CA2019187A1 - Method of producing soft magnetic steel materials - Google Patents
Method of producing soft magnetic steel materialsInfo
- Publication number
- CA2019187A1 CA2019187A1 CA002019187A CA2019187A CA2019187A1 CA 2019187 A1 CA2019187 A1 CA 2019187A1 CA 002019187 A CA002019187 A CA 002019187A CA 2019187 A CA2019187 A CA 2019187A CA 2019187 A1 CA2019187 A1 CA 2019187A1
- Authority
- CA
- Canada
- Prior art keywords
- soft magnetic
- magnetic
- temperatures
- annealing
- materials
- 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.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
- C21D8/1216—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the working step(s) being of interest
- C21D8/1222—Hot rolling
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
- C21D8/1244—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest
- C21D8/1272—Final recrystallisation annealing
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Organic Chemistry (AREA)
- Metallurgy (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Crystallography & Structural Chemistry (AREA)
- Thermal Sciences (AREA)
- Electromagnetism (AREA)
- Soft Magnetic Materials (AREA)
- Manufacturing Of Steel Electrode Plates (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The invention is concerned with a method of producing economically soft magnetic ferrous materials with high magnetic permeability. A cast piece or a steel piece, where sol.Al is added 0.5 to 2.0 wt% to pure iron - composition and Ti is added 0.005 to 1.0 wt% as required, is hot worked as specified temperatures and at specified work finishing temperatures, and finally annealed 900 to 1300°C, preferably 1000 to 1300°C, thereby to obtain soft magnetic materials having coercive force of lower than 0.4 Oe and magnetic flux density of more than 10000 G at the magnetic field of 0.5 Oe.
The invention is concerned with a method of producing economically soft magnetic ferrous materials with high magnetic permeability. A cast piece or a steel piece, where sol.Al is added 0.5 to 2.0 wt% to pure iron - composition and Ti is added 0.005 to 1.0 wt% as required, is hot worked as specified temperatures and at specified work finishing temperatures, and finally annealed 900 to 1300°C, preferably 1000 to 1300°C, thereby to obtain soft magnetic materials having coercive force of lower than 0.4 Oe and magnetic flux density of more than 10000 G at the magnetic field of 0.5 Oe.
Description
S P E C I F I C A T I O N
A METHOD OF PRODUCING SOFT MAGNETIC STEEL MATERIALS
TECHNICAL FIELD
The present invention relates to a method of producing ~ e~n V~s ~e ~, ~ /S
soft magnetic steeVl mate~ s, and more particularly such as electromagnetic core or a magneti~ ~eenl~g material where ~aod DC magnetization properties are required TECHNICAL BACKGROUND
Soft irons or pure irons obtained at relatively cheap costs or very expensive permalloy or supermalloy have been used c sh ie ~
as DC electromagnetic iron cores, or magneti ~ s~F~_~ds materials of medical appliancesr physical machinery, electronic parts or appliances, which have recently been remarkable espe-~ e l ~ d~D~ A I
cially ~ dev ~ ~ ;tribuA~io~ A magnetic flux density ~called as "B1 value" hereinafter)J ~n 1 Oe~of the soft iron It h~s or the pure iron is about 3000 to 11000 G ~ey-~æ been used c sh;411`~
as the magneti~ s~ecn-i-A~ materials of MRI (tomogram diagnosis (5hle~ pt~ ~ /e~
apparatus by a nuclear magnetic resonance) or t~ 4~ around D~ t;~ X) several ga~ , o~ s electromagnetic iron core ~aterials In the usage where the DC magne-tization property is important, ~_refc-rcncc--w~-l---be ~a~e--k~ problams of conven-tional -~vl the c ~ & ~w;ll be de~clvl;b~d techniques -~k~Rg~ he magneti~ ~i~g, for example The pure iron which is cheap at cost and high in a saturated magnetization has been exclusively used to the magnetic shielding of MRI. Even an O grade (for example, JIS C 2504 SUYPO) requiring the most sever properties in JIS specification on electromagnetic soft irons specifies a lower limit of the B1 value only to be 8000 G. Thus it us difficult for them to shielding a level of the earth magnetism, and a shielding system of a level lower than several gausses has become bulky.
A Fe-Ni alloy known as the permalloy of supermalloy is sometimes used for more effectively shielding. Those materials are possible to screen the magnetism lower than the earth magnetism but they are very expensive, and further their saturated magnetizations are as low as 1/3 to 2/3 of that of the pure iron. For shielding a high magnetic field, their thickness must be increased extremely.
A good deal of their use however is from an economical view point.
Taking the above mentioned situations into consideration, some studies have been made on heightening of the magnetic permeability without spoiling the high saturated magnetization of the pure iron materials. They are, for example, methods taught in Japanese Patent Publication No. 63-45443, Japanese Patent Laid Open No. 62-77420 or "Developments of Ultra Thick Electromagnetic Steel Plates" mentioned in No.5 of vol.23, (published in 1984) by Japan Metal Society. Each of these methods aims at improving of the magnetic permeability through accomplishing with coarsening of ferrite crystal grains. However, those technologies limit objects to hot rolled plates of relatively small thickness, or they could not accomplish more than 10000.
,~, G with the magnetic flux density (called as "Bo 5 value"
hereinafter) in== ~ ere DC magnetization f~F~e~ hc~ ot b~vl su~ t ~ e ~,~se ~,vh;~) proper-ty is appreciated as the present invention.
~pto Un~e~ the presentr e~e~=s~e~e2s, such materials have not e ,~a~tl~tlc pD~ h;~ , t~.c~t is, yet been offered that thé saturated maynetiza~Ion ~ls~~h~igh,`f-he high magnetic flux density is revealed in a low magnetic field corresponding to an extent of the earth magnetism , ~
thc magne~ic po-rmc~bili-~y i6 high~ It is an object of the C~l invention to provide a method which ~ produce such materials at economical costs.
DISCLOSURE OF THE INVENTION
For solving the above stated problems, the inventors made b~s;c investigations on industrial pure irons which were ~a~c~
soft magnetic materials for the DC magnetic field so a3 to~cleari~
defects thereof, ~ obtained knowledge under mentioned.
~o~ .
From standpoints e~ obtaining the high magnetic permeabi-~ DIIOUJ;~ P~DC~d~ S ~e~e ~ouv~d ~o be ef~e~ctiue~ (l) ~rhe /
lity, Vaddition of Alr=~ makes an effective deoxidation possible, improves the magnetic permeability in company wi~h decreasings of an oxygen amount and oxid ~
S ~
L=~L~s~J:s, and lower~/solute N harmful to the magnetic permeabi-~ ixih~it~ p~ecipit~teslity by ~ AlN ~; (2) The addition of a certain co~'f5e~;~ ed necessary amount enables co~esic~ a Of finely scatter~g AlN~
~-e d ~ce ~ ~e~k~ bad influences of AlN ~ h~ 1~ V
_;sL_pYssibl~, and 4~ns}de~ab~ accelerates coarsening of ferrite cr~stal grains -b~-~h~ e~li~g-w~ich_is_an in.s~ru~nt to remove s, and each of these effects is profitable to the improvement of the permeablity; ~3) Especially the ~'se addition of more than 0.5% he*~h~e~ remarkably transformation C~ ~
temperatures, or ~ provide a ferrite ~e phase, and enables annealing~ at temperatures exceeding 900C without introducing ph~se strain~ by th ~ nsformation, accordingly. The annealing at high temperatures brings about removal of lattice strain,~
and the coarsening of the ferrite ~ grains. The improvement of the magnetic permeability of solute Al itself may be also considered, but by synergetic effects thereof, very excellent permeability may be provided; (4) If Ti is added as required, the solute N is preferentially fixed by Ti and attributes to the improvement of the properties, so that an effe~t is not required for decreasing N content ~ From a I h~ ol~ou,~ .s IIJQI~`~ abtQihel, standpoint of holding the saturatecl magnetization~~ (5) ~eA
addition exceeding 5~ should be avoided; (6) If C and amounts are ~ , the transformation temperature lowers, or the necessary amount of Al increases. Further, the properties are deteriorated by the increment of the lattice strain by p~c;~ ;t~t,o~
increasings of solute C and M or gcncrations of carbides and nitrides~ The inventors found ~pper limits of C and N amounts for avoiding them, and accomplished the present invention.
