CN104884660B - Carburizing steel - Google Patents
Carburizing steel Download PDFInfo
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- CN104884660B CN104884660B CN201380067800.9A CN201380067800A CN104884660B CN 104884660 B CN104884660 B CN 104884660B CN 201380067800 A CN201380067800 A CN 201380067800A CN 104884660 B CN104884660 B CN 104884660B
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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
- C21D1/06—Surface hardening
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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
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
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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
- C22C38/008—Ferrous alloys, e.g. steel alloys containing tin
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- 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
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- 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
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
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- 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
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- 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
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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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
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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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
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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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
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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
- C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
- C23C8/20—Carburising
- C23C8/22—Carburising of ferrous surfaces
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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
- C21D2211/004—Dispersions; Precipitations
Abstract
The chemical composition of the steel of the present invention contains C in terms of quality %：0.16～0.30%, Si：0.01～2.0%, Mn：0.35～1.45%, Cr：0.05～3.0%, Al：0.001～0.2%, Ni：0.04～5.0%, Sn：0.015%～1.0%, S：0.004～0.05%, N：0.003～0.03%, O：Less than 0.005%, P：Less than 0.025%, Mo：0～1.0%, Cu：0～1.0%, B：0～0.005%, Nb：0～0.3%, Ti：0～0.3%, V：0～1.0%, Ca：0～0.01%, Mg：0～0.01%, Zr：0～0.05%, Te：0～0.1% and rare earth element：0～0.005%, and remainder is Fe and impurity, when the content of Si, Ni, Al and Sn is expressed as in terms of quality % [Si%], [Ni%], [Al%], [Sn%], meets following relations：+ 32 × [Al%] >=8.5 of 42 >=21 × [Si%]+40 × [Sn%] of+5 × [Ni%].
Description
Technical field
The present invention relates to the adjustment that need not carry out car-burization condition for each carburizing steel part can just improve various oozing
The carburizing steel of the impact resistance characteristic of carbon steel part.
The Patent 2012-288131 CLAIM OF PRIORITY that the application was filed an application in Japan based on December 28th, 2012,
And by its content quotation in this.
Background technology
Mechanical realization part is sometimes damaged because being sharp subject to larger stress.Particularly in differential gearing, transmission
In the vehicle gear such as gear and the carburizing axle with gear, sometimes due to the emergency start of vehicle and negative when stopping in emergency
Carry and make tooth root damaged because of impact failure.In order to prevent this phenomenon, especially for differential gearing and travelling gear, phase
Hope and further improve its impact value (impact resistance characteristic).By fully improving the impact value of these mechanical realization parts, energy
The amount of the material used by mechanical realization part is enough reduced, the lightweight of mechanical realization part is reached.
In the past, for above-mentioned part, generally by by the such as C content such as JIS SCr420 and JIS SCM420 being
0.2% or so case-hardened steel guarantees the toughness of core as raw material.Also, for above-mentioned part, implement to ooze
The lonneal of carbon Quenching Treatment and 150 DEG C or so, it is 0.8% or so to return to make the metallographic structure of parts surface become C content
Fiery martensitic structure.Thus, high circulation bending fatigue strength and the wearability of part are improved.
Hereinafter the prior art for improving impact value is illustrated.In patent documentation 1, it is proposed that such as lower gear
With steel and used the gear of the gear steel, in the gear steel, it is stipulated that the content of Al, B and N, by solid solution B come
Improve impact fatigue-resistant characteristic and face fatigue strength.But, the gear described in patent documentation 1 causes de- B in carburizing
Phenomenon, the solid solution B of Surface of Gear disappear, and therefore the raising of its impact value is less.
In patent documentation 2, it is proposed that the gear of following excellent impact resistance, the gear is by regulation Mo, Si, P, Mn
And obtained from the content of Cr, the particularly content of raising Mo.But, make Mo contents increase when, need reduce Si, Mn with
And the content of Cr, therefore the gear described in patent documentation 2 intensity decreases are caused due to the reduction of quenching degree.
In patent documentation 3, the surface for having by containing obtained from appropriate Cu, having high intensity and high tenacity is proposed
Comentation hardening steel.But, the Cu at high temperature in steel becomes liquid layer, promotes the embrittlement of steel.Thus, described in patent documentation 3
There is restriction in the manufacturing condition of case-hardened steel.
The present inventors intently implement the investigation of the relation between Carburized Characteristic and impact resistance characteristic.As a result,
The present inventors obtain following opinion：As described later, the infiltration capacity for making C penetrate into steel in carburizing reduces and makes carburized material
It is effective that the way that surface C concentration reduces is used for improving impact value.But, in the too low feelings of the surface C concentration of carburized material
Under condition, it is impossible to reach the raising of the characteristics such as fatigue strength and the wearability of original purpose as Carburization Treatment.Thus, it is
Make carburizing steel part take into account the characteristics such as impact resistance characteristic, fatigue strength and wearability, need the surface C of carburizing steel part
Concentration is controlled to appropriate level.
The minimizing of surface C concentration can be realized by reducing carbon potential in Carburization Treatment.But, using oozing
It is difficult to be implemented in the production process of the reality of carbon stove.Its reason is, in actual production process, it is right that carburizer needs
The different various parts of purposes are simultaneously and continuously processed in a large number.Carry out characteristic required by the part of carburizing not as above
State.For example, carburizing steel part also requires that the characteristics such as wearability and fatigue strength.Thus, oozing
It is effective but strong in major requirement fatigue to the part of major requirement impact resistance characteristic to make the way that carbon potential reduces during carbon process
Harmful effect is brought in the part of degree, produces by the reduction of fatigue strength caused problem.If the attempt to passing through not how
Carry out carburizing to control the surface C concentration of carburizing steel part under conditions of playing carburizing, now need to adjust for each part
Whole car-burization condition.But, this causes the reduction of productivity ratio, therefore unsatisfactory in terms of industrial applicibility.
