CN105951000A - Steel for vanadium/niobium-contained motor train unit axle and heat treatment process thereof - Google Patents

Steel for vanadium/niobium-contained motor train unit axle and heat treatment process thereof Download PDF

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CN105951000A
CN105951000A CN201610550341.5A CN201610550341A CN105951000A CN 105951000 A CN105951000 A CN 105951000A CN 201610550341 A CN201610550341 A CN 201610550341A CN 105951000 A CN105951000 A CN 105951000A
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steel
axle
niobium
vanadium
train unit
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CN105951000B (en
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杜松林
孙维
苏世怀
高海潮
汪开忠
龚志翔
吴林
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Maanshan Iron and Steel Co Ltd
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Maanshan Iron and Steel Co Ltd
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    • 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
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • C21D1/28—Normalising
    • 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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
    • 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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/005—Heat treatment of ferrous alloys containing Mn
    • 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
    • C21D9/28—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for plain shafts
    • 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
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • 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
    • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
    • 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
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • 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
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • 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
    • C22C38/16—Ferrous alloys, e.g. steel alloys containing copper

Abstract

The invention relates to steel for a vanadium/niobium-contained motor train unit axle and a heat treatment process thereof. The steel comprises the following components in percentage by weight: 0.24-0.30% of C, 0.20-0.40% of Si, 0.70-1.00% of Mn, 0.90-1.20% of Cr, 0.70-1.30% of Ni, 0.20-0.30% of Mo, 0.10-0.60% of Cu, 0.01-0.04% of Zr, 0.03-0.06% of V, 0.015-0.040% of Nb, 0.001-0.005% of Ca, P not more than 0.010%, S not more than 0.008%, 0.0040-0.0060% of [N], T[O] not more than 0.0015%, 0.0015-0.045% of Als, and the balance of Fe and inevitable impurities; the structure of the steel is tempered sorbite and a little lower bainite, wherein the content of the tempered sorbite near the surface of the axle is 100%; the content of the tempered sorbite in 1/2 radius place of the axle is 80-90%; and the steel is obviously better than commercial steel in plasticity and toughness after heat treatment, is prominently higher than the commercial steel in fatigue limit, is excellent in strength and toughness matching, and is excellent in fatigue resistance.

Description

A kind of containing vanadium niobium axle of motor train unit steel and Technology for Heating Processing thereof
Technical field
The present invention relates to field of alloy steel, be specifically related to be applicable to tensile strength 750～900MPa, yield strength >=600MPa, -40℃KV2>=150J, requires EMU axles steel and the Technology for Heating Processing thereof with the anti-fatigue performance of excellence simultaneously.
Background technology
Axletree is to relate to one of safe most important motion and load bearing component in various vehicle.Owing to axletree subjects dynamic loading, Stress is more complicated, such as bending load, torsional load, bending combined load, and by certain impact, particularly at a high speed Axle of motor train unit, its stress is increasingly complex.Therefore, EMU axletree under arms during may because of tired, Bending, reverse or tensile stress etc. and rupture, wherein fatigue fracture is the universal fracture mode of high speed axletree.For guaranteeing car Safe operation, EMU axletree must have enough reliabilities and fatigue safety coefficient.Motor train unit axial wood Material is one of key factor determining axletree service life and reliability, therefore, attaches great importance to both at home and abroad EMU axletree With research and development and the research of fatigue behaviour of steel.
