CN101215665A - Steel having excellent machinability and production method therefor - Google Patents
Steel having excellent machinability and production method therefor Download PDFInfo
- Publication number
- CN101215665A CN101215665A CNA2007101960130A CN200710196013A CN101215665A CN 101215665 A CN101215665 A CN 101215665A CN A2007101960130 A CNA2007101960130 A CN A2007101960130A CN 200710196013 A CN200710196013 A CN 200710196013A CN 101215665 A CN101215665 A CN 101215665A
- Authority
- CN
- China
- Prior art keywords
- steel
- machinability
- mns
- cooling
- equal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Abstract
The present invention provides steel superior in machinability comprised of, by wt %, C: 0.005 to 0.2%, Si: 0.001 to 0.5%, Mn: 0.2 to 3.0%, P: 0.001 to 0.2%, S: 0.03 to 1.0%, T.N: 0.002 to 0.02%, T.O: 0.0005 to 0.035%, and the balance of Fe and unavoidable impurities, said steel satisfying one or both of Mn/S in the steel being 1.2 to 2.8 or an area ratio of pearlite over a grain size of 1 mum in a microstructure of the steel being not more than 5%.
Description
The application is that application number is 200380103425.5, the applying date is on November 14th, 2003, enter State Period date the dividing an application that be on May 16th, 2005, denomination of invention for the patent application of " steel of excellent in machinability and manufacture method thereof ".
Technical field
The invention relates to the steel and the manufacture method thereof that are used for automobile or common mechanical etc., the steel and the manufacture method thereof of the excellent in machinability that life tools during particularly about cutting and cutting surface smooth finish and the smear metal property handled are good.
Background technology
Common mechanical or automobile are to be made up by multiple parts to make, but its parts, are made through the smear metal operation in many occasions from the viewpoint of claimed accuracy and manufacturing efficient.At this moment, require cost to reduce and boost productivity, concerning steel, also require to improve machinability.Pay attention to machinability especially in the past and develop SUM23 and SUM24L.Known so far, in order to improve machinability, it is effective adding machinabilities raising elements such as S, Pb.But because the person's of needs difference, Pb often avoids using as environmental pressure, has the tendency that lowers its usage quantity.
Even up to the present, under the situation of not adding Pb, also use as S and under the cutting environment, form the skill and technique that the soft inclusion of MnS improves machinability.But in so-called low-carbon (LC) Lead Treated Steel SUM24L, add the S with amount with low-carbon (LC) sulphur free-cutting steel SUM23.Therefore need to add above in the past S amount.But, add the S of volume, except only making the MnS alligatoring, not only can not be formed on machinability and improve and go up effective MnS and distribute, and in rolling, casting etc., become the destruction starting point, cause the problem that rolling defect etc. is made more.Have again,, built-up edge takes place easily adhere to, follow coming off and the smear metal separation phenomenon of built-up edge based on the sulphur free-cutting steel of SUM23, concavo-convex in the cutting surface generation, surface smoothness generation deterioration.Therefore, from the viewpoint of machinability, also be the problem that the precision that caused by the surface smoothness deterioration reduces.On the smear metal property handled, smear metal is short, mutilator also is counted as well easily, but only adds S, and the ductility of matrix is big, thereby can not be cut off fully, and can not obtain very big improvement.
Have again, element beyond the S, Te, Bi, P etc. improve element as machinability, also be known, though can improve machinability to a certain degree, but when rolling or forge hot, also be easy to generate crackle, thereby wish that its content is as far as possible few, this spy open flat 9-71840 communique, the special 2000-160284 of hope communique, spy open 2000-219936 communique, spy open had in the 2001-329335 communique open.
Have again, open in the flat 11-222646 communique the spy and proposed, by with the length that connects into the shape of roughly connecting more than or equal to sulfide or the multiple sulfide of 20 μ m separately more than or equal to the sulfide group of 20 μ m at 1 millimeter
2Exist in the visual field of rolling direction section on 30 or its, improve the method that property is handled in smear metal.But, comprise that about dispersion in fact manufacture method does not all mention, and can not expect from its composition system to the most effective ultra micro meter level of machinability sulfide.
In addition, opening in the flat 11-293391 communique the spy and to have proposed, is 50 μ m or following and per 1 millimeter by the mean sizes that makes sulfide-based inclusion
2Existence improves the method for the smear metal property handled more than or equal to 750 these sulfide-based inclusiones.But,, open in the flat 11-222646 communique equally without any mentioning the dispersion of the most effective ultra micro meter level of machinability sulfide about in fact the spy, and manufacturing technology and investigation method about recognizing this, also not record.
On the other hand, about the cutting tool life-span, because directly efficient etc. is made in influence, therefore often paid close attention to, but in machinability, what the difficulty of technology was high also is surface smoothness, about surface smoothness, therefore cut the influence of the person's character of material, it is difficult making surface smoothness reach more than in the past the steel.This surface smoothness is directly related with the performance of parts, so the reason that increases of the fraction defective of the deterioration of surface smoothness when becoming the reduction of component capabilities and goods and making, often than more being paid attention to life tools.On this meaning, Lead Treated Steel in the past is good, compares with the sulf onyl free-cutting steel, and not only life tools, and surface smoothness are also good, thereby in order to prevent the reduction of component capabilities, are used more.
In about technology for the steel that improves surface smoothness, the easy cutting element of general most interpolation as Pb, Bi, but outside this, for example as open flat 5-345951 communique the spy in, see, be refined to by the mean size that makes the MnS inclusion and be less than or equal to 50 μ m and guarantee surfaceness, long-pending in ferrite matrix, to have 0.20～1.0% average section: 5～30 μ m
2Graphite be good graphite free-cutting steel of life tools of feature and machined surface smooth finish etc.
But even these means, the surface smoothness that obtains more than or equal in the past Lead Treated Steel also is difficult, so-called low-carbon (LC) Lead Treated Steel SUM24L, and up to the present surface smoothness still belongs to good.Its reason is inferred as, the fine dispersion level of the inclusion under these regulations, but be that particle to mean diameter 3 μ m degree carries out processing treatment, its homodisperse is inadequate, therefore become built-up edge takes place easily, can not as in the past Lead Treated Steel etc., improve surface smoothness.
Summary of the invention
The invention provides, one side is avoided bad in rolling or the forge hot, and one side is improved life tools and surface smoothness, has and in the past the equal or above machinability of low-carbon (LC) Lead Treated Steel steel that surface smoothness is good and manufacture method thereof.
Cutting is to make the isolating breakoff phenomenon of smear metal, promotes that cutting is an emphasis.Be in particular and obtained surface of good smooth finish,, become easy and make to destroy by making the matrix embrittlement, when prolonging life tools, by doing one's utmost to suppress inhomogeneous in the steel, stable breakoff phenomenon also takes place thus, to suppress the concavo-convex of cutting surface on microcosmic.A kind of distribution that is conceived to the steel Medium pearlite specifically is provided, and C disperses to form stable destruction equably as nodular troostite (being cementite strictly speaking) in the steel by making, and foundes concavo-convex few cutting surface thus, and feasible manufacture method.Main points of the present invention are as follows.