Thus, even if seeking to carry out carburizing under strong car-burization condition that can be corresponding with the carburizing of various parts
Process, also can by the control of the infiltration capacity of C proper level carburizing steel.
As the control technology of surface C concentration, containing by regulation Si, Ni, Cu and Cr is proposed in patent documentation 4
The relation of amount is suppressing the carburizing steel part of excess carburizing.But, the carburizing atmosphere for becoming object in the publication is by steel
Surface C concentration is set as 1.0% or so carburizing atmosphere.In the case where the surface C concentration by steel is set as such value,
The surface of steel produces carbide.In this case, it is impossible to realize the reduction for improving effective surface C concentration to impact value.
Prior art literature
Patent documentation
Patent documentation 1：Japanese Unexamined Patent Publication 2008-179848 publications
Patent documentation 2:Japanese Unexamined Patent Publication 1-108347 publication
Patent documentation 3:No. 3927355 publications of Japan Patent
Patent documentation 4:Japanese Unexamined Patent Publication 2007-291486 publications
Content of the invention
Invent problem to be solved
For as described previously for the carburizing steel part of mechanical realization, need to take into account impact resistance characteristic and wearability.Energy
The design of enough change parts, so that by the impact resistance characteristic for fully improving the carburized material used by carburizing steel part, from
And the impact resistance characteristic of part is also assured that while suppressing using quantity of material.Furthermore, it is desirable under single car-burization condition or
Different to the purposes various parts under the car-burization condition of species as few as possible of person carry out the carburizing steel part of mechanical realization
Reality production process in Carburization Treatment.
In the public technology of patent documentation 1～4, it is impossible to fully meet and take into account the raising of impact value and avoid productivity ratio
The demand of reduction, specifically following demands：Impact resistance just need not can be obtained for each part adjustment car-burization condition
The carburizing steel part of excellent.
The present invention provides a kind of steel, is obtained in that impact value (impact resistance when the steel to be used as the material of carburizing steel part
Characteristic) and excellent carburizing steel part both wearability, and, carburizing bar need not be changed when the carburizing steel part is manufactured
Part.
The means of solve problem
The present inventors are in order to realize being obtained in that the carburizing for avoiding reducing productivity ratio and with excellent impact value
The steel of steel part, to making chemical composition and carburized material matter characteristic on a large scale and the steel that systematically changes implements carburizing
And impact test.As a result, obtaining the opinion of following explanation.
Fig. 1 is the pass between the surface C concentration and impact value for representing the carburized material that steel is carried out Carburization Treatment and obtained
The chart of system.The surface C concentration of steel is made to increase by Carburization Treatment.Obtain following opinion：In order that the impact of carburized material
Value is improved, as shown in figure 1, the surface C concentration after by carburizing controls in appropriate level to be effective.
Also, the present inventors obtain following opinion：The surface C concentration of control carburized material can as described above
Could be adjusted to realize by the content to the alloying element being solid-solution in steel.Specifically, by the content of each alloying element
It is respectively set as in prescribed limit and by content (unit in the steel of Si, Ni, Al and Sn in the alloying element in steel：Matter
Amount %) when being set as [Si%], [Ni%], [Al%], [Sn%], the present inventors have understood following content and have completed this
Invention：By meeting following formula (A), the surface C concentration of carburized material becomes appropriate value, and impact value is improved.
42 >=21 × [Si%]+5 × [Ni%]+32 × [Al%] >=8.5 of+40 × [Sn%] (A)
The present invention is completed based on above neodoxy, and the purport of the present invention is as described below.
(1) steel of a technical scheme of the invention, its chemical composition contain C in terms of quality %：0.16～0.30%, Si：
0.01～2.0%, Mn：0.35～1.45%, Cr：0.05～3.0%, Al：0.001～0.2%, Ni：0.04～5.0%, Sn：
0.015～1.0%, S：0.004～0.05%, N：0.003～0.03%, O：Less than 0.005%, P：Less than 0.025%, Mo：0
～1.0%, Cu：0～1.0%, B：0～0.005%, Nb：0～0.3%, Ti：0～0.3%, V：0～1.0%, Ca：0～
0.01%th, Mg：0～0.01%, Zr：0～0.05%, Te：0～0.1% and rare earth element：0～0.005%, and remain
Remaining part is divided into Fe and impurity, by the content of Si, Ni, Al and Sn be expressed as in terms of quality % [Si%], [Ni%],
When [Al%], [Sn%], following formula (A) is met.
42 >=21 × [Si%]+5 × [Ni%]+32 × [Al%] >=8.5 of+40 × [Sn%] (A)
(2) steel according to described in above-mentioned (1), the chemical composition can also contain Mo in terms of quality %：0.05～
1.0%th, Cu：0.01～1.0% and B：One or more in 0.0002～0.005%.
(3) steel according to described in above-mentioned (1) or (2), the chemical composition can also contain Nb in terms of quality %：
0.005～0.3%, Ti：0.005～0.3% and V：One or more in 0.01～1.0%.
(4) steel according to described in any one of above-mentioned (1)～(3), the chemical composition can also be contained in terms of quality %
There is Ca：0.0005～0.01%, Mg：0.0005～0.01%, Zr：0.0005～0.05%, Te：0.0005～0.1% and
Rare earth element：One or more in 0.0001～0.005%.
Invention effect
If using the present invention steel manufacturing carburizing steel part, need not be in order to improve the impact value of carburizing steel part
For each carburizing steel part adjustment car-burization condition.Thus, it is possible to manufacture efficiency is improved by the unification of method for carburizing, and
The carburizing steel part of excellent impact value is obtained in that, the industrial effect that is brought by the present invention is very big.