Along with the fast development of China Express Railway, the needs of axle of motor train unit are sharply increased, but still depend at present into Mouthful, therefore, it is applicable to the high-strength and high ductility of China railways development characteristic and the plastics on new materials axle steel of long-fatigue life in the urgent need to exploitation. In recent years, carry out resisting fatigue both at home and abroad and destroy the research and development of axle steel.In Chinese patent application 201110417295.9 Resisting fatigue destroys axle steel, still uses the high C content thinking of carbon axle steel in tradition, and C content (0.42～0.45%) is higher, This makes the toughness of steel poor, it is impossible to meet the axle of motor train unit requirement to toughness, and the limited extent that anti-fatigue performance improves is high. A kind of novel hollow axletree steel alloy in Chinese patent application 201210384581.4, although carbon content is relatively low, has preferably Combination of strength and toughness, but fatigue strength is the most relatively low.The axle of motor train unit introduced from Europe mainly uses the steel alloy of modifier treatment EA4T, although give chemical composition and mechanical property requirements, but do not provide crucial heat treatment process parameter, it is often more important that The alloying element content affecting quenching degree in steel is on the low side, causes the tissue within the axle of motor train unit of big specification (to exist and do not allow Exist ferrite) and performance (nearly heart portion intensity, toughness and fatigue behaviour are on the low side) be often difficult to the requirement of the standard that reaches.This Being restricted the most in actual applications a bit, the amplitude that the most crucially axle steel anti-fatigue performance improves is the most limited, affects it Popularization and application.
Summary of the invention
For above problems of the prior art, it is an object of the invention to provide a kind of tensile strength 750～900MPa, bend Take intensity >=600MPa ,-40 DEG C of KV2>=150J, requires the EMU axles steel with the anti-fatigue performance of excellence simultaneously And Technology for Heating Processing.Concrete technical scheme is as follows:
A kind of niobium axle of motor train unit steel Han vanadium, contains C:0.24～0.30 according to percentage by weight, Si:0.20～0.40, Mn:0.70～1.00, Cr:0.90～1.20, Ni:0.70～1.30, Mo:0.20～0.30, Cu:0.10～0.60, Zr: 0.01～0.04, V:0.03～0.06, Nb:0.015～0.040, Ca:0.001～0.005, P≤0.010, S≤0.008, [N]: 0.0040～0.0060, T [O]≤0.0015, Als:0.015～0.045, remaining for Fe with other inevitable impurity； Described steel be organized as tempered sorbite+a small amount of lower bainite, wherein, axletree near surface tempered sorbite content is 100%, car At axle 1/2 radius, tempered sorbite content is 80～90%.
Further, contain C:0.30, Si:0.31, Mn:0.79, Cr:0.91, Ni:0.82 according to percentage by weight, Mo:0.2, Cu:0.54, Zr:0.04, V:0.03, Nb:0.021, Ca:0.002, P:0.003, S:0.001, [N]: 0.0049, T [O]: 0.0007, Als:0.019, remaining for Fe with other inevitable impurity.
Further, the vertical mixing coefficient of steel reaches: Rm: 750MPa～900MPa, ReLOr Rp0.2>=600MPa, A >=18%, Z >=40% ,-40 DEG C of impacts of collision absorb merit KV2≥150J；Fracture toughness KQValue >=120MPa m1/2；The rotation of Specimens is curved Bent fatigue limit RfL>=375MPa, the endurance limit under rotating bending R of notched specimenfE>=310MPa, notch sensitivity RfL/RfE≤1.15；The magnitude of interference is the Fretting Fatigue Limit >=215MPa of 0.04mm sample；Salt air corrosion 14 circulates cycle sample Corrosion fatigue limit is >=275MPa；The autstenitic grain size of steel is more than or equal to 8.0 grades.
Above-mentioned containing vanadium niobium axle of motor train unit Heat-Treatment of Steel technique, comprise the steps:
(1) normalizing: vanadium niobium EMU axles steel will be contained and be heated to temperature 870～900 DEG C, in this temperature section heating and thermal insulation time Calculate by 1.2～1.7min/mm, air cooling；
(2) quenching: vanadium niobium EMU axles steel will be contained and be heated to temperature 850～880 DEG C, in this temperature section heating and thermal insulation time Calculate by 1.5～2.0min/mm, water-cooled；
(3) tempering: vanadium niobium EMU axles steel will be contained and be heated to temperature 620～680 DEG C, in this temperature section heating and thermal insulation time Calculating by 2～2.5min/mm, air cooling is to room temperature.
