EP1538231B1 - A microalloy bainitic steel with high resistance to fatigue and to fretting fatigue - Google Patents
A microalloy bainitic steel with high resistance to fatigue and to fretting fatigue Download PDFInfo
- Publication number
- EP1538231B1 EP1538231B1 EP04016413A EP04016413A EP1538231B1 EP 1538231 B1 EP1538231 B1 EP 1538231B1 EP 04016413 A EP04016413 A EP 04016413A EP 04016413 A EP04016413 A EP 04016413A EP 1538231 B1 EP1538231 B1 EP 1538231B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- amount
- temperature
- comprised
- fatigue
- wheel
- 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 - Lifetime
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- 229910000831 Steel Inorganic materials 0.000 title abstract description 15
- 239000010959 steel Substances 0.000 title abstract description 15
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 7
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 7
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 7
- 238000000034 method Methods 0.000 claims description 16
- 238000001816 cooling Methods 0.000 claims description 14
- 238000005496 tempering Methods 0.000 claims description 11
- 238000005096 rolling process Methods 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 claims description 9
- 229910000851 Alloy steel Inorganic materials 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 6
- 229910052799 carbon Inorganic materials 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 229910052758 niobium Inorganic materials 0.000 claims description 5
- 229910052719 titanium Inorganic materials 0.000 claims description 5
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- 229910052796 boron Inorganic materials 0.000 claims description 4
- 229910052791 calcium Inorganic materials 0.000 claims description 4
- 229910052757 nitrogen Inorganic materials 0.000 claims description 4
- 238000010791 quenching Methods 0.000 claims description 4
- 230000000171 quenching effect Effects 0.000 claims description 4
- 229910052726 zirconium Inorganic materials 0.000 claims description 4
- 239000012535 impurity Substances 0.000 claims description 3
- 229910052742 iron Inorganic materials 0.000 claims description 3
- 238000003754 machining Methods 0.000 claims description 2
- 229910052748 manganese Inorganic materials 0.000 abstract description 6
- 229910052710 silicon Inorganic materials 0.000 abstract description 6
- 235000013619 trace mineral Nutrition 0.000 abstract 1
- 239000011573 trace mineral Substances 0.000 abstract 1
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 9
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 5
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 5
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 5
- 239000011651 chromium Substances 0.000 description 5
- 239000011572 manganese Substances 0.000 description 5
- 239000010703 silicon Substances 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 4
- 238000005275 alloying Methods 0.000 description 4
- 239000011733 molybdenum Substances 0.000 description 4
- 239000010955 niobium Substances 0.000 description 4
- 238000004901 spalling Methods 0.000 description 4
- 230000002269 spontaneous effect Effects 0.000 description 4
- 239000010936 titanium Substances 0.000 description 4
- 239000011575 calcium Substances 0.000 description 3
- 229910052720 vanadium Inorganic materials 0.000 description 3
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 2
- 239000004411 aluminium Substances 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 2
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
-
- 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
- C21D1/18—Hardening; Quenching with or without subsequent tempering
-
- 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
- C21D9/34—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tyres; for rims
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/78—Combined heat-treatments not provided for above
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/002—Bainite
Definitions
- the present invention refers to a microalloy bainitic steel with high resistance to fatigue and to fretting fatigue.
- the present invention refers to a microalloy bainitic steel with high resistance to fatigue and to fretting fatigue being particularly suitable to be used for the manufacturing of rail wheels, i.e. wheels for railway, tramway and/or metro fields.
- the wheel is one of the most important components making the rolling stock.
- the wheel is submitted to complex phenomena such as ratchetting, fretting fatigue wear friction, etc. intervening on the wheel/rail interface.
- complex phenomena such as ratchetting, fretting fatigue wear friction, etc. intervening on the wheel/rail interface.
- great stresses occur due to the severe load conditions. These stresses give rise both to the first stages of fretting fatigue failures and to wearing.
- Fatigue failures are very dangerous as they can cause the detachment of small portions of wheel, with serious consequences both on suspensions, on the axle-box bearings of the vehicle and on the railway infrastructure.
- fretting fatigue failures can be spallings due to ratchetting phenomena or to heat loads or spallings due to shellings or deep shellings.