Description of the drawings
Fig. 1 is the chart for representing the relation between impact value and surface C concentration.
Fig. 2 is that the section vertical with the bearing of trend of breach for representing the charpy impact test piece that uses in the present invention shows
It is intended to.
Fig. 3 is the schematic diagram of the measured zone for representing surface C concentration.
Fig. 4 is the semi-log chart for representing the relation between surface C concentration and impact value ratio.
Fig. 5 is to represent+32 × [Al%] of 21 × [Si%]+40 × [Sn%] of+5 × [Ni%] with surface C concentration and impact
The chart of relation of the value than between.
Specific embodiment
Mode for implementing the present invention explained in detail below.
First, the restriction reason of the chemical composition of the steel of present embodiment is illustrated.Hereinafter, will be used as alloying element
" quality % " of unit of content be abbreviated as " % ".In the following description, unless otherwise specified, with regard to steel (carburizing
With steel) explanation be also suitable for carburizing steel part (carburized material).
C：0.16～0.30%
C content determines the intensity of the core of carburizing steel part, and also produces impact to the depth of effective hardness layer.In order to
The lower limit of C content is set as 0.16% by the core strength needed for guaranteeing.On the other hand, if C content is excessive, manufacturing
Reduce, the higher limit of C content is set as 0.30% therefore.C content is preferably 0.18～0.25%.
Si：0.01～2.0%
Si is the effective element of the deoxidation to steel, and is to give institute to the carburizing steel part as mechanical realization part
The effective element of intensity and quenching degree for needing.Also, the increase by Si contents, carburizing during carburizing reduce, carburizing steel
The impact value of part is improved.When Si contents are less than 0.01%, its effect is simultaneously insufficient.In addition, if Si contents are more than 2.0%,
Decarburization when then manufacturing becomes notable, and the intensity of carburizing steel part and effective case depth are not enough.For the above-mentioned reasons, need
Si contents are made in the range of 0.01～2.0%.Si contents are preferably 0.2～1.5%.
Mn：0.35～1.45%
Mn is the effective element of the deoxidation to steel, and is effectively first to the intensity and quenching degree needed for steel imparting
Element.When Mn contents are less than 0.35%, martensite start temperature is uprised, and causes self tempering, reduces hardness.If in addition,
More than 1.45%, even then after subzero process, retained austenite is also stably present in steel Mn contents, strong so as to steel
Degree reduces.For the above-mentioned reasons, need to make Mn contents in the range of 0.35～1.45%.Mn contents be preferably 0.50～
1.10%.
Cr：0.05～3.0%
Cr is the intensity needed for giving to steel and the effective element of quenching degree.When Cr contents are less than 0.05%, which is imitated
Really insufficient.If Cr contents are more than 3.0%, its effect saturation.For the above-mentioned reasons, need for Cr contents to be located at 0.05～
In the range of 3.0%.Cr contents are preferably 0.2～1.5%.
Al：0.001～0.2%
Al is the effective element of the deoxidation to steel, and is to become nitride and separate out in steel, play crystal grain miniaturization
The element of effect.If also, increasing Al content, the carburizing of steel reduces, and thus the impact value of carburizing steel part is improved.In Al
When content is less than 0.001%, its effect is insufficient.In addition, if Al content is more than 0.2%, precipitate (Al nitride) is thick
Change, become steel and carburizing steel part brittle the reason for.For the above-mentioned reasons, need for Al content to be located at 0.001～0.2%
In the range of.The optimum range of Al content is 0.01～0.15%.
Ni：0.04～5.0%
Ni is the intensity needed for giving to steel and the effective element of quenching degree.Also, by increasing Ni contents, during carburizing
Carburizing reduce, thus carburizing steel part impact value improve.When Ni contents are less than 0.04%, its effect is insufficient.If
Ni contents are more than 5.0%, even if implementing subzero process to steel, retained austenite is also stably present in steel, strong so as to steel
Degree reduces.For the above-mentioned reasons, need Ni contents are located in the range of 0.04～5.0%.Preferably Ni contents be 1.0～
2.0%.
Sn：0.015～1.0%
By the increase of Sn contents, carburizing during carburizing reduces, and thus the impact value of carburizing steel part is improved.Contain in Sn
When amount is less than 0.015%, its effect is insufficient.On the other hand, if Sn contents are more than 1.0%, the high-temperature ductility of steel reduces.Base
In above reason, need the content of Sn is located in the range of 0.015～1.0%.The optimum range of Sn contents be 0.02～
0.1%.
S：0.004～0.05%
S forms MnS in steel, thus improves the machinability of steel.When S contents are less than 0.004%, its effect is not filled
Point.On the other hand, if S contents are more than 0.05%, its effect saturation, on the contrary produce cyrystal boundary segregation and cause embrittlement of grain boundaries.Base
In above reason, need the content of S is located in the range of 0.004～0.05%.The optimum range of S contents be 0.01～
0.04%.
N：0.003～0.03%
N is combined with Al, Ti, Nb and V etc. in steel and is generated nitride or carbonitride.These nitride and carbon nitrogen
Compound has the effect of the coarsening for suppressing crystal grain.When N content is less than 0.003%, its effect is insufficient.If N content exceedes
0.03%, then its effect saturation.For the above-mentioned reasons, need N content is located in the range of 0.003～0.03%.N content
Optimum range is 0.005～0.008%.
O：Less than 0.005%
O forms oxide in steel.Sometimes the oxide makes cyrystal boundary segregation and causes embrittlement of grain boundaries.In addition, O is to be easy to
Harder oxide system field trash is formed in steel and causes the element of brittle break.Need by O content be limited in 0.005% with
Under.The optimum range of O content is less than 0.0025%.O content is more few more preferred, and therefore the lower limit of O content is 0%.