Further, in step (1)-(3), firing rate is 50～100 DEG C/h.
Further, in step (2) in quenching tank, by nozzle, axletree is carried out underwater water-spraying rapid water and be cooled to room temperature.
Further, step (1) is heated to temperature 900 DEG C, heating and thermal insulation time 300min, air cooling with 80 DEG C/h.
Further, step (2) is heated to temperature 880 DEG C, heating and thermal insulation time 270min, rapid water with 80 DEG C/h Cold.
Further, step (3) is heated to temperature 650 DEG C, heating and thermal insulation time 420min, air cooling with 80 DEG C/h； And/or, step (1) and (2) rate of cooling control at 1.5～2.5 DEG C/s.
Further, it is applied to containing in vanadium niobium axle of motor train unit steel production technology, and this technique comprises the steps: electricity Arc stove or converter smelting → LF stove refine → RH or VD vacuum outgas → continuous casting → strand heating furnace heating → axle blank rolling → Axle blank forging → blank axletree is rough turn → and axletree neat end face processing → normalizing+Tempering and Quenching → axletree outer circle finish turning processing → Axletree internal bore boring processing → cylindricalo grinding → flaw detection.
Compared with currently available technology, the chemical composition of the present invention, technological process and Technology for Heating Processing technological parameter is used to produce Containing vanadium niobium EMU axles steel, the vertical mixing coefficient measuring steel can reach: Rm: 750MPa～900MPa, ReLOr Rp0.2>=600MPa, A >=18%, Z >=40% ,-40 DEG C of impacts of collision absorb merit KV2≥150J；Fracture toughness KQValue ≥120MPa·m1/2；The endurance limit under rotating bending R of SpecimensfL>=375MPa, the rotary bending fatigue pole of notched specimen Limit RfE>=310MPa, notch sensitivity RfL/RfE≤1.15；The magnitude of interference is the Fretting Fatigue Limit >=215MPa of 0.04mm sample； It is >=275MPa that salt air corrosion 14 circulates the corrosion fatigue limit of cycle sample；The autstenitic grain size of steel is more than or equal to 8.0 Level；After EMU axletree " normalizing+quenched (quenching+high tempering) " heat treatment steel be organized as tempered sorbite+ A small amount of lower bainite, wherein, axletree near surface tempered sorbite content is 100%, tempered sorbite at axletree 1/2 radius Content is 80～90%.
Detailed description of the invention
Describing the present invention below, it is a kind of preferred embodiment in numerous embodiments of the present invention.
In a preferred embodiment, a kind of niobium axle of motor train unit steel Han vanadium, contain C:0.24～0.30 according to percentage by weight, Si:0.20～0.40, Mn:0.70～1.00, Cr:0.90～1.20, Ni:0.70～1.30, Mo:0.20～0.30, Cu: 0.10～0.60, Zr:0.01～0.04, V:0.03～0.06, Nb:0.015～0.040, Ca:0.001～0.005, P≤0.010, S≤0.008, [N]: 0.0040～0.0060, T [O]≤0.0015, Als:0.015～0.045, remaining for Fe and other can not keep away The impurity exempted from；Described steel be organized as tempered sorbite+a small amount of lower bainite, wherein, axletree near surface tempered sorbite content is 100%, at axletree 1/2 radius, tempered sorbite content is 80～90%；It is above-mentioned containing vanadium niobium axle of motor train unit Heat-Treatment of Steel technique, Comprise the steps: (1) normalizing: vanadium niobium EMU axles steel will be contained and be heated to temperature 870～900 DEG C, in this temperature The section heating and thermal insulation time is by 1.2～1.7min/mm calculating, air cooling；(2) quenching: vanadium niobium EMU axles steel will be contained and add Heat is to temperature 850～880 DEG C, in this temperature section heating and thermal insulation time by 1.5～2.0min/mm calculating, water-cooled；(3) tempering: Vanadium niobium EMU axles steel will be contained and be heated to temperature 620～680 DEG C, this temperature section heating and thermal insulation time by 2～ 2.5min/mm calculates, and air cooling is to room temperature.