- spallings are induced by cold ratchetting. It is known that the wheel/rail contact develops in cyclic elastic-plastic conditions with localized ratchetting and the sum of ratchetting deriving from various cycles may give rise to local failures for damage accumulation.
- spallings are due to the detachment of small portions of wheels with cratering forming on the rolling surface in conditions of high axle loads or in the presence of macrodefects at depths comprised between 6 and 30 mm under the rolling surface.
- EP-A-1 241 277 on which is based the preamble of claim 1, discloses a steel alloy, particularly for railway wheels, comprising carbon, silicon, manganese as alloying elements imparting hardness, and chromium, nickel, molybdenum, as alloying elements improving the tempering properties, but no elements with microalloying properties.
- Both FR-A-2 166 585 and EP-A-0 884 396 disclose the manufacturing of a steel alloy comprising carbon, silicon, manganese as alloying elements imparting hardness, and chromium, nickel, molybdenum, as alloying elements improving the tempering properties, the former document additionally disclosing the use of V in the composition.
- EP 0612852 discloses a process for manufacturing high-strength bainitic steel rails with excellent rolling contact fatigue resistance, the steel comprising carbon, silicon, manganese and chromium, and optionally at least one element selected from three groups of elements, namely Ni, Mo, Cu; Nb, V, Ti; B.
- the object of the present invention is to remove the above-mentioned drawbacks.
- the object of the present invention is to provide a steel suitable for the manufacturing of wheels for the railway, tramway and/or metro fields having a high resistance to fretting fatigue failures.
- a further object of the present invention is to provide a steel suitable for the manufacturing of wheels for the railway, tramway and/or metro fields having high mechanical resistance and toughness features combined with high resistance features to wearing and fretting fatigue.
- microalloying elements in well defined ratios among them and compared with the other steel elements helps the steel hardening and protects its toughness.
- These elements with microalloying properties are Nb, Zr, Al and Ti in quantities not higher than 0.06% by weight for each element and B, Ca and N in quantities not higher than 0.007% by weight, for each element.
- a steel according to an embodiment of the present invention preferably comprises: Carbon 0.15 - 0.35% by weight Silicon 0.60 - 1.20% by weight Manganese 0.60 - 1.50% by weight Chromium 0.10 - 1.00% by weight Nickel 0.10 - 1.00% by weight Molybdenum 0.10 - 0.90% by weight Vanadium 0.01 - 0.15% by weight Niobium 0.01 - 0.05% by weight Zirconium 0.005 - 0.06% by weight Aluminium 0.005 - 0.06% by weight Titanium 0.005 - 0.06% by weight Boron 0.0005 - 0.005% by weight Calcium 0.0002 - 0.005% by weigh Nitrogen 0.003 - 0.007% by weight
- the remaining part up to 100 being iron without impurities.
- the product is submitted to austenitization and quenching in water.
- This process consists in the heating at a temperature comprised between 850 and 950° C, a stay at this temperature for one hour for about each 40 mm of thickness of the processed product and in a quick cooling in water until room temperature is reached.
- the product is then submitted to two thermal tempering processes in order to attenuate internal stresses caused by the abrupt cooling.
- the first thermal tempering process is carried out by heating at a variable temperature comprised between 500 and 700°C according to the required features for a stay time at this temperature of about one hour for each 20 mm of thickness of the processed product, followed by a spontaneous air cooling until room temperature is reached.
- the second thermal tempering process is carried out by heating at a temperature lower than 20°C compared to the one of the first thermal tempering process for a stay time at this temperature of about one hour for each 20 mm of thickness of the processed product followed by a spontaneous air cooling for at least 25 minutes and in any case being such to cool the rail wheel rolling until room temperature is reached.
- the cooling of the rail wheel rolling can be carried out at a different speed from the one used for the cooling of the web in order to give different properties to each part of the wheel.
- the steel of the present invention is characterized by an excellent balancing between tensile and toughness features. Toughness values are very high at any temperature level.