P：Less than 0.025%
P segregations in carburizing, in austenite grain boundary, thus cause intercrystalline failure.It is, P makes the impact of carburizing steel part
Value reduces.It is then desired to P content is limited in less than 0.025%.The optimum range of P content is less than 0.01%.P content is got over
Few more preferred, therefore the lower limit of P content is 0%.But, in the case where the removing of P has carried out more than desirable degree, manufacture
Cost increases.Thus, the substantial lower limit of P content ordinarily be about 0.004%.
The steel of present embodiment is in order to improve impact value, it is also possible to the one or two kinds of in containing Mo, Cu and B with
On.But, it is not required in that containing these elements.
Mo：0～1.0%
Mo is used for suppressing P in cyrystal boundary segregation, is therefore to improving the effective element of the impact value of steel.If Mo contents exceed
1.0%, then its effect saturation, it is therefore desirable to which the upper limit of Mo contents is set as 1.0%.The lower limit of Mo contents is 0%, but
Steel is made to contain Mo and in the case of obtaining the effect above, preferably Mo contents are more than 0.05%.The scope preferably of Mo contents
For 0.05～0.25%.
Cu：0～1.0%
Cu is the effective element of the quenching degree to raising steel, and is to improve the impact value of steel by improving quenching degree
Element.If Cu contents are more than 1.0%, high-temperature ductility reduces, it is therefore desirable to which the upper limit of Cu contents is set as 1.0%.Cu contains
The lower limit of amount is 0%, but makes steel contain Cu and in the case of obtaining the effect above, preferably Cu contents are more than 0.01%.
The scope preferably of Cu contents is 0.01～0.2%.
B：0～0.005%
B has the effect of the cyrystal boundary segregation for suppressing P.In addition, B also has the raising effect of grain-boundary strength and intragranular intensity
And the raising effect of quenching degree, these effects improve the impact value of steel.If B content is more than 0.005%, its effect is satisfied
With, it is therefore desirable to the higher limit of B content is set as 0.005%.The lower limit of B content is 0%, but obtains making steel contain B
In the case of obtaining the effect above, preferably B content is more than 0.0002%.The scope preferably of B content be 0.0005～
0.003%.
The steel of present embodiment also may be used to can also prevent the reduction of impact value in the case where long-time carburizing has been carried out
With in scope shown below containing Nb, Ti and V in one or two kinds of more than.But, containing these elements not
It is required.
Nb：0～0.3%
Nb generates Nb carbonitrides in steel.Applying the so-called high-temperature carburizing that carburizing temperature is more than 980 DEG C
In the case of and in the case where the so-called long-time carburizing that carburizing time is more than 10 hours is applied, suitable by making
The Nb carbonitrides of amount be present in steel, austenite grain grain refined can be made, the reduction of impact value is prevented from.If Nb contents
More than 0.3%, then machinability is deteriorated, and the upper limit of Nb contents is set as 0.3%.The lower limit of Nb contents is 0%, but makes steel
In the case of the effect above is obtained containing Nb, preferably Nb contents are more than 0.005%.The scope preferably of Nb contents is
0.02～0.05%.
Ti：0～0.3%
Ti generates fine TiC and/or TiCS in steel.Applying the so-called height that carburizing temperature is more than 980 DEG C
In the case of warm carburizing and in the case where the so-called long-time carburizing that carburizing time is more than 10 hours is applied, lead to
The TiC and TiCS for crossing the amount for making suitable is present in steel, can make austenite grain grain refined, be prevented from the impact value of steel
Reduce.If Ti contents become many more than the precipitate of 0.3%, TiN main bodys, the fatigue properties of steel reduce.For the above-mentioned reasons, need
The higher limit of Ti contents is set as 0.3%.The lower limit of Ti contents is 0%, but obtains above-mentioned effect making steel contain Ti
In the case of fruit, preferably Ti contents are more than 0.005%.The scope preferably of Ti contents is 0.02～0.2%.
V：0～1.0%
V generates V carbonitrides in steel.In the feelings for applying the so-called high-temperature carburizing that carburizing temperature is more than 980 DEG C
Under condition and in the case of applying the so-called long-time carburizing that carburizing time is more than 10 hours, by making suitable amount
V carbonitrides be present in steel, austenite grain grain refined can be made, the reduction of the impact value of steel is prevented from.If V content surpasses
1.0% is crossed, then makes the machinability of steel be deteriorated.For the above-mentioned reasons, need for the higher limit of V content to be set as 1.0%.V content
Lower limit be 0%, but make steel contain V and in the case of obtaining the effect above, preferably V content is more than 0.01%.V content
Scope preferably be 0.03～0.1%.
The steel of present embodiment is in order to improve machinability, it is also possible in scope shown below contain Ca, Mg, Zr, Te
And more than the one or two kinds of in rare earth element.But, it is not required in that containing these elements.
Ca：0～0.01%
Ca reduces the fusing point of oxide, softens as temperature rises in machining, therefore improves cutting
Property.But, if Ca contents are generated in a large number more than 0.01%, CaS, machinability reduces.For the above-mentioned reasons, it may be desirable to by Ca
The higher limit of content is set as 0.01%.The lower limit of Ca contents is 0%, but obtains the feelings of the effect above making steel contain Ca
Under condition, preferably Ca contents are more than 0.0005%.The scope preferably of Ca contents is 0.0005～0.0015%.
Mg：0～0.01%
Mg is deoxidant element, generates oxide in steel.Also, the Mg systems oxide formed by Mg is easily made into MnS's
Crystallization and/or the core for separating out.In addition, the sulfide of Mg becomes the complex sulfide of Mn and Mg, so that MnS spheroidizings.This
Sample one, Mg are to controlling the dispersion of MnS, improving the effective element of machinability.But, if Mg contents are more than 0.01%, MgS
A large amount of generate, the machinability of steel reduces, it is therefore desirable for be that the higher limit of Mg contents is set as 0.01%.The lower limit of Mg contents
It is worth for 0%, but makes steel contain Mg and in the case of obtaining the effect above, preferably Mg contents are more than 0.0005%.Mg contents
Scope preferably be 0.0005～0.0015%.