In a further advantageous embodiment, following scheme can be used: (1) suitably reduces the C element in tradition carbon axle Content, improves toughness and the plasticity of steel；(2) in steel, add Ni, Cu element and improve quenching degree and the corrosion resistance of steel, and add The Zr of trace, Nb, V, [N] element are with crystal grain thinning, thus improve the toughness particularly low-temperature flexibility of steel, and improve the strong of steel Degree and toughness coordinate, and improve the anti-fatigue performance of steel；(3) add appropriate Ca element, the field trash in steel is carried out at degeneration Reason, impurity element T [O], the content of P, S etc. in the strictest control steel, to improve the anti-fatigue performance of steel further.This Bright it is critical that optimizing components is adjusted and controls organically to combine with metallurgical quality, while acquisition high intensity, Obtain excellent resisting fatigue destructive characteristics and relatively low cost.
The specific chemical composition (weight %) of steel of the present invention is as follows: C:0.24～0.30, Si:0.20～0.40, Mn:0.70～ 1.00, Cr:0.90～1.20, Ni:0.70～1.30, Mo:0.20～0.30, Cu:0.10～0.60, Zr:0.01～0.04, V:0.03～0.06, Nb:0.015～0.040, Ca:0.001～0.005, P≤0.010, S≤0.008, [N]: 0.0040～0.0060, T [O]≤0.0015, Als:0.015～0.045, remaining for Fe with other inevitable impurity.
The effect of above-mentioned each element and proportioning are according to as follows:
C:C element is that axle steel obtains necessary to high intensity, hardness.C content in tradition axle steel is higher, as at present Carbon content in lorry axle steel LZ50 is about 0.50%.Although high C content is favourable to the intensity of steel, hardness etc., But plasticity and toughness to steel are totally unfavorable, and make yield tensile ratio reduce, Decarburization Sensitivity increase, deteriorate steel anti-fatigue performance and Processing characteristics.The most suitably reduce the C content in steel, controlled below 0.30%.But, after quenching and high tempering In order to obtain required high intensity and necessary fatigue behaviour, C content must more than 0.24%, thus C content preferably control be 0.24～0.30%.
Si:Si is deoxidant element main in steel, has the strongest solution strengthening effect, but Si too high levels will make moulding of steel Property and toughness decline, the activity increase of C, promote steel decarburization in rolling and heat treatment process and graphitization tendency, and make Smelt difficulty and be easily formed field trash, deteriorating the anti-fatigue performance of steel.Therefore controlling Si content is 0.20～0.40%.
Mn:Mn is the effective element of deoxidation and desulfurization, it is also possible to improve quenching degree and the intensity of steel, when content is less than 0.70%, It is difficult to function as described above.But during hardened steel tempering, Mn and P has strong grain boundary cosegregation to be inclined to, and promotes temper brittleness, dislikes Change the toughness of steel, thus control Mn content below 1.00%.
Cr:Cr can be effectively improved quenching degree and the resistance to tempering of steel, the high intensity needed for obtaining；Cr also can drop simultaneously The activity of low C, it is possible to decrease heat, roll and steel surface decarburizing tendency in heat treatment process, have utilize obtain high anti-tired Labor performance.But too high levels can deteriorate the toughness of steel, thus controlling Cr content is 0.90～1.20%.
Ni:Ni can improve the quenching degree of steel, corrosion resistance and guarantee steel toughness at low temperatures.In view of economy, control Ni Content is 0.80～1.30%.
Mo:Mo effect in steel predominantly improves quenching degree, improves resistance to tempering and prevent temper brittleness.Additionally, Mo element Quenching degree and resistance to tempering can be made to be improved significantly with the reasonable coordination of Cr element.Mo content the most above-mentioned too low limited use, Mo too high levels, the most above-mentioned effect is saturated, and improves the cost of steel.Therefore, controlling Mo content is 0.20～0.30%.
