CN101680069A - High carbon steel sheet superior in fatiugue lifeand manufacturing method thereof - Google Patents
High carbon steel sheet superior in fatiugue lifeand manufacturing method thereof Download PDFInfo
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- CN101680069A CN101680069A CN200780053145A CN200780053145A CN101680069A CN 101680069 A CN101680069 A CN 101680069A CN 200780053145 A CN200780053145 A CN 200780053145A CN 200780053145 A CN200780053145 A CN 200780053145A CN 101680069 A CN101680069 A CN 101680069A
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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
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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
- C21D1/26—Methods of annealing
- C21D1/32—Soft annealing, e.g. spheroidising
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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
- C21D1/34—Methods of heating
- C21D1/44—Methods of heating in heat-treatment baths
- C21D1/46—Salt baths
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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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
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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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0236—Cold rolling
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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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0268—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment between cold rolling steps
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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
- C21D9/02—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for springs
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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
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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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
- C21D2211/003—Cementite
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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
- C21D2211/005—Ferrite
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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
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
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Abstract
The present invention relates to a high carbon steel sheet that is superior in fatigue life and a method of manufacturing the high carbon steel sheet. The high carbon steel sheet includes about 0.75wt% to about 0.95wt% of carbon, smaller than about 1.8wt% of silicon, about 0.1 wt% to about 1.5wt% of manganese, about 0.1wt%-1.0wt% of chromium, smaller than about 0.02wt% of phosphorus, smaller thanabout 0.02wt% of sulfur, a residual amount of iron, and inevitable impurities. A layer interval between laminar carbides included in the high carbon steel sheet is smaller than about 0.5[mu]m. The high carbon steel sheet may include a fine pearlite having a lamellar structure. The fine pearlite included in the high carbon steel sheet may have a volume percentage of larger than about 90%. A ratio of length to width of the lamellar structure may be larger than about 10:1.
Description
Technical field
Embodiment of the present invention relate to a kind of high carbon steel sheet and a kind of method of making this high carbon steel sheet.More specifically, embodiment of the present invention relate to a kind of high carbon steel sheet and a kind of method of making this high carbon steel sheet with better fatigue lifetime.
Background technology
Recently, people's having relatively high expectations to vehicle safety.Therefore, also the fatigue lifetime to spring requirement is arranged, to make safe automobile.When spring was worked in the elastic deformation scope, the fatigue lifetime of spring was longer relatively.Therefore, in order to improve the fatigue lifetime of spring, now to improve and comprise YIELD STRENGTH in the spring to increase the elastic deformation scope of this spring.Thereafter, this spring is preferably worked in the elastic deformation scope.
Yet according to the type difference of spring, the working range of spring is contained in the plastic deformation scope sometimes.In this case, crackle may very fast generation, this with situation that spring is worked in the elastic deformation scope under different.At this, fatigue lifetime mainly by the growth of crackle but not forming of crackle determine.Therefore, be contained in board-like leaf spring in the plastic deformation scope for working range, this board-like leaf spring preferably includes a kind of like this fine structure, and described structure can avoid the growth of crackle to improve the fatigue lifetime of this spring.
The conventional steel plate that is used to form spring contains perlite.Yet laminar carbide is relatively large and its yield strength is little.Therefore, fatigue lifetime is not long.
Proposed a kind of yield strength and improved its method of fatigue life by the expansion spring.In the method, the yield strength of spring improves in the following manner: before steel plate is carried out cold-rolled process, under low relatively temperature a kind of fine structure is converted into bainite.Yet, if the plastic deformation scope is contained in the working range of spring, although yield strength owing to form and the blended bainite improves, reduce fatigue lifetime.
Summary of the invention
Embodiment of the present invention provide a kind of high carbon steel sheet with better fatigue lifetime.
Embodiment of the present invention provide a kind of method of making this high carbon steel sheet.
According to embodiment of the present invention, high carbon steel sheet comprises that about 0.75wt% is to the carbon of about 0.95wt%, the silicon that is less than about 1.8wt%, about 0.1wt% extremely manganese, the chromium of about 0.1wt% to 1.0wt%, the phosphorus that is less than about 0.02wt%, the sulphur that is less than about 0.02wt%, the iron and the unavoidable impurities of residual volume of about 1.5wt%.Be contained in interlamellar spacing between the carbide lamella in this high carbon steel sheet less than about 0.5 μ m.
This high carbon steel sheet can comprise the fine pearlite with flaky texture.Be contained in fine pearlite in this high carbon steel sheet and can have volume percent greater than about 90%.The long-width ratio of this flaky texture can be greater than about 10: 1.
This high carbon steel sheet also can comprise vanadium, niobium, molybdenum, titanium, tungsten or the copper of about 0.05wt% to about 0.25wt%.These materials can separately or be used in combination.This high carbon steel sheet also can comprise the nitrogen of about 30ppm to about 120ppm.