The invention is set forth as follows.
~ 1) A method of producing soft magnetic StCC~ materials characterized by heating higher than 700C but lower than 1300C
a steel piece or a cast piece composed of C: not more than 0.004 wt~, Si: not more than 0.5 Wt%, Mn: not more than 0.50 wt%, P: not more than 0.015 wt~, S: not more than 0.01 wt%, sol.Al:
0.5 to 2.0 wt%, N: not more than 0.005 wt%, oxygen: not more than 0.005wt%, and the rest being Fe and unavoidable impurities, accomplishiny a hot working at temperatures of higher than 700C, and finally annealing at tempera~uresof 900 to 1300C, thereby ~ .Q~
to obtain a soft magnetic ~ ~aterial having a coercive force of lower than 0~4 Oe and the magnetic flux density of more than he ~ ,Qn e t i c ~f ie Id 10000 G _ ~e of 0.5 Oe.
~Le~Dc~s ~ 2) A method of producing soft magnetic ~ materials characterized by heating higher than 700C but lower than 1300C
a steel piece or a cast piece composed of Co not more than 0.004 wt%, Si: not more than 0.1 Wt%~ Mn: not more than 0.15 wt~, ~P: not more than 0.015 wt%, S: not more than 0.01 wt% t sol.Al:
0.5 to 2.0 wt%, N: not more than 0.005 wt%, oxygen: not more than 0.005wt%, and the rest being Fe and unavoidable impurities, accomplishing a hot working at temperatures of higher than 700C, and finally annealing at t~empe-r~ature~of 1000 to 1300C, thereby to obtain a soft magnetic ~ material having a coercive force of lower than 0.4 Oe and the magnetic flux density of moxe than a~ ~the ~hGa.~e,tIc ~ Id 10000 G ln thc--co~rci~c force of 0.5 Oe.
~e ~r~O,u~
(3~ A method of producing soft magnetic stee~ materials characterized by heating higher than 700C but lower than 1300C
a steel piece or a cast piece composed of C: not more than 0.004 wt~, Si: not more than 0.5 Wt%, Mn: not more than 0.50 wt%, P: not more than 0.015 wt%, S: not more than 0.01 wt%, sol~Al:
0.5 to 2.0 wt%, N: not more than 0.012 wt%, oxygen: not more - 6 ~ 7 than 0~005wt%, Tio 0 005 to 1.0 wt% and the rest being Fe and unavoidable impurities, accomplishing a hot working at tempera-tures of higher than 700C, and finally annealing at temperature of 900 to 1300C, thereby to obtain a soft magnetic ,'',j~e~/-ouS''`) ~1 material having a coercive force of lower than 0.4 Oe and the magnetic flux density of more than 10000 G ~ t-~e ~ neti~ ~1 e Id cocrci~ of 0.5 Oe.
DETAII,ED DESCRIPTION OF THE INVENTION
An explanation will be made to reasons for limiting the chemical composition of this invention.
C is ~e1~ ~ e to be as low as possible for securing an fe~ic ~ c~S ~(~ a~
X excellent ~ ermeability similar~r-txr~ but an utmost ~i CG4ses ~h decrease is difficult in industrial production since it invite~
extreme cost-up. In view of ke~h~e~}~ the transformation temperature by Al addition, if the amount of C addition is not incl-e~5eJ
controlled to be low, the amount of Al addition should be m~h7 resulting in lowering the saturated magnetization, which is contrary to the intention of the invention. Therefore an upper limit of C is 0.004 wt~.
Si contributes to the improvement of the magnetic perme-ability, but the present invention aims at satisfying the magnetic permeability by the Al addition. Rather, an upper limit is 0.5 wt~, preferably 0.1 wt~, paying attentions to a lowering of a saturated magnetization by much addition of Si.
Since Mn deteriorates the DC magnetization property, ,~te,1t ~ CRuse~!
loweri~ Yis desirable, but an extreme lowering ~i~e~ the cost-up and the increase of N content. Further, this element S~lp~e~,S
also chce]~- a hot brittleness by fixing S. It may be contained -5%s preferably 0.15 wt%, as an upper limit within a range at i o that~Mn/S ~ ot lower than 10.
P and S are impurities, and lower~ are preferable,if not costing up, and their upper limits are 0.015 wt% and 0.1 wt%.
Al is, as said above, the most important element of this invention. That is, Al brings about the fixt ~ of the solute co~se~ S,n,~
N, the G~esi~ of AlN ~ri~s, and the he}gh~ee~s of the G,nd o.S/
transformation temperature1 ~ lts~thereby expands a ferrite p~Se If æQ ion ~ YIQ 61 es ~a~g~, so that this element ~oalize~ annealings at high tempe~
ratures, thereby to accomplish the coarsening of the ferrite ~ al ~ F{~het/no~e ~ J
grains and the decreasing of the inter~ strain~ lS
( th~t S~lute f~e itSe~~ ssume~= e~r~r~r~ hr magnetic permeability~ b~ thc -EoL~te- ~l p~eve~t ) i~selt-. Thus, in the~l-n-vention, this element must be added for providing -the excellent DC magnetization property~ Such effects of Al may be obtained by adding more than 0.5~ in a f ~ of sol.Al. On the other hand, it is undesirable to add xceedingly ~ , because the saturated magnetization is lowered.
~ e Al addition is determined to be 0.5 to ~ in the -~E~ of sol.Al.
1l5caolue5 Similarly to C, N ~ o the lattice~, and m~ creates the lattice strain~ to deteriorate the DC magnetization pro-perties. It is desirable that N is as low as possible for not p~oduc l'n,~ p~ecrp:~tes ge~e~*r~ Al ~E~. This consideration is to make the added Al exist as useful solute Al, and N content should be not more ~ ill b~ c~ b~
than 0~005 ~t%o In the invention, as later mentioned Ti dded as requiredtwhich is a strong nitride former~ This is c c~ n trO lliJ-,~
added for decreasing the above said harms of N ~ithout ~cfini~
~ rn~J ca~Sea~
a severe uper limit of the N content whic~ ost~-up, and in this case the upper limit of N is 0.012 wt%.
As is apparent from the above mentioned findings, it is desirable to regulate the total amount of N ~d C for more exactly securing the DC magnetization propertiesO It is preferable that in a case of no Ti addition, C+N is not more than 0.007 wt%, while in a case of Ti addition, C+N is not more than 0.014 wt~.
Oxygen, similarly to ~n, deteriorates the DC magnetization ~ ;~e~t~l proeprties, and especially gives det~i~ri~g influences to the magnetic permeability by generating non metallic inclusions.
When preparing a molten steel, oxygen must be enough decreased, and an upper limit is specified to be 0.005 wt%.
Ti is the strong nitride former as said above. If adding it 0~005 to 1.0%, it is possible to avoid considerable damages of the DC magnetization property by a fixing e~ol-of solute N even in such materials where N content is not fully decreased, that is, cheap materials. If the N content is relatively low, the generating amount of nitride ~ are low, and the DC
magnetization property may be expected to be improved more or less, accordingly. The Ti addition of more than the upper limit deterirates the DC magnetization property.
A further explanation will be made to conditions for produc-ing steels of the inventionO
2 ~
The present invention employs ordinary hot working conditions for hot rollings, and h~ats the steel pieces or cast pieces of the above mentioned chemical compositions at the temperatures of higher than 700C but lower than 1300C for the hot working. In the invention, a lower limit of the work is ending temperature ~ determined to be 700C, since cost-ups always depend upon increase of deformation resistance at the hot workirlg in accompany with rollings at low temperature range as well as lengthening of time to be taken for the hot working, C~Se~
and rollings at extreme low temperatures possibly ~i~es grain refining by recrystallization during the annealing.
