 0.000 claims description 9
- 239000000203 mixture Substances 0.000 claims description 9
- 238000007493 shaping process Methods 0.000 claims description 9
- 238000012546 transfer Methods 0.000 claims description 9
- 229910045601 alloy Inorganic materials 0.000 claims description 7
- 239000000956 alloy Substances 0.000 claims description 7
- 239000002826 coolant Substances 0.000 claims description 6
- 229910052742 iron Inorganic materials 0.000 claims description 6
- 239000007788 liquid Substances 0.000 claims description 6
- 230000002093 peripheral effect Effects 0.000 claims description 6
- 238000005507 spraying Methods 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 230000033001 locomotion Effects 0.000 claims description 5
- 230000005484 gravity Effects 0.000 claims description 4
- 229910000734 martensite Inorganic materials 0.000 claims description 4
- 230000009467 reduction Effects 0.000 claims description 4
- 230000001105 regulatory effect Effects 0.000 claims description 4
- 238000007711 solidification Methods 0.000 claims description 4
- 230000008023 solidification Effects 0.000 claims description 4
- 230000007935 neutral effect Effects 0.000 claims description 3
- 230000003534 oscillatory effect Effects 0.000 claims description 3
- 230000001143 conditioned effect Effects 0.000 claims description 2
- 230000005855 radiation Effects 0.000 claims description 2
- 238000005336 cracking Methods 0.000 claims 1
- 230000007423 decrease Effects 0.000 claims 1
- 238000003856 thermoforming Methods 0.000 claims 1
- 230000015572 biosynthetic process Effects 0.000 description 6
- 229910001566 austenite Inorganic materials 0.000 description 5
- 230000002349 favourable effect Effects 0.000 description 5
- 238000009826 distribution Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000005275 alloying Methods 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- 239000013078 crystal Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 150000002505 iron Chemical class 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000010137 moulding (plastic) Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 238000010583 slow cooling Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/62—Quenching devices
- C21D1/63—Quenching devices for bath quenching
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- 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
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/009—Pearlite
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2221/00—Treating localised areas of an article
- C21D2221/02—Edge parts
-
- 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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
Abstract
Description
Izum se odnosi na postupak za toplinsku obradu profiliranih valjanih pripravaka, naročito tračnica za industrijske kolosijeke i za željeznicu, s povećanim odvodom topline s dijelova površine profila hlađenjem iz γ-područja materijala na bazi željeza, pri čemu se postiže u željenom području, ili područjima, poprečnog presjeka, naročito u području glave tračnice, transformacija u finoperiltsku strukturu povećane čvrstoće, naročito povećane otpornosti na habanje, kao i smanjivanje, poželjno u suštini izbjegavanje, deformiranja odnosno savijanja uslijed termički uvjetovanog krivljenja valjanog pripravka, naročito tračnice, uzdužno na uzdužnu os kod hlađenja na sobnu temperaturu, naročito nakon transformacije strukture u pojačano hlađenom području, ili područjima, poprečnog presjeka, kao i povećana krutost i otpornost na naizmjenično savijanje valjanog pripravka. The invention relates to a process for heat treatment of profiled rolled products, especially rails for industrial tracks and railways, with increased heat removal from parts of the profile surface by cooling from the γ-region of the iron-based material, whereby it is achieved in the desired area, or areas, of the cross-section, especially in the area of the rail head, transformation into a finoperilt structure of increased strength, especially increased resistance to wear, as well as reduction, preferably essentially avoiding, deformation or bending due to thermally conditioned bending of the rolled product, especially the rail, longitudinally to the longitudinal axis during cooling at room temperature, especially after the transformation of the structure in the reinforced cooled area, or areas, of the cross-section, as well as the increased stiffness and resistance to alternating bending of the rolled product.
Izum se dalje odnosi na uređaj za toplinsku obradu profiliranog valjanog pripravka, naročito tračnica za industrijske kolosijeke, odnosno željezničkih tračnica, koji se u suštini sastoji od najmanje jednog pripremnog područja za valjane pripravke na transporteru s valjcima, s uređajem za pozicioniranje valjanog pripravka, područja za obradu hlađenjem s uređajima za parcijalno odvođenje topline velikog intenziteta sa površine valjanog pripravka i područja za završno hlađenje, za hlađenje valjanog pripravka na sobnu temperaturu, kao i uređaj za odlaganje, poprečno prenošenje, držanje i rukovanje. The invention further relates to a device for heat treatment of a profiled rolled product, in particular rails for industrial tracks, i.e. railway tracks, which essentially consists of at least one preparation area for rolled products on a conveyor with rollers, with a device for positioning the rolled product, an area for cooling treatment with devices for partial removal of high-intensity heat from the surface of the rolled product and the area for final cooling, for cooling the rolled product to room temperature, as well as a device for storage, transverse transfer, holding and handling.
Najzad se izum odnosi na profilirani pripravak, naročito tračnicu za industrijske kolosijeke ili željezničku tračnicu, koja se sastoji od glavne tračnice s najmanje djelomično perlitnom strukturom, nožice tračnice i vrata između glave tračnice i nožice tračnice. Finally, the invention relates to a profiled preparation, especially a rail for industrial tracks or a railway rail, which consists of a main rail with at least partially pearlite structure, a rail foot and a door between the rail head and the rail foot.
Profilirani pripravak, naročito tračnice za industrijske kolosijeke, odnosno željezničke tračnice, izrađene su najčešće od legura na bazi željeza, sadržaja, u masenim postocima C od 0,4 do 1,0, Si od 0,1 do 1,2, Mn od 0,5 do 3,5, eventualno Cr do 1,5, kao i drugih elemenata za legiranje u koncentracijama ispod 1 %, ostatak željezo i nečistoće uvjetovane procesom izrade. Na temelju uobičajenih dimenzija, na primjer kod mase od 30 do 100 kg/m, i iz toga dobivenog odnosa poprečnog presjeka i obujma tračnica, dolazi kod hlađenja valjanog pripravka od topline deformiranja (oblikovanja) na mirujućem zraku, na primjer na postolju za hlađenje i sl., uslijed polaganog hlađenja do transformacije strukture, od austenitne u krupno perlitnu strukturu, koja, eventualno, ima neki udio ferita. Ranije spomenuti materijali navedene strukture imaju pri tome tvrdoću od 250 HB do 350 HB. Profiled preparation, especially rails for industrial tracks, i.e. railway rails, are most often made of iron-based alloys, content, in mass percentages, of C from 0.4 to 1.0, Si from 0.1 to 1.2, Mn from 0 .5 to 3.5, possibly Cr to 1.5, as well as other alloying elements in concentrations below 1%, the rest of iron and impurities determined by the manufacturing process. Based on the usual dimensions, for example with a mass of 30 to 100 kg/m, and the resulting ratio of the cross-section and the volume of the rails, cooling of the rolled product from the heat of deformation (shaping) occurs in still air, for example on a cooling stand and Fig., as a result of slow cooling until the transformation of the structure, from austenite to a coarse pearlite structure, which possibly has some portion of ferrite. The previously mentioned materials of the specified structure have a hardness of 250 HB to 350 HB.
Povećanje obujma prometa i povećana osovinska opterećenja, kao i želja da se poveća trajnost željezničkih tračnica u praktičnoj primjeni, dovelo je do velikog broja prijedloga kako da se poveća čvrstoća i otpornost na habanje materijala. Pri tome se mogu postići povoljnija ili poboljšana svojstva materijala s tvrdoćom od 400 HB, i većom, toplinskom obradom i/ili legiranjem. The increase in the volume of traffic and increased axle loads, as well as the desire to increase the durability of railway rails in practical application, led to a large number of proposals on how to increase the strength and wear resistance of the material. At the same time, more favorable or improved properties of materials with a hardness of 400 HB and higher can be achieved by heat treatment and/or alloying.