According to embodiment of the present invention, provide a kind of method of making high carbon steel sheet.In the method, form a kind of steel member that contains following material: about 0.75wt% is to the carbon of about 0.95wt%, the silicon that is less than about 1.8wt%, about 0.1wt% extremely manganese, about 0.1wt% extremely chromium, the phosphorus that is less than about 0.02wt%, the sulphur that is less than about 0.02wt%, the iron and the unavoidable impurities of residual volume of about 1.0wt% of about 1.5wt%.This steel member is implemented course of hot rolling, cold-rolled process and annealing process so that it has a kind of spheroidite and a kind of initial ferrite (initial ferrite).Behind this steel member of heating, this steel member through heating is implemented malleableize annealing process (patentingannealing process).This malleableize annealing process maintains about 500 ℃ by use temperature and implements about more than 60 seconds to about 530 ℃ solder pot.
Implement to heat this steel member to about 1100 ℃ temperature at about 800 ℃ before the malleableize annealing process.This steel member also can comprise at least a material that be selected from vanadium, niobium, molybdenum, titanium, tungsten and copper of about 0.05wt% to about 0.25wt%.This steel member also can comprise the nitrogen of about 30ppm to about 120ppm.
In order to make high carbon steel sheet, can after the malleableize annealing process, implement process of cooling.Thereby can implement the compression ratio that cold-rolled process makes cold-rolled process and be higher than about 85%.
Embodiment of the present invention provide a kind of method of making high carbon steel sheet.In the method, form a kind of steel member that contains following material: about 0.75wt% is to the carbon of about 0.95wt%, the silicon that is less than about 1.8wt%, about 0.1wt% extremely manganese, about 0.1wt% extremely chromium, the phosphorus that is less than about 0.02wt%, the sulphur that is less than about 0.02wt%, the iron and the unavoidable impurities of residual volume of about 1.0wt% of about 1.5wt%.This steel member is implemented course of hot rolling, cold-rolled process and annealing process so that it has a kind of spheroidite and a kind of initial ferrite.Behind this steel member of heating this steel member through heating is implemented the malleableize annealing process, wherein this malleableize annealing process maintains about 500 ℃ by use temperature and implements about more than 20 seconds to about 530 ℃ solder pot.
Implement to heat this steel member to about 1100 ℃ temperature at about 800 ℃ before the malleableize annealing process.This steel member also can comprise vanadium, niobium, molybdenum, titanium, tungsten or the copper of about 0.05wt% to about 0.25wt%.These materials can separately or be used in combination.This steel member also can comprise the nitrogen of about 30ppm to about 120ppm.
In order to make high carbon steel sheet, can after the malleableize annealing process, implement process of cooling.Thereby can implement the compression ratio that cold-rolled process makes cold-rolled process and be higher than about 85%.
The high carbon steel sheet of embodiment of the present invention has a large amount of so laminar carbide, and wherein said laminar carbide has and is higher than about 10: 1 relatively large long-width ratio.Thus, can avoid the growth of crackle effectively.
In addition, because the growth of crackle avoided, so can be improved the fatigue lifetime of this high carbon steel sheet.
In addition, if use the high carbon steel sheet of embodiment of the present invention to form spring, the crackle of generation can be not easy growth.Thus, even working in the plastic deformation scope, this spring also can work the long relatively time.
Description of drawings
Fig. 1 is the sectional view of the high carbon steel sheet of explanation one embodiment of the present of invention.
Fig. 2 is the sectional view that a comparative example's high carbon steel sheet is shown.
Fig. 3 shows the fracture shape of a kind of high carbon steel sheet of the embodiment of the invention.
Fig. 4 shows the fracture shape of a comparative example's high carbon steel sheet.
Embodiment
According to embodiment of the present invention, high carbon steel sheet comprises that about 0.75wt% is to the carbon of about 0.95wt%, the silicon that is less than about 1.8wt%, about 0.1wt% extremely manganese, the chromium of about 0.1wt% to 1.0wt%, the phosphorus that is less than about 0.02wt%, the sulphur that is less than about 0.02wt%, the iron and the unavoidable impurities of residual volume of about 1.5wt%.
In addition, this high carbon steel sheet also can comprise vanadium, niobium, molybdenum, titanium, tungsten or the copper of about 0.05wt% to about 0.25wt%.These materials can separately or be used in combination.This high carbon steel sheet also can comprise the nitrogen of about 30ppm to about 120ppm.
Herein, the interlamellar spacing that is contained between the carbide lamella in this high carbon steel sheet is less than about 0.5 μ m.This high carbon steel sheet can comprise the fine pearlite with flaky texture.Be contained in fine pearlite in this high carbon steel sheet and can have volume percent greater than about 90%.The long-width ratio of this flaky texture can be greater than about 10: 1.