- Some castings have been manufactured according to the following objective analysis: Carbon 0.27 - 0.32% by weight Silicon 0.60 - 0.80% by weight Manganese 0.90 - 1.10% by weight Chromium 0.20 - 0.50% by weight Nickel 0.20 - 0.50% by weight Molybdenum 0.20 - 0.50% by weight Vanadium 0.020 - 0.050% by weight Niobium 0.020 - 0.040% by weight Zirconium 0.015 - 0.045% by weight Aluminium 0.015 -0.055% by weight Titanium 0.010 - 0.040% by weight Boron 0.0010 - 0.040% by weight Calcium 0.002 - 0.003% by weight Nitrogen 0.003 - 0.004% by weight
- the remaining part up to 100 being iron without impurities.
- Each wheel has been submitted to austenitization and quenching by heating at a temperature of about 900°C for a stay time at this temperature of about 3 hours and a quick cooling in water until room temperature was reached.
- Each wheel was then submitted to two subsequent thermal tempering processes the first of which was carried out by heating at a temperature of about 520°C - 600°C for a stay time at this temperature of about six hours and a spontaneous air cooling until room temperature was reached; the second one was carried out by heating at a temperature of 20°C lower than the one of the first process for a stay time at such temperature of about six hours and a spontaneous air cooling for 60 minutes until room temperature was reached.
- PROPERTIES STANDARD UNIT VALUE Monotonic yield UNI EN10002 Mpa 1,090 Tensile stress UNI EN10002 Mpa 1,210 Elongation at break UNI EN10002 % 16 Reduction coeff. UNI EN 10002 % 55 WEB PROPERTIES STANDARD UNIT VALUE Monotonic yield UNI EN10002 Mpa 1,090 Tensile stress UNI EN10002 Mpa 1,210 Elongation at break UNI EN10002 % 16 Reduction coeff. UNI EN10002 % 55
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
Description
- The present invention refers to a microalloy bainitic steel with high resistance to fatigue and to fretting fatigue.
- More particularly, the present invention refers to a microalloy bainitic steel with high resistance to fatigue and to fretting fatigue being particularly suitable to be used for the manufacturing of rail wheels, i.e. wheels for railway, tramway and/or metro fields.
- It is known that the wheel is one of the most important components making the rolling stock. During the running of the vehicle, the wheel is submitted to complex phenomena such as ratchetting, fretting fatigue wear friction, etc. intervening on the wheel/rail interface. In fact, during the wheel/rail contact on a thin layer of material placed immediately under the contact area, great stresses occur due to the severe load conditions. These stresses give rise both to the first stages of fretting fatigue failures and to wearing.
- Fatigue failures are very dangerous as they can cause the detachment of small portions of wheel, with serious consequences both on suspensions, on the axle-box bearings of the vehicle and on the railway infrastructure.
- According to the working conditions, fretting fatigue failures can be spallings due to ratchetting phenomena or to heat loads or spallings due to shellings or deep shellings.
- In the first case, spallings are induced by cold ratchetting. It is known that the wheel/rail contact develops in cyclic elastic-plastic conditions with localized ratchetting and the sum of ratchetting deriving from various cycles may give rise to local failures for damage accumulation.
- In the second case, spallings are due to the detachment of small portions of wheels with cratering forming on the rolling surface in conditions of high axle loads or in the presence of macrodefects at depths comprised between 6 and 30 mm under the rolling surface.
- Steels with high resistance levels are known on the market, they successfully remove the drawbacks due to wearing phenomena, but the problems connected to fretting fatigue failures which constitute an ever higher percentage of the damage phenomena of wheels and rails are still present.
-
EP-A-1 241 277 on which is based the preamble of claim 1, discloses a steel alloy, particularly for railway wheels, comprising carbon, silicon, manganese as alloying elements imparting hardness, and chromium, nickel, molybdenum, as alloying elements improving the tempering properties, but no elements with microalloying properties. - Both
andFR-A-2 166 585 EP-A-0 884 396 disclose the manufacturing of a steel alloy comprising carbon, silicon, manganese as alloying elements imparting hardness, and
chromium, nickel, molybdenum, as alloying elements improving the tempering properties, the former document additionally disclosing the use of V in the composition. -
EP 0612852 discloses a process for manufacturing high-strength bainitic steel rails with excellent rolling contact fatigue resistance, the steel comprising carbon, silicon, manganese and chromium, and optionally at least one element selected from three groups of elements, namely Ni, Mo, Cu; Nb, V, Ti; B. - The object of the present invention is to remove the above-mentioned drawbacks.