Tračnice trebaju na mjestu ugradnje, između ostalog za izradu bezudarnih pruga, odnosno višestrukih duljina, biti dobro pogodne za zavarivanje, tako da se legiranje u cilju povećanja tvrdoće, odnosno jačine i žilavosti materijala, zbog problema zavarivanja najčešće može izvesti u malom obujmu, a može se ostvariti toplinskom obradom prilagođenom sastavu čelika (DE-C 3 446 794, EP-B-0187904, EP-B-01 186373). Također zbog ekonomskih razloga nisu se ovakvi postupci u većoj mjeri ostvarivali. Rails should be well suited for welding at the place of installation, among other things for the production of shock-free tracks, i.e. multiple lengths, so that alloying in order to increase the hardness, i.e. strength and toughness of the material, due to welding problems, can usually be carried out in a small volume, and can can be achieved by heat treatment adapted to the steel composition (DE-C 3 446 794, EP-B-0187904, EP-B-01 186373). Also, due to economic reasons, such procedures were not carried out to a greater extent.
Da bi se upotrebna svojstva tračnica i dijelova skretnica od navedenih materijala poboljšala, moguće je, kako je poznato stručnjacima, da se termičkim poboljšanjem ostvari sitnoperlitna struktura materijala. Pri tome je važno da se kod hlađenja sa temperature formiranja austenita podese odgovarajući uvjeti hlađenja, odnosno brzine hlađenja. U EP-B-0293002 je, na primjer, u tom cilju predloženo da se nakon početnog velikog intenziteta hlađenja izvede praktično izotermna transformacija strukture materijala na oko 530°C. Iz DE-OS-2 820 784 dalje je poznato da se skrutnjavanje tračnica određenog sastava vrši u ključaloj vodi i pomoću raznih dodataka kao i kretanjem tračnica ostvaruje željeni intenzitet hlađenja radi ostvarivanja sitnoperiitne strukture. In order to improve the performance of rails and parts of switches made of the above-mentioned materials, it is possible, as is known to experts, to achieve a fine pearlite structure of the material through thermal improvement. In doing so, it is important that appropriate cooling conditions, i.e. cooling rates, are set when cooling from the austenite formation temperature. In EP-B-0293002, for example, it is proposed for this purpose that after the initial high intensity of cooling, a practically isothermal transformation of the material structure is carried out at around 530°C. From DE-OS-2 820 784 it is further known that the solidification of rails of a certain composition is carried out in boiling water and with the help of various additives as well as the movement of the rails, the desired intensity of cooling is achieved in order to achieve a fine periitic structure.
Pokušana je, prema AT-PS-323 224, izrada tračnica s homogenom sitnoperlitnom strukturom jedne odabrane legure primjenom određenih parametara hlađenja, na primjer brzine hlađenja između 10 i 20°C/s do temperature od najviše 550°C. Opisani postupci imaju zajednički nedostatak u tome što isti intenzitet hlađenja površine može, u ovisnosti o koncentraciji masa valjanog pripravka, izazvati različite brzine hlađenja i različite strukture u zonama u blizini površine, i da se često moraju poduzeti skupe mjere predostrožnosti, kako bi se izbjegle nenormalne lokalne strukture odnosno svojstva materijala, naročito prekomjerna tvrdoća i krutost, u dijelovima tračnica pretežno opterećenim na savijanje. An attempt was made, according to AT-PS-323 224, to produce rails with a homogeneous fine pearlite structure of a selected alloy by applying certain cooling parameters, for example a cooling rate between 10 and 20°C/s up to a maximum temperature of 550°C. The described processes have a common disadvantage in that the same surface cooling intensity can, depending on the mass concentration of the rolled preparation, cause different cooling rates and different structures in the zones near the surface, and that expensive precautions must often be taken to avoid abnormal local structures, i.e. material properties, especially excessive hardness and stiffness, in parts of the rails predominantly loaded with bending.
Više puta je predlagano da se po poprečnom presjeku jedne tračnice ostvari jedna heterogena mikrostruktura koja je prilagođena predviđenim opterećenjima. Iz DE-C-3 006 695 poznat je, na primjer, postupak po kome se od topline valjanja pomoću hlađenja tračnice ostvaruje transformacija po cijelom poprečnom presjeku, pri čemu se u glavi tračnice, naročito indukcijskim zavarivanjem, ponovo uspostavlja austenitna struktura nakon čega se glava sktrutnjava. Dalje je prema WO 94/02652 predloženo da se glava tračnice hladi do temperature površine između 450 i 550°C u nekom sredstvu za hlađenje s posebno podešenim intenzitetom hlađenja, i time u njoj ostvari sitnoperlitna struktura. It has been proposed more than once that a heterogeneous microstructure adapted to the expected loads should be created per cross-section of one rail. From DE-C-3 006 695, for example, a process is known by which the heat of rolling is used to cool the rail to transform it over the entire cross-section, whereby the austenite structure is re-established in the head of the rail, especially by induction welding, after which the head solidification. Furthermore, according to WO 94/02652, it was proposed that the rail head be cooled to a surface temperature between 450 and 550°C in a cooling medium with a specially adjusted cooling intensity, and thereby achieve a fine pearlite structure in it.
Za takvu obradu je pogodan uređaj za otvrdnjavanje obješenih tračnica prema DE-C-4 003 363. A device for hardening suspended rails according to DE-C-4 003 363 is suitable for such processing.
Nehomogeno hlađenje po poprečnom presjeku profiliranog valjanog pripravka može, međutim, dovesti do krivljenja, odnosno odstupanja od ravnoće na sobnoj temperaturi. Da bi se ovi nedostaci izbjegli, predloženo ie (DE-A-4 237 991) da se tračnice obješene, poželjno glavom na dolje, prenesu na postolje za hlađenje, odnosno ohlade, pri čemu, ipak, usmjereno ostvarivanje heterogene strukture po poprečnom presjeku jedva da je moguće. Inhomogeneous cooling across the cross-section of the profiled rolled preparation can, however, lead to bending, i.e. deviation from flatness at room temperature. In order to avoid these shortcomings, it is proposed (DE-A-4 237 991) that the rails are suspended, preferably upside down, transferred to a cooling stand, i.e. cooled, whereby, however, the directional realization of a heterogeneous structure in cross-section is hardly that it is possible.
Svi do sada poznati postupci i uređaji imaju zajednički nedostatak, a to je da kod izrade profiliranih valjanih pripravaka daju rješenja koja su ostvariva ipak samo na ograničenim područjima, odnosno, odnose se na pojedinačne stupnjeve postupka, i da se ipak ne može govoriti o nekom zadovoljavajućem rješenju cjelokupne problematike ekonomičnom izradom visokokvalitetnih dugih tračnica specijalne kvalitete. All procedures and devices known so far have a common drawback, which is that when making profiled valid preparations, they provide solutions that are achievable only in limited areas, that is, they refer to individual stages of the procedure, and that one cannot speak of any satisfactory to the solution of the entire problem by economical production of high-quality long rails of special quality.
Izum treba pomoći i ima za cilj da se otklanjanjem nedostataka poznatih načina izrade dobije novi postupak kojim se može izrađivati valjani pripravak s posebno pogodnim upotrebnim svojstvima. Dalje je zadatak izuma pripremiti jedan uređaj posebno za izvođenje postupka, kao i načiniti valjani pripravak, naročito tračnice, za najveća opterećenja. The invention should help and has the goal of eliminating the shortcomings of known manufacturing methods to obtain a new process that can produce a valid preparation with particularly suitable usage properties. Furthermore, the task of the invention is to prepare a device specifically for carrying out the procedure, as well as to make a valid device, especially rails, for the highest loads.