(1) a kind of steel of excellent in machinability is characterized in that, it be by quality % by
C：0.005～0.2％、
Si：0.001～0.5％、
Mn：0.2～3.0％、
P：0.001～0.2％、
S：0.03～1.0％、
Total N:0.002～0.02%,
Total O:0.0005～0.035%,
Surplus is the steel that Fe and unavoidable impurities constitute, satisfy Mn/S in the steel and be 1.2～2.8 or particle diameter surpasses 1 μ m in the microstructure of steel pearlitic area occupation ratio be either party or two sides that are less than or equal in 5%, and the surface smoothness Rz of steel is less than or equal to 11 μ m.
(2) a kind of steel of excellent in machinability, it is characterized in that, contain C:0.005～0.2%, Mn:0.3～3.0%, S:0.1～1.0% by quality %, about using the MnS that takes with the extraction replica method of transmission electron microscope observation, in the section parallel, be that to have density be more than or equal to 10000/millimeter for the MnS of 0.1～0.5 μ m with diameter of equivalent circle with the rolling direction of steel
2, and the cutting surface smooth finish Rz of steel becomes and is less than or equal to 11 μ m.
(3) as the steel of record in (1) or (2), it is characterized in that also containing B:0.0005～0.05% quality.
(4) steel as putting down in writing in (1), it is characterized in that, about using the MnS that takes with the extraction replica method of transmission electron microscope observation, in the section parallel, be that to have density be more than or equal to 10000/millimeter for the MnS of 0.1～0.5 μ m according to diameter of equivalent circle with the rolling direction of steel
2
(5) steel as putting down in writing in (1), it is characterized in that, also contain the S amount is limited in 0.25～0.75 quality %, the B amount is limited in 0.002～0.014 quality %, and S and B content satisfy the interior S and the B amount of A shown in Figure 4, B, C, D area surrounded of following formula 1, and comprise the sulfide of separating out BN in MnS.
(B-0.008)
2/ 0.006
2+ (S-0.5)
2/ 0.25
2≤ 1... formula (1)
(6) in the steel as record in (1) or (2), it is characterized in that % also contains by quality
V：0.05～1.0％、
Nb：0.005～0.2％、
Cr：0.01～2.0％、
Mo：0.05～1.0％、
W：0.05～1.0％、
Ni：0.05～2.0％、
Cu：0.01～2.0％、
Sn：0.005～2.0％、
Zn：0.0005～0.5％、
Ti：0.0005～0.1％、
Ca：0.0002～0.005％、
Zr：0.0005～0.1％、
Mg：0.0003～0.005％、
Te：0.0003～0.05％、
Bi：0.005～0.5％、
Pb：0.01～0.5％、
Al：≤0.015％
1 kind or more than or equal to 2 kinds.
(7) manufacture method of the steel of the excellent in machinability of putting down in writing in each of a kind of (1)～(3) is characterized in that, will have the molten steel casting of composition of (1) record after, with 10～100 ℃/minute speed of cooling cooling, from A
3O'clock carry out cooling after the hot rolling with 0.5 ℃/second or speed of cooling more than it to 550 ℃ scope.
(8) manufacture method of the steel of the excellent in machinability of a kind of (4) or (5) record, it is characterized in that, will have the molten steel casting of composition of (2) record after, with 10～100 ℃/minute speed of cooling cooling, then the hot rolled outlet temperature is limited in 1000 ℃ or more than it, from A
3O'clock carry out cooling after the hot rolling with 0.5 ℃/second or speed of cooling more than it to 550 ℃ scope.
(9) manufacture method of the steel of the excellent in machinability of putting down in writing in each of a kind of (1)～(6) is characterized in that, after the cooling after hot rolling, will be limited in 750 ℃ or below it again for the Heating temperature of adjusting hardness.
(10) manufacture method of the steel of the excellent in machinability of putting down in writing in each of a kind of (7)～(9) is characterized in that above-mentioned steel also contains by quality %
V：0.05～1.0％、
Nb：0.005～0.2％、
Cr：0.01～2.0％、
Mo：0.05～1.0％、
W：0.05～1.0％、
Ni：0.05～2.0％、
Cu：0.01～2.0％、
Sn：0.005～2.0％、
Zn：0.0005～0.5％、
Ti：0.0005～0.1％、
Ca：0.0002～0.005％、
Zr：0.0005～0.1％、
Mg：0.0003～0.005％、
Te：0.0003～0.05％、
Bi：0.005～0.5％、
Pb：0.01～0.5％、
Al：≤0.015％
In more than a kind or a kind.
Description of drawings
Fig. 1 is the microphotograph of the ferritic-pearlitic tissue of expression steel of the present invention.
Fig. 2 (a) is the microphotograph of fine dispersion state of MnS in the expression steel of the present invention, and Fig. 2 (b) is a microphotograph of representing the existence of the thick MnS in the steel in the past.
Fig. 3 is the figure of the relation of expression perlite area occupation ratio and surface smoothness.
Fig. 4 is the figure of the S amount and the optimum scope that B measures of expression steel of the present invention.
Fig. 5 be expression with MnS of the present invention as principal constituent, the transmission electron microscope replica photo of the form of compound sulfide of separating out BN.
Fig. 6 is the figure of the EDX analytical results of expression BN.
Fig. 7 is the figure of expression cut-in type cutting process.
Embodiment
The present invention, not adding lead, for obtain sufficient machinability, when particularly surface of good smooth finish makes the matrix embrittlement, lubricated good for the contact surface that makes instrument/cutting material, it is feature that volume ground adds B.In addition, also relatively volume ground adds S, critically controls the ratio of the addition of Mn and S in order to make its fine dispersion.In addition, about the microstructure of steel, also be controlled at the perlite of seeing in the carbon steel in the past.Promptly control C addition suppresses thick pearlitic separating out in chemical ingredients, perhaps contain C for a long time, suppressing the steel of the excellent in machinability that thick perlite particulate generates, the perlite band that promptly suppressed often to see at naturally cooling generates by thermal treatment.
Then, the qualification reason of the composition of steel of regulation in the present invention is described.
C is relevant with the oxygen amount in the steel with the fundamental strength of steel, therefore machinability is had bigger influence.Volume ground adds C, improve intensity but machinability is reduced, so its upper limit is defined as 0.2%.On the other hand, generate, suppress the disadvantage of the solid solution oxygen under the high temperature such as fine pores in the process of setting, need to control in right amount oxygen making amount in order to prevent the hardening oxidation thing that machinability is reduced.If merely by blowing the C amount is too lowered, not only cost increases, and oxygen amount volume ground is residual in the steel, becomes the reason of unfavorable conditions such as fine pores.Therefore, with the C amount 0.005% that can prevent unfavorable conditions such as fine pores easily as lower limit.The best lower limit of C amount is 0.05%.
The excessive interpolation of Si generates the hardening oxidation thing, machinability is reduced, but the interpolation of appropriateness makes oxide compound generation softening, and do not reduce machinability.Its upper limit is 0.5%, more than this, generates the hardening oxidation thing.0.001% when following, when the softening of oxide compound became difficulty, industrial cost increased.
Mn be for make sulphur in the steel as MnS and fixing disperse necessary.To be that oxide compound softens in the steel in order making in addition, to make oxide compound innoxious necessary.Its effect also depends on the S amount of interpolation, but less than 0.2% o'clock, can not fix fully as MnS adding S, and S forms FeS and becomes fragile.If the Mn quantitative change is big, then the hardness of matrix becomes big, and machinability or cold-workability reduce, so the upper limit is defined as 3.0%.