Embodiment of the present invention provide a kind of method of making high carbon steel sheet.In the method: i) form a kind of steel member that contains following material: about 0.75wt% is to the carbon of about 0.95wt%, the silicon that is less than about 1.8wt%, about 0.1wt% extremely manganese, about 0.1wt% extremely chromium, the phosphorus that is less than about 0.02wt%, the sulphur that is less than about 0.02wt%, the iron and the unavoidable impurities of residual volume of about 1.0wt% of about 1.5wt%; Ii) this steel member is implemented course of hot rolling, cold-rolled process and annealing process so that it has a kind of spheroidite and a kind of initial ferrite; And iii) behind this steel member of heating this steel member through heating is implemented the malleableize annealing process to about 1100 ℃ temperature at about 800 ℃.This malleableize annealing process maintains about 500 ℃ by use temperature and implements about more than 60 seconds to about 530 ℃ solder pot.Perhaps, this malleableize annealing process maintains about 530 ℃ by use temperature and implemented about 20 seconds to about 570 ℃ solder pot.
This steel member also can comprise vanadium, niobium, molybdenum, titanium, tungsten or the copper of about 0.05wt% to about 0.25wt%.These materials can separately or be used in combination.This steel member also can comprise the nitrogen of about 30ppm to about 120ppm.
In order to make this high carbon steel sheet, can after the malleableize annealing process, implement process of cooling and cold-rolled process, thereby make the compression ratio of cold-rolled process be higher than about 85%.
The chemical constitution of this high carbon steel sheet hereinafter, is disclosed.
The content of carbon (C) is that about 0.75wt% is to about 0.95wt%.If carbon content is lower than about 0.75wt%, then hardness may be because the quenching process improve.Therefore, be difficult to obtain weather resistance preferably.If carbon content is higher than about 0.95wt%, then may form retained austenite easily.In addition, may be when implementing cold-rolled process owing to stress-induced conversion forms crackle.In addition, the toughness of this steel plate and fatigue lifetime are worsened.
The content of silicon (Si) is less than about 1.8wt%.If silicone content increases, intensity and plastic deformation resistance may increase.Yet, if silicone content greater than about 1.8wt%, the plastic deformation resistance may reduce and when implementing heat treatment process decarburization may take place easily.In addition, Biao Mian quality may be because of the increase deterioration of surface imperfection.
The content of manganese (Mn) is that about 0.1wt% is to about 1.5wt%.If manganese (Mn) content is lower than about 0.1wt%, then---it comprises unavoidable impurities sulphur (S) and iron (Fe)---produces red brittleness to possibility owing to sulphur-iron (FeS).On the other hand, if manganese (Mn) content is higher than about 1.5wt%, toughness may reduce.In addition, if manganese (Mn) content is higher than about 1.5wt%, thereby then hardenability may exceedingly improve the processing speed of this steel plate of needs reduction to obtain meticulous structure.Thus, the productive rate of steel plate may reduce.
The content of chromium (Cr) can be about 0.1wt% to about 1.0wt%.Chromium (Cr) has and the identical effect of manganese (Mn) basically.Especially, chromium can improve hardenability and intensity.In addition, chromium can be avoided decarburization and greying.If chromium (Cr) content is less than about 0.1wt%, then be difficult to obtain enough hardenabilitys.In addition, can not avoid decarburization effectively.On the other hand, if chromium (Cr) content is higher than about 1.0wt%, then hardenability may exceedingly improve.
The content of sulphur (S) is less than about 0.02wt%.If sulphur (S) content is greater than about 0.02wt%, then toughness may be owing to grain boundary segregation reduces.
The content of phosphorus (P) is less than about 0.02wt%.If phosphorus content is greater than about 0.02wt%, then toughness may be owing to grain boundary segregation reduces.
Molybdenum (Mo), niobium (Nb), titanium (Ti), vanadium (V) or tungsten (W) can combine to produce precipitation hardening with carbon (C) or the nitrogen (N) in this steel plate.Copper (Cu) can produce precipitation hardening independently.The content of molybdenum (Mo), niobium (Nb), titanium (Ti), vanadium (V) or tungsten (W) can be about 0.05wt% to about 0.25wt%.These materials can separately or be used in combination.By above element cause independently or complementary precipitation hardening can improve the intensity of this steel plate.Yet, if excessively comprise above element, may reduce rolling performance owing to excessively improve hardenability, saturated because the effect of above element is tended to.Therefore, need optionally use above element.If the content of above element is less than about 0.05wt%, then may reduce the effect of precipitation hardening.On the other hand, if the content of above element greater than about 0.25wt%, then the fragility of this steel plate may improve when implementing course of hot rolling.
The content of nitrogen (N) is that about 30ppm is to about 120ppm.If nitrogen content is less than about 30ppm, then the reckoning amount of carbonitride is inadequate.Therefore, the improvement of intensity and plastic deformation resistance is less.On the other hand, if nitrogen (N) content greater than about 120ppm, then the effect of precipitation hardening may be saturated and material supersaturation in matrix of producing.Therefore, the toughness of this steel plate may reduce.