Ovaj je cilj ostvaren postupkom opisane vrste, tako što je valjani pripravak, naročito tračnica, s prosječnom temperaturom od najviše 1100°C, poželjno od najviše 900°C, a najmanje od 750°C, u uzdužnom pravcu poravnata plastičnim deformiranjem (oblikovanjem), u poravnatom stanju pomaknuta u poprečnom pravcu i držana, i u prvom stupnju hlađenja valjanog pripravka, odnosno tračnice, ista puštena da se ohladi na temperaturu ispod 860°C, poželjno na oko 820°C, naročito od 5 do 120ºC iznad Ar3-temperature legure, s istim lokalnim intenzitetom hlađenja, poželjno u suštini zračenjem u mirujućem zraku, nakon čega se u drugom stupnju hlađenja valjanom pripravku u uzdužnom pravcu odvodi toplina s lokalno u suštini jednakim, gledano po poprečnom presjeku, a različitim po opsegu, intenzitetom, a intenzitet hlađenja je najmanje u jednoj zoni na opsegu profiliranog valjanog pripravka povećan, pri čemu se povećani intenzitet hlađenja odnosi na područje, ili područja, s velikim odnosom poprečnog presjeka prema opsegu, odnosno s velikim udjelom zapremine u odnosu na površinu, odnosno s velikom koncentracijom mase i/ili sva ona s lokalno povišenom temperaturom valjanog pripravka, naročito tračnice, pa se područje, ili područja, s ovako povećanom brzinom hlađenja dovode na temperaturu transformacije, a pri ovakvim uvjetima hlađenja se dobiva bezmartensitna sitnoperlitna struktura nakon čega se u sljedećem stupnju s istim lokalnim intenzitetom hlađenja, na primjer u mirujućem zraku, vrši hlađenje do sobne temperature. This goal was achieved by the process of the described type, in that the rolled preparation, especially the rail, with an average temperature of no more than 1100°C, preferably no more than 900°C, and no less than 750°C, was aligned in the longitudinal direction by plastic deformation (shaping), in the aligned state moved in the transverse direction and held, and in the first stage of cooling of the rolled preparation, i.e. the rail, the same is allowed to cool to a temperature below 860°C, preferably to around 820°C, especially from 5 to 120ºC above the Ar3-temperature of the alloy, with the same local intensity of cooling, preferably essentially by radiation in still air, after which, in the second stage of cooling, heat is removed to the rolled preparation in the longitudinal direction with locally essentially equal, seen in cross-section, but different in extent, intensity, and the intensity of cooling is at least in one zone on the circumference of the profiled rolled preparation increased, whereby the increased intensity of cooling refers to the area, or areas, with a large cross section ratio according to the circumference, i.e. with a large proportion of volume in relation to the surface, i.e. with a high concentration of mass and/or all of them with a locally elevated temperature of the rolled product, especially the rails, so the area, or areas, with this increased cooling rate are brought to the transformation temperature , and under these cooling conditions, a martensitic-free fine pearlite structure is obtained, after which, in the next stage, with the same local cooling intensity, for example, in still air, cooling to room temperature is carried out.
Bitno je da se potom vrši pravocrtno ispravljanje valjanog pripravka plastičnim oblikovanjem i da se to izvede u temperaturnom opsegu između 750°C i 1100°C. Temperature niže od 750°C mogu, kako je utvrđeno, dovesti do djelomično elastičnog savijanja uz odstupanje od pravocrtnog poravnanja a time do nehomogenog intenziteta hlađenja u uzdužnom pravcu tračnice. Temperature valjanog pripravka više od 1100°C najčešće izazivaju porast austenitnih zrna, odnosno oblikovanje krupnih zrna, što na kraju može negativno utjecati na svojstva materijala. It is essential that the straight-line straightening of the rolled preparation is then carried out by plastic molding and that this is done in the temperature range between 750°C and 1100°C. Temperatures lower than 750°C can, as determined, lead to partially elastic bending with deviation from straight line alignment and thus to inhomogeneous cooling intensity in the longitudinal direction of the rail. Temperatures of the rolled preparation above 1100°C most often cause the growth of austenite grains, i.e. the formation of large grains, which can ultimately negatively affect the properties of the material.
Polazeći od pravocrtno poravnatog valjanog pripravka pokazalo se kao bitno za oblikovanje jednog, u uzdužnom pravcu ravnomjerno raspoređenog sitnoperlitnog područja poprečnog presjeka, da se valjani pripravak drži, i u prvom stupnju hlađenja pusti da se ravnomjerno ohladi na temperaturu ispod 860°C s jednakim lokalnim intenzitetom hlađenja. Time se može, s jedne strane, izjednačiti lokalna nehomogenost rasporeda temperatura u uzdužnom pravcu, prouzročena, eventualno, mjestimičnim oslanjanjem na uređaj za poprečno prenošenje, a, s druge strane, ostvarit će se osnosimetrična ili centralnosimetrična raspodjela temperature po poprečnom presjeku profiliranog valjanog pripravka, čime će se njegova ravnoća stabilizirati. Posebno je pogodno ako se ovo izjednačavajuće hlađenje izvodi na temperaturi od 5°C do 120°C iznad Ar3-temperature legure, kako bi se ostvarili povoljni uvjeti za djelomičnu transformaciju strukture u sitnoperlitsku strukturu u dijelovima poprečnog presjeka. Pri tome je Ar3-temperatura svaka ona temperatura na kojoj počinje transformacija γ-kristalne rešetke u α -kristalnu rešetku pri brzini hlađenja od 3°C/min. Starting from a rectilinearly aligned rolled product, it has been shown to be essential for the formation of one, longitudinally evenly distributed fine pearlite cross-sectional area, to hold the rolled product and in the first stage of cooling let it cool evenly to a temperature below 860°C with the same local cooling intensity . This can, on the one hand, equalize the local inhomogeneity of the temperature distribution in the longitudinal direction, possibly caused by partial reliance on the device for transverse transmission, and, on the other hand, axisymmetric or centrally symmetric temperature distribution across the cross section of the profiled rolled product will be achieved. which will stabilize its balance. It is particularly suitable if this equalizing cooling is performed at a temperature of 5°C to 120°C above the Ar3-temperature of the alloy, in order to achieve favorable conditions for the partial transformation of the structure into a fine pearlitic structure in the cross-sectional parts. Here, the Ar3-temperature is any temperature at which the transformation of the γ-crystal lattice into the α-crystal lattice begins at a cooling rate of 3°C/min.