Cu:Cu is similar to Ni in terms of solution strengthening, raising quenching degree.Meanwhile, steel adds copper and also can improve the anti-of steel Corrosion Fatigue Properties, because tiny Cu precipitation has blocked the formation of the initial stage vein texture of fatigue, and copper precipitate There is good plasticity, the extension of fatigue crack can be hindered；The steel corrosion resistance effect it addition, Cu also improves；Thus carry The corrosion fatigue strength of Gao Gang.But Cu too high levels, steel easily causes hot-short in heating rolling or forging process.Consider, Range-controllable system is 0.10～0.60%.
Zr: adding a small amount of zirconium has degassing, purification and Grain refinement, be conducive to improving the low temperature impact properties of steel and intensity, Fatigue behaviour index.Considering, range-controllable system is 0.010～0.040%.
V:V is carbide, is combined crystal grain when formed small and dispersed carbide can stop heating with C and grows up, Play the effect of refined crystalline strengthening and precipitation strength, thus the intensity of steel, toughness and anti-fatigue performance can be improved simultaneously.V content is less than 0.03%, above-mentioned effect is inconspicuous；V content is higher than 0.10%, and above-mentioned effect is saturated, and improves the cost of steel.Thus control V Content is 0.03～0.06%.
Nb:Nb mainly shows as crystal grain refinement, precipitation strength and phase transformation strengthening to the Strengthening and Toughening effect of axle steel.Nb is in steel Existing with displacement solute atoms, Nb atomic ratio iron atom size is big, easily segregation on dislocation line, produces strong to dislocation climb Effect of dragging, makes Recrystallization nucleation be suppressed, and has strong interception to recrystallization, improves the recrystallization of austenite Temperature, thus reach the purpose of fining austenite grains, crystal grain refinement can not only improve the obdurability of steel, and improves steel Cryogenic property.But it is expensive.Considering, the range-controllable system of Nb is 0.015%～0.040%.
Ca:Ca has deoxidization desulfuration and the effect to non-metallic inclusion degenerative treatments, thus improves toughness and the fatigue resistance of steel Energy.Ca content does not has above-mentioned effect less than 0.001%, but content is more than 0.005%, then add extremely difficult, and field trash Amount increases.Thus controlling Ca content is 0.001～0.005%.
P:P can form microsegregation when solidification of molten steel, and when austenitizing temperature heats, segregation, at crystal boundary, makes the crisp of steel subsequently Property significantly increase, so control P content below 0.012%.
S: inevitable impurity in steel, forms MnS and is mingled with and can deteriorate toughness and the anti-fatigue performance of steel at Grain Boundary Segregation, Thus control its content below 0.008%.
[N]: in the presence of having V, Al, Nb, Ti etc. in steel, nitrogen can form carbonitride with them, austenite can be stoped to tie again Crystalline substance, crystal grain thinning, improves the toughness of steel, and can improve the intensity of steel.As nitrogen content is higher, can exist with solid solution condition, from And deteriorate the toughness plasticity index of steel.Considering, range-controllable system is 0.0040～0.0060%.
T [O]: oxygen forms various oxide in steel and is mingled with.Under the effect of stress, easily produce at these oxide places of being mingled with Stress is concentrated, and causes the germinating of micro-crack, thus deteriorates mechanical property particularly toughness and the anti-fatigue performance of steel.Therefore, exist Metallurgical production must take measures reduce its content as far as possible.In view of economy, control its content below 0.0015%.
Present invention niobium EMU axles steel technological process of production Han vanadium is: electric arc furnace or converter smelting → LF stove refine → RH Or VD vacuum outgas → continuous casting → strand heating furnace heating → axle blank rolling → axle blank forging → blank axletree rough turn → axletree Neat end face processing → normalizing+Tempering and Quenching → axletree outer circle finish turning processing → axletree internal bore boring processing → cylindricalo grinding → flaw detection.