- More particularly, the object of the present invention is to provide a steel suitable for the manufacturing of wheels for the railway, tramway and/or metro fields having a high resistance to fretting fatigue failures.
- A further object of the present invention is to provide a steel suitable for the manufacturing of wheels for the railway, tramway and/or metro fields having high mechanical resistance and toughness features combined with high resistance features to wearing and fretting fatigue.
- According to the present invention these and other objects, that will be clear from the following description, are obtained by a steel alloy as claimed in claim 1.
- The presence of small amounts of microalloying elements in well defined ratios among them and compared with the other steel elements helps the steel hardening and protects its toughness. These elements with microalloying properties are Nb, Zr, Al and Ti in quantities not higher than 0.06% by weight for each element and B, Ca and N in quantities not higher than 0.007% by weight, for each element.
- A steel according to an embodiment of the present invention preferably comprises:
Carbon 0.15 - 0.35% by weight Silicon 0.60 - 1.20% by weight Manganese 0.60 - 1.50% by weight Chromium 0.10 - 1.00% by weight Nickel 0.10 - 1.00% by weight Molybdenum 0.10 - 0.90% by weight Vanadium 0.01 - 0.15% by weight Niobium 0.01 - 0.05% by weight Zirconium 0.005 - 0.06% by weight Aluminium 0.005 - 0.06% by weight Titanium 0.005 - 0.06% by weight Boron 0.0005 - 0.005% by weight Calcium 0.0002 - 0.005% by weigh Nitrogen 0.003 - 0.007% by weight - The remaining part up to 100 being iron without impurities.
- After the mechanical machining of the steel of the present invention for the manufacturing of wheels for the railway, tramway and/or metro fields, the product is submitted to austenitization and quenching in water. This process consists in the heating at a temperature comprised between 850 and 950° C, a stay at this temperature for one hour for about each 40 mm of thickness of the processed product and in a quick cooling in water until room temperature is reached.
- The product is then submitted to two thermal tempering processes in order to attenuate internal stresses caused by the abrupt cooling.
- The first thermal tempering process is carried out by heating at a variable temperature comprised between 500 and 700°C according to the required features for a stay time at this temperature of about one hour for each 20 mm of thickness of the processed product, followed by a spontaneous air cooling until room temperature is reached.
- The second thermal tempering process is carried out by heating at a temperature lower than 20°C compared to the one of the first thermal tempering process for a stay time at this temperature of about one hour for each 20 mm of thickness of the processed product followed by a spontaneous air cooling for at least 25 minutes and in any case being such to cool the rail wheel rolling until room temperature is reached.
- The cooling of the rail wheel rolling can be carried out at a different speed from the one used for the cooling of the web in order to give different properties to each part of the wheel.
- The steel of the present invention is characterized by an excellent balancing between tensile and toughness features. Toughness values are very high at any temperature level.
- A clear demonstration of said feature balancing is due to the fact that the ductile/brittle transition temperature, defined by the F.A.T.T. value corresponding to 50% is placed at - 40°C even though the tensile stress values are very high.
- In order to better understand the present invention and put it into practice the following illustrative and non limitative example is given.
- Some castings have been manufactured according to the following objective analysis:
Carbon 0.27 - 0.32% by weight Silicon 0.60 - 0.80% by weight Manganese 0.90 - 1.10% by weight Chromium 0.20 - 0.50% by weight Nickel 0.20 - 0.50% by weight Molybdenum 0.20 - 0.50% by weight Vanadium 0.020 - 0.050% by weight Niobium 0.020 - 0.040% by weight Zirconium 0.015 - 0.045% by weight Aluminium 0.015 -0.055% by weight Titanium 0.010 - 0.040% by weight Boron 0.0010 - 0.040% by weight Calcium 0.002 - 0.003% by weight Nitrogen 0.003 - 0.004% by weight - The remaining part up to 100 being iron without impurities.
- With the steels thus obtained some rail wheels have been manufactured according to the prior arts each of them having a rolling diameter of 915 mm.
- Each wheel has been submitted to austenitization and quenching by heating at a temperature of about 900°C for a stay time at this temperature of about 3 hours and a quick cooling in water until room temperature was reached.