An annealing to be finally performed should be practi~ed whicl within a rang~ not falling to a transformation temperaturet-~o ~e decided mainly by the amount of Al addition, and unless practi~ing at the temperature of at least 900C, preferably higher than 1000C, it is not possible to accomplish much excell-ent DC magnetization property to be intended by the invention.
Acually, if adding 0.001 wt% C, 0.0020 wt% N and around 1 wt%
Al, the inventive steel is rendered to be a ferrite sigle phase, and it is therefore posible to carry out the annealing at very high temperatures of higher than 1100C, but since the annealing at temperature ranges exceeding 1300~C is difficult and it Q.Ue ~ice t~, ~es the cost-up, the annealing temperatures are determined to be 900 to 1300C, preferably 1000 to 1300C. The , O.7~ the a~eO~
---~a~a~R~ times ~are varied in dependence upon the heat capacity of the material, and it is desirable to ~t more than 30 minutes. With respect to the cooling after the heating -~h~
--- m~-in-t~ining, in view of introduction of no ~e~ strain,- a slow cooling is desirable. If an attention is paid so that a tl~ ~ ~n~l uniform cooling may be provided, the ~e~t- strain is difficult to be introduced, and in such a case, the slow cooling is not always required.
If the annealing temperature is especially limi-ted with the chemical composition and under the producing conditions -f~ ~ous specified in the invention, it is possible to produce s~4~1 materials of high saturated magnetization and Bo 5 value, that is, excellent soft magnetic properties at the DC magnetic field.
The present invention also includes a case where a hot ei~lo yed ~ ou~
direct rolling is sub~titutcd for the hot rolling. The Etee~
materials to be produced by the invention includes both of hot worked materials and cold worked materials ~including a warm worXing). Th~ final annealing is therefore irrespective of a case after the hot working or a case after the hot working - cold working. The invention of course includes such case of performing thc ~--w~}~g~ the intermediate annealing on the half way of the cold working, or a case of performing each of the above workings in the several steps. The steels at which the invention aimS include ~ plates, ~ sheets, bar,m~aterials (shape steels), forged materials, etc~
EXAMPLES
Example 1 Table 1 shows chemical compositions of steels used in the invention and comparative exam~les. Steels A to E were formed 2 ~ Q~ 7 ~ntD s~ee~S uJ;tllJ ~IrOih ~thicknesses of 1 -to 5 mm by hot roling at 1200 ~ngots having ~ ed thickness of 110 mm after h~ving beerl ms~e~, wherein steels A to C fall within the inventive chemical composition, and Steels D, E, F and G are comparative. Table 1 shows transformation points when the temperatures were elevated up to 1300C at heating rate of 0.5C/s. The measures of the transformation points tell that the inventive steels have ferrite single phases.
Table 2 shows the DC magnatization properties of the invent-ive steels and the comparative steels, wherein the annealings 0~ edwere carried out on test pieces ~ from the center parts of the thicknesses of the hot rolled steels, having an outer diameter of 45 mm, an inner diameter of 33 mm and a thickness o~ 6 mm for measuring the DÇ magnetization permeability and the ferrite grain sizes. The annealings herein corresponds to the final annealing defined in the invention~ In the holl;~l~
annealing, the heating - ma}~a}~}~ time was set to be 1 to 3 hours, and the cooling rate was set to be a slow cooling of about l00C/hr.
Table 2 shows Examples in accordance with the invention where No.1 carried out the annealing 4~ 1100C on Steel A.
In this Example~ since the steel has the ferrite single phase ~u~
tD
lowering of the C content and Al addition, the annealing at the high temperature is possible without introducing ~ 'f~
transformation strain~ an ~refining g~i~s by the transformation.
Ra~h~ `~onsiderable coarsening of more than 2 mm in the ferrite grain sizes was acomplished by the annealing at the high tempera-ture as 1100C, and concurrently the lattice strain~ were removed, so that very excellent properties of Bo 5 value being around 13000 G and the maximum magnetic permeability exceeding 60000 were obtained.
No.2 is an Example where the annealing at ~ C was done on Steel A where the annealing temperature was lower than that of No.1, although the ferrite grain sizes were smaller than those of No~1 as around 0.5 to 1.0 mm, the properties were good as the maximum magnetic permeability being 23900 Nos.3 and 4 are Examples of Steels B and C. Also herein, the ferrite single phases were made by the Al additions, and in each of them, it was possible to perform the annealings at the high temperatures exceeding 1000C. By the synergestic çffects of coarsening of the ferrite cr~1 grains and the removal of .interisr strain~, the excellent properties ~7ere pe~ ec. b; /;ty available as the maximum magnetic pl~p~ being 56000 in No.3, and 37200 in No.4.
In each of the above Examples Nos.1 to 4, the excellent DC magnetization properties of the maximum magnetic permeability ~ , being 20000 and the coercive force being not more than 0.4 Oe were accomplished, which not only satisfied enough the prop-erties specified in JIS C 2504 S~YPO but also even Bo 5 value exceedS 11000 G, and thus enabled to ~e~ee~ the magnetism to p~ ced an extent ~-~r~d the earth m~t-ksm.
Nos.5, 6 and 7 are comparative Examples of Steels D, E
and F. These Steels correspond to industrial pure irons, and are out of the inventive chemical composition. A shown in Nos.5 and 6, the remarkable coarsening of the ferrite ~ grains - 13 ~ $7 could not be expected in spite of the annealing at more than 1000C~ Further, the strain~ were introduced durinq trans- k formation from an austenite to a ferrite, and desired properties were not therefore imparted. No.7 shows results when the annealing temperature was lower than the transfromation poin-t, and so good properties were not p~ovided.
_ _ _ __ C~ ~ ~ ~ (1, W ~
~: u~ ~3 rt__ O O O O O O D~
O Oo O O o o C-~ ID
~ _~ O crl O O O _ I_ ~3 O o O O O o O V~
~1 o o o o ` o o o 1~.
tll r~ ~_ ~_ I_ )- I_ ~_ l cn o o o o o o ::~
o ~ o o o o o o 3 o cn o o o o o ~ n O O O Crl O C~l 1-o o oO o o o o--3 ~ r~ cn o lo o o ~n l _ __ -- rt O o O O O l_ l_ O ~
O O o O ~O )-- W
I_ O O O ~ O tD ~ ~
_ _ _ _ _ _ I_ r~
O O O O O O O
O O 00 O O 00 00 ~:
~r ~ ~ ~ ~ ~_ ~
O O O O o O o O O O O O O O O
o O ~ W o O O
t~r co O a) ~_ ~_ ~_ _ ~ O O __ C~
Co 1~ r~o ~ ~Z ~2:
l Cr~ o crl O O O ~C
__(~ (~ O __ :
__ _--,~ _ _ _ _ .
. ~ ~ ~ ~ ~ o U~ .
(~ H = _ I_ __ _ ~) 3 <~ ~ ~C o ,_ ,_ ,_ ,_ ,_ ~ ô
. . ' 3 co ~1- o o o o o o (~
3 ~ ___ _ _ __ ~ ~_ ~ ~ ~ ~ ~ O
(D ~ CJl O cn ~ o c~ cn ~ o o o o o o o rt ~ O O O O O O O O
~OH) X _ rt 3 ~ o o o o o o o o o X (D ~D ~D (D _ ~ o CJl o C~ t`~ (~ o * ~ ~ C~ l CO, ~_ CJl G~ot~
~D ~ 1 l o o o o o o o r~ It (D ~1 ' ~ .