Zr：0～0.05%
Zr is deoxidant element, generates oxide.Also, the Zr systems oxide formed by Zr be easily made into MnS crystallization and/
Or the core for separating out.So, Zr is to controlling the dispersion of MnS, improving the effective element of machinability.But, if Zr amounts exceed
0.05%, then its effect saturation, it is therefore desirable for be that the higher limit of Zr contents is set as 0.05%.The lower limit of Zr contents is
0%, but make steel contain Zr and in the case of obtaining the effect above, preferably Zr contents are more than 0.0005%.In addition, in order to promote
Enter the spheroidizing of MnS, the lower limit of particularly preferred Zr contents is set as more than 0.003%.
Te：0～0.1%
Te promotes the spheroidizing of MnS, therefore improves the machinability of steel.If Te contents are more than 0.1%, its effect saturation,
Therefore the higher limit of Te contents is set as 0.1% preferably.The lower limit of Te contents is 0%, but obtains making steel contain Te
In the case of the effect above, preferably Te contents are more than 0.0005%.The scope preferably of Te contents be 0.0005～
0.0015%.
Rare earth element：0～0.005%
Rare earth element generates sulfide in steel, and the sulfide becomes the precipitation core of MnS, and therefore rare earth element is to promote
Enter the element of the generation of MnS, improve the machinability of steel.But, if total content of rare earth element is more than 0.005%, sulfur
Compound becomes thick, reduces the fatigue strength of steel, it is therefore desirable to be set as the higher limit of total content of rare earth element
0.005%.The lower limit of total content of rare earth element is 0%, but is obtaining the effect above containing rare earth element
In the case of, total content of preferably rare earth element is more than 0.0001%.Total content of rare earth element preferably
Scope is 0.001～0.003%.
The steel of present embodiment contains above-mentioned alloying component, and remainder contains Fe and impurity.Above-mentioned alloy into
It is not right that as long as the element beyond point is mixed into the such case in steel its mixed volume as impurity from raw material and manufacture device
The characteristic of steel brings the level of impact, then allow.
Above the content of each alloying component contained by the steel of present embodiment is discussed.But, only by right
The content of each alloying component is individually controlled, it is impossible to realize following steel, and the steel is used for obtaining the no matter shape of carburizing steel part
How shape can obtain the carburizing steel part with sufficient impact value under single car-burization condition.Present inventors found that
Following opinion：Need to control the content of alloying component based on formula (1).
+ 32 × [Al%] >=8.5 (1) of 42 >=21 × [Si%]+40 × [Sn%] of+5 × [Ni%]
In formula (1), [Si%], [Ni%], [Sn%] and [Al%] is referred to, with quality % represent Si, Ni, Sn and
The content of Al.Hereinafter the basis of the derivation of formula (1) is illustrated.
First, the content of the below research that explanation the present inventors are carried out to evaluate the resistance to impact of carburized material.
First, C will be contained：0.20 mass %, Si：0.24 mass %, Mn：0.79 mass %, P：0.014 mass %, S：
0.015 mass %, Cr：1.21 mass %, Al：0.031 mass %, Ni：0.05 mass %, Sn：0 mass %, N：0.005 matter
Amount % and O：0.001 mass % and remainder be Fe and the carburizing steel definition of impurity on the basis of steel.Secondly, will figure
Shown in 2, overall dimensions be 10mm × 10mm × 55mm and with radius of curvature be 10mm and depth for 2mm arc-shaped
The charpy impact test piece of breach (recess) be defined as the charpy impact test piece 3 in present embodiment.For with benchmark steel
The charpy impact test piece 3 formed for material, first treatment temperature be 930 DEG C, process time be that 5 hours and carbon potential are
0.8 car-burization condition (hereinafter sometimes referred to benchmark car-burization condition) carries out gas carburizing, then carry out temperature for 150 DEG C and
Tempering time is the tempering of 90 minutes, and the Xia Shi impact absorbings by thus obtained carburized material at 25 DEG C can be defined as base
Quasi- impact value.
Also, by impact value than the value that is defined as：According to the car-burization condition that applies when standardized impact value is obtained
(i.e., benchmark car-burization condition) charpy impact test piece 3 is carried out by carburizing and tempering and is obtained 25 DEG C of carburized material when
Xia Shi impact absorbings can divided by obtained from standardized impact value be worth.
Said reference steel is the steel with the chemical composition equivalent to SCr420 for being often used as gear steel, and aftermentioned
Comparative example 26 steel identical.The gas carburizing carried out under said reference car-burization condition is to manufacture mechanical realization part
And the common Carburization Treatment for carrying out.
The side view (shape in the section vertical with the bearing of trend of breach) of above-mentioned charpy impact test piece 3 is represented
In Fig. 2.The radius of curvature of breach 2 is 10mm.The shape of the shape of charpy impact test piece 3 and common charpy impact test piece
(shape specified in such as JIS-Z2242 " the charpy impact test method of metal material ") is different.Charpy impact test piece 3
The shape of breach 2 be intended to the shape of the root portion for simulating gear determining.By carrying out to the test film with this breach
Charpy impact test, can estimate the impact resistance characteristic of the root portion of gear.Have the test film of this breach such as Japanese
It is widely used as what the impact resistance characteristic of the steel to carburizing was measured described in JP 2013-40376 publication like that
Test plate shape.In addition to the shape of charpy impact test piece 3, according to JIS-Z2242 " the Xia Shi impact examinations of metal material
Proved recipe method " has carried out the measurement of Xia Shi impact absorbings energy.The enforcement temperature of charpy impact test is 25 DEG C.Charpy impact test piece
3 are fabricated to by machining.