The Technology for Heating Processing step of present invention key is as follows:
(1) normalizing: by maximum gauge be about 200mm, length reach about 2200mm containing vanadium niobium EMU axletree use Steel heating (firing rate is 50～100 DEG C/h), to temperature 870～900 DEG C, is pressed in this temperature section heating and thermal insulation time 1.2～1.7min/mm calculate, air cooling.After normalizing, not only refined crystal grain, and improved the inhomogeneities of tissue, for After finished heat treatment carry out tissue prepare.
(2) quenching: by maximum gauge be about 200mm, length reach about 2200mm containing vanadium niobium EMU axletree use Steel heating (firing rate is 50～100 DEG C/h), to temperature 850～880 DEG C, is pressed in this temperature section heating and thermal insulation time 1.5～2.0min/mm calculate, and subsequently in quenching tank, by nozzle, axletree carry out underwater water-spraying quick water-cooled (rate of cooling Control at 1.5～2.5 DEG C/s) to room temperature.
(3) tempering: by maximum gauge be about 200mm, length reach about 2200mm containing vanadium niobium EMU axletree use Steel heating (firing rate is 50～100 DEG C/h) to temperature 620～680 DEG C, this temperature section heating and thermal insulation time by 2～ 2.5min/mm calculates, and air cooling is to room temperature subsequently.Through tempering, uniform fine and closely woven tempered sorbite+a small amount of lower bainite can be obtained Metallographic structure, thus good toughness plasticity and suitable intensity index can be obtained.
In a further advantageous embodiment, following scheme can be used: containing the vanadium niobium EMU axles steel technological process of production For: electric arc furnace or converter smelting → LF stove refine → RH or VD vacuum outgas → continuous casting → strand heating furnace heating → axle blank roll System → axle blank forging → blank axletree is rough turn → and axletree neat end face processing → normalizing+quenched (quenching+high tempering) heat treatment → Axletree outer circle finish turning processing → axletree internal bore boring processing → cylindricalo grinding → flaw detection.
The present invention is containing the enforcement of the melting chemical composition of vanadium niobium EMU axles steel, main heat treatment process parameter and performance Under such as:
Technology for Heating Processing step and parameter be:
(1) normalizing: be heated to temperature 900 DEG C, heating and thermal insulation time 300min, air cooling with 80 DEG C/h.
(2) quenching: be heated to temperature 880 DEG C, heating and thermal insulation time 270min, quick water-cooled (rate of cooling with 80 DEG C/h Control at 1.5～2.5 DEG C/s).
(3) tempering: be heated to temperature 650 DEG C, heating and thermal insulation time 420min, air cooling with 80 DEG C/h.
Maximum gauge is Φ 200mm, length reaches the melting chemical composition mass percent (wt%) of 2200mm EMU axletree Being shown in Table 1, EMU axletree performance indications after above heat treatment are shown in Table 2.
The melting chemical composition mass percent (wt%) of table 1 EMU axletree steel
Performance indications after table 2 EMU axletree heat treatment
Performance indications after continued 2 EMU axletree heat treatment
The present invention compared with prior art has the advantage that intensity is high, anti-fatigue performance is excellent.The high-strength of more than 700MPa can be obtained Spending, its plasticity and toughness are substantially better than business steel, and its fatigue limit business to be significantly higher than steel presents good strength and toughness Coordinate and the anti-fatigue performance of excellence.Wherein: Rm: 750MPa～900MPa, ReLOr Rp0.2>=600MPa, A >=18%, Z >=40%, -40 DEG C of impacts of collision absorb merit KV2≥150J；Fracture toughness KQValue >=120MPa m1/2；The rotary bending fatigue pole of Specimens Limit RfL>=375MPa, the endurance limit under rotating bending R of notched specimenfE>=310MPa, notch sensitivity RfL/RfE≤1.15；Interference Amount is the Fretting Fatigue Limit >=215MPa of 0.04mm sample；Salt air corrosion 14 circulates the corrosion fatigue limit of cycle sample ≥275MPa；The autstenitic grain size of steel is more than or equal to 8.0 grades；EMU axletree " normalizing+quenched (quenching+high temperature Tempering) " steel is organized as tempered sorbite+a small amount of lower bainite, wherein, axletree near surface tempered sorbite content after heat treatment Being 100%, at axletree 1/2 radius, tempered sorbite content is 80～90%.