O' 1- 3 ,_ ,_ ,_ ,_ ~: ~ ~_ C~ CJl r~ ~ )- C~ _~
It ~I l tD ~ ~ I_ 00 ~ ~ ~ C~`
O) SU l o o o o C~ o o ` , _ o O o O o O O _UI
N (D I . o o o o o o o G~ W
1 o o o o o o O
_ _ _ ~, 1-'--1-~D cn a) cn c~ a) a~ a~ ^ W
~: ~ l O O ~ O 10 O oo G~ , 0~ O O O O O O O Ul, ~ ~. o o o ~ ~ o CJ~ ~
w 1~. l ;~ ;~ O Ul C o ~3 N
¦--O _ _ H ._ :~: ~ ::, 3 _ : _ C
*
_ __ ._ - 15 _ 2 ~
Example 2 b~,~-h of Table 3 shows~ hemical compositions ~se~--in the inventive Examples and the comparative Examples. With respect to Steels ~e/t ~
I to U, steel ingots of 110 mm thickness were made from ~ t-en teel, and the ingots were hot rolled b~he~ to 15 b~ h e c-t ill~ / 7~o c , mm thickness~ Steel I to S, W to Y, Z and b to d fall within the inventive chemical composition, while Steels T, U, V and a are comparative steels. Table 4 shows results o~ ~3i~uz3sg the DC magnetization properties and the ferrite cI~st~l grain sizes of the inventive steels and the comparative steels. In h~/d~
the annealings of the present Example, the heating - ~a~i-~ti~i-~i~y times were 1 to 3 hours, and the cooling rates were around 100C/hr to 500C/hr.
In Table 4, Nos.10 to 13 varied the Mn content within the ranges specified by the invention.
Nos.23 to 26 observed influences of the sol.Al content~
No.28 observed influences of the C content, and Nos.29 to 31 observed influences of the Si content.
Nos.14 to 16 added Ti. Also herein, the ferrite single phase were made by the Al addition, and further N was fixed by the Ti addition. Nos.14 to 16 show desirable properties.
No.15 is a~ ~special example where Ti was added to a steel equivalent to No.22 in accordance with the invention, and N
was sufficiently fixed by Ti addition so that a great improvement was observed in comparison with the comparative example of No.22.
NoO21 is a comparative example where Ti was added more than the specified range of the invention, and the DC magnetizat-ion property is remarkabl~ deteriorated.
No.22 is a comparative example where N addition was high and Ti was not added. Since a precipitation of AlN was stable, the ferrite ~r~ a~ grains were not fully coarsened in spite of the annealing, and a solute N content was high so that satisfied properties could not be realized. Nos.17 and 18 are examples where Steels P and Q were annealed at 1000C
Each of Nos.10 to 18, Nos.24 to 26, No.27 and Nos.29 to 31 not only can accomplish the excellent DC magnetization Iwhe~re ~`5 property ~ the coerceive force ~si~g not more than 0.4 Oe and the Bo 5 value ~e~g more than 10000 G and by far satisfy the `properties specified ~ JIS C 2504 SUYPO but also may be applied c 5~ p~es e h t;~l~
to as the magneti~ scr~cr-~ng material for }pepa~g magnetic field circumstances of a magnetic field level below the earth magnetism.
Nos.19 and 20 investigated influerlces of Ti in relationwith the N content and the C~N content, and the both had N > 0.005%
and C+N > 0.007%, but No.20 obtained a desired properties due to Ti addition.
Each of the inventive examples show the desirous DC magneti-zation property, and has coarse ferrite cr-ys~L grain of more than 0.5 mm.
As is seen from the above mentioned, the soft magnetic ou~
fi~ee~ materials according to the invention have the excellent h~
DC magnetization properties and may ~ /magnetized even in weak magnetic fields, and those are useful as iron core materials -- ~7 --C 5~1~e ldl s~q of high functions or magneti~ ~ material of high f unction .
_ _ _ DJ _ _ _ __ ~ _ _ _ _ _ _ O _ ~ _ _ ~, ~ p.~
U~
_ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ o o o o o o o o o o o o o o o o o o o o o o ~
o o o o o o o o o o o o o o o o o o o (~ 1-o o o o o o o o o o o o o o o o o o o o o o ,_ o o co ~ I_ ~ ~ r~ ,_ , ~ ~ ~ ~ ~ ,_ ~ o o o o o e~ ~ oo o vl ,~ C.~ _~ O ~ ~ ~ O ~ W r~ vl co Oo co ~ ~D W
. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ o o o o o o o o o o o o o o o o o o o o o o U~
Vl ,._ o o o o o o o o o o o O O o o o o o o o 1_, o _~ al ~_ ,_ e~ w ,_. ,_ ,_ ,_ ,_ ~_ ,_ ,- )- ~- ~- 1- ~ ~- ~-_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ O O O O O O O O O O O O O O O O O O ~ ~ ,_ O :7 . . _ _ _ I-- _ __ _ _ I._A _ _ _ _ _ _ _ _ _ _ _ _ U _ . o o o o o o o o o o o o o o o o o o o o o o 3 o o o o o o o o o o o o o o o o o o o o o o ~ ,..
O O O O O O O O O O O O O O O O O O O O O O n O O O O O O O O O ~ ~_ O l_ O l_ ~ ~_ ~_ O O O O ~
c~'l c7~ a) t,. a'l vl Vl ~:71 ~ W I_ C~ )- ~D O Crl C~l Vl Vl C'~ ~ -~ 1-_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ o3 o o o o o o o o o o . o o o o o o o o o o o ~
o o o o o o ~ o o o o o o o o o o o o o o o V~ U~
o o o o o o o o o o o o o o o o o o IJ
o o o o o o o o o o o o o o o o o ~ o o o o .
a) a~ a~ vl Vl ~ W C~ .~ ~ ~ Vl ~ ~ W Vl ~o O W ~ I`~ t`~ I' _ __ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ O
i_ I_ ~_ ~_ I_ )~ t O O ~_ ~_ ~_ ~_ 1~ O I_ t~ ~_ ~_ )~ ~_ ~_ O ~
t~ ~J ~ t-- ~ V) ~ t~ W ~_ ~ ~ ~ ~_ _1 ~ 1_ i_ ~ 1~ 1_ ~ . o\o c~ w 1~ 1~ vl t~ Iv cn o t~ ~ ul ,1~ _~ W _~ ~ ~ Vl ~ t~ O ~ _, . _ _ _ _ _ _ _ _. _ _ _ _ _ _ _ _ ~_ ~ _ _ _ O O O O O O O O O O O O O O O O O O O O O O
O O O O O O O O O ,._ O O O O O O ~_ O O O O O
)- ~_ I_ O ~ I_ O ~_ I_ ~ O V) ~1 O O O ~- ~ )- 1-' t- ~-~ ~ ot ~O cn ,_ o~ v w v) o~ ~1 o ~ tD ~ O~ ~ a~ ~ w ~
. _ _ _ - - - - - 1- - - - - - - - -- - - - - - -O O O O O O O O O O O O O O O O O O O O O O
O O O O O O O O O O O O O O O O O O O O O O O
O O O O O O O O O O O O O O O O O O O O O O
_ I_ ~ O ~_ ~_ 1~ I ~ _ ~ ~ )- ~ t~ ~ ~ ~ )~ O I_ O
~ O r~ o~ oo _) O V C~ V) O _ t~ O O O o O C~7 ,_ o7 _ ~ ~
rt rt r~ rt r~ rt rt ot rt r~ . . rt rt rt . . . rt rt rt r~ ~
~ ,,~ '1 ~ '1 '1 ~ ~ ~ ~ W O t~ ~ '1 O~ O O ~ ~ ~ 't 1~.
. . . _- . . . . . o C~ . . . W V) ~_ _- . . _ r~
/
_ _ _ _ _ _ _ _ ~ _ _ ~ _ _ _ ~_ _ _ _ _ ,_ ~:
~: !--O CD O~ ~ O) CJI ~ C~ _ _ O _ _ _ r cn _ _ _ _ o . O _ _ _ _ __ _ _ _ _ rt ~,. ~1 ~, ,rJ rJ~ ~u t~ ~1 ~ ~! ~ c1~ ~ cn ~:) Æ) ~ O ~ ~ t~ ~ c~ ~ ~ (D
H ~ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ~ _ _ ~:
~...