- Each wheel was then submitted to two subsequent thermal tempering processes the first of which was carried out by heating at a temperature of about 520°C - 600°C for a stay time at this temperature of about six hours and a spontaneous air cooling until room temperature was reached; the second one was carried out by heating at a temperature of 20°C lower than the one of the first process for a stay time at such temperature of about six hours and a spontaneous air cooling for 60 minutes until room temperature was reached.
- The rail wheels thus obtained had the following average mechanical features:
-
PROPERTIES STANDARD UNIT VALUE Monotonic yield UNI EN10002 Mpa 1,090 Tensile stress UNI EN10002 Mpa 1,210 Elongation at break UNI EN10002 % 16 Reduction coeff. UNI EN 10002 % 55 WEB PROPERTIES STANDARD UNIT VALUE Monotonic yield UNI EN10002 Mpa 1,090 Tensile stress UNI EN10002 Mpa 1,210 Elongation at break UNI EN10002 % 16 Reduction coeff. UNI EN10002 % 55
Claims (7)
- A microalloy bainitic steel alloy for rail wheels with high resistance to fatigue and to fretting fatigue, comprising: C, Si , Mn, Cr, Ni, Mo,
characterized in that it comprises, in weight percentage:an amount of C comprised between 0.15 and 0.35%,an amount of Si comprised between 0.6 and 1.20%,an amount of Mn comprised between 0.6 and 1.50%,an amount of Cr comprised between 0.10 and 1.00%,an amount of Ni comprised between 0.10 and 1.00%,an amount of Mo comprised between 0.10 and 0.90%,and in that it further comprise the following elements having microalloying properties, in weight percentage:- V in an amount comprised between 0.01 and 0.15%, and- Nb, Zr, Al, Ti each present in an amount not higher than 0.06%,- B, Ca and N, each present in an amount not higher than 0.007%,the remaining part up to 100 being iron, without impurities. - A method for manufacturing a rail wheel with high resistance to fatigue and fretting fatigue from a microalloy bainitic steel alloy as claimed in claim 1 comprising the steps of:mechanically machining said steel alloy;submitting it to austenitization;quenching it in water; andsubjecting it to two thermal tempering processes.
- A method as claimed in claim 2, characterized in that said austenitization and quenching in water comprises:heating the wheel to a temperature between 850°C and 950°C;maintaining the wheel at such a temperature for one hour for about each 40 mm of thickness of the processed product;quick cooling it in water until room temperature is reached.
- A method as claimed in claim 2 or 3, characterized in that said first thermal tempering process comprises
heating to a temperature between 500 and 700°C,
maintaining the wheel at such a temperature for about one hour for each 20 mm of thickness of the processed product;
and air cooling until room temperature is reached. - A method as claimed in claims 2 or 3 or 4, characterized in that said second thermal tempering treatment comprises:heating the product to a temperature lower than 20°C compared to the one of the first thermal tempering process;maintaining the product at this temperature for about one hour for each 20 mm of thickness of the processed product; andair cooling the product for at least 25 minutes, and in any case being such to cool the rail wheel rolling until room temperature is reached.
- A method as claimed in claim 7, characterized in that the cooling of the wheel rolling is carried out at a different speed from the one used for the cooling of the web.