Hereinafter, in conjunction with Fig. 1 and 2 a kind of fine structure and a kind of effect of avoiding crackle to grow are described in high carbon steel sheet.
Fig. 1 is the sectional view of the high carbon steel sheet of an a kind of embodiment of the invention of explanation.This high carbon steel sheet has the fine pearlite that comprises carbide lamella 101, and wherein this carbide lamella 101 is longer relatively on rolling direction.Herein, carbide lamella 101 forms interlamellar spacing between the carbide less than about 0.5 μ m.Carbide lamella 101 forms long-width ratio greater than about 10: 1.If the interlamellar spacing between the carbide lamella 101 is greater than about 0.5 μ m, then the carbide number of unit volume is less.Therefore, may not avoid fatigue crack growth effectively.On the other hand, if long-width ratio less than about 10: 1, then crackle can easily be grown between carbide.
The density of carbide is greater than the density of peripheral ferrite (peripheral ferrite).Therefore, the crackle of this steel plate can not run through this carbide growth.Therefore, crackle tends to growth between carbide lamella 101.Yet this high carbon steel sheet comprises the highdensity carbide lamella that has than the aspect ratio.Therefore, crackle can not be grown between carbide.Therefore, the crackle that forms on edge surface may be not easy growth, because this crackle will be had to along complicated " A " path " A " growth.Fig. 2 is a sectional view that a kind of comparative example's 3 high carbon steel sheet is shown.Comparative example 3 high carbon steel sheet comprises bainite and fine pearlite.In conjunction with Fig. 2, the carbide lamella 201 that is contained in comparative example 3 the high carbon steel sheet has less long-width ratio.Therefore, crackle can growth easily between carbide.That is, crackle may easily be grown along " B " path, thus the fatigue lifetime that may reduce this steel plate.
That is, the carbide lamella 101 that is contained in the accompanying drawing 1 in this high carbon steel sheet has bigger length to height ratio.In addition, it is bigger to be contained in the density of the carbide lamella 101 in this high carbon steel sheet.Therefore, crackle can not be connected with each other between carbide.Therefore, can prevent the growth of fatigue cracking effectively.
Hereinafter, a kind of method of making high carbon steel sheet has been described.
Formed a kind of steel member.This steel member comprise about 0.75wt% to the carbon (C) of about 0.95wt%, be less than the silicon (Si) of about 1.8wt%, about 0.1wt% extremely about 1.5wt% manganese (Mn), about 0.1wt% extremely about 1.0wt% chromium (Cr), be less than about 0.02wt% phosphorus (P), be less than the sulphur (S) of about 0.02wt%, the iron (Fe) and the unavoidable impurities of residual volume.This steel member also can comprise a kind of predetermined-element.This predetermined-element can be about 0.05wt% to the vanadium (V) of about 0.25wt%, about 0.05wt% to the niobium (Nb) of about 0.25wt%, about 0.05wt% is to the molybdenum (Mo) of about 0.25wt%, about 0.05wt% titanium (Ti), about 0.05wt% tungsten (W), the about 0.05wt% copper (Cu) of about 0.25wt% or the about 30ppm nitrogen (N) of about 120ppm extremely extremely of about 0.25wt% extremely of about 0.25wt% extremely.These materials can separately or be used in combination.The chemical constitution of this steel plate has been described before.Therefore, will omit any other explanation.
Thereby this steel member is implemented course of hot rolling, cold-rolled process and annealing process can be formed and have spheroidite and ferritic steel plate.To about 1100 ℃ temperature, heat this steel plate at about 800 ℃ then.If this steel plate heats being lower than under about 800 ℃ temperature, then spheroidite may not dissolve fully in quenching technology.Thus, use the intensity of the formed product of this steel plate after thermal treatment, to reduce.On the other hand, when this steel plate is being higher than when heating under about 1100 ℃ temperature, the surface decarburization of spring steel may take place.In addition, thus the granularity of austenite phase may lower may need significantly the sclerosis.Therefore, be difficult to obtain fine structure.
Afterwards, this steel plate was implemented the malleableize annealing process about 60 seconds at a certain temperature, described temperature is the temperature of solder pot, maintains about 500 ℃ to about 530 ℃.Perhaps, this steel plate was implemented the malleableize annealing process about 20 seconds to about 570 ℃ temperature maintaining about 530 ℃.If the temperature and time deficiency that the malleableize annealing process is required, then the austenite that forms in the quenching process may not be converted into fine pearlite in solder pot.If so, austenite may be converted into martensite.Perhaps, may stay austenite.The austenite that stays may become stress-induced martensite and crack, thereby reduces the fatigue lifetime in the cold-rolled process.In addition, rolling characteristic may be because stress-induced martensite cracks and deterioration in cold-rolled process.On the other hand, if this steel plate is implemented annealing process maintaining to be higher than under about 570 ℃ temperature, then the spacing between the fine pearlite layer increases.Therefore, be difficult to form the fine structure of the growth that can avoid fatigue cracking by use cold-rolled process subsequently.In addition, intensity may be difficult for being improved by work hardening.