.. ~_ ~_ ~_ ~_ ~_ ~_ ~_ ~_ ~_ I_ ~_ ~_ ,--~_ ~ Y ~ ~_ ,_ ,_ ~_ ~_ ,_ _ ~ ,_ ,_ ~ ,- ~ ,_ ,_ o ,_ ,_ ,_ ~ o o ,_ ,_ o o ,_ ~_ ,_ ~ _ t~ ~) O O O O O O O O O O O O O O O O O ~n o o o o ~
X ~ o o o o o o o o o o o o o o o o o o o o o o ~_ _ 3~ _ _ _ _ _ _ _ _ _ _ ------------------ - - - l ~a ~ ~ ~ ,_ c~ .~ _, cn ~ ~ crl ~ cn cn ~ ~ cn ~ _~ ~ a~ ~
O co C~ ~ tO ~ ~ ~ ~ ~ ~ ~ ~ ~ -a ~ o~ c:n r~ _~ o ~ ~D
~h rt o o o _J o o ~ co o o cn o o _l o ~ o ~ o o o o n ~D o o o o o o o o o o o o o o o o o o o o o o D~
rt 3 o o o o o o o o o o o o o o o o o o o o o o - - - - - - - - - - - - - - - - - - - - - -rt o o o o o o o o o o . o o o o o o o o o o o O ~
tD ~1 ~ ~ ~ ~ ~ ,_ ,_ ,_ c~ u~ v- ~ .P ,_ ,_ ,_ ~ ~ ~ ,_ ,_ ,_ t~ ~
(D ~ r~ c~ a~ _~ ID r~ ~o ~o o ~ _~ v ~ o~ co ~ o ~ ~ r~ ~ ~_ rt U~
O-'`' _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ --~ ~_ ,_ )--~_ ~ ,_ ~_ ~_ ,_ ~_ )--~ ~_ ~_ ~ ~_ ~ --: ~ CA~ ~ ~ C`~ W C.~ ~ O ~_ C~ O ~ ~ ~ C~ C~ ~ C~ ~ C.
C17 O W _1 V~ ~_ V~ Vl .t:. ~ ~ ~_ _~ O Oo O~ V~ Vl t~ W --~ r~ o o o o o o o o o o o o o o o o o o o o o o o _~
O'' o o o o o o o o o o o o o o o o o o o o o o 3': _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ~ ~D ~ l- ~- ~ 1- ~- )- 1- ~' ~- 1- ~- ~- '- - ~ ~ ~- '- ~ ~-' ~ ~ C~ ~ C.~ ~ C~ ~ V- ~ C.~ ~ ~ ~P ~ ~ ~ ~ Cl~ C.
~1 ~D ~n o tD ~ ~ ,_ ,_ a- ~D rJ~ ~_ oo ~> ~ ~ Vl Cl~ I_ CO t~ tl~ C~ ~_ O (L~ o o o o o o o o o o o o o o o o o o o o o o 30 (D. o o o o o o o o o o o o o o o o o o o o o o ~H~ _ _ _ . _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ .
~ ~ ,- ~- ,- ,- ,- ,- ,- ,- --~- ,- ,- ,- ,- ,- ,- ,- ,- ~ ~- ~ ,-rt l't V7 rJ~ rJ~ v~ v7 r~ r o v- rJ7 ~ v7 r v7 r~ Vl V~ V7 Vl C V~ n r.7 td ~- (D o o o o o o o o o o o o o o o o o o o o o o ~' u~
(~ O O O O O O O O O O O O O O O O O O O O O O
3~t __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ~
~ n~ ~_ ~ ~~ O ~ c~ ~ ~ O O O ~ ~_ ~ ~ ~_ ~ ~ w ~ ~ ~ _~ ~
~ Vl ~ V~ O O ~Jl C~l ~ W O O Ln O C~1 O V~ O O V- CJ~ ~l _ ~' _ _ _ _ _ _ _ _ _ ~- _ _ _ _ _ _ _ _ _ _ __ _ _ ~J. .
N H O . H ( ) H ( ) ~
a ~ <~ ~0, ~ ~7 ~ . ~ ~ 3 ~ ~, ~ ::, ~, :, ~ ~ :, ~ . ;
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . .
- 20 - 2~
INDUSTRIAL APPLICABILITY
The present invention may be applied to production of soft magnetic materials, for example, electromagnetic cores or magnet~
5~,'e Id J~
~ r~in~ materials which require high DC magnetization propertles.
A METHOD OF PRODUCING SOFT MAGNETIC STEEL MATERIALS
TECHNICAL FIELD
The present invention relates to a method of producing ~ e~n V~s ~e ~, ~ /S
soft magnetic steeVl mate~ s, and more particularly such as electromagnetic core or a magneti~ ~eenl~g material where ~aod DC magnetization properties are required TECHNICAL BACKGROUND
Soft irons or pure irons obtained at relatively cheap costs or very expensive permalloy or supermalloy have been used c sh ie ~
as DC electromagnetic iron cores, or magneti ~ s~F~_~ds materials of medical appliancesr physical machinery, electronic parts or appliances, which have recently been remarkable espe-~ e l ~ d~D~ A I
cially ~ dev ~ ~ ;tribuA~io~ A magnetic flux density ~called as "B1 value" hereinafter)J ~n 1 Oe~of the soft iron It h~s or the pure iron is about 3000 to 11000 G ~ey-~æ been used c sh;411`~
as the magneti~ s~ecn-i-A~ materials of MRI (tomogram diagnosis (5hle~ pt~ ~ /e~
apparatus by a nuclear magnetic resonance) or t~ 4~ around D~ t;~ X) several ga~ , o~ s electromagnetic iron core ~aterials In the usage where the DC magne-tization property is important, ~_refc-rcncc--w~-l---be ~a~e--k~ problams of conven-tional -~vl the c ~ & ~w;ll be de~clvl;b~d techniques -~k~Rg~ he magneti~ ~i~g, for example The pure iron which is cheap at cost and high in a saturated magnetization has been exclusively used to the magnetic shielding of MRI. Even an O grade (for example, JIS C 2504 SUYPO) requiring the most sever properties in JIS specification on electromagnetic soft irons specifies a lower limit of the B1 value only to be 8000 G. Thus it us difficult for them to shielding a level of the earth magnetism, and a shielding system of a level lower than several gausses has become bulky.
A Fe-Ni alloy known as the permalloy of supermalloy is sometimes used for more effectively shielding. Those materials are possible to screen the magnetism lower than the earth magnetism but they are very expensive, and further their saturated magnetizations are as low as 1/3 to 2/3 of that of the pure iron. For shielding a high magnetic field, their thickness must be increased extremely.
A good deal of their use however is from an economical view point.
Taking the above mentioned situations into consideration, some studies have been made on heightening of the magnetic permeability without spoiling the high saturated magnetization of the pure iron materials. They are, for example, methods taught in Japanese Patent Publication No. 63-45443, Japanese Patent Laid Open No. 62-77420 or "Developments of Ultra Thick Electromagnetic Steel Plates" mentioned in No.5 of vol.23, (published in 1984) by Japan Metal Society. Each of these methods aims at improving of the magnetic permeability through accomplishing with coarsening of ferrite crystal grains. However, those technologies limit objects to hot rolled plates of relatively small thickness, or they could not accomplish more than 10000.
,~, G with the magnetic flux density (called as "Bo 5 value"
hereinafter) in== ~ ere DC magnetization f~F~e~ hc~ ot b~vl su~ t ~ e ~,~se ~,vh;~) proper-ty is appreciated as the present invention.
~pto Un~e~ the presentr e~e~=s~e~e2s, such materials have not e ,~a~tl~tlc pD~ h;~ , t~.c~t is, yet been offered that thé saturated maynetiza~Ion ~ls~~h~igh,`f-he high magnetic flux density is revealed in a low magnetic field corresponding to an extent of the earth magnetism , ~
thc magne~ic po-rmc~bili-~y i6 high~ It is an object of the C~l invention to provide a method which ~ produce such materials at economical costs.