Hlađenje valjanog pripravka s intenzitetom odvođenja topline u uzdužnom pravcu u suštini jednakim, gledano po poprečnom presjeku a različitim po opsegu, samo po sebi je poznato. Ipak je važno da se područja povećanog intenziteta na odgovarajući način rasporede po površini koncentracije mase valjanog pripravka. U vezi sa pravocrtnim poravnavanjem, izjednačujuće hlađenje i podešavanje simetrične raspodjele temperature i oblikovanje različitih područja hlađenja, može se, po području poprečnog presjeka različita, brzina hlađenja održati u suštini jednakom u uzdužnom pravcu valjanog pripravka. Zbog toga je važno da se veličina brzine hlađenja, kojom se predviđeno područje valjanog pripravka dovodi na temperaturu transformacije, podesi inače poznatim postupcima. Kao što se vidi na slici 3, koja predstavlja stručnjaku poznat dijagram vrijeme-temperatura transformacije jedne legure određenog sastava, oblikovat će se kod većih brzina hlađenja od Ar3-temperature, na primjer krivulje c i d, u strukturi udio martenzita, uslijed čega će materijal poprimiti veću čvrstoću, ali bitno izgubiti na elastičnosti i bit će više podložan opasnosti od loma, pa njegova predviđena upotreba više nije moguća. Manje brzine hlađenja, na primjer krivulja h, daju krupnoperlitnu, meku strukturu. Zbog toga je važno da se lokalne brzine hlađenja podese na takvu veličinu da se kod transformacije u svakom slučaju izbjegne oblikovanje martenzita, a da se u područjima povećanog intenziteta hlađenja oblikuje sitnoperlitna struktura. The cooling of a rolled product with the intensity of heat removal in the longitudinal direction is essentially the same, seen in cross-section and different in circumference, is known in itself. However, it is important that the areas of increased intensity are appropriately distributed over the mass concentration surface of the rolled preparation. In connection with straight line alignment, equalizing cooling and adjustment of symmetrical temperature distribution and shaping of different cooling areas, the cooling rate can be kept essentially equal in the longitudinal direction of the rolled product, which is different by cross-sectional area. For this reason, it is important that the size of the cooling rate, by which the intended area of the rolled preparation is brought to the transformation temperature, is adjusted by otherwise known procedures. As can be seen in Figure 3, which represents the time-temperature diagram of the transformation of an alloy of a certain composition known to the expert, at higher cooling rates than the Ar3-temperature, for example curves c and d, a portion of martensite will form in the structure, as a result of which the material will acquire a greater strength, but significantly lose elasticity and will be more susceptible to breakage, so its intended use is no longer possible. Lower cooling rates, for example curve h, give a coarse pearlitic, soft structure. For this reason, it is important that the local cooling rates are set to such a size that the formation of martensite is avoided in any case during the transformation, and that a fine pearlite structure is formed in areas of increased cooling intensity.
Nakon potpune transformacije strukture, da bi se savijanje valjanog pripravka smanjilo, odnosno u suštini izbjeglo, on se dovodi na sobnu temperaturu uz isti lokalni intenzitet hlađenja. Naročito je pogodno ako se toplinska obrada nakon toplinskog oblikovanja valjanog pripravka sa stupnjem deformiranja od 1,8% do 8%, poželjno od 2 do 5%, izvodi u posljednjem prolazu na temperaturi od najmanje 750°C i najviše 1050°C ostvarenoj od topline toplinskog oblikovanja. Završno oblikovanje sa stupnjem deformiranja, odnosno smanjenja površine poprečnog presjeka, od 1,8 do 8 % izaziva povoljno smanjenje austenitnih zrna, ako se oblikovanje vrši u temperaturnom opsegu od 770°C do 1050°C. Stupnjevi deformiranja manji od 1,8% izazivaju, kako se pokazalo, na pojedinim mjestima izuzetno jako grubo zrno, odnosno povećanje zrna, dok nasuprot tome, deformacije veće od 8% izazivaju jak porast temperature u središnjim, odnosno unutarnjim područjima, vjerojatno zbog oslobođene energije oblikovanja, čime se stvaraju lokalne nehomogenosti strukture i može se izazvati pogoršanje kvalitete. After the complete transformation of the structure, in order to reduce or essentially avoid bending of the rolled preparation, it is brought to room temperature with the same local cooling intensity. It is particularly convenient if the heat treatment after heat forming of the rolled product with a degree of deformation from 1.8% to 8%, preferably from 2 to 5%, is performed in the last pass at a temperature of at least 750°C and at most 1050°C achieved by heat thermal forming. Final shaping with a degree of deformation, i.e. reduction of the cross-sectional area, from 1.8 to 8% causes a favorable reduction of austenite grains, if the shaping is performed in the temperature range from 770°C to 1050°C. Degrees of deformation less than 1.8% cause, as it turned out, extremely coarse grains, i.e. an increase in grains, in some places, while in contrast, deformations greater than 8% cause a strong increase in temperature in the central, i.e. inner areas, probably due to released energy forming, which creates local structural inhomogeneities and can cause quality deterioration.
Uzimajući u obzir održavanje u najvećoj mjeri pravocrtno ispravljenog ili poravnatog valjanog pripravka nakon hlađenja na sobnu temperaturu a naročito tračnica povećane krutosti i otpornosti na promjenjivo savijanje, veoma je pogodno ako se u drugom stupnju hlađenja intenzitet hlađenja u dvije ili više zona na opsegu profiliranog pripravka poveća. Time se može u više područja u blizini površine poprečnog presjeka ostvariti veća tvrdoća i veća čvrstoća materijala sitnijom perlitnom strukturom. Kod opterećenja valjanog pripravka na savijanje, kod kojeg zone poprečnog presjeka koje su najudaljenije od neutralnog vlakna ili nulte linije podnose najveća naprezanja, mogu se ostvariti najmanje dvije takve periferne zone povećane čvrstoće. Pri tome se kod tračnice, kako je utvrđeno, može povećati žilavost materijala na pukotine u području nožice. Taking into account the maintenance to the greatest extent of a rectilinearly straightened or aligned rolled product after cooling to room temperature, and especially a rail of increased stiffness and resistance to variable bending, it is very convenient if, in the second stage of cooling, the intensity of cooling in two or more zones on the circumference of the profiled product is increased . In this way, in several areas near the surface of the cross-section, greater hardness and greater strength of the material can be achieved with a finer pearlite structure. When loading a rolled preparation to bending, in which the cross-sectional zones farthest from the neutral fiber or zero line bear the greatest stresses, at least two such peripheral zones of increased strength can be realized. At the same time, it has been found that the toughness of the material to cracks in the area of the leg can increase with the rail.
Pogodno je da se dio valjanog pripravka u kome je najveća koncentracija materijala, na primjer glava tračnice, hladi postupkom potapanja, odnosno potapanjem u neku tekućinu za hlađenje, pri čemu se istodobno sa dijela, ili dijelova, valjanog pripravka, predviđenih za pojačano hlađenje, a s manjom koncentracijom mase, na primjer nožica tračnice, toplina odvodi pomoću sredstava manjeg intenziteta hlađenja, na primjer zrakom pod pritiskom ili prskanjem smjesom zraka i vode. Ovakvim postupkom se može suzbiti oblikovanje velikih unutarnjih napona i toplinsko iskrivljavanje valjanog pripravka. It is convenient for the part of the rolled preparation in which the material concentration is highest, for example the rail head, to be cooled by immersion, i.e. by immersion in a cooling liquid, while at the same time the part, or parts, of the rolled preparation, intended for enhanced cooling, and with with a lower concentration of mass, for example rail legs, the heat is removed using means of lower cooling intensity, for example pressurized air or spraying with a mixture of air and water. This procedure can prevent the formation of large internal stresses and thermal distortion of the rolled product.
Da bi se kod spomenutih legura na bazi željeza izbjeglo nepovoljno oblikovanje martenzita i ostvarila sitnoperlitna struktura, pogodno je da veličina intenziteta hlađenja, a naročito sastav tekućine za hlađenje potapanjem bude tako podešen, da se u području temperatura od 800°C do 450°C ostvari hlađenje zone u blizini površine, naročito potopljenog dijela, brzinom uglavnom od 1,6 do 2,4°C/s, poželjno oko 2,0°C/s. Ova je brzina hlađenja pogodna i iz ekonomskih razloga, jer je nakon postizanja željene kvalitete valjanog proizvoda potrebno kratko vrijeme hlađenja u drugom stupnju, čime se može ostvariti veća proizvodnost. In order to avoid the unfavorable formation of martensite and achieve a fine pearlite structure in the mentioned iron-based alloys, it is suitable that the magnitude of the cooling intensity, and especially the composition of the liquid for immersion cooling, should be adjusted in such a way that temperatures in the range of 800°C to 450°C are achieved cooling of the zone near the surface, especially the submerged part, at a rate mostly of 1.6 to 2.4°C/s, preferably around 2.0°C/s. This cooling speed is also suitable for economic reasons, because after achieving the desired quality of the rolled product, a short cooling time is required in the second stage, which can achieve higher productivity.