As mentioned above, can form the high carbon steel sheet that contains fine structure by the condition of regulating the malleableize annealing process with better fatigue lifetime.
Hereinafter, can describe more completely embodiment of the present invention in conjunction with the embodiments.Be understood that the foregoing description is to exemplary illustration of the present invention, should not be construed as the restriction to disclosed specific embodiments.
Embodiment
Preparation is used to form the carbon steel sheet with above-mentioned composition of high-strength spring.Then this high carbon steel sheet is implemented the operation of rolling, have the board-like coil of about 1.3mm to about 1.6mm thickness thereby wherein implement the formation of Spheroidizing Annealing process.Afterwards, this board-like coil was heated about 2 minutes to about 1200 ℃ quenching temperature at about 750 ℃.The about 300 ℃ of extremely about 650 ℃ solder pots of use temperature are implemented malleableize annealing process (being austempering) then.Afterwards, form the board-like coil of the about 0.23mm of thickness by the operation of rolling.As a result, although form the material that in cold-rolled process, has different compression ratio thickness homogeneous.The coil of the about 0.23mm of thickness is cut into about the 8mm width to form spring.Afterwards, implement burr and remove process, forming process, curly course and strain aging process to form spring.
Required malleableize (or austempering) annealing conditions, quenching annealing conditions and the compression ratio of the high carbon steel sheet with better fatigue lifetime that is formed for spring is disclosed in [table 1].
The enforcement fatigue test is with the fatigue lifetime of measuring spring.In fatigue test, this spring is placed the tired measuring apparatus of implementing rotation and reverse rotation.In order to make spring in the plastic deformation scope, work, between 22 rotating ranges of the 2nd rotating range to the, repeat rotation and reverse rotation up to spring breakage.Tired measuring apparatus replicate measurement fatigue lifetime, and the result is disclosed in [table 1].
[table 1]
| The temperature of quenching annealing process (℃) | Malleableize (austempering) annealing process temperature (℃) | Hold time (second) | Cold reduction is than (%) | Fine structure | Fatigue lifetime (inferior) | |
| Embodiment 1 | ??900 | ??550 | ??30 | ??85.6 | Fine pearlite | ??31,556 |
| Embodiment 2 | ??1000 | ??525 | ??80 | ??85.6 | Fine pearlite | ??29,032 |
| The comparative example 1 | ??750 | ??550 | ??80 | ??85.6 | Fine pearlite+perlite+cementite (not fusion) | ??17,853 |
| The comparative example 2 | ??1200 | ??480 | ??80 | ??85.6 | Upper bainite+fine pearlite+martensite+surface ferrite (decarburization) | ??7,856 |
| The comparative example 3 | ??1050 | ??450 | ??80 | ??85.6 | Upper bainite+part fine pearlite | ??14,229 |
| The comparative example 4 | ??950 | ??600 | ??80 | ??85.6 | Perlite | ??16,886 |
| The comparative example 5 | ??950 | ??500 | ??10 | ??85.6 | Fine pearlite+martensite | ??11,238 |
| The comparative example 6 | ??900 | ??550 | ??80 | ??82.4 | Fine pearlite | ??16,389 |
Reverse conversion if the temperature of quenching process is lower than about 800 ℃ (comparative example 1), then takes place in associative list 1 in matrix.Yet spheroidite may not dissolve fully.Not dissolved cementite structure can stay after the austempering annealing process.Thus, the concentration of the carbon that records in the matrix may be not enough, so conversion curve moves forward.As a result, perlite may form annotating to solder pot, though malleableize (or austempering) annealing process implement with identical rate of cooling, and some austenites may be converted into fine pearlite simultaneously remaining austenite be retained in the solder pot.In this case, do not dissolve the amount of the amount of spheroidite greater than the strained carbide lamella.Thus, can not effectively avoid fatigue cracking and the yield strength may be very low.As a result, fatigue lifetime may be shorter relatively.
If the quenching annealing temperature is higher than about 1100 ℃ (comparative example 2), then conversion curve may move backward owing to the increase of austenitic grain size.Thus, a small amount of martensite may through behind the solder pot by cooling step in remaining martensite and forming.In addition, the ferrite that forms owing to decarburization is found in the surface element office.Even martensitic amount is less, martensite also can damage the fatigue lifetime in the plastic deformation scope.In addition, if surface decarburization takes place, then fatigue strength may further reduce owing to the reduction of surface strength.
When the time that keeps in the solder pot was lacked (comparative example 3), remaining martensite can stay or may reduce fatigue lifetime owing to the martensite that forms in through solder pot postcooling step.
If the holding temperature of malleableize (or austempering) annealing process becomes lower temperature (comparative example 3), then the yield strength that records after the annealing may increase.