DISCLOSURE OF THE INVENTION
For solving the above stated problems, the inventors made b~s;c investigations on industrial pure irons which were ~a~c~
soft magnetic materials for the DC magnetic field so a3 to~cleari~
defects thereof, ~ obtained knowledge under mentioned.
~o~ .
From standpoints e~ obtaining the high magnetic permeabi-~ DIIOUJ;~ P~DC~d~ S ~e~e ~ouv~d ~o be ef~e~ctiue~ (l) ~rhe /
lity, Vaddition of Alr=~ makes an effective deoxidation possible, improves the magnetic permeability in company wi~h decreasings of an oxygen amount and oxid ~
S ~
L=~L~s~J:s, and lower~/solute N harmful to the magnetic permeabi-~ ixih~it~ p~ecipit~teslity by ~ AlN ~; (2) The addition of a certain co~'f5e~;~ ed necessary amount enables co~esic~ a Of finely scatter~g AlN~
~-e d ~ce ~ ~e~k~ bad influences of AlN ~ h~ 1~ V
_;sL_pYssibl~, and 4~ns}de~ab~ accelerates coarsening of ferrite cr~stal grains -b~-~h~ e~li~g-w~ich_is_an in.s~ru~nt to remove s, and each of these effects is profitable to the improvement of the permeablity; ~3) Especially the ~'se addition of more than 0.5% he*~h~e~ remarkably transformation C~ ~
temperatures, or ~ provide a ferrite ~e phase, and enables annealing~ at temperatures exceeding 900C without introducing ph~se strain~ by th ~ nsformation, accordingly. The annealing at high temperatures brings about removal of lattice strain,~
and the coarsening of the ferrite ~ grains. The improvement of the magnetic permeability of solute Al itself may be also considered, but by synergetic effects thereof, very excellent permeability may be provided; (4) If Ti is added as required, the solute N is preferentially fixed by Ti and attributes to the improvement of the properties, so that an effe~t is not required for decreasing N content ~ From a I h~ ol~ou,~ .s IIJQI~`~ abtQihel, standpoint of holding the saturatecl magnetization~~ (5) ~eA
addition exceeding 5~ should be avoided; (6) If C and amounts are ~ , the transformation temperature lowers, or the necessary amount of Al increases. Further, the properties are deteriorated by the increment of the lattice strain by p~c;~ ;t~t,o~
increasings of solute C and M or gcncrations of carbides and nitrides~ The inventors found ~pper limits of C and N amounts for avoiding them, and accomplished the present invention.
The invention is set forth as follows.
~ 1) A method of producing soft magnetic StCC~ materials characterized by heating higher than 700C but lower than 1300C
a steel piece or a cast piece composed of C: not more than 0.004 wt~, Si: not more than 0.5 Wt%, Mn: not more than 0.50 wt%, P: not more than 0.015 wt~, S: not more than 0.01 wt%, sol.Al:
0.5 to 2.0 wt%, N: not more than 0.005 wt%, oxygen: not more than 0.005wt%, and the rest being Fe and unavoidable impurities, accomplishiny a hot working at temperatures of higher than 700C, and finally annealing at tempera~uresof 900 to 1300C, thereby ~ .Q~
to obtain a soft magnetic ~ ~aterial having a coercive force of lower than 0~4 Oe and the magnetic flux density of more than he ~ ,Qn e t i c ~f ie Id 10000 G _ ~e of 0.5 Oe.
~Le~Dc~s ~ 2) A method of producing soft magnetic ~ materials characterized by heating higher than 700C but lower than 1300C
a steel piece or a cast piece composed of Co not more than 0.004 wt%, Si: not more than 0.1 Wt%~ Mn: not more than 0.15 wt~, ~P: not more than 0.015 wt%, S: not more than 0.01 wt% t sol.Al:
0.5 to 2.0 wt%, N: not more than 0.005 wt%, oxygen: not more than 0.005wt%, and the rest being Fe and unavoidable impurities, accomplishing a hot working at temperatures of higher than 700C, and finally annealing at t~empe-r~ature~of 1000 to 1300C, thereby to obtain a soft magnetic ~ material having a coercive force of lower than 0.4 Oe and the magnetic flux density of moxe than a~ ~the ~hGa.~e,tIc ~ Id 10000 G ln thc--co~rci~c force of 0.5 Oe.
~e ~r~O,u~
(3~ A method of producing soft magnetic stee~ materials characterized by heating higher than 700C but lower than 1300C
a steel piece or a cast piece composed of C: not more than 0.004 wt~, Si: not more than 0.5 Wt%, Mn: not more than 0.50 wt%, P: not more than 0.015 wt%, S: not more than 0.01 wt%, sol~Al:
0.5 to 2.0 wt%, N: not more than 0.012 wt%, oxygen: not more - 6 ~ 7 than 0~005wt%, Tio 0 005 to 1.0 wt% and the rest being Fe and unavoidable impurities, accomplishing a hot working at tempera-tures of higher than 700C, and finally annealing at temperature of 900 to 1300C, thereby to obtain a soft magnetic ,'',j~e~/-ouS''`) ~1 material having a coercive force of lower than 0.4 Oe and the magnetic flux density of more than 10000 G ~ t-~e ~ neti~ ~1 e Id cocrci~ of 0.5 Oe.
DETAII,ED DESCRIPTION OF THE INVENTION
An explanation will be made to reasons for limiting the chemical composition of this invention.
C is ~e1~ ~ e to be as low as possible for securing an fe~ic ~ c~S ~(~ a~
X excellent ~ ermeability similar~r-txr~ but an utmost ~i CG4ses ~h decrease is difficult in industrial production since it invite~
extreme cost-up. In view of ke~h~e~}~ the transformation temperature by Al addition, if the amount of C addition is not incl-e~5eJ
controlled to be low, the amount of Al addition should be m~h7 resulting in lowering the saturated magnetization, which is contrary to the intention of the invention. Therefore an upper limit of C is 0.004 wt~.
Si contributes to the improvement of the magnetic perme-ability, but the present invention aims at satisfying the magnetic permeability by the Al addition. Rather, an upper limit is 0.5 wt~, preferably 0.1 wt~, paying attentions to a lowering of a saturated magnetization by much addition of Si.
Since Mn deteriorates the DC magnetization property, ,~te,1t ~ CRuse~!
loweri~ Yis desirable, but an extreme lowering ~i~e~ the cost-up and the increase of N content. Further, this element S~lp~e~,S
also chce]~- a hot brittleness by fixing S. It may be contained -5%s preferably 0.15 wt%, as an upper limit within a range at i o that~Mn/S ~ ot lower than 10.
P and S are impurities, and lower~ are preferable,if not costing up, and their upper limits are 0.015 wt% and 0.1 wt%.
Al is, as said above, the most important element of this invention. That is, Al brings about the fixt ~ of the solute co~se~ S,n,~
N, the G~esi~ of AlN ~ri~s, and the he}gh~ee~s of the G,nd o.S/
transformation temperature1 ~ lts~thereby expands a ferrite p~Se If æQ ion ~ YIQ 61 es ~a~g~, so that this element ~oalize~ annealings at high tempe~
ratures, thereby to accomplish the coarsening of the ferrite ~ al ~ F{~het/no~e ~ J
grains and the decreasing of the inter~ strain~ lS
( th~t S~lute f~e itSe~~ ssume~= e~r~r~r~ hr magnetic permeability~ b~ thc -EoL~te- ~l p~eve~t ) i~selt-. Thus, in the~l-n-vention, this element must be added for providing -the excellent DC magnetization property~ Such effects of Al may be obtained by adding more than 0.5~ in a f ~ of sol.Al. On the other hand, it is undesirable to add xceedingly ~ , because the saturated magnetization is lowered.
~ e Al addition is determined to be 0.5 to ~ in the -~E~ of sol.Al.