P is in steel, and it is big that the hardness of matrix becomes, and not only cold-workability, and hot workability or casting characteristics also reduce, so its upper limit must be defined as 0.2%.On the other hand, it is to improve effective elements on the machinability, thereby lower value is defined as 0.001%.
S combines with Mn, exists with the MnS inclusion.MnS can make machinability improve, but the MnS that has extended produces one of anisotropic reason when forging.Big MnS must avoid, but from improving the viewpoint of machinability, the interpolation of volume is preferred.Therefore preferably make the fine dispersion of MnS.Machinability is being brought up to more than the sulphur free-cutting steel in the past that does not add Pb, the interpolation more than or equal to 0.03% is necessary.On the other hand,, not only can not avoid the generation of thick MnS if surpass 1%, and since the casting characteristics that cause by FeS etc., the deterioration of thermal distortion characteristic crack in the mill, therefore with 1% as the upper limit.
If B separates out as BN, on the raising machinability, just produce effect.These effects less than 0.0005% o'clock not remarkable, add even surpass 0.05%, its effect also reaches capacity, if separate out BN too much, casting characteristics, thermal distortion characteristic be deterioration on the contrary, cracks in the mill.Therefore with 0.0005～0.05% as its scope.
In the present invention, especially by above-mentioned S measures and oval interior A, B, C, the D area surrounded shown in Figure 4 of B amount extremely to limit, promptly by being limited to following formula (1)
(B-0.008)
2/ 0.006
2+ (S-0.5)
2/ 0.25
2≤ 1... formula (1)
The zone, and obtain the best characteristic.
N (total N) makes hardening of steel under the situation of solid solution N.In cutting,, the life-span of instrument is reduced, but the effect of improving cutting surface smooth finish is also arranged especially because the dynamic strain timeliness is hardened near blade.In addition, combine generation BN with B, improve machinability.Less than 0.002% o'clock, can't see the surface smoothness that causes by solid solution nitrogen and improve effect or improve effect by the machinability that BN causes, therefore with 0.002% as lower limit.In addition, if surpass 0.02%, solid solution nitrogen exists with regard to volume, therefore reduces life tools on the contrary.And in casting way, generate bubble, and become the reason of defective etc.Therefore in the present invention, with 0.02% as the upper limit.
Under the situation that O (total O) exists with unbound state, when cooling, become bubble, and become the reason of fine pores.In addition,, be suppressed at deleterious hardening oxidation thing on the machinability, also need to suppress in order to make the oxide compound softening.And then, when making the fine dispersion of MnS, utilize oxide compound as separating out nuclear.Less than 0.0005% o'clock, can not make the fine dispersion of MnS fully, and produce thick MnS, on mechanical property, also bring bad influence, therefore with 0.0005% as lower limit.If have the oxygen amount to surpass 0.035% again, in casting, just form bubble, and become fine pores, so its upper limit be defined as 0.035%.
Then, illustrate the perlite area occupation ratio is defined as 5% or reason below it.In general, when the temperature of carbon steel more than transformation temperature cooled off, become the ferritic-pearlitic tissue.Become the less steel of C amount of object of the present invention, from transformation temperature (A
3Point) behind the Yi Shang temperature air cooling, cuts, and carry out mirror ultrafinish,, just can observe its inner microstructure as Fig. 1 if carry out etch with nitric acid ethanol.Black particle is the complex tissue that is called pearlitic ferrite and cementite, but usually, the black particle of seeing by the etch of nitric acid ethanol is a hard than the white ferrite crystal grain of seeing like this, in the distortion/fracture behaviour of steel, shows the movement different with ferrite crystal grain partly.This in the disrumpent feelings behavior of smear metal, hinders homogeneous deformation/disrumpent feelings in cutting, thereby relevant greatly with the generation of built-up edge, and then makes the surface smoothness deterioration in face of tool.Therefore, do one's utmost to get rid of result from the tissue odds of C even be important.Therefore will regard the perlite particle as with the black particle of nitric acid ethanol etch, if this perlite particle is too much, just causes that tissue odds is even, and become the reason of surface smoothness deterioration, therefore its area occupation ratio is limited in and is less than or equal to 5%, and surface smoothness Rz is limited in and is less than or equal to 11 μ m.The relation of expression perlite area occupation ratio and surface smoothness in Fig. 3.
Here, narrated about the details of measuring method.The sample that will cut off, imbed resin along vertical section (L section) of the steel after rolling or the forging carries out mirror ultrafinish, carries out the etch of nitric acid ethanol.Use image processing apparatus, to become removal in the black thing with the etch of nitric acid ethanol the particle diameter (diameter of equivalent circle) behind the gray MnS resolve more than or equal to the particle of 1 μ m, obtain its area occupation ratio.When the picture processing that area occupation ratio is measured, by setting and the black perlite that can see corresponding " threshold value ", it is deep or light to adjust image, by eliminating the gray inclusion (MnS etc.) that can see from image, only with perlite as determination object.The minimum perlite of the identification of this moment is about 1 μ m, but less than the perlite of 1 μ m, machinability is not brought influence, even therefore can not discern, and also not influence.
The mensuration visual field among the present invention is with more than or equal to 400 times multiplying power, to 0.2 millimeter in 1 visual field
2(0.4 millimeter * 0.5 millimeter) carries out 20 visuals field mensuration, is to add up to 4 millimeters
2Area, calculate the perlite area occupation ratio.
About Mn/S, known already that it was bigger to the hot rolling influence, usually,, will reduce the manufacturing of steel greatly if do not reach Mn/S＞3.Its reason is to have generated FeS, but finds in the present invention, and the zone at low C and high S can make its ratio further be reduced to Mn/S:1.2～2.8.Less than 1.2 o'clock, the FeS volume generated, and hot rolling is reduced terrifically, and reduce manufacturing greatly at Mn/S.
Replica method is used in expression in Fig. 2, with the example of the fine MnS of transmission electron microscope observation Mn/S≤2.8 and Mn/S＞2.8 o'clock.In Mn/S＞2.8 o'clock, only form the thick MnS shown in Fig. 2 (b), surfaceness is diminished.On the other hand, be constrained at 1.2～2.8 o'clock, obtain generating the fine MnS shown in Fig. 2 (a) at Mn/S.
After utilizing the casting of continuous casting or steel ingot,, just can increase the number of this fine MnS by being greater than or equal to 900 ℃ heating repeatedly.
Then, in the form of MnS and size thereof with in distributing, about being that the density that exists of 0.1～0.5 μ m is defined as more than or equal to 10000/millimeter with diameter of equivalent circle
2Reason be illustrated.
MnS is the inclusion that improves machinability, disperses with fine, high-density, improves machinability significantly.In order to bring into play its effect, be that the MnS of 0.1～0.5 μ m exists the density need be more than or equal to 10000/millimeter by diameter of equivalent circle
2Usually distribute with observation by light microscope MnS sulfide, measure its size, density.To MnS sulfide that should size, the observation under opticmicroscope is impossible confirm that (TEM) just can be observed with transmission electron microscope.Even do not have difference on the size under opticmicroscope, the density, also being with the MnS of the size of seeing significant difference in the tem observation sulfide as principal constituent, in the present invention, is by control MnS, make to exist form to quantize, and seek differential with prior art.