Then, the present inventors contain alloy to (wherein not considering the regulation related to formula 1) in the range of mentioned component
The various steel of element carry out forging, machining and carburizing, obtain the impact value ratio of the carburized material obtained from these steel.And
And, the present inventors are measured to the surface C concentration of each carburized material.
The measuring method of surface C concentration is below described.First, along with carried out gas carburizing under benchmark car-burization condition
The vertical direction cut-out Xia Shi impacts of the recess face (forming face jaggy) of the charpy impact test piece 3 of process and breach 2
Test film 3, is ground to section.The skeleton diagram of section is shown in Fig. 3.Then, towards charpy impact test
The short transverse of piece 3 is spaced with 5 μm in the region (surface C concentration measuring area 1) of 5～50 μm of the lower surface of breach 2
Measure C concentration.The measurement that C concentration has been carried out by EPMA.The size (beam diameter of EPMA) of measurement point is 5 μm of φ.
Thus, the meansigma methodss of obtained 10 measurement data are set as surface C concentration.The unit of surface C concentration is quality %.
Carburizing when so, to making the chemical composition and carburized material matter characteristic of steel on a large scale and systematically changing
That surface C concentration afterwards is measured as a result, present inventors found that following opinion：Surface C concentration is with alloy unit
Element addition change and correspondingly change.It is believed that the phenomenon is to penetrate into using alloying element and by carburizing steel surface
C between chemical interaction producing.The impact that Si, Ni, Al and Sn are particularly to surface C concentration is stronger, with
The increase of the content of these elements, surface C concentration are reduced.According to above-mentioned opinion, in the chemical composition of the steel of present embodiment
In, the relational of the content of Si, Ni, Al and Sn is specified by formula 1 such that it is able to control the carburizing of steel.
Following reason is based on, impact value ratio is needed for more than 1.2.As described above, it is capable of the design of change parts, so that
Fully improved by the impact resistance characteristic for making the carburized material used by carburizing steel part, so as to suppress using the same of quantity of material
When also assure that impact resistance destructive.In the technical field of mechanical realization part, in order to implement such design alteration, phase is needed
For impact value is improved by said reference impact value (having carried out the impact value of the SCr420 of carburizing under common car-burization condition)
20%.
As described above, there is dependency relation between impact value ratio and surface C concentration.Fig. 4 is the table for representing carburized material
The semi-log chart of the dependency relation between face C concentration and impact value ratio.In the diagram, the impact value of the data point under dotted line
Than being less than 1.2.As shown in Figure 4, it is known that：In order to obtain the carburized material of the impact value ratio with more than 1.2, needs will be in benchmark
Car-burization condition has carried out the surface C concentration of the carburized material of gas carburizing and has controlled below 0.75%.
Here, having carried out multiple regression analysis using the respective content of Si, Ni, Al and Sn as factor pair surface C concentration.
As a result, in the case where gas carburizing has been carried out with benchmark car-burization condition, being 0.75 matter as being used for obtaining surface C concentration
The critical condition of the carburized material of amount %, obtains following formula (1 ') and formula (2 ').
21 × [Si%]+5 × [Ni%]+32 × [Al%]=α (1 ') of+40 × [Sn%]
α=8.5 (2 ')
Fig. 5 is the chart for representing the relation between relation and α values between α values and surface C concentration and impact value ratio.
In Figure 5, the α values of the data point for keeping left than left dotted line are less than 8.5, and the α values of the data point that keeps right than right dotted line are more than 42.From this
Chart understand, if α values be more than 8.5, in the case where gas carburizing has been carried out with benchmark car-burization condition, surface C concentration into
Below 0.75 mass %.As α values increase, the surface C concentration of carburized material reduces, therefore corresponding to this, carburized material
Impact value increases therewith.It is preferred that α values are more than 12.
On the other hand, in the case where carburizing is significantly reduced, wearability is made significantly to drop as case hardness reduces
Low, the intensity as carburizing steel part becomes and insufficient.In the case where gas carburizing has been carried out with benchmark car-burization condition, the phase
It is higher than HV550 that hoped is the case hardness of carburized material.In order to reach this case hardness, need to carry out with benchmark car-burization condition
The surface C concentration of the carburized material of gas carburizing is more than 0.4 mass %.Also, understand：In order that with benchmark car-burization condition
The surface C concentration for having carried out the carburized material of gas carburizing is more than 0.4 mass %, and it is less than 42 to need α values.Additionally, entering one
Step has preferably carried out the surface C concentration of the carburized material of gas carburizing as more than 0.55 mass % with benchmark car-burization condition, in order to
The surface C concentration is reached, preferably α values are less than 25.
The preferred gas carburizing of method for carburizing for obtaining carburizing steel part from the steel of present embodiment (can also be modified
Either type in stove mode and dripping type).In addition, nitriding can also be implemented in addition to implementing carburizing.
Additionally, also sometimes the effective case depth of the metewand as carburizing steel part is studied, but differential
Characteristic as the vehicle gear such as gear required by part compared to effective case depth more with case hardness consumingly
Associated.Thus, it is controlled to appropriate level, thus enables that case hardness most using the surface C concentration by carburizing steel part
The steel of the present embodiment of optimization, can obtain favourable effect in terms of industrial practicality.
The steel of present embodiment can also for example be made into pole steel first by hot rolling, then, be applied in forging,
Machining and be made for the shape of gear etc., be then carried out carburizing and quenching and make carburizing steel part.
Embodiment
Then, illustrate the condition in embodiments of the invention, but embodiment be in order to confirm the present invention exploitativeness with
And effect and a condition example adopting, the present invention is not limited to a condition example.Master without departing from the present invention
Purport simultaneously reaches the purpose of the present invention, and the present invention can adopt various conditions.