1l5caolue5 Similarly to C, N ~ o the lattice~, and m~ creates the lattice strain~ to deteriorate the DC magnetization pro-perties. It is desirable that N is as low as possible for not p~oduc l'n,~ p~ecrp:~tes ge~e~*r~ Al ~E~. This consideration is to make the added Al exist as useful solute Al, and N content should be not more ~ ill b~ c~ b~
than 0~005 ~t%o In the invention, as later mentioned Ti dded as requiredtwhich is a strong nitride former~ This is c c~ n trO lliJ-,~
added for decreasing the above said harms of N ~ithout ~cfini~
~ rn~J ca~Sea~
a severe uper limit of the N content whic~ ost~-up, and in this case the upper limit of N is 0.012 wt%.
As is apparent from the above mentioned findings, it is desirable to regulate the total amount of N ~d C for more exactly securing the DC magnetization propertiesO It is preferable that in a case of no Ti addition, C+N is not more than 0.007 wt%, while in a case of Ti addition, C+N is not more than 0.014 wt~.
Oxygen, similarly to ~n, deteriorates the DC magnetization ~ ;~e~t~l proeprties, and especially gives det~i~ri~g influences to the magnetic permeability by generating non metallic inclusions.
When preparing a molten steel, oxygen must be enough decreased, and an upper limit is specified to be 0.005 wt%.
Ti is the strong nitride former as said above. If adding it 0~005 to 1.0%, it is possible to avoid considerable damages of the DC magnetization property by a fixing e~ol-of solute N even in such materials where N content is not fully decreased, that is, cheap materials. If the N content is relatively low, the generating amount of nitride ~ are low, and the DC
magnetization property may be expected to be improved more or less, accordingly. The Ti addition of more than the upper limit deterirates the DC magnetization property.
A further explanation will be made to conditions for produc-ing steels of the inventionO
2 ~
The present invention employs ordinary hot working conditions for hot rollings, and h~ats the steel pieces or cast pieces of the above mentioned chemical compositions at the temperatures of higher than 700C but lower than 1300C for the hot working. In the invention, a lower limit of the work is ending temperature ~ determined to be 700C, since cost-ups always depend upon increase of deformation resistance at the hot workirlg in accompany with rollings at low temperature range as well as lengthening of time to be taken for the hot working, C~Se~
and rollings at extreme low temperatures possibly ~i~es grain refining by recrystallization during the annealing.
An annealing to be finally performed should be practi~ed whicl within a rang~ not falling to a transformation temperaturet-~o ~e decided mainly by the amount of Al addition, and unless practi~ing at the temperature of at least 900C, preferably higher than 1000C, it is not possible to accomplish much excell-ent DC magnetization property to be intended by the invention.
Acually, if adding 0.001 wt% C, 0.0020 wt% N and around 1 wt%
Al, the inventive steel is rendered to be a ferrite sigle phase, and it is therefore posible to carry out the annealing at very high temperatures of higher than 1100C, but since the annealing at temperature ranges exceeding 1300~C is difficult and it Q.Ue ~ice t~, ~es the cost-up, the annealing temperatures are determined to be 900 to 1300C, preferably 1000 to 1300C. The , O.7~ the a~eO~
---~a~a~R~ times ~are varied in dependence upon the heat capacity of the material, and it is desirable to ~t more than 30 minutes. With respect to the cooling after the heating -~h~
--- m~-in-t~ining, in view of introduction of no ~e~ strain,- a slow cooling is desirable. If an attention is paid so that a tl~ ~ ~n~l uniform cooling may be provided, the ~e~t- strain is difficult to be introduced, and in such a case, the slow cooling is not always required.
If the annealing temperature is especially limi-ted with the chemical composition and under the producing conditions -f~ ~ous specified in the invention, it is possible to produce s~4~1 materials of high saturated magnetization and Bo 5 value, that is, excellent soft magnetic properties at the DC magnetic field.
The present invention also includes a case where a hot ei~lo yed ~ ou~
direct rolling is sub~titutcd for the hot rolling. The Etee~
materials to be produced by the invention includes both of hot worked materials and cold worked materials ~including a warm worXing). Th~ final annealing is therefore irrespective of a case after the hot working or a case after the hot working - cold working. The invention of course includes such case of performing thc ~--w~}~g~ the intermediate annealing on the half way of the cold working, or a case of performing each of the above workings in the several steps. The steels at which the invention aimS include ~ plates, ~ sheets, bar,m~aterials (shape steels), forged materials, etc~
EXAMPLES
Example 1 Table 1 shows chemical compositions of steels used in the invention and comparative exam~les. Steels A to E were formed 2 ~ Q~ 7 ~ntD s~ee~S uJ;tllJ ~IrOih ~thicknesses of 1 -to 5 mm by hot roling at 1200 ~ngots having ~ ed thickness of 110 mm after h~ving beerl ms~e~, wherein steels A to C fall within the inventive chemical composition, and Steels D, E, F and G are comparative. Table 1 shows transformation points when the temperatures were elevated up to 1300C at heating rate of 0.5C/s. The measures of the transformation points tell that the inventive steels have ferrite single phases.
Table 2 shows the DC magnatization properties of the invent-ive steels and the comparative steels, wherein the annealings 0~ edwere carried out on test pieces ~ from the center parts of the thicknesses of the hot rolled steels, having an outer diameter of 45 mm, an inner diameter of 33 mm and a thickness o~ 6 mm for measuring the DÇ magnetization permeability and the ferrite grain sizes. The annealings herein corresponds to the final annealing defined in the invention~ In the holl;~l~
annealing, the heating - ma}~a}~}~ time was set to be 1 to 3 hours, and the cooling rate was set to be a slow cooling of about l00C/hr.
Table 2 shows Examples in accordance with the invention where No.1 carried out the annealing 4~ 1100C on Steel A.
In this Example~ since the steel has the ferrite single phase ~u~
tD
lowering of the C content and Al addition, the annealing at the high temperature is possible without introducing ~ 'f~
transformation strain~ an ~refining g~i~s by the transformation.
Ra~h~ `~onsiderable coarsening of more than 2 mm in the ferrite grain sizes was acomplished by the annealing at the high tempera-ture as 1100C, and concurrently the lattice strain~ were removed, so that very excellent properties of Bo 5 value being around 13000 G and the maximum magnetic permeability exceeding 60000 were obtained.
No.2 is an Example where the annealing at ~ C was done on Steel A where the annealing temperature was lower than that of No.1, although the ferrite grain sizes were smaller than those of No~1 as around 0.5 to 1.0 mm, the properties were good as the maximum magnetic permeability being 23900 Nos.3 and 4 are Examples of Steels B and C. Also herein, the ferrite single phases were made by the Al additions, and in each of them, it was possible to perform the annealings at the high temperatures exceeding 1000C. By the synergestic çffects of coarsening of the ferrite cr~1 grains and the removal of .interisr strain~, the excellent properties ~7ere pe~ ec. b; /;ty available as the maximum magnetic pl~p~ being 56000 in No.3, and 37200 in No.4.
In each of the above Examples Nos.1 to 4, the excellent DC magnetization properties of the maximum magnetic permeability ~ , being 20000 and the coercive force being not more than 0.4 Oe were accomplished, which not only satisfied enough the prop-erties specified in JIS C 2504 S~YPO but also even Bo 5 value exceedS 11000 G, and thus enabled to ~e~ee~ the magnetism to p~ ced an extent ~-~r~d the earth m~t-ksm.
Nos.5, 6 and 7 are comparative Examples of Steels D, E
and F. These Steels correspond to industrial pure irons, and are out of the inventive chemical composition. A shown in Nos.5 and 6, the remarkable coarsening of the ferrite ~ grains - 13 ~ $7 could not be expected in spite of the annealing at more than 1000C~ Further, the strain~ were introduced durinq trans- k formation from an austenite to a ferrite, and desired properties were not therefore imparted. No.7 shows results when the annealing temperature was lower than the transfromation poin-t, and so good properties were not p~ovided.