Above the present invention is exemplarily described, it is clear that the present invention implements and is not subject to the restrictions described above, as long as adopting The various improvement carried out with technical scheme are conceived by the method for the present invention, or the most improved that directly apply to other occasion, all Within protection scope of the present invention.

Claims (10)

1. a niobium axle of motor train unit steel Han vanadium, it is characterised in that contain C:0.24～0.30, Si according to percentage by weight: 0.20～0.40, Mn:0.70～1.00, Cr:0.90～1.20, Ni:0.70～1.30, Mo:0.20～0.30, Cu:0.10～0.60, Zr:0.01～0.04, V:0.03～0.06, Nb:0.015～0.040, Ca:0.001～ 0.005, P≤0.010, S≤0.008, [N]: 0.0040～0.0060, T [O]≤0.0015, Als:0.015～0.045, Remaining is Fe and other inevitable impurity；Described steel be organized as tempered sorbite+a small amount of lower bainite, wherein, Axletree near surface tempered sorbite content is 100%, and at axletree 1/2 radius, tempered sorbite content is 80～90%.
2. the niobium axle of motor train unit steel Han vanadium as claimed in claim 1, it is characterised in that contain C according to percentage by weight: 0.30, Si:0.31, Mn:0.79, Cr:0.91, Ni:0.82, Mo:0.2, Cu:0.54, Zr:0.04, V:0.03, Nb:0.021, Ca:0.002, P:0.003, S:0.001, [N]: 0.0049, T [O]: 0.0007, Als:0.019, remaining for Fe with other inevitable impurity.
3. the niobium axle of motor train unit steel Han vanadium as claimed in claim 1 or 2, it is characterised in that the vertical mixing coefficient of steel Reach: Rm: 750MPa～900MPa, ReLOr Rp0.2>=600MPa, A >=18%, Z >=40% ,-40 DEG C of impacts of collision absorb Merit KV2≥150J；Fracture toughness KQValue >=120MPa m1/2；The endurance limit under rotating bending R of SpecimensfL>=375MPa, The endurance limit under rotating bending R of notched specimenfE>=310MPa, notch sensitivity RfL/RfE≤1.15；The magnitude of interference is 0.04mm Fretting Fatigue Limit >=the 215MPa of sample；Salt air corrosion 14 circulates the corrosion fatigue limit of cycle sample ≥275MPa；The autstenitic grain size of steel is more than or equal to 8.0 grades.
4. the niobium axle of motor train unit Heat-Treatment of Steel technique Han vanadium as described in claim 1-3, it is characterised in that include walking as follows Rapid:
(1) normalizing: vanadium niobium EMU axles steel will be contained and be heated to temperature 870～900 DEG C, in this temperature section heating and thermal insulation time Calculate by 1.2～1.7min/mm, air cooling；
(2) quenching: vanadium niobium EMU axles steel will be contained and be heated to temperature 850～880 DEG C, in this temperature section heating and thermal insulation time Calculate by 1.5～2.0min/mm, water-cooled；
(3) tempering: vanadium niobium EMU axles steel will be contained and be heated to temperature 620～680 DEG C, in this temperature section heating and thermal insulation time Calculating by 2～2.5min/mm, air cooling is to room temperature.
5. the niobium axle of motor train unit Heat-Treatment of Steel technique Han vanadium as claimed in claim 4, it is characterised in that step (1)-(3) Middle firing rate is 50～100 DEG C/h.
6. the niobium axle of motor train unit Heat-Treatment of Steel technique Han vanadium as described in claim 4 or 5, it is characterised in that step (2) In in quenching tank, by nozzle, axletree is carried out underwater water-spraying rapid water and is cooled to room temperature.