Various steel billet forgings with the chemical composition shown in table 1-1 and table 1-2 are being stretched as length direction
After square rod shape of the sectional dimension for vertical 50mm and horizontal 50mm (50mm × 50mm), implement all heat-treated and normalizing (normalizing)
Afterwards, the sectional dimension for being further divided into 4 length directions is the square rod shape of vertical 25mm and horizontal 25mm.From being obtained
The each rod for obtaining acquires the overall dimensions shown in Fig. 2 and is 10mm × 10mm × 55mm and there is radius of curvature along its center axis
For 10mm and depth for the breach (recess) of the arc-shaped of 2mm charpy impact test piece.The test plate shape and above-mentioned summer
Family name's impact test piece 3 is identical.Then, Carburization Treatment is implemented to the charpy impact test piece.Enforcement beyond comparative example 29
In example and comparative example, with treatment temperature be 930 DEG C, process time is 5 hours and carbon potential is that 0.8 car-burization condition is carried out
Gas carburizing.The treatment conditions are identical with said reference car-burization condition.In comparative example 29, with treatment temperature as 930 DEG C, process
Time is 5 hours and carbon potential is that 0.6 car-burization condition has carried out gas carburizing.It is that 150 DEG C and tempering time are in temperature
Tempering is implemented under conditions of 90 minutes.
After tempering, the surface C concentration of each sample is measured.The measuring method of surface C concentration is as described below.First, edge
The direction cut-out charpy impact test vertical with the recess face of charpy impact test piece (forming face jaggy) and breach
Piece, is ground to section.Then, the short transverse towards charpy impact test piece apart from breach 2 lower surface 5
In～50 μm of region (surface C concentration measuring area 1) with 5 μm of interval measurements C concentration.C concentration has been carried out by EPMA
Measurement.The size (beam diameter of EPMA) of measurement point is set as 5 μm of φ.Thus, by the flat of 10 measurement data for obtaining
Average is used as surface C concentration.The unit of surface C concentration is quality %.
In addition, implementing charpy impact test after tempering, Xia Shi impact absorbings energy (impact value) are measured.Except
Beyond the shape of the recess of charpy impact test piece, implemented for 25 DEG C with test temperature according to the method for JIS-Z2242 defineds
Charpy impact test.
Also, by by the impact value of each sample divided by comparative example 26 impact value calculating the impact value of each sample
Than.Additionally, the steel of comparative example 26 is said reference steel.
Additionally, for the wearability for evaluating each sample, carrying out abrasion test to each sample and being surveyed to wearing away depth
Amount.The square rod of the 50mm × 50mm after the normalizing being fabricated to from method described above acquires following shapes along its center axis
Abrasion test piece：There is a diameter of 26mm and length for the cylindrical portion of 28mm and there is same central axis with the cylindrical portion
A diameter of 24mm and length for 51mm cylindric grip.Grip is configured in the two ends of the length direction of cylindrical portion.
Also, to the abrasion test piece implementing Carburization Treatment with aforesaid charpy impact test piece identical condition.Abrasion depth
Refer to, roller is pressed on the cylindrical portion of abrasion test piece and makes the roller 1,000,000 times be have rotated afterwards in the generation of abrasion test piece
The depth of abrasion.Abrasion test condition is as described below.Sample of the abrasion depth less than 30 μm is judged as with sufficiently wear-resisting
Property.
The material of roller：Bearing steel (SUJ2)
The hardness of roller：HV700～800
Roller diameter：130mm
Roller width：18mm
Roll shape：It is formed on the outer periphery the convex surface of R=150mm
Roller contact force：Hertz stress 1500MPa (face pressure)
Slip rate：- 100%
Surface C concentration, impact value ratio and the abrasion depth of each sample is shown in table 2.Comparative example 26 have equivalent to
It is typically used as the chemical composition of the SCr420 of the JIS-G4053 defineds of gear steel ,+5 × [Ni%]+40 of 21 × [Si%]
+ 32 × [Al%] of × [Sn%] is 6.3, and in the case where gas carburizing has been carried out with benchmark car-burization condition, impact value is 10J/
cm2.Can it is clear that：The impact value ratio of example 1～25 is more than 1.3, with excellent impact strength.For example invent
+ 32 × [Al%] of in example 1 21 × [Si%]+40 × [Sn%] of+5 × [Ni%] is 41.1, and surface C concentration is 0.46%, because
This obtains good impact value.
On the other hand, comparative example 26～35 does not have gratifying characteristic.
Comparative example 26 and 28 does not contain Sn, and therefore carburizing is exceedingly carried out, compared with embodiment, only relatively low
Impact value.In addition, prescribed limit of the Sn contents of comparative example 31 less than the present invention, therefore same with comparative example 26 and 28, ooze
Carbon is exceedingly carried out, compared with embodiment, only relatively low impact value.
With regard to comparative example 27, in the prescribed limit of the content of each alloying element in the present invention, but 21 × [Si%]+5 ×
Prescribed limits of+32 × [Al%] of [Ni%]+40 × [Sn%] beyond the present invention.Thus, the wearability of comparative example 27 is low.
With regard to comparative example 30, in the prescribed limit of the content of each alloying element in the present invention, but 21 × [Si%]+5 ×
Prescribed limits of+32 × [Al%] of [Ni%]+40 × [Sn%] less than the present invention, therefore carburizing are exceedingly carried out.Thus,
Comparative example 30 compared with embodiment, only relatively low impact value.
With regard to comparative example 32, Sn contents have exceeded the prescribed limit of the present invention, and therefore high-temperature ductility is reduced.Thus, than
Multiple compared with crackle on the surface of the carburized material obtained in example 32.