Fatigue lifetime is longer relatively in the elastic deformation scope.Yet if the plastic deformation scope is contained in the working range, fatigue lifetime may be shorter.This is because the bainite carbide can not prevent crack growth effectively.
If the plastic deformation scope is contained in (the pressure role that promptly is applied to the surface is bigger than yield strength) in the spring working range, then may be easy to generate crackle.Thus, may depend on the growth of crackle to a great extent fatigue lifetime.In conjunction with Fig. 2, sneak in the fine structure if will have the carbide of less long-width ratio, then the growth of crackle may not be avoided.Thus, thus the length in path, crack growth place may shorten and makes that in comprising the spring working range of plastic deformation scope fatigue lifetime may step-down.
Fig. 3 and 4 shows the spring breakage shape of embodiment 1 and comparative example 3 after the fatigue test.
Fig. 3 shows at the fatigue cracking of a kind of high carbon steel sheet of the embodiment of the invention being implemented produce after the fatigue test.Fig. 4 shows at the fatigue cracking of a kind of comparative example's high carbon steel sheet being implemented produce after the fatigue test.In conjunction with Fig. 3 and 4, produce the fracture of stairstepping in the embodiments of the invention.Yet, produce linear fracture among the comparative example.That is, the generation of crackle and growth can be at embodiments of the invention but not are effectively prevented among the comparative example.
If the holding temperature of malleableize (or austempering) is higher than 570 ℃ (comparative example 4), then may produce the perlite fine structure.Carbon may the distortion significantly owing to higher compression ratio.Yet opposite with the embodiment of the invention, the amount of the carbide lamella of unit volume is less relatively.Thus, opposite with example of the present invention, the growth of fatigue cracking may not be avoided effectively.
If no matter the quenching annealing temperature how, cold reduction is than not enough (being comparative example 6), and the temperature and time of malleableize (or austempering) is contained in the suitable scope, and then fatigue lifetime is less than the fatigue lifetime of the embodiment of the invention.But should fatigue lifetime greater than fatigue lifetime of other comparative example.
As shown in table 1, be better than comparative example's fatigue lifetime the fatigue lifetime of the embodiment of the invention.This is because the high carbon steel sheet of the embodiment of the invention has the distortion carbide lamella that has the bigger fine structure of long-width ratio in a large number.This carbide lamella can be avoided the growth of fatigue cracking.If the plastic deformation scope is contained in (the pressure role that promptly is applied to the surface is bigger than yield strength) in the spring working range, then may be easy to generate crackle.Thus, may depend primarily on the growth of crackle fatigue lifetime.As a result, may change according to the length in the fine structure that can avoid crack growth and path, fatigue crack growth place fatigue lifetime.
The high carbon steel sheet of the embodiment of the invention comprises a kind of like this fine structure, wherein is arranged with a large amount of fine pearlites that rolling technology is out of shape that passes through in the unit volume.This fine structure is useful to improving fatigue lifetime.
Industrial applicability
The high carbon steel sheet of embodiment of the present invention has a large amount of having greater than about 10: 1 carbide lamella than the aspect ratio.Thus, can avoid crack growth effectively.
In addition, possible growth because of the crackle fatigue lifetime of high carbon steel sheet is avoided and is improved.
In addition, if use the high carbon steel sheet of embodiment of the present invention to form spring, the crackle of generation may be not easy growth.Thus, even this spring is worked in the plastic deformation scope, spring also can be worked the long time.
Claims (16)
1. a high carbon steel sheet comprises
About 0.75wt% is to the carbon of about 0.95wt%, the silicon that is less than about 1.8wt%, about 0.1wt% extremely manganese, the chromium of about 0.1wt% to 1.0wt%, the phosphorus that is less than about 0.02wt%, the sulphur that is less than about 0.02wt%, the iron and the unavoidable impurities of residual volume of about 1.5wt%
Wherein be contained in interlamellar spacing between the carbide lamella in this high carbon steel sheet less than about 0.5 μ m.
2. the high carbon steel sheet of claim 1, wherein this high carbon steel sheet comprises the fine pearlite with flaky texture.
3. the high carbon steel sheet of claim 2 wherein is contained in fine pearlite in this high carbon steel sheet and has volume percent greater than about 90%.
4. the high carbon steel sheet of claim 2, wherein the long-width ratio of this flaky texture was greater than about 10: 1.
5. the high carbon steel sheet of claim 1 also comprises at least a material that be selected from vanadium, niobium, molybdenum, titanium, tungsten and copper of about 0.05wt% to about 0.25wt%.
6. the high carbon steel sheet of claim 5 also comprises the nitrogen of about 30ppm to about 120ppm.