Da bi se minimiziralo krivljenje, pokazalo se pogodnim da se kod profiliranog valjanog pripravka s jednim T-oblikovanim područjem poprečnog presjeka, kao što je na primjer nožica željezničke tračnice, zona nasuprot vrata, odnosno plosnati dio, hladi povećanim intenzitetom, najbolje zrakom pod pritiskom ili mješavinom vode i zraka. Pri tome se u smislu poboljšanja trajnosti pokazalo kao posebno povoljno da je površinska zona s povećanim intenzitetom hlađenja, postavljena nasuprot vrata tračnice, načinjena uglavnom simetrično u odnosu na os vrata tračnice i bočno ograničena. Ako treba izbjeći povećan intenzitet hlađenja područja poprečnog presjeka profiliranog valjanog pripravka, koja su udaljena od koncentracije mase ili prijelaznih zaobljenja vrata tračnica, i/ili treba ta područja zaštiti od višekratnog odvođenja topline ili ih bar kratkotrajno treba zagrijati, može se u kutovima valjanog pripravka ostvariti struktura iste ili manje čvrstoće materijala. Time se neočekivano smanjuje opasnost od loma, naročito kod udarnih i/ili promjenjivih trajnih opterećenja valjanog materijala. In order to minimize warping, it has been shown to be convenient for a profiled rolled product with a single T-shaped cross-sectional area, such as for example a railway leg, the zone opposite the door, i.e. the flat part, to be cooled with increased intensity, preferably with pressurized air or a mixture of water and air. At the same time, in terms of improving durability, it turned out to be particularly advantageous that the surface zone with increased cooling intensity, placed opposite the rail door, was made mostly symmetrically in relation to the axis of the rail door and was laterally limited. If the increased intensity of cooling of the cross-sectional area of the profiled rolled product, which is far from the concentration of mass or transitional roundings of the rail doors, needs to be avoided, and/or these areas need to be protected from repeated heat removal or they need to be heated at least for a short time, it can be realized in the corners of the rolled product structure of the same or lower material strength. This unexpectedly reduces the risk of breakage, especially in case of impact and/or variable permanent loads of the rolled material.
Posebna stabilnost oblika može se ostvariti ako se intenzitet hlađenja na površini profiliranog valjanog pripravka, naročito tračnice, tako podesi, da su zone, u kojima se vrši transformacija γ -strukture hlađenjem, izvedene uglavnom paralelno simetrične i/ili paralelno neutralnoj ravnini, preporučljivo koncentrično u odnosu na težišnu liniju, odnosno na težište površine poprečnog presjeka. Special shape stability can be achieved if the intensity of cooling on the surface of the profiled rolled product, especially the rail, is adjusted so that the zones, in which the transformation of the γ-structure is carried out by cooling, are mainly parallel symmetric and/or parallel to the neutral plane, preferably concentric in relative to the center of gravity, that is, to the center of gravity of the cross-sectional area.
Da bi se postigao u uzdužnom pravcu potpuno isti intenzitet hlađenja i održao stabilan prijenos topline na medij za hlađenje, može se, prema izumu, valjani pripravak, čiji se jedan dio, u odnosu na poprečni presjek, potapa u tekućinu za hlađenje u nekom rezervoaru ili bazenu za potapanje, u tijeku hlađenja u istom pomicati u uzdužnom pravcu u odnosu na bazen s tekućinom za hlađenje, odnosno bazen za potapanje, i/ili se bar tijekom vremena u kome je dio valjanog pripravka potopljen u tekućinu za hlađenje, ova podvrći vibracijama, odnosno pustiti vibrirati. Ovi postupci, kako je utvrđeno, znatno poboljšavaju homogenost ostvarene kvalitete. Uređaj spomenute vrste za integralno rješenje problema kod izrade profiliranog valjanog pripravka posebnih svojstava naznačen je, prema izumu, time što transporter s valjcima u pripremnom području ima jedan inače poznat uređaj za pozicioniranie valjanog pripravka i uređaj za pravocrtno ili aksijalnoporavnato ravnanje profiliranog valjanog profila njegovim plastičnim deformiranjem, zatim ima uređaj za poprečno prenošenje za pravocrtno odnosno aksijalnoporavnato nošenje valjanog pripravka uglavnom uzdužno na njegovu os iz pripremnog područja u područje obrade hlađenjem, u kom je području postavljen jedan inače poznat uređaj za skrutnjavanje valjanog pripravka, naročito glave tračnice, pomoću tekućine za hlađenje u kupki za potapanje s uređajima za držanje i rukovanje i jednim reguliranim dodatnim uređajem za hlađenje za intenzivno hlađenje najmanje jednog drugog područja valjanog pripravka, naročito nožice tračnice, i što područje završnog hlađenja ima oslonac za valjani pripravak za hlađenje istog na sobnu temperaturu. In order to achieve exactly the same cooling intensity in the longitudinal direction and to maintain stable heat transfer to the cooling medium, according to the invention, a rolled preparation, one part of which, in relation to the cross section, is immersed in a cooling liquid in a reservoir or the immersion pool, during the cooling process, move in the same longitudinal direction in relation to the pool with the cooling liquid, i.e. the immersion pool, and/or at least during the time in which part of the rolled preparation is immersed in the cooling liquid, the latter is subjected to vibrations, that is, let it vibrate. These procedures, as determined, significantly improve the homogeneity of the achieved quality. A device of the mentioned type for an integral solution to the problem of making a profiled rolled product with special properties is indicated, according to the invention, by the fact that the conveyor with rollers in the preparation area has an otherwise known device for positioning the rolled product and a device for rectilinear or axially aligned straightening of the profiled rolled profile by its plastic deformation , then has a device for transverse transfer for rectilinear or axially aligned carrying of the rolled product mainly longitudinally on its axis from the preparation area to the cooling treatment area, in which area a known device for solidification of the rolled product, especially the rail head, using the cooling liquid in immersion baths with holding and handling devices and one regulated additional cooling device for intensive cooling of at least one other area of the rolled product, in particular the rail legs, and that the final cooling area has a support for the rolled product for cooling bringing it to room temperature.
Poznato je da je pravocrtno, odnosno osno ravnanje važno, naročito kod parcijalnog, odnosno u dijelovima poprečnog presjeka izvođenog, poboljšanja profiliranog valjanog pripravka. Sprječavanjem krivljenja po cijeloj duljini ili u pojedinim područjima, mogu se unaprijed određeni uvjeti hlađenja ili intenziteti hlađenja valjanog pripravka, gledano u pravcu osi, održati istim, tako da su promjene čvrstoće, odnosno tvrdoće duž profila koji se izrađuje isključene. Ispitivanja su pokazala da različite udaljenosti od stijenke jednog bazena s tekućinom za hlađenje i/ili od osi mlaza za hlađenje, mogu izazvati prekomjema odstupanja vrijednosti tvrdoće i čvrstoće. It is known that straight-line, i.e. axial alignment is important, especially in the case of partial, i.e. in parts of the cross-section performed, improvement of the profiled rolled preparation. By preventing bending along the entire length or in certain areas, predetermined cooling conditions or cooling intensities of the rolled product, seen in the direction of the axis, can be kept the same, so that changes in strength or hardness along the profile being made are excluded. Tests have shown that different distances from the wall of a pool with cooling liquid and/or from the axis of the cooling jet can cause significant deviations in hardness and strength values.