7. the niobium axle of motor train unit Heat-Treatment of Steel technique Han vanadium as described in claim 4-6, it is characterised in that in step (1) It is heated to temperature 900 DEG C, heating and thermal insulation time 300min, air cooling with 80 DEG C/h.
8. the niobium axle of motor train unit Heat-Treatment of Steel technique Han vanadium as described in claim 4-7, it is characterised in that in step (2) It is heated to temperature 880 DEG C, heating and thermal insulation time 270min, quick water-cooled with 80 DEG C/h.
9. the niobium axle of motor train unit Heat-Treatment of Steel technique Han vanadium as described in claim 4-8, it is characterised in that in step (3) It is heated to temperature 650 DEG C, heating and thermal insulation time 420min, air cooling with 80 DEG C/h；And/or, step (1) and (2) Rate of cooling controls at 1.5～2.5 DEG C/s.
10. the niobium axle of motor train unit Heat-Treatment of Steel technique Han vanadium as described in claim 4-9, it is characterised in that it is applied to contain Vanadium niobium axle of motor train unit is with in steel production technology, and this technique comprises the steps: electric arc furnace or converter smelting → LF stove essence Refining → RH or VD vacuum outgas → continuous casting → strand heating furnace heating → axle blank rolling → axle blank forging → blank vehicle Axle is rough turn → and axletree neat end face processing → normalizing+Tempering and Quenching → axletree outer circle finish turning processing → axletree internal bore boring adds Work → cylindricalo grinding → flaw detection.
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CN109487163A (en) * 2018-12-13 2019-03-19 河钢股份有限公司 Direct quenching type surrenders 800MPa level structure steel plate and its production method
CN111363974A (en) * 2020-03-24 2020-07-03 马鞍山钢铁股份有限公司 Niobium-vanadium-containing axle for urban rail subway and heat treatment process thereof
CN112522612A (en) * 2020-11-19 2021-03-19 宝武集团马钢轨交材料科技有限公司 Cold-resistant axle for large-axle heavy-duty freight train and heat treatment process and production process thereof
CN115747645A (en) * 2022-11-04 2023-03-07 马鞍山钢铁股份有限公司 Steel for high-toughness high-contact-fatigue high-power wind power yaw bearing ring, bearing ring and production process

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CN102876860A (en) * 2012-10-11 2013-01-16 清华大学 Heat treatment method of novel alloy steel hollow car axle material
CN104233109A (en) * 2014-10-11 2014-12-24 马钢(集团)控股有限公司 Heat-treating process of high-speed train axle containing niobium and titanium

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CN1873042A (en) * 2005-06-03 2006-12-06 株式会社神户制钢所 Steel for forging having excellent hydrogen embrittlement resistance and crankshaft
CN102758147A (en) * 2012-08-01 2012-10-31 清华大学 Axle material and application thereof in high-speed railway carriage
CN102876860A (en) * 2012-10-11 2013-01-16 清华大学 Heat treatment method of novel alloy steel hollow car axle material
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109487163A (en) * 2018-12-13 2019-03-19 河钢股份有限公司 Direct quenching type surrenders 800MPa level structure steel plate and its production method
CN111363974A (en) * 2020-03-24 2020-07-03 马鞍山钢铁股份有限公司 Niobium-vanadium-containing axle for urban rail subway and heat treatment process thereof
CN112522612A (en) * 2020-11-19 2021-03-19 宝武集团马钢轨交材料科技有限公司 Cold-resistant axle for large-axle heavy-duty freight train and heat treatment process and production process thereof
CN112522612B (en) * 2020-11-19 2022-03-01 宝武集团马钢轨交材料科技有限公司 Cold-resistant axle for large-axle heavy-duty freight train and heat treatment process and production process thereof
CN115747645A (en) * 2022-11-04 2023-03-07 马鞍山钢铁股份有限公司 Steel for high-toughness high-contact-fatigue high-power wind power yaw bearing ring, bearing ring and production process

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