7. method of making high carbon steel sheet, this method comprises:
Form a kind of steel member that contains following material: about 0.75wt% is to the carbon of about 0.95wt%, the silicon that is less than about 1.8wt%, about 0.1wt% extremely manganese, about 0.1wt% extremely chromium, the phosphorus that is less than about 0.02wt%, the sulphur that is less than about 0.02wt%, the iron and the unavoidable impurities of residual volume of about 1.0wt% of about 1.5wt%;
This steel member is implemented course of hot rolling, cold-rolled process and annealing process so that it has a kind of spheroidite and a kind of initial ferrite; And
Heat behind this steel member this steel member through heating is implemented the malleableize annealing process, wherein this malleableize annealing process maintains about 500 ℃ by use temperature and implements about more than 60 seconds to about 530 ℃ solder pot.
8. the method for claim 7 is wherein implemented this steel member to be heated to about 1100 ℃ temperature at about 800 ℃ before the malleableize annealing process.
9. the method for claim 7, wherein this steel member also comprises at least a material that be selected from vanadium, niobium, molybdenum, titanium, tungsten and copper of about 0.05wt% to about 0.25wt%.
10. the method for claim 9, wherein this steel member also comprises the nitrogen of about 30ppm to about 120ppm.
11. the method for claim 7 also comprises:
After the malleableize annealing process, implement process of cooling; And
Thereby implementing cold-rolled process makes the compression ratio of cold-rolled process be higher than about 85%.
12. a method of making high carbon steel sheet, this method comprises:
Form a kind of steel member that contains following material: about 0.75wt% is to the carbon of about 0.95wt%, the silicon that is less than about 1.8wt%, about 0.1wt% extremely manganese, about 0.1wt% extremely chromium, the phosphorus that is less than about 0.02wt%, the sulphur that is less than about 0.02wt%, the iron and the unavoidable impurities of residual volume of about 1.0wt% of about 1.5wt%;
This steel member is implemented course of hot rolling, cold-rolled process and annealing process so that it has spheroidite and initial ferrite; And
Heat behind this steel member this steel member through heating is implemented the malleableize annealing process, wherein this malleableize annealing process maintains about 500 ℃ by use temperature and implements about more than 20 seconds to about 530 ℃ solder pot.
13. the method for claim 12 is wherein implemented this steel member to be heated to about 1100 ℃ temperature at about 800 ℃ before the malleableize annealing process.
14. the method for claim 12, wherein this steel member also comprises at least a material that be selected from vanadium, niobium, molybdenum, titanium, tungsten and copper of about 0.05wt% to about 0.25wt%.
15. the method for claim 14, wherein this steel member also comprises the nitrogen of about 30ppm to about 120ppm.
16. the method for claim 12 also comprises:
After the malleableize annealing process, implement process of cooling; And
Thereby implementing cold-rolled process makes the compression ratio of cold-rolled process be higher than about 85%.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR10-2007-0055199 | 2007-06-05 | ||
| KR1020070055199 | 2007-06-05 | ||
| KR1020070055199A KR101445868B1 (en) | 2007-06-05 | 2007-06-05 | High carbon steel sheet superior in fatiugue lifeand manufacturing method thereof |
| PCT/KR2007/006863 WO2008150056A1 (en) | 2007-06-05 | 2007-12-27 | High carbon steel sheet superior in fatiugue lifeand manufacturing method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101680069A true CN101680069A (en) | 2010-03-24 |
| CN101680069B CN101680069B (en) | 2012-07-04 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2007800531456A Active CN101680069B (en) | 2007-06-05 | 2007-12-27 | High carbon steel sheet superior in fatiugue lifeand manufacturing method thereof |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US20100218859A1 (en) |
| JP (1) | JP5581205B2 (en) |
| KR (1) | KR101445868B1 (en) |
| CN (1) | CN101680069B (en) |
| WO (1) | WO2008150056A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106399647A (en) * | 2016-09-26 | 2017-02-15 | 南京钢铁股份有限公司 | Process for realizing sorbitizing cold rolling of high-strength and high-fatigue spring narrow band steel |
| CN107868905A (en) * | 2016-09-28 | 2018-04-03 | Posco公司 | High carbon steel sheet and its manufacture method |
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| JP5630002B2 (en) * | 2008-11-17 | 2014-11-26 | Ｊｆｅスチール株式会社 | High-strength steel sheet having a tensile strength of 1500 MPa or more and a method for producing the same |