Kod poravnavanja je, dalje, važno da se valjani pripravak pomoću odgovarajućih uređaja podvrgne plastičnom oblikovanju, kako bi se spriječilo elastično vraćanje u eventualno djelomično zakrivljeni oblik. Prenošenje aksijalnoporavnatog profiliranog valjanog pripravka u područje hlađenja pravocrtnim poprečnim prenošenjem od velikog je značaja radi izbjegavanja korištenja uređaja za naknadno ravnanje. Pored toga je u području hlađenja predviđen uređaj za rukovanje (manipulaciju), kojim se vrši prenošenje i držanje, potapanje u bazen s tekućinom za hlađenje, odnosno skrutnjavanje dijelova područja valjanog pripravka, kao i prenošenje u područje završnog hlađenja. Pri tome se može za intenzivirano hlađenje drugih područja poprečnog presjeka predvidjeti barem još jedan dodatni uređaj za hlađenje. When aligning, it is also important that the rolled preparation is subjected to plastic shaping using appropriate devices, in order to prevent it from elastically returning to a possibly partially curved shape. Transferring the axially aligned profiled rolled preparation to the cooling area by straight transverse transfer is of great importance in order to avoid the use of post-straightening devices. In addition, a handling (manipulation) device is provided in the cooling area, which is used to transfer and hold, immerse in a pool with cooling liquid, i.e. solidify parts of the rolled preparation area, as well as transfer to the final cooling area. At the same time, at least one additional cooling device can be provided for intensified cooling of other cross-sectional areas.
Kod daljnjeg usavršavanja uređaja pogodno je ako se dodatni uređaj za hlađenje može podesiti prema valjanom pripravku i ako se njegov intenzitet može regulirati, čime se može ostvariti daljnje lokalno odvođenje topline, koje odgovara izvođenom postupku. When further improving the device, it is convenient if the additional cooling device can be adjusted according to the valid preparation and if its intensity can be regulated, so that further local heat removal can be achieved, which corresponds to the performed procedure.
Također je pogodna izvedba kod koje dodatni uređaj za hlađenje ima dijelove za oblikovanje struje sredstva za hlađenje, koja je u uzdužnom, odnosno aksijalnom pravcu valjanog pripravka neprekinuta a u poprečnom pravcu ograničena, i eventualno neko sredstvo za sprečavanje pojačanog odvođenja topline sa površina koje se nalaze uz hlađenu površinu. Na taj način je moguće oblikovati točno ograničene zone hlađenja a uz njih susjedne zone isključiti od intenziviranog odvođenja topline, odnosno u njima ostvariti manju tvrdoću materijala, pri čemu je daljnja izvedba dodatnog uređaja za hlađenje načinjena kao uređaj za hlađenje zrakom pod pritiskom ili prskanjem tekućinom. Also suitable is the version in which the additional cooling device has parts for shaping the current of the cooling medium, which is continuous in the longitudinal, i.e. axial, direction of the rolled product and limited in the transverse direction, and possibly some means to prevent increased heat removal from the surfaces located next to cooled surface. In this way, it is possible to form precisely limited cooling zones and to exclude the adjacent zones from intensified heat removal, i.e. to achieve a lower hardness of the material in them, while the further design of the additional cooling device is made as a device for cooling with pressurized air or liquid spraying.
Homogenost tvrdoće i čvrstoće u uzdužnom pravcu profiliranog valjanog pripravka može se dalje povećati ako se valjani pripravak može u tekućini za hlađenje pomicati u pravcu uzdužne osi u odnosu na bazen za potapanje i/ili u odnosu na bazen za potapanje i/ili u odnosu na dodatni uređaj za hlađenje postavljenog uređaja, pomoću kojih se tekućina za hlađenje može turbulentno kretati i/ili dovesti u oscilatorno kretanje. Utvrđeno je da relativno kretanje kao i oscilatorno kretanje ili udarni valovi između medija za hlađenje i radnog predmeta izjednačuju lokalne intenzitete hlađenja i ostvaruju pogodne uvjete za poboljšanje. The homogeneity of hardness and strength in the longitudinal direction of the profiled rolled product can be further increased if the rolled product can be moved in the cooling liquid in the direction of the longitudinal axis in relation to the immersion pool and/or in relation to the immersion pool and/or in relation to the additional a device for cooling the installed device, by means of which the cooling liquid can move turbulently and/or be brought into oscillatory motion. Relative motion as well as oscillatory motion or shock waves between the cooling medium and the workpiece were found to equalize local cooling intensities and achieve favorable conditions for improvement.
Tračnica prema izumu, naročito načinjena prema jednom od naprijed spomenutih postupaka, eventualno načinjena u naprijed opisanom uređaju, naznačena je time, što tračnica po poprečnom presjeku ima u gornjem dijelu glave veliku vrijednost čvrstoće i tvrdoće materijala, koje se u donjem području glave, vratu tračnice i perifernim dijelovima nožice smanjuju, dok u središnjem dijelu na donjoj površini nožice ima, u usporedbi s perifernim dijelovima i vratom tračnice, povećanu vrijednost tvrdoće materijala, pri čemu se naročito ravnomjerna kvaliteta može postići kada su simetrično u odnosu na glavnu os poprečnog presjeka profila, odnosno simetrično u odnosu na okomitu os poprečnog presjeka tračnice, ostvarene uglavnom iste vrijednosti tvrdoće materijala. Takva jedna tračnica ima kod povećanih opterećenja, kao što su velika osovinska opterećenja i/ili velika frekvencija korištenja i/ili mali polupromjeri krivulje kolosijeka, poboljšana upotrebna svojstva. The rail according to the invention, especially made according to one of the above-mentioned methods, possibly made in the above-described device, is indicated by the fact that the cross-section of the rail has a high value of strength and hardness of the material in the upper part of the head, which in the lower area of the head, the neck of the rail and the peripheral parts of the leg are reduced, while in the central part on the lower surface of the leg, compared to the peripheral parts and the neck of the rail, the hardness value of the material is increased, whereby a particularly uniform quality can be achieved when they are symmetrical in relation to the main axis of the cross-section of the profile, that is, symmetrically in relation to the vertical axis of the cross-section of the rail, achieved mostly the same hardness values of the material. Such a single rail has, with increased loads, such as high axle loads and/or high frequency of use and/or small radii of the track curve, improved serviceability.
U daljnjem će tekstu izum biti detaljnije objašnjen s pozivom na crteže koji prikazuju samo jednu njegovu izvedbu. Pri tome: In the following text, the invention will be explained in more detail with reference to the drawings showing only one of its embodiments. Thereby:
- slika 1 prikazuje tehnološku shemu toplinske obrade tračnice, - picture 1 shows the technological scheme of heat treatment of the rail,
- slika 2 prikazuje poprečni presjek tračnice, - picture 2 shows the cross-section of the rail,
- slika 3 prikazuje dijagram vrijeme-temperatura transformacije jednog tračnog materijala. - Figure 3 shows the time-temperature diagram of the transformation of one strip material.
Kao što je na slici 1 shematski prikazano, u pripremnom području A se na transporter 21 s valjcima postavlja profilirani pripravak, kao što je tračnica, pomoću jednog pokretnog potiskivača ili sličnog (nije prikazano). Pomoću uređaja 22 i 23 za ravnanje tračnica 1 će biti poravnata, pri čemu je pogodan jedan centrirajući oblik uređaja za ravnanje koji također korigira i okomitu iskrivljenost. Nakon izravnavanja valjanog pripravka 1 vrši se poprečno prenošenje pomoću nosača 2 u područje B za hlađenje i prihvaćanje u uređaj za rukovanje sa sredstvima 24 za držanje, pri čemu je kod prenošenja predviđeno takvo oslanjanje, da ne dolazi do savijanja poprečno na uzdužnu os. As shown schematically in Fig. 1, in the preparation area A, a profiled preparation, such as a rail, is placed on the roller conveyor 21 by means of a movable pusher or the like (not shown). By means of devices 22 and 23 for straightening the rail 1 will be aligned, whereby a centering form of straightening device is suitable which also corrects the vertical curvature. After straightening the rolled product 1, it is transferred transversely by means of the carrier 2 to the area B for cooling and acceptance into the handling device with holding means 24, whereby such a support is provided during the transfer, that it does not bend transversely to the longitudinal axis.