For making the MnS that surpasses above-mentioned size with more than or equal to 10000/millimeter
2Density exist, be necessary to add the S of the volume that surpasses scope of the present invention, if but volume add, a large amount of probability that exist of then thick MnS also uprise, and become the anisotropic reason when forging.With the S addition of the scope stipulated among the present invention, if MnS surpasses this size, the amount of MnS is just not enough, can not keep and improve the necessary density of machinability.In addition, the MnS that minimum diameter 0.1 μ m is following does not exert an influence to machinability in fact.Therefore, be that the density that exists of the MnS of 0.1～0.5 μ m exists 10000/millimeter with diameter of equivalent circle
2Be necessary.For size, the density that obtains this MnS, except controlled chilling speed,, then more effective if make contained Mn and the ratio of S reach 1.5～2.5.
Have, in the present invention, among the above-mentioned MnS, as shown in Figure 5, importantly 10 quality % wherein or its above boron nitride (BN) have the form of compound sulfide of separating out again.
BN separates out at crystal boundary usually easily, is difficult for disperseing equably in matrix.Can not be created in for this reason and improve the even embrittlement of necessary matrix on the machinability, promptly can not bring into play the effect of BN fully.Become separating out the position and also be that effective MnS disperses equably being necessary of BN for BN being disperseed equably, making in matrix improving on the machinability in matrix.BN and MnS are compound to separate out by making, and reaches the homodisperse of BN, and improves machinability significantly.For this reason, need be to being less than 10% or BN more than it and MnS is compound separates out.
At this said BN, be meant in Fig. 5 and represent with TEM replica photo, analyze the B at peak of the B that confirms clearly and N and the compound of N at the EDX of Fig. 6.
Moreover, so-called MnS not only comprises pure MnS, and be included in and comprise MnS's in the main body, Fe, Ca, Ti, Zr, Mg, the sulfide of REM (rare earth element) etc. combines the inclusion of coexistence with the MnS solid solution, or S element and Mn in addition forms compound as MnTe, with the MnS solid solution. combine and inclusion that coexists or the above-mentioned inclusion of separating out as nuclear with oxide compound, be meant that its chemical formula can (Mn, X) (S, Y) (wherein, X is the sulfide forming element beyond the Mn, Y be beyond the S with Mn bonded element) general name of the sulfide-based inclusion of Mn of expression.
Then, in the present invention, except above-mentioned composition, as required, can also add V, Nb, Cr, Mo, W, Ni, Sn, Zn, Ti, Ca, Zr, Mg, Te, Bi, more than a kind or a kind of Pb.
V-arrangement becomes carbonitride, by the secondary precipitation-hardening steel is strengthened.Less than 0.05% o'clock, on high strength, do not have effect, add if surpass 1.0%, the carbonitride of just separating out volume damages mechanical property on the contrary, therefore with 1.0% as the upper limit.
Nb also separates out carbonitride, by the secondary precipitation-hardening steel is strengthened.Less than 0.005% o'clock, on high strength, do not have effect, add if surpass 0.2%, the carbonitride of just separating out volume damages mechanical property on the contrary, therefore with 0.2% as the upper limit.
Cr is that raising hardening capacity, anti-temper softening are given element.Therefore in needing the steel of high strength, add.In the case, be necessary with interpolation more than or equal to 0.01%.If but volume ground adds, the embrittlement with regard to generating the Cr carbide, therefore with 2.0% as the upper limit.
Mo is when giving anti-temper softening, improves the element of hardening capacity.Less than 0.05% o'clock, can not get its effect, add even surpass 1.0%, its effect also reaches capacity, with 0.05%～1.0% as the interpolation scope.
W forms carbide, separates out by secondary steel is strengthened.Less than 0.05% o'clock, high strength is not had effect, add if surpass 1.0%, the carbide of just separating out volume damages mechanical property on the contrary, therefore with 1.0% as the upper limit.
The Ni reinforced ferrite is improving ductile simultaneously, also is effective improving hardening capacity, improving on the solidity to corrosion.Less than 0.05% o'clock, can not get its effect, add even surpass 2.0%, also reach capacity in the effect of mechanical properties, therefore with 2.0% as the upper limit.
The Cu reinforced ferrite also is effective improving hardening capacity, improving on the solidity to corrosion.Less than 0.01% o'clock, can not get its effect, add even surpass 2.0%, also reach capacity in the effect of mechanical properties, therefore with 2.0% as the upper limit.Hot rolling ductility is reduced, and become the reason of the defective when rolling easily, therefore preferred and Ni adds simultaneously.
Sn makes the ferrite embrittlement, when prolonged life tools, also produces effect on the raising surface smoothness.Less than 0.005% o'clock, can not get its effect, add even surpass 2.0%, also reach capacity in the effect of mechanical properties, therefore with 2.0% as the upper limit.
Zn makes the ferrite embrittlement, when prolonged life tools, also produces effect on the raising surface smoothness.Less than 0.0005% o'clock, can not get its effect, add even surpass 0.5%, also reach capacity in the effect of mechanical properties, therefore with 0.5% as the upper limit.
Ti also forms carbonitride and strengthens steel.Also be deoxidant element in addition, can improve machinability by forming soft oxide compound.Less than 0.0005% o'clock, can not get its effect, to add even surpass 0.1%, its effect also reaches capacity, and in addition, Ti at high temperature also forms nitride, suppresses austenite crystal and grows up.Therefore with 0.1% as the upper limit.Moreover, Ti and N chemical combination and form TiN, but TiN is a hardness of matter, reduces machinability.And make that machinability is improved is that the necessary N amount of effective BN reduces in order to make.Therefore, Ti addition preferred 0.010% or below it.
Ca is a deoxidant element, generates soft oxide compound, not only improves machinability, and solid solution makes its energy of deformation reduce in MnS, even be rolled or forge hot, the effect of the extension that suppresses the MnS shape is arranged also.Therefore, be to lowering the anisotropy effective elements.Less than 0.0002% o'clock, its effect is not remarkable, even add greater than 0.005%, and the extreme variation of yield rate not only, and generate the CaO of hard in a large number, reduce machinability on the contrary.Therefore, adding scope dictates is 0.0002～0.005%.
Zr is a deoxidant element, generates oxide compound.Oxide compound becomes the nuclear of separating out of MnS, and the fine homodisperse of MnS is produced effect.Solid solution reduces its energy of deformation in MnS, even rolling or forge hot also has the effect of the extension that suppresses the MnS shape.Therefore, be to anisotropic attenuating effective elements.Less than 0.0005% o'clock, its effect is not remarkable, even add greater than 0.1%, and the extreme variation of yield rate not only, and generate the ZrO of hard in a large number
2, ZrS etc., reduce machinability on the contrary.Therefore, adding scope dictates is 0.0005～0.1%.In addition, when the fine dispersion of seeking MnS, the compound interpolation of preferred Zr and Ca.
Mg is a deoxidant element, generates oxide compound.Oxide compound becomes the nuclear of separating out of MnS, the fine homodisperse of MnS produced effect, and be to anisotropic attenuating effective elements.Less than 0.0003% o'clock, its effect is not remarkable, even add greater than 0.005%, and the extreme variation of yield rate not only, and also effect also reaches capacity.Therefore adding scope dictates is 0.0003～0.005%.