_ _ _ __ C~ ~ ~ ~ (1, W ~
~: u~ ~3 rt__ O O O O O O D~
O Oo O O o o C-~ ID
~ _~ O crl O O O _ I_ ~3 O o O O O o O V~
~1 o o o o ` o o o 1~.
tll r~ ~_ ~_ I_ )- I_ ~_ l cn o o o o o o ::~
o ~ o o o o o o 3 o cn o o o o o ~ n O O O Crl O C~l 1-o o oO o o o o--3 ~ r~ cn o lo o o ~n l _ __ -- rt O o O O O l_ l_ O ~
O O o O ~O )-- W
I_ O O O ~ O tD ~ ~
_ _ _ _ _ _ I_ r~
O O O O O O O
O O 00 O O 00 00 ~:
~r ~ ~ ~ ~ ~_ ~
O O O O o O o O O O O O O O O
o O ~ W o O O
t~r co O a) ~_ ~_ ~_ _ ~ O O __ C~
Co 1~ r~o ~ ~Z ~2:
l Cr~ o crl O O O ~C
__(~ (~ O __ :
__ _--,~ _ _ _ _ .
. ~ ~ ~ ~ ~ o U~ .
(~ H = _ I_ __ _ ~) 3 <~ ~ ~C o ,_ ,_ ,_ ,_ ,_ ~ ô
. . ' 3 co ~1- o o o o o o (~
3 ~ ___ _ _ __ ~ ~_ ~ ~ ~ ~ ~ O
(D ~ CJl O cn ~ o c~ cn ~ o o o o o o o rt ~ O O O O O O O O
~OH) X _ rt 3 ~ o o o o o o o o o X (D ~D ~D (D _ ~ o CJl o C~ t`~ (~ o * ~ ~ C~ l CO, ~_ CJl G~ot~
~D ~ 1 l o o o o o o o r~ It (D ~1 ' ~ .
O' 1- 3 ,_ ,_ ,_ ,_ ~: ~ ~_ C~ CJl r~ ~ )- C~ _~
It ~I l tD ~ ~ I_ 00 ~ ~ ~ C~`
O) SU l o o o o C~ o o ` , _ o O o O o O O _UI
N (D I . o o o o o o o G~ W
1 o o o o o o O
_ _ _ ~, 1-'--1-~D cn a) cn c~ a) a~ a~ ^ W
~: ~ l O O ~ O 10 O oo G~ , 0~ O O O O O O O Ul, ~ ~. o o o ~ ~ o CJ~ ~
w 1~. l ;~ ;~ O Ul C o ~3 N
¦--O _ _ H ._ :~: ~ ::, 3 _ : _ C
*
_ __ ._ - 15 _ 2 ~
Example 2 b~,~-h of Table 3 shows~ hemical compositions ~se~--in the inventive Examples and the comparative Examples. With respect to Steels ~e/t ~
I to U, steel ingots of 110 mm thickness were made from ~ t-en teel, and the ingots were hot rolled b~he~ to 15 b~ h e c-t ill~ / 7~o c , mm thickness~ Steel I to S, W to Y, Z and b to d fall within the inventive chemical composition, while Steels T, U, V and a are comparative steels. Table 4 shows results o~ ~3i~uz3sg the DC magnetization properties and the ferrite cI~st~l grain sizes of the inventive steels and the comparative steels. In h~/d~
the annealings of the present Example, the heating - ~a~i-~ti~i-~i~y times were 1 to 3 hours, and the cooling rates were around 100C/hr to 500C/hr.
In Table 4, Nos.10 to 13 varied the Mn content within the ranges specified by the invention.
Nos.23 to 26 observed influences of the sol.Al content~
No.28 observed influences of the C content, and Nos.29 to 31 observed influences of the Si content.
Nos.14 to 16 added Ti. Also herein, the ferrite single phase were made by the Al addition, and further N was fixed by the Ti addition. Nos.14 to 16 show desirable properties.
No.15 is a~ ~special example where Ti was added to a steel equivalent to No.22 in accordance with the invention, and N
was sufficiently fixed by Ti addition so that a great improvement was observed in comparison with the comparative example of No.22.
NoO21 is a comparative example where Ti was added more than the specified range of the invention, and the DC magnetizat-ion property is remarkabl~ deteriorated.
No.22 is a comparative example where N addition was high and Ti was not added. Since a precipitation of AlN was stable, the ferrite ~r~ a~ grains were not fully coarsened in spite of the annealing, and a solute N content was high so that satisfied properties could not be realized. Nos.17 and 18 are examples where Steels P and Q were annealed at 1000C
Each of Nos.10 to 18, Nos.24 to 26, No.27 and Nos.29 to 31 not only can accomplish the excellent DC magnetization Iwhe~re ~`5 property ~ the coerceive force ~si~g not more than 0.4 Oe and the Bo 5 value ~e~g more than 10000 G and by far satisfy the `properties specified ~ JIS C 2504 SUYPO but also may be applied c 5~ p~es e h t;~l~
to as the magneti~ scr~cr-~ng material for }pepa~g magnetic field circumstances of a magnetic field level below the earth magnetism.
Nos.19 and 20 investigated influerlces of Ti in relationwith the N content and the C~N content, and the both had N > 0.005%
and C+N > 0.007%, but No.20 obtained a desired properties due to Ti addition.
Each of the inventive examples show the desirous DC magneti-zation property, and has coarse ferrite cr-ys~L grain of more than 0.5 mm.
As is seen from the above mentioned, the soft magnetic ou~
fi~ee~ materials according to the invention have the excellent h~
DC magnetization properties and may ~ /magnetized even in weak magnetic fields, and those are useful as iron core materials -- ~7 --C 5~1~e ldl s~q of high functions or magneti~ ~ material of high f unction .
_ _ _ DJ _ _ _ __ ~ _ _ _ _ _ _ O _ ~ _ _ ~, ~ p.~
U~
_ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ o o o o o o o o o o o o o o o o o o o o o o ~
o o o o o o o o o o o o o o o o o o o (~ 1-o o o o o o o o o o o o o o o o o o o o o o ,_ o o co ~ I_ ~ ~ r~ ,_ , ~ ~ ~ ~ ~ ,_ ~ o o o o o e~ ~ oo o vl ,~ C.~ _~ O ~ ~ ~ O ~ W r~ vl co Oo co ~ ~D W
. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ o o o o o o o o o o o o o o o o o o o o o o U~
Vl ,._ o o o o o o o o o o o O O o o o o o o o 1_, o _~ al ~_ ,_ e~ w ,_. ,_ ,_ ,_ ,_ ~_ ,_ ,- )- ~- ~- 1- ~ ~- ~-_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ O O O O O O O O O O O O O O O O O O ~ ~ ,_ O :7 . . _ _ _ I-- _ __ _ _ I._A _ _ _ _ _ _ _ _ _ _ _ _ U _ . o o o o o o o o o o o o o o o o o o o o o o 3 o o o o o o o o o o o o o o o o o o o o o o ~ ,..
O O O O O O O O O O O O O O O O O O O O O O n O O O O O O O O O ~ ~_ O l_ O l_ ~ ~_ ~_ O O O O ~
c~'l c7~ a) t,. a'l vl Vl ~:71 ~ W I_ C~ )- ~D O Crl C~l Vl Vl C'~ ~ -~ 1-_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ o3 o o o o o o o o o o . o o o o o o o o o o o ~
o o o o o o ~ o o o o o o o o o o o o o o o V~ U~
o o o o o o o o o o o o o o o o o o IJ
o o o o o o o o o o o o o o o o o ~ o o o o .
a) a~ a~ vl Vl ~ W C~ .~ ~ ~ Vl ~ ~ W Vl ~o O W ~ I`~ t`~ I' _ __ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ O
i_ I_ ~_ ~_ I_ )~ t O O ~_ ~_ ~_ ~_ 1~ O I_ t~ ~_ ~_ )~ ~_ ~_ O ~
t~ ~J ~ t-- ~ V) ~ t~ W ~_ ~ ~ ~ ~_ _1 ~ 1_ i_ ~ 1~ 1_ ~ . o\o c~ w 1~ 1~ vl t~ Iv cn o t~ ~ ul ,1~ _~ W _~ ~ ~ Vl ~ t~