With regard to comparative example 33, Ni contents exceed the prescribed limit of the present invention, therefore intensity decreases.Thus, comparative example 33
Wearability low.
With regard to comparative example 34, Al content exceedes the prescribed limit of the present invention, therefore generates embrittlement.Thus, comparative example 34
Impact value than low.
Reference example 29 is and 26 identical steel of comparative example, but car-burization condition is different, set carbon potential (0.6 Carburization Treatment)
Must be relatively low, it may thus be appreciated that：Surface C concentration is relatively low, obtains good impact value.But, carbon potential is set in actual production
Fixed relatively low productivity ratio can be caused to reduce, therefore not good.
Table 1-1
Mark "-" in ※ tables represents that the content of element is 0 or is considered the amount of impurity.
Table 1-2
Mark "-" in ※ tables represents that the content of element is 0 or is considered the amount of impurity.
Table 2
The car-burization condition of ※ comparative examples 29 is different from other examples
Symbol description
1 surface C concentration measuring area
2 breach (recess)
3 charpy impact test pieces (carburized material)
Claims (6)
1. a kind of carburizing steel, it is characterised in that its chemical composition is contained in terms of quality %：
C：0.16～0.30%,
Si：0.01～2.0%,
Mn：0.35～1.45%,
Cr：0.05～3.0%,
Al：0.001～0.2%,
Ni：0.04～5.0%,
Sn：0.015～1.0%,
S：0.004～0.05%,
N：0.003～0.03%,
O：Less than 0.005%,
P：Less than 0.025%,
Mo：0～1.0%,
Cu：0～1.0%,
B：0～0.005%,
Nb：0～0.3%,
Ti：0～0.3%,
V：0～1.0%,
Ca：0～0.01%,
Mg：0～0.01%,
Zr：0～0.05%,
Te：0～0.1% and
Rare earth element：0～0.005%,
Also, remainder is Fe and impurity,
When the content of Si, Ni, Al and Sn is expressed as in terms of quality % [Si%], [Ni%], [Al%], [Sn%], full
Sufficient following formula (1),
+ 32 × [Al%] >=8.5 (1) of 42 >=21 × [Si%]+40 × [Sn%] of+5 × [Ni%].
2. carburizing steel according to claim 1, it is characterised in that the chemical composition contains Mo in terms of quality %：
0.05～1.0%, Cu：0.01～1.0% and B：One or more in 0.0002～0.005%.
3. carburizing steel according to claim 1 and 2, it is characterised in that the chemical composition contains Nb in terms of quality %：
0.005～0.3%, Ti：0.005～0.3% and V：One or more in 0.01～1.0%.
4. carburizing steel according to claim 1 and 2, it is characterised in that the chemical composition contains Ca in terms of quality %：
0.0005～0.01%, Mg：0.0005～0.01%, Zr：0.0005～0.05%, Te：0.0005～0.1% and terres rares
Element：One or more in 0.0001～0.005%.
5. carburizing steel according to claim 3, it is characterised in that the chemical composition contains Ca in terms of quality %：
0.0005～0.01%, Mg：0.0005～0.01%, Zr：0.0005～0.05%, Te：0.0005～0.1% and terres rares
Element：One or more in 0.0001～0.005%.
6. a kind of carburizing steel, it is characterised in that its chemical composition is contained in terms of quality %：
C：0.16～0.30%,
Si：0.01～2.0%,
Mn：0.35～1.45%,
Cr：0.05～3.0%,
Al：0.001～0.2%,
Ni：0.04～5.0%,
Sn：0.015～1.0%,
S：0.010～0.05%,
N：0.003～0.03%,
O：Less than 0.005%,
P：Less than 0.025%,
Mo：0～1.0%,
Cu：0～1.0%,
B：0～0.005%,
Nb：0～0.012%,
Ti：0～0.035%,
Ca：0～0.01%,
Mg：0～0.01%,
Zr：0～0.05%,
Te：0～0.1% and
Rare earth element：0～0.005%,
Also, remainder is Fe and impurity,
When the content of Si, Ni, Al and Sn is expressed as in terms of quality % [Si%], [Ni%], [Al%], [Sn%], full
Sufficient following formula (2),
+ 32 × [Al%] >=8.5 (2) of 42 >=21 × [Si%]+40 × [Sn%] of+5 × [Ni%].
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| Application Number | Priority Date | Filing Date | Title |
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| JP2012288131 | 2012-12-28 | ||
| JP2012-288131 | 2012-12-28 | ||
| PCT/JP2013/084708 WO2014104113A1 (en) | 2012-12-28 | 2013-12-25 | Steel for carburizing |
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| CN104884660B true CN104884660B (en) | 2017-03-15 |
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| KR (1) | KR101745224B1 (en) |
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| CN105349897A (en) * | 2015-11-10 | 2016-02-24 | 宁波市鸿博机械制造有限公司 | Steel slide valve |
| CN105420456A (en) * | 2015-11-10 | 2016-03-23 | 宁波市鸿博机械制造有限公司 | Manufacturing method for pump shaft |
| CN105420467A (en) * | 2015-11-10 | 2016-03-23 | 宁波市鸿博机械制造有限公司 | Manufacturing method for steel slide valve |
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| JP2006307271A (en) * | 2005-04-27 | 2006-11-09 | Kobe Steel Ltd | Case hardening steel having excellent crystal grain coarsening resistance and cold workability and in which softening can be obviated, and method for producing the same |
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| CN104884660A (en) | 2015-09-02 |
| WO2014104113A1 (en) | 2014-07-03 |
| JP5862802B2 (en) | 2016-02-16 |
| KR101745224B1 (en) | 2017-06-08 |
| KR20150086365A (en) | 2015-07-27 |
| JPWO2014104113A1 (en) | 2017-01-12 |
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