Te improves the machinability element.And generate MnTe, or reduce the energy of deformation of MnS, the effect of the extension that suppresses the MnS shape is arranged owing to coexisting with MnS.Therefore be that anisotropy is lowered effective elements.Less than 0.0003 o'clock, can not get this effect, if surpass 0.05%, effect just reaches capacity.
Bi and Pb improve effective elements to machinability.Less than 0.005% o'clock, can not get this effect, add even surpass 0.5%, not only machinability raising effect reaches capacity, and the reduction of forge hot characteristic, becomes the reason of defective easily.
Al is a deoxidant element, forms Al in steel
2O
3And AlN.But, Al
2O
3Be hard, become the reason of instrument damage when cutting, promote wearing and tearing.Therefore being limited in not, volume generates Al
2O
3Be less than or equal to 0.015%.Making under preferential situation life tools, preferably be less than or equal to 0.005% especially.
In addition, in the present invention, preferentially avoiding the machinability fault not equal under the situation of the fault in preferentially avoiding quenching, in the allowed band of machinability, lower the B amount, during for example the one-tenth of regulation is grouped in the present invention, B:0.0005～0.005% and the S amount that is defined as also is defined as 0.5～1.0%, also can be as the steel of excellent in machinability.This under a large amount of situations about existing of B, residual solid solution B, it is big that hardening capacity becomes, by thermal treatments such as carburizing and quenchings, it is dark that hardened layer became, or strain is strengthened, or make sclerosis portion embrittlement, thereby afore mentioned rules of the present invention can prevent various faults such as hardening crack.Have again, in the present invention, cold forging or wire drawing etc. to free-cutting steel except that the cutting working method in, MnS becomes the destructive starting point easily and cracks, thereby mechanical property often reduces, therefore by guaranteeing to be controlled at 0.03～0.5 quality %, also can suppress the surface crack that cold forging or high frequency produce as the S amount of the MIN machinability of free-cutting steel.
Then, the manufacture method that makes the fine dispersive steel of above-mentioned MnS, BN is illustrated.
As principal constituent, compound fine dispersion of separating out the sulfide of BN, is effective improving on the machinability with MnS.In order to make the fine dispersion of this sulfide, need control to separate out as the crystallization of the sulfide of principal constituent, the compound BN of separating out with MnS, in this control, the speed of cooling scope when needing the regulation casting.Below 10 ℃/minute the time, solidify too slowly in speed of cooling, thickization taken place as the sulfide of the compound BN of separating out of principal constituent in MnS that separate out with crystallization, can not finely disperse.During greater than 100 ℃/minute, the density of the fine sulfide of generation reaches capacity in speed of cooling, and the hardness of steel ingot rises, and the risk of crack increase takes place.In order to obtain this speed of cooling, the size of mold cross-section, casting rate etc. are controlled at suitable value, just can obtain easily.This can be applied to continuous metal cast process, ingot casting method simultaneously.
Be meant the speed of the liquidus temperature from the thickness direction Q portion of ingot casting during to the cooling of solidus temperature in this said speed of cooling.The interval of 2 ingotism branch arms of the ingot casting thickness direction solidified structure of speed of cooling after solidify, calculate according to following formula and to obtain:
Promptly owing to the cooling conditions difference, the interval of 2 ingotism branch arms changes, and therefore changes by measuring this, just can confirm the speed of cooling of controlling.
BN when being greater than or equal to 1000 ℃ solid solution in austenite.In the temperature that is lower than 1000 ℃, remain in crystal boundary from casting the BN that separates out to the roughing process, can not separate out the sulfide as principal constituent, the compound BN of separating out with MnS.In the finish to gauge process when hot rolling, by being rolled in the temperature that is greater than or equal to 1000 ℃, the BN of solid solution examines and compound the separating out easily that become as separating out with MnS sulfide again.If carry out finish to gauge being lower than 1000 ℃, separate out to become as the sulfide of principal constituent compound with BN and MnS and be difficult for taking place.
Then, in the present invention, for the manufacture method of the microstructure that obtains being less than or equal to 5% perlite area occupation ratio is illustrated.
The generation behavior of built-up edge on instrument produces big influence to cutting surface smooth finish.Originally, be to the harshest environment of material directly over cutting tool on the mechanics, think the destruction/separation of easy generating material, this should not have built-up edge to adhere to thus, but in fact because organizing of the adhesion of the brute force between instrument/cutting material and cutting material is irregular, and built-up edge takes place.Therefore think the microstructure uniformity of importantly doing one's utmost to increase material.Its result, the inventor find, think that so far the perlite that almost it doesn't matter distributes relevant greatly with microstructure uniformity.
Here, so-called perlite is meant the black tissue of seeing after the etch of mirror ultrafinish face enforcement nitric acid ethanol.So-called strictly speaking perlite is meant that ferrite and tabular cementite are alternatively arranged and the group that constitutes, but 1 particle of the erect image of under opticmicroscope, seeing.And then as shown in Figure 1, when utilizing common rolling cold manufacturing process of putting, this perlite particle is arranged bandedly and is separated out (being referred to as the perlite band later on).This pearlitic mechanical property is different with the single-phase ferrite of matrix, therefore makes near the uneven homogenize of the deformation failure of point of a knife, and then encourages the growth of built-up edge.
Therefore, by adjust composition of steel or thermal history control with more than or equal to the perlite area occupation ratio in the perlite particle of the 1 μ m field of view relevant, 4 millimeter 2 in the mensuration visual field, it is clear when investigation obtains the critical field of surface of good smooth finish, in order to suppress the deterioration of surface smoothness, more than or equal to the shared area occupation ratio of the perlite particle of 1 μ m for being less than or equal to 5%.The relation of perlite area occupation ratio shown in Figure 2 and surface smoothness.
As shown in Figure 1, as can be known according to free-cutting steel of the present invention, the black tissue of seeing is few.Strictly speaking, become tempered martensite or tempering bainite tissue in the present invention, carbide is not perlite (in other words, the banded structure that is produced by tabular cementite and ferrite), but can not negate the possibility that the form with cementite particle exists.But, be that carbide is generically and collectively referred to as perlite and represents with such iron at this.
Then, the manufacture method to free-cutting steel of the present invention is illustrated.
[quenching thermal history: from A
3Point or its above temperature to 550 ℃ or below it be 0.5 ℃/second]
In the present invention, as the thermal history after the hot rolling, importantly, after the hot rolling from A
3Point or its above temperature to 550 ℃ or below it, to cool off more than or equal to the speed of cooling of 0.5 ℃/s.
In the past, so-called low-carbon free-cutting steel was not carried out chilling.Low-carbon free-cutting steel C amount is few, even thereby quenching hardness change also few.Therefore utilize in the past " Q-tempering " that intensity/toughness is not had influence yet, so concerning free-cutting steel, be subjected to the constraint of the unnecessary fixed ideas of what is called.But, consider in the essence of getting back to cutting, pursue under the inhomogeneity situation of material, by from A
3The point chilling can freeze moving of C in the steel, the generation of the thick cementite that the phase transformation when being suppressed at air cooling produces, and then suppress pearlitic generation and get final product.Therefore in the case, the sclerosis that is caused by quenching is not a purpose, even do not form the quenching structure with martensitic structure, can freeze moving of C in the steel, stops thick cementite or pearlitic generation just.For this reason, as shown in Figure 3, from A
3Point need be to cool off more than or equal to 0.5 ℃/second speed to being less than or equal to 550 ℃.Improving the few occasion of hardening capacity element etc. down, be preferably greater than or equal 1 ℃/second speed of cooling.Surpass 550 ℃ in cooled temperature, or speed of cooling generates thick perlite than under 0.5 ℃ of/second slow situation.General most band shape of separating out is called the perlite band.Certainly,,, do not generate the perlite band even speed of cooling is slower than 0.5 ℃/second if volume ground adds alloying element as stainless steel yet, but owing to be set at general free-cutting steel at this, so be defined as 0.5 ℃/second.