- A rail wheel manufactured from a microalloy bainitic steel alloy as claimed in claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PL04016413T PL1538231T3 (en) | 2003-12-03 | 2004-07-13 | A microalloy bainitic steel with high resistance to fatigue and to fretting fatigue |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT002370A ITMI20032370A1 (en) | 2003-12-03 | 2003-12-03 | HIGH BAINITH MICROLEGATE STEEL FOR FATIGUE RESISTANCE |
| ITMI20032370 | 2003-12-03 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP1538231A1 EP1538231A1 (en) | 2005-06-08 |
| EP1538231B1 true EP1538231B1 (en) | 2010-08-25 |
Family
ID=34452266
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP04016413A Expired - Lifetime EP1538231B1 (en) | 2003-12-03 | 2004-07-13 | A microalloy bainitic steel with high resistance to fatigue and to fretting fatigue |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP1538231B1 (en) |
| AT (1) | ATE478970T1 (en) |
| DE (1) | DE602004028791D1 (en) |
| ES (1) | ES2350204T3 (en) |
| IT (1) | ITMI20032370A1 (en) |
| PL (1) | PL1538231T3 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104325838A (en) * | 2014-10-22 | 2015-02-04 | 雷帮荣 | High-speed rail wheel and hot-extrusion integrated forming method thereof |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100374606C (en) * | 2005-07-30 | 2008-03-12 | 马鞍山钢铁股份有限公司 | Medium-carbon low-alloy steel for light-duty high-speed train wheels |
| DE102007023309A1 (en) * | 2007-05-16 | 2008-11-20 | Benteler Stahl/Rohr Gmbh | Use of a steel alloy for axle tubes and axle tube made of a steel alloy |
| CN101821414B (en) * | 2007-06-19 | 2013-07-17 | 昆士兰铁路有限公司 | Treatment of railway wheels |
| CN104975229A (en) * | 2015-06-15 | 2015-10-14 | 柳州金特新型耐磨材料股份有限公司 | Gear sleeve |
| CN106191666B (en) * | 2016-07-06 | 2018-01-02 | 马钢(集团)控股有限公司 | Track traffic bainitic steel wheel and its manufacture method of a kind of inexpensive lean production |
| CN106048430B (en) * | 2016-07-06 | 2017-11-03 | 马钢(集团)控股有限公司 | A kind of high tenacity track traffic bainitic steel wheel and its manufacture method |
| EA201891069A1 (en) * | 2018-05-30 | 2019-12-30 | РЕЙЛ 1520 АйПи ЛТД. | ALLOY CASTING STEEL AND PRODUCTS FROM IT |
| CN113186446A (en) * | 2021-04-02 | 2021-07-30 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Process for controlling pearlite morphology and carbon-nitrogen compound precipitation of microalloyed medium plate |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2166585A5 (en) * | 1971-12-30 | 1973-08-17 | Creusot Loire | Steel alloy - for use in pressurised hydrogen or during hydrogen production |
| IT957295B (en) * | 1972-03-02 | 1973-10-10 | Italsider Spa | PERFECTED PROCESS FOR THE REALIZATION OF STEEL MONOBLOCK WHEELS |
| DE4234192C2 (en) * | 1992-10-10 | 1996-01-11 | Gutehoffnungshuette Man | Heavy-duty full wheels and wheel tires for rail traction vehicles and cars |
| US5518685A (en) * | 1994-02-03 | 1996-05-21 | Mitsubishi Steel Mfg. Co., Ltd. | Steel for carburized gear |
| FR2763601B1 (en) * | 1997-05-23 | 1999-06-25 | Valdunes | METHOD FOR MANUFACTURING A STEEL RAILWAY WHEEL AND A RAILWAY WHEEL OBTAINED |
| US6783610B2 (en) * | 2001-03-05 | 2004-08-31 | Amsted Industries Incorporated | Railway wheel alloy |
-
2003
- 2003-12-03 IT IT002370A patent/ITMI20032370A1/en unknown
-
2004
- 2004-07-13 EP EP04016413A patent/EP1538231B1/en not_active Expired - Lifetime
- 2004-07-13 AT AT04016413T patent/ATE478970T1/en active
- 2004-07-13 ES ES04016413T patent/ES2350204T3/en not_active Expired - Lifetime
- 2004-07-13 DE DE602004028791T patent/DE602004028791D1/en not_active Expired - Lifetime
- 2004-07-13 PL PL04016413T patent/PL1538231T3/en unknown
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104325838A (en) * | 2014-10-22 | 2015-02-04 | 雷帮荣 | High-speed rail wheel and hot-extrusion integrated forming method thereof |
| CN104325838B (en) * | 2014-10-22 | 2016-08-24 | 雷帮荣 | A kind of high ferro wheel and hot extrusion integral forming method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| ITMI20032370A1 (en) | 2005-06-04 |
| ES2350204T3 (en) | 2011-01-20 |
| PL1538231T3 (en) | 2011-02-28 |
| EP1538231A1 (en) | 2005-06-08 |
| ATE478970T1 (en) | 2010-09-15 |
| DE602004028791D1 (en) | 2010-10-07 |
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