Valjani pripravak, odnosno tračnica 1 će se na poznati način, pomoću držača 24 djelomično potopiti u tekućinu 37 za hlađenje koja se nalazi u bazenu 38 za potapanje. Pri tome je važno da udaljenost površine tračnice 1 od stijenki bazena za potapanje bude cijelom duljinom jednaka s obje strane, pri čemu je važno da se, u cilju intenziviranja, a naročito u cilju izjednačavanja intenziteta hlađenja površine valjanog pripravka, valjani pripravak 1 može u bazenu 38 za potapanje, odnosno u mediju 37 za hlađenje, pomicati za duljinu od, na primjer, 0,5 do 5 m. U medij 37 za hlađenje, ili na bazen za potapanje može se postaviti jedan vibrator (nije prikazan), koji na medij za hlađenje prenosi vibracije koje pogodno utječu na intenzitet hlađenja, a sa frekvencijom od, na primjer, 100 do 800 1/min. The rolled preparation, i.e. the rail 1, will be partially submerged in the cooling liquid 37 located in the immersion basin 38 using the holder 24 in a known manner. In doing so, it is important that the distance of the surface of the rail 1 from the walls of the dipping pool is the same on both sides along its entire length, while it is important that, in order to intensify, and especially in order to equalize the cooling intensity of the surface of the rolled product, the rolled product 1 can be placed in the pool 38 for immersion, that is, in the medium 37 for cooling, move for a length of, for example, 0.5 to 5 m. In the medium 37 for cooling, or on the pool for immersion, one vibrator (not shown) can be placed, which on the medium for cooling, it transmits vibrations that favorably affect the intensity of cooling, with a frequency of, for example, 100 to 800 1/min.
Na ravni dio valjanog profila, eventualno na nožicu 13 tračnice 1, može se postaviti dodatni uređaj 3 za hlađenje. Takav uređaj za hlađenje može imati dovod 32 za vodu i dovod 33 za zrak, i oblikovati struju 31 za prskanje usmjerenu na dio površine valjanog pripravka, odnosno na nožicu tračnice. Da bi se na perifernim dijelovima 132 ostvario manji intenzitet hlađenja, a samo u središnjem području 131 površine valjanog pripravka, odnosno nožice tračnice oblikovala zona povećane tvrdoće materijala, može biti pogodno predvidjeti odvođenje rashladnog sredstva pomoću, na primjer, nekog uređaja za usisavanje. An additional device 3 for cooling can be placed on the flat part of the rolled profile, possibly on the foot 13 of the rail 1. Such a cooling device can have an inlet 32 for water and an inlet 33 for air, and form a current 31 for spraying directed at part of the surface of the rolled preparation, that is, at the leg of the rail. In order to achieve a lower intensity of cooling on the peripheral parts 132, and only in the central area 131 of the surface of the rolled preparation, i.e. the rail legs, a zone of increased hardness of the material is formed, it may be convenient to provide for the removal of the coolant using, for example, a suction device.
Nakon hlađenja dijela valjanog pripravka, odnosno tračnice 1, potopljenog u sredstvo 37 za hlađenje i njemu nasuprotnog dijela izloženog struji 31 za prskanje, ispod temperature transformacije materijala, a s intenzitetom kojim se se ostvaruje sitnoperlitna struktura, na primjer prema slici 3, na oko 500°C, a brzinom hlađenja koja odgovara krivulji f, može se ista u području C završnog hlađenja postaviti na oslonac 25 da bi se ohladila na sobnu temperaturu. After cooling the part of the rolled preparation, i.e. the rail 1, immersed in the means 37 for cooling and the part opposite to it exposed to the current 31 for spraying, below the temperature of material transformation, and with the intensity with which the fine pearlite structure is realized, for example according to Figure 3, at about 500° C, and with a cooling rate corresponding to the curve f, it can be placed in the area C of the final cooling on the support 25 to cool down to room temperature.
Kao što je prikazano na slici 2, tračnica 1 prema izumu ima tri područja s različitim strukturama, odnosno tvrdoćom, pri čemu su prijelazi izvedeni kontinuirano. U glavi 11 tračnice je ostvarena sitnoperlitna zona 111 s vrijednošću tvrdoće između 340 i 390 HB, eventualno do 425 HB, koja potom prelazi na dolje u zonu 112 manje tvrdoće od, na primjer, 300 do 340 HB. U produžetku, u vratu 12 tračnice, koji u praktičnoj primjeni mora imati veliku žilavost, ostvarene su odgovarajuće vrijednosti tvrdoće od 280 do 320 HB. U nožici 13 tračnice je u perifernim područjima 132, kao i u vratu 12, ostvarena perlitna struktura sa grubljim zrnima, odnosno lamelasta struktura, i tvrdoća od 280 do 320 HB. As shown in Figure 2, rail 1 according to the invention has three areas with different structures, i.e. hardness, where the transitions are performed continuously. In the head 11 of the rail, a fine pearlite zone 111 with a hardness value between 340 and 390 HB, possibly up to 425 HB, is realized, which then passes downwards into a zone 112 of lower hardness, for example, 300 to 340 HB. In the extension, in the neck of the 12 rail, which in practical application must have great toughness, corresponding hardness values of 280 to 320 HB were achieved. In the leg 13 of the rail, in the peripheral areas 132, as well as in the neck 12, a pearlite structure with coarser grains, i.e. a lamellar structure, and a hardness of 280 to 320 HB has been achieved.
Ovakvom strukturom i svojstvima materijala s malim vrijednostima tvrdoće u najvećoj mogućoj mjeri je izbjegnuta pojava pukotina ili lomova. Središnje na donjoj površini nožice 13 ostvareno je područje 131 povećane čvrstoće materijala i vrijednosti tvrdoće od 300 do 350 HB i veće. Takva raspodjela prema izumu mehaničkih svojstava materijala po poprečnom presjeku osigurava, kako je utvrđeno, veliku stabilnost i povoljnu trajnost naročito pri otežanim uvjetima. Due to this structure and properties of materials with low hardness values, the appearance of cracks or fractures is avoided to the greatest extent possible. Centrally on the lower surface of the foot 13, an area 131 of increased material strength and hardness values of 300 to 350 HB and higher has been realized. Such a distribution according to the invention of the mechanical properties of the material across the cross-section ensures, as established, great stability and favorable durability, especially under difficult conditions.