Then, in the present invention, after above-mentioned chilling is handled, implement to remain below or equal the thermal treatment of 750 ℃ temperature, just more can make the homogeneous microstructureization of free-cutting steel.
In actual manufacturing processed, in order further to increase the stability of goods, though the C amount is few, the technology that the hardness deviation in the steel is reduced.For this reason, by high temperature maintenance once again, just can reduce the material inequality.At first in order to suppress thick perlite, importantly from being greater than or equal to A
3The temperature of point thickly pearliticly is not less than or equal to 550 ℃ and is carried out chilling to not generating.Then, more as shown in Figure 4, by remaining on the temperature T of regulation once more
2℃, be adjusted to the hardness that the sufficer requires, just can reduce the hardness deviation.By heating and being retained to the temperature of being less than or equal to 750 ℃, be adjusted to the hardness of sufficer's requirement.
About keeping temperature T
2℃, this maintenance temperature and hold-time should be got the hardness that requires due to the sufficer.But, if keep temperature T
2℃ surpass 750 ℃, just begin, therefore, just generated the perlite band if the speed of cooling when cooling off again is slow to austenitic phase transformation.Therefore, keep temperature T
2℃ be defined as and be less than or equal to 750 ℃.In subsequent process, often apply secondary processing such as wire drawing again, therefore preferably be adjusted to the maintenance temperature T of the hardness of the operation that is suitable for these subsequent processes
2℃.About this hold-time, and be to be less than or equal to situation about keeping hardly in 3 minutes to compare on the industrial production, hardness etc. do not change, and therefore are preferably more than 3 minutes.
Moreover, on industrial production, because rolling or forge difference such as size,, therefore also must consider for 550 ℃ the temperature T of being less than or equal to after preventing thick pearlitic chilling even steel inside also produces the irregular of temperature
1Hold-time under ℃.Be less than or equal to 550 ℃ temperature T behind the chilling
1Be preferably greater than under ℃ or equal and kept in 5 minutes, just have nothing to do, can promote uniform ferrite transformation with material size or segregation line.Like this, even be warming up to later the maintenance temperature T
2℃ (≤750 ℃) do not generate thick perlite or perlite band yet.On the contrary, rolling or forge after the big situation of size under, if be less than or equal to hold-time 550 ℃ under than 1 minute weak point, inner phase transformation does not just have end, therefore after this when the temperature that is higher than 550 ℃ keeps, just generate thick perlite or thick perlite band.
Embodiment
Embodiment 1
Use embodiment that effect of the present invention is described.Shown in table 1, table 2 (table 1 continuous 1), table 3 (table 1 continuous 2), table 4 (table 1 continuous 3), table 5 (table 1 continuous 4), the table 6 (table 1 continuous 5) in the test material, No.13 is with 270 tons of converter meltings, other with 2 tons of vacuum melting furnace meltings after, piecemeal rolls into steel plate, rolls into again
60 millimeters.
In the thermal treatment item of table, the embodiment that note is done normalizing is 920 ℃ of maintenances 10 minutes or more than it, carries out air cooling.Note is made the example of the present invention of QT (Q-tempering), from 920 ℃ the tank of rolling line rear end, drop into impatient cold after, in annealing 710 ℃ of maintenances more than or equal to 1 hour.Adjust the perlite area occupation ratio thus.In example of the present invention,, in normalizing, also can lower the perlite area occupation ratio though the C amount is low.
The bit bore test is used in the machinability evaluation of material shown in the embodiment 1～81 of table 1～table 6, represents machining condition in table 7.Estimate machinability with the highest cutting speed (so-called VL1000, unit: meter/minute) that can be cut to 1000 millimeters of accumulation hole depths.
Again the cutting surface smooth finish of the surface quality in the expression cutting is estimated.Its machining condition is shown in Table 8, and the summary of its evaluation method (after, be called the cut-in type cutting test) is shown among Fig. 7 (a), Fig. 7 (b).In the cut-in type cutting test, instrument carries out the short period of time cutting repeatedly.In cutting at one time, instrument does not vertically move along the cutting material, move to the cutting material center of rotation, so after the cutting of short period of time, puller, but its shape, the point of a knife shape transferred thereon of instrument is on cutting material surface basically.Because adhering to or the wearing and tearing of instrument of built-up edge, the surface smoothness in the face of tool of this transfer printing is affected.With fixed this surface smoothness of surface smoothness instrumentation.With the index of 10 surface smoothness Rz (μ m) as presentation surface smooth finish.
Example 1～75 is with respect to Comparative Examples 76～81, and the boring bar tool life-span is all good, and meanwhile, the surface smoothness in the cut-in type cutting is good.Think that this is because B ferrite generation local embrittlement carries out the surface glossily and foundes, and therefore obtains surface of good smooth finish.
These surface smoothnesses improve effect, it is significant surpassing at 0.5% o'clock at S, though in the S amount than 0.5% after a little while, handle on the property in smear metal and also to see effect.
The ratio that Mn and S are arranged again, even in steel in the past, often see about 3, also can see effect, if but Mn/S is diminished, when further improving life tools, also improve surface smoothness.Its reason is considered to because under the environment that the B volume is added, fine MnS is also fine dispersion in ferrite, lubricant effect and embrittlement effect two aspect play a role effectively.But, as embodiment 80,, just generate FeS if Mn/S is too small, therefore produce rolling crack.Relevant evaluation of the present invention, embodiment 70 is because rolling crack, can not carry out the evaluation of machinability etc. fully, do not represent its evaluation result in table.
Even do by adding B in large quantities, further to control the perlite area occupation ratio under the situation of some change (table 1～table 6, embodiment 37～75) in the C amount, can access good life tools and cutting surface smooth finish.
Moreover, handle property about smear metal, the little smear metal of curvature during preferred chip curling, the perhaps smear metal of disjunction.Therefore, with smear metal surpass 20 millimeters radius-of-curvature, continuously involve in more than or equal to 3 that row curls and the smear metal that prolongs as bad.Though the volume number is many, the smear metal that radius-of-curvature is little, though perhaps radius-of-curvature is big, length of chip does not reach 100 millimeters smear metal for good.
Table 7
Table 8 cut-in type machining condition
Shown in table 9, table 10 (table 9 continuous 1), table 11 (table 9 continuous 2), table 12 (table 9 continuous 3), table 13 (table 9 continuous 4), the table 14 (table 9 continuous 5) for the test material, a part is with after 270 tons of converter meltings, and speed of cooling is 10～100 ℃/minute Di to cast.Piecemeal rolls into steel plate, rolls into again
50 millimeters.Other roll into 2 tons of vacuum melting furnace meltings
50 millimeters.At this moment, adjust the speed of cooling of ingot casting by changing the mold cross-section size.The machinability of material, the cut-in type cutting of condition shown in bit bore test by condition shown in the table 7 and the table 8 is estimated.The boring drifting test is a method of estimating machinability with the highest cutting speed (so-called VL1000, unit: meter/minute) that can be cut to 1000 millimeters of accumulation hole depths.Cut-in type cutting is to utilize parting tool molding transfer tool shape and the method for estimating surface smoothness.Summary at this experimental technique shown in Fig. 7 (a), Fig. 7 (b).In this experiment, add the surface smoothness in man-hour with fixed 200 ditches of surface smoothness instrumentation.With 10 surface smoothness Rz (unit: μ m) as the index of presentation surface smooth finish.