| JP5630003B2 (en) * | 2008-11-17 | 2014-11-26 | Ｊｆｅスチール株式会社 | High-strength steel sheet having a tensile strength of 1500 MPa or more and a method for producing the same |
| DE102009010442A1 (en) * | 2009-02-26 | 2010-09-02 | C.D. Wälzholz GmbH | Micro-alloyed carbon steel as a texture-rolled strip steel, in particular for spring elements |
| EP2280199B1 (en) * | 2009-07-31 | 2016-07-13 | ElringKlinger AG | Cyclinder head gasket, and process for manufacturing a functional layer of a cylinder head gasket. |
| JP5630006B2 (en) * | 2009-11-04 | 2014-11-26 | Ｊｆｅスチール株式会社 | High-strength steel sheet having a tensile strength of 1500 MPa or more, its manufacturing method, and cold rolling material |
| JP5630004B2 (en) * | 2009-11-04 | 2014-11-26 | Ｊｆｅスチール株式会社 | High-strength steel sheet having a tensile strength of 1500 MPa or more and a method for producing the same |
| JP5630005B2 (en) * | 2009-11-04 | 2014-11-26 | Ｊｆｅスチール株式会社 | High-strength steel sheet having a tensile strength of 1500 MPa or more and a method for producing the same |
| EP2617840B1 (en) | 2010-09-16 | 2021-08-11 | Posco | High-carbon hot-rolled steel sheet, cold-rolled steel sheet and a production method therefor |
| KR101304670B1 (en) | 2011-08-01 | 2013-09-06 | 주식회사 포스코 | Steel without spheroidizing heat treatment and method for manufacturing the same |
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| KR101492800B1 (en) | 2014-10-13 | 2015-02-12 | 장인금속(주) | Spheroidizing-annealing heat method of carbon steel and blade-metal products |
| JP6189819B2 (en) * | 2014-11-21 | 2017-08-30 | 株式会社神戸製鋼所 | High strength high ductility steel sheet |
| KR102043511B1 (en) | 2017-12-12 | 2019-11-12 | 주식회사 포스코 | Quenched high carbon steel sheet and method for manufacturing the same |
| KR102327929B1 (en) * | 2019-12-20 | 2021-11-17 | 주식회사 포스코 | Steel sheet having fatigue life for leaf spring and manufacturing method for the same |
| CN115341076B (en) * | 2022-07-15 | 2023-08-18 | 大冶特殊钢有限公司 | Spring steel and spheroidizing annealing method thereof |
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Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61261430A (en) * | 1985-05-14 | 1986-11-19 | Shinko Kosen Kogyo Kk | Manufacture of high strength and toughness steel wire |
| JPH04124216A (en) * | 1990-09-12 | 1992-04-24 | Sumitomo Metal Ind Ltd | Production of high carbon steel sheet having superior formability |
| JP3176226B2 (en) * | 1994-08-11 | 2001-06-11 | 株式会社神戸製鋼所 | Manufacturing method of high strength and high toughness hot-dip coated steel wire |
| JPH08302428A (en) * | 1995-05-10 | 1996-11-19 | Nisshin Steel Co Ltd | Production of high strength steel strip for spring |
| JP3036416B2 (en) * | 1995-11-15 | 2000-04-24 | 株式会社神戸製鋼所 | Hot forged non-heat treated steel having high fatigue strength and method for producing forged product |
| JP3859331B2 (en) * | 1997-11-06 | 2006-12-20 | 住友電工スチールワイヤー株式会社 | High fatigue strength steel wires and springs and methods for producing them |
| JP4425368B2 (en) * | 1999-03-19 | 2010-03-03 | 日新製鋼株式会社 | Manufacturing method of high carbon steel sheet with excellent local ductility |
| CN1159470C (en) * | 2001-09-30 | 2004-07-28 | 宝山钢铁股份有限公司 | Ultrahigh carbon steel base material with superplasticity, its production method and application |
| DE602004026995D1 (en) * | 2003-01-27 | 2010-06-17 | Nippon Steel Corp | ROLLING WIRE MADE OF HIGH-TIGHT HIGH-TEETH CARBON STEEL AND MANUFACTURING METHOD THEREFOR |
| JP4375615B2 (en) * | 2004-06-15 | 2009-12-02 | 日新製鋼株式会社 | Steel plate for door parts |
| CN1840729A (en) * | 2005-03-30 | 2006-10-04 | 株式会社神户制钢所 | High carbon steel wires excellent in spinnability and method for producing same |
-
2007
- 2007-06-05 KR KR1020070055199A patent/KR101445868B1/en active IP Right Grant
- 2007-12-27 CN CN2007800531456A patent/CN101680069B/en active Active
- 2007-12-27 WO PCT/KR2007/006863 patent/WO2008150056A1/en active Application Filing
- 2007-12-27 JP JP2010510190A patent/JP5581205B2/en active Active
- 2007-12-27 US US12/600,161 patent/US20100218859A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106399647A (en) * | 2016-09-26 | 2017-02-15 | 南京钢铁股份有限公司 | Process for realizing sorbitizing cold rolling of high-strength and high-fatigue spring narrow band steel |
| CN107868905A (en) * | 2016-09-28 | 2018-04-03 | Posco公司 | High carbon steel sheet and its manufacture method |
| CN107868905B (en) * | 2016-09-28 | 2020-02-21 | Posco公司 | High carbon steel sheet and method for producing same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2010528189A (en) | 2010-08-19 |
| WO2008150056A1 (en) | 2008-12-11 |
| JP5581205B2 (en) | 2014-08-27 |
| US20100218859A1 (en) | 2010-09-02 |
| KR20080107196A (en) | 2008-12-10 |
| CN101680069B (en) | 2012-07-04 |
| KR101445868B1 (en) | 2014-10-01 |
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