Claims (19)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT0143194A AT402941B (en) | 1994-07-19 | 1994-07-19 | METHOD AND DEVICE FOR THE HEAT TREATMENT OF PROFILED ROLLING MATERIAL |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| HRP950386A2 true HRP950386A2 (en) | 1997-04-30 |
| HRP950386B1 HRP950386B1 (en) | 2000-02-29 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| HRA1431/94A HRP950386B1 (en) | 1994-07-19 | 1995-07-07 | Process and apparatus for heat-treating shaped rolled pieces |
Country Status (19)
| Country | Link |
|---|---|
| EP (1) | EP0693562B1 (en) |
| JP (1) | JP3811865B2 (en) |
| KR (1) | KR100372402B1 (en) |
| CN (1) | CN1045214C (en) |
| AT (2) | AT402941B (en) |
| AU (1) | AU702091B2 (en) |
| BR (1) | BR9503367A (en) |
| CA (1) | CA2154090C (en) |
| CZ (1) | CZ290866B6 (en) |
| DE (1) | DE59508080D1 (en) |
| ES (1) | ES2145247T3 (en) |
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| PL (1) | PL178079B1 (en) |
| RU (1) | RU2101369C1 (en) |
| SI (1) | SI9500230B (en) |
| SK (1) | SK282161B6 (en) |
| TW (1) | TW300920B (en) |
| UA (1) | UA34469C2 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT407057B (en) * | 1996-12-19 | 2000-12-27 | Voest Alpine Schienen Gmbh | PROFILED ROLLING MATERIAL AND METHOD FOR THE PRODUCTION THEREOF |
| AT409268B (en) * | 2000-05-29 | 2002-07-25 | Voest Alpine Schienen Gmbh & C | METHOD AND DEVICE FOR HARDENING RAILS |
| DE10148305A1 (en) * | 2001-09-29 | 2003-04-24 | Sms Meer Gmbh | Process and plant for the thermal treatment of rails |
| RU2336336C2 (en) | 2004-01-09 | 2008-10-20 | Ниппон Стил Корпорейшн | Method of fabricating rails |
| JP5169030B2 (en) * | 2007-06-08 | 2013-03-27 | 日産自動車株式会社 | Quenching method and quenching apparatus |
| AT505930B1 (en) * | 2008-02-04 | 2009-05-15 | Voestalpine Schienen Gmbh | DEVICE FOR HARDENING RAILS |
| EP2253394B1 (en) | 2008-02-27 | 2018-04-04 | Nippon Steel & Sumitomo Metal Corporation | Cooling system and cooling method of rolling steel |
| DE102012020844A1 (en) * | 2012-10-24 | 2014-04-24 | Thyssenkrupp Gft Gleistechnik Gmbh | Process for the thermomechanical treatment of hot-rolled profiles |
| JP6137093B2 (en) * | 2014-09-18 | 2017-05-31 | Ｊｆｅスチール株式会社 | Rail cooling method and cooling equipment |
| BR112021015414A2 (en) | 2019-03-15 | 2021-10-05 | Nippon Steel Corporation | RAIL |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2087346A (en) * | 1930-08-21 | 1937-07-20 | United States Steel Corp | Method of producing steel rails |
| FR2109121A5 (en) | 1970-10-02 | 1972-05-26 | Wendel Sidelor | |
| 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 |
| BE854834A (en) * | 1977-05-18 | 1977-09-16 | Centre Rech Metallurgique | PROCESS FOR MANUFACTURING RAILS WITH IMPROVED CHARACTERISTICS |
| DE3006695C2 (en) | 1980-02-22 | 1988-12-01 | Klöckner-Werke AG, 4100 Duisburg | Process for heat treatment of rails |
| US4486248A (en) * | 1982-08-05 | 1984-12-04 | The Algoma Steel Corporation Limited | Method for the production of improved railway rails by accelerated cooling in line with the production rolling mill |
| LU84417A1 (en) * | 1982-10-11 | 1984-05-10 | Centre Rech Metallurgique | IMPROVED PROCESS FOR THE MANUFACTURE OF RAILS AND RAILS OBTAINED BY THIS PROCESS |
| DE3446794C1 (en) | 1984-12-21 | 1986-01-02 | BWG Butzbacher Weichenbau GmbH, 6308 Butzbach | Process for the heat treatment of pearlitic rail steel |
| DE3579681D1 (en) * | 1984-12-24 | 1990-10-18 | Nippon Steel Corp | METHOD AND DEVICE FOR TREATING THE RAILS. |
| US4886558A (en) * | 1987-05-28 | 1989-12-12 | Nkk Corporation | Method for heat-treating steel rail head |
| US4895605A (en) * | 1988-08-19 | 1990-01-23 | Algoma Steel Corporation | Method for the manufacture of hardened railroad rails |
| 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 |
| AT399346B (en) | 1992-07-15 | 1995-04-25 | Voest Alpine Schienen Gmbh | METHOD FOR TREATING RAILS |
| DE4237991A1 (en) | 1992-11-11 | 1994-05-19 | Schloemann Siemag Ag | Cooling hot-rolled products, rails - using appts. with carrier elements allowing rails to be suspended with their top downwards |
-
1994
- 1994-07-19 AT AT0143194A patent/AT402941B/en not_active IP Right Cessation
-
1995
- 1995-06-14 UA UA95062801A patent/UA34469C2/en unknown
- 1995-06-29 AU AU23349/95A patent/AU702091B2/en not_active Expired
- 1995-07-06 JP JP20265295A patent/JP3811865B2/en not_active Expired - Fee Related
- 1995-07-07 HR HRA1431/94A patent/HRP950386B1/en not_active IP Right Cessation
- 1995-07-07 CN CN95109955A patent/CN1045214C/en not_active Expired - Lifetime
- 1995-07-13 DE DE59508080T patent/DE59508080D1/en not_active Expired - Lifetime
- 1995-07-13 EP EP95890136A patent/EP0693562B1/en not_active Expired - Lifetime
- 1995-07-13 ES ES95890136T patent/ES2145247T3/en not_active Expired - Lifetime
- 1995-07-13 AT AT95890136T patent/ATE191241T1/en active
- 1995-07-14 PL PL95309657A patent/PL178079B1/en unknown
- 1995-07-17 SK SK901-95A patent/SK282161B6/en not_active IP Right Cessation
- 1995-07-17 CZ CZ19951861A patent/CZ290866B6/en not_active IP Right Cessation
- 1995-07-18 RU RU95113234A patent/RU2101369C1/en active
- 1995-07-18 CA CA002154090A patent/CA2154090C/en not_active Expired - Lifetime
- 1995-07-18 SI SI9500230A patent/SI9500230B/en not_active IP Right Cessation
- 1995-07-18 BR BR9503367A patent/BR9503367A/en not_active IP Right Cessation
- 1995-07-18 HU HU9502162A patent/HU218230B/en not_active IP Right Cessation
- 1995-07-19 KR KR1019950021120A patent/KR100372402B1/en not_active IP Right Cessation
- 1995-07-19 TW TW084107478A patent/TW300920B/zh not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
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| AU702091B2 (en) | 1999-02-11 |
| HU9502162D0 (en) | 1995-09-28 |
| PL178079B1 (en) | 2000-02-29 |
| RU2101369C1 (en) | 1998-01-10 |
| CZ290866B6 (en) | 2002-11-13 |
| SK282161B6 (en) | 2001-11-06 |
| HRP950386B1 (en) | 2000-02-29 |
| CZ186195A3 (en) | 1996-02-14 |
| SK90195A3 (en) | 1996-03-06 |
| AU2334995A (en) | 1996-02-01 |
| CA2154090A1 (en) | 1996-01-20 |
| DE59508080D1 (en) | 2000-05-04 |
| CN1045214C (en) | 1999-09-22 |
| SI9500230A (en) | 1997-02-28 |
| EP0693562A1 (en) | 1996-01-24 |
| TW300920B (en) | 1997-03-21 |
| JP3811865B2 (en) | 2006-08-23 |
| EP0693562B1 (en) | 2000-03-29 |
| HU218230B (en) | 2000-06-28 |
| HUT72292A (en) | 1996-04-29 |
| JPH08170120A (en) | 1996-07-02 |
| ATA143194A (en) | 1997-02-15 |
| ES2145247T3 (en) | 2000-07-01 |
| UA34469C2 (en) | 2001-03-15 |
| KR100372402B1 (en) | 2003-05-09 |
| ATE191241T1 (en) | 2000-04-15 |
| BR9503367A (en) | 1996-09-10 |
| PL309657A1 (en) | 1996-01-22 |
| CN1123331A (en) | 1996-05-29 |
| CA2154090C (en) | 2005-01-11 |
| SI9500230B (en) | 2001-12-31 |
| AT402941B (en) | 1997-09-25 |
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