With diameter of equivalent circle is the mensuration of the MnS of 0.1～0.5 μ m size as the sulfide density of principal constituent, use to extract replica method from
The Q portion of the section that 50 millimeters rolling direction after rolling is parallel takes, and carries out on transmission electron microscope.Mensuration is with 10000 times, 1 visual field, 80 μ m
2, carry out more than or equal to 40 visuals field, it is converted into per 1 square centimeter MnS calculates as the sulfide number of principal constituent.In formula (1) calculated value of table 10, table 12 and table 14, be less than or equal to 1 be to satisfy exploitation steel of the present invention.
Shown in Fig. 2 (a), Fig. 2 (b), the opticmicroscope level can not be confirmed the MnS of size, and by transmission electron microscope observation, example and Comparative Examples are seen tangible difference on size, density.
Moreover the cutting resistance of table 10, table 12, table 14 and the cutting lay property handled is as follows.Piezoelectric element type tool's power meter (キ ス ラ-corporate system) is installed on the capstan head of lathe,, is carried out the cut-in type cutting and measure cutting resistance so that thereon with the stationkeeping instrument identical with common cutting.Thus,, just can measure respectively as voltage signal with the main component that is added in the load on the instrument and back of the body component.Machining condition such as cutting speed, feeding speed is identical with evaluation cutting surface smooth finish.
Handle property about smear metal, the smear metal of the little or disjunction of preferential curvature when selecting cutting to curl.Therefore, with smear metal surpass 20 millimeters radius-of-curvature, continuously involve in more than or equal to 3 that row curls and the smear metal that prolongs as bad.Though the volume number is many, the smear metal that radius-of-curvature is little, though perhaps radius-of-curvature is big, length of chip does not reach 100 millimeters smear metal for good.
About machinability, example is all good with respect to the boring bar tool life-span of Comparative Examples, and meanwhile, the surface smoothness in the cut-in type cutting is also good.Especially for surface smoothness, because the compound effect of separating out of fine MnS and BN can access very good value.
Utilize possibility on the industry
As mentioned above, because have life tools and cutting surface fineness and the smear metal in when cutting The characteristic that the property processed is good, the present invention can be applicable to automobile component with material, common mechanical with the member material.
Claims (9)
1. the steel of an excellent in machinability is characterized in that, it be by quality % by
C：0.005～0.2％、
Si：0.001～0.5％、
Mn：0.2～3.0％、
P：0.001～0.2％、
S：0.03～1.0％、
Total N:0.002～0.02%,
Total O:0.0005～0.035%,
Surplus is the steel that Fe and unavoidable impurities constitute, satisfy that Mn/S is 1.2～2.8 in the steel, and about using the MnS that takes with the extraction replica method of transmission electron microscope observation, in the section parallel, be that to have density be more than or equal to 10000/millimeter for the MnS of 0.1～0.5 μ m according to diameter of equivalent circle with the rolling direction of steel
2, and the surface smoothness Rz of steel is less than or equal to 11 μ m.
2. the steel of an excellent in machinability, it is characterized in that, contain C:0.005～0.2%, Mn:0.3～3.0%, S:0.1～1.0% by quality %, about using the MnS that takes with the extraction replica method of transmission electron microscope observation, in the section parallel, be that to have density be more than or equal to 10000/millimeter for the MnS of 0.1～0.5 μ m with diameter of equivalent circle with the rolling direction of steel
2, and the cutting surface smooth finish Rz of steel becomes and is less than or equal to 11 μ m.
3. the steel of excellent in machinability as claimed in claim 1 or 2 is characterized in that, also contains B:0.0005～0.05 quality %.
4. the steel of excellent in machinability as claimed in claim 1, it is characterized in that, also contain the S amount is limited in 0.25～0.75 quality %, the B amount is limited in 0.002～0.014 quality %, and S and B content satisfy the interior S and the B amount of A shown in Figure 4, B, C, D area surrounded of following formula 1, and in MnS, comprise the sulfide of separating out BN
(B-0.008)
2/ 0.006
2+ (S-0.5)
2/ 0.25
2≤ 1 ... formula (1).
5. the steel of the excellent in machinability described in claim 1 or 2 is characterized in that, also contains by quality %
V：0.05～1.0％、
Nb：0.005～0.2％、
Cr：0.01～2.0％、
Mo：0.05～1.0％、
W：0.05～1.0％、
Ni：0.05～2.0％、
Cu：0.01～2.0％、
Sn：0.005～2.0％、
Zn：0.0005～0.5％、
Ti：0.0005～0.1％、
Ca：0.0002～0.005％、
Zr：0.0005～0.1％、
Mg：0.0003～0.005％、
Te：0.0003～0.05％、
Bi：0.005～0.5％、
Pb：0.01～0.5％、
Al：≤0.015％
More than a kind or a kind.
6. as the manufacture method of the steel of each described excellent in machinability in the claim 1～3, it is characterized in that the molten steel with the described composition of steel of claim 1 is after casting, with 10～100 ℃/minute speed of cooling cooling, from A
3O'clock carry out cooling after the hot rolling with 0.5 ℃/s or the speed of cooling more than it to 550 ℃ scope.
7. as the manufacture method of the steel of claim 1 or 4 described excellent in machinability, it is characterized in that, will have the molten steel casting of the composition that claim 1 puts down in writing after, with 10～100 ℃/minute speed of cooling cooling, then the hot rolled outlet temperature is limited in 1000 ℃ or more than it, from A
3O'clock carry out cooling after the hot rolling with 0.5 ℃/second or speed of cooling more than it to 550 ℃ scope.
8. as the manufacture method of the steel of each described excellent in machinability in the claim 1～5, it is characterized in that, after the cooling after hot rolling, will be limited in 750 ℃ or below it again for the Heating temperature of adjusting hardness.
9. as the manufacture method of the steel of each described excellent in machinability in the claim 6～8, it is characterized in that above-mentioned steel also contains by quality %
V：0.05～1.0％、
Nb：0.005～0.2％、
Cr：0.01～2.0％、
Mo：0.05～1.0％、
W：0.05～1.0％、
Ni：0.05～2.0％、
Cu：0.01～2.0％、
Sn：0.005～2.0％、
Zn：0.0005～0.5％、
Ti：0.0005～0.1％、
Ca：0.0002～0.005％、
Zr：0.0005～0.1％、
Mg：0.0003～0.005％、
Te：0.0003～0.05％、
Bi：0.005～0.5％、
Pb：0.01～0.5％、
Al：≤0.015％
In more than a kind or a kind.
Applications Claiming Priority (18)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002332707A JP4213948B2 (en) | 2002-11-15 | 2002-11-15 | Steel with excellent machinability |
| JP2002332669 | 2002-11-15 | ||
| JP332665/2002 | 2002-11-15 | ||
| JP332669/2002 | 2002-11-15 | ||
| JP2002332658A JP4323778B2 (en) | 2002-11-15 | 2002-11-15 | Manufacturing method of steel with excellent machinability |
| JP332695/2002 | 2002-11-15 | ||
| JP332668/2002 | 2002-11-15 | ||
| JP332707/2002 | 2002-11-15 | ||
| JP2002332665 | 2002-11-15 | ||
| JP2002332695 | 2002-11-15 | ||
| JP332658/2002 | 2002-11-15 | ||
| JP2002332668A JP4264247B2 (en) | 2002-11-15 | 2002-11-15 | Steel with excellent machinability and method for producing the same |
| JP374517/2003 | 2003-11-04 | ||
| JP2003374489A JP4348163B2 (en) | 2002-11-15 | 2003-11-04 | Steel excellent in machinability and manufacturing method thereof |
| JP2003374511A JP4264329B2 (en) | 2002-11-15 | 2003-11-04 | Steel with excellent machinability |
| JP374489/2003 | 2003-11-04 | ||
| JP2003374517A JP4348164B2 (en) | 2002-11-15 | 2003-11-04 | Steel with excellent machinability |
| JP374511/2003 | 2003-11-04 |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2003801034255A Division CN100529136C (en) | 2002-11-15 | 2003-11-14 | Steel excellent in machinability and method for production thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101215665A true CN101215665A (en) | 2008-07-09 |
| CN101215665B CN101215665B (en) | 2010-12-22 |
Family
ID=32697619
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2007101960130A Expired - Fee Related CN101215665B (en) | 2002-11-15 | 2003-11-14 | Steel having excellent machinability and production method therefor |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP4323778B2 (en) |
| CN (1) | CN101215665B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102803541A (en) * | 2010-03-19 | 2012-11-28 | 杰富意钢铁株式会社 | Hot-rolled steel sheet having excellent cold working properties and hardening properties, and method for producing same |
| CN103498115A (en) * | 2013-09-29 | 2014-01-08 | 苏州市凯业金属制品有限公司 | High-ductility U-shaped metal tube |
| CN104313466A (en) * | 2014-10-31 | 2015-01-28 | 武汉钢铁(集团)公司 | Low-carbon microalloyed free-cutting steel |
| CN104388800A (en) * | 2014-11-03 | 2015-03-04 | 无锡贺邦金属制品有限公司 | Lead-tin alloy die casting |
| CN104995324A (en) * | 2013-02-18 | 2015-10-21 | 新日铁住金株式会社 | Lead-containing free-machining steel |
| TWI747777B (en) * | 2020-03-31 | 2021-11-21 | 日商杰富意鋼鐵股份有限公司 | Free-cutting steel and its manufacturing method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4741786A (en) * | 1986-06-10 | 1988-05-03 | Stanadyne, Inc. | Cold drawn free-machining steel bar including bismuth |
-
2002
- 2002-11-15 JP JP2002332658A patent/JP4323778B2/en not_active Expired - Fee Related
-
2003
- 2003-11-14 CN CN2007101960130A patent/CN101215665B/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102803541A (en) * | 2010-03-19 | 2012-11-28 | 杰富意钢铁株式会社 | Hot-rolled steel sheet having excellent cold working properties and hardening properties, and method for producing same |
| CN104995324A (en) * | 2013-02-18 | 2015-10-21 | 新日铁住金株式会社 | Lead-containing free-machining steel |
| CN104995324B (en) * | 2013-02-18 | 2016-08-24 | 新日铁住金株式会社 | Lead treated steel |
| CN103498115A (en) * | 2013-09-29 | 2014-01-08 | 苏州市凯业金属制品有限公司 | High-ductility U-shaped metal tube |
| CN104313466A (en) * | 2014-10-31 | 2015-01-28 | 武汉钢铁(集团)公司 | Low-carbon microalloyed free-cutting steel |
| CN104388800A (en) * | 2014-11-03 | 2015-03-04 | 无锡贺邦金属制品有限公司 | Lead-tin alloy die casting |
| TWI747777B (en) * | 2020-03-31 | 2021-11-21 | 日商杰富意鋼鐵股份有限公司 | Free-cutting steel and its manufacturing method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101215665B (en) | 2010-12-22 |
| JP2004169051A (en) | 2004-06-17 |
| JP4323778B2 (en) | 2009-09-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100529136C (en) | Steel excellent in machinability and method for production thereof | |
| US8137484B2 (en) | Method of production of steel superior in machinability | |
| CN109642295B (en) | Steel sheet and method for producing same | |
| KR101355321B1 (en) | Case hardened steel and method for producing the same | |
| US10131973B2 (en) | High strength spring steel and steel wire | |
| CN100480411C (en) | Steel and steel wire for high strength spring | |
| KR100794157B1 (en) | Stainless steel having a high hardness and excellent mirror-finished surface property, and method of producing the same | |
| CN101321884A (en) | Heat-treatment steel for high-strength spring | |
| KR20030034165A (en) | Low carbon martensitic stainless steel and production method thereof | |
| CN109666856A (en) | A kind of high-strength tenacity semiaxis non-hardened and tempered steel and its production method instead of 42CrMo quenched and tempered steel | |
| AU706022B2 (en) | Process for manufacturing thin strip of perritic stainless steel, and thin strip thus obtained | |
| CN102378822A (en) | Steel for case hardening which has excellent cold workability and machinability and which exhibits excellent fatigue characteristics after carburizing and quenching, and process for production of same | |
| CN101573463A (en) | Free-cutting steel excellent in manufacturability | |
| KR20080009713A (en) | High strength spring heat-treated steel | |
| BRPI0607042B1 (en) | HIGH-RESISTANCE SPRING STEEL | |
| EP3480333A1 (en) | Steel for mechanical structures | |
| EP3492614A1 (en) | Steel for machine structures | |
| JP4465057B2 (en) | High carbon steel sheet for precision punching | |
| EP3382051A1 (en) | Steel, carburized steel component, and carburized steel component production method | |
| EP3492615A1 (en) | Steel for machine structures | |
| US20190368014A1 (en) | Quench hardened steel | |
| CN101215665B (en) | Steel having excellent machinability and production method therefor | |
| JP6683074B2 (en) | Steel for carburizing, carburized steel parts and method for manufacturing carburized steel parts | |
| CN1122840A (en) | Micro-alloying and high toughness cold working die steel | |
| JP6683073B2 (en) | Steel for carburizing, carburized steel parts and method for manufacturing carburized steel parts |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C56 | Change in the name or address of the patentee |
Owner name: NIPPON STEEL + SUMITOMO METAL CORPORATION Free format text: FORMER NAME: SHIN NIPPON STEEL LTD. |
|
| CP01 | Change in the name or title of a patent holder |
Address after: Tokyo, Japan, Japan Patentee after: Nippon Steel Corporation Address before: Tokyo, Japan, Japan Patentee before: Nippon Steel Corporation |
|
| CP01 | Change in the name or title of a patent holder | ||
| CP01 | Change in the name or title of a patent holder |
Address after: Tokyo, Japan, Japan Patentee after: Nippon Iron & Steel Corporation Address before: Tokyo, Japan, Japan Patentee before: Nippon Steel Corporation |
|
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20101222 Termination date: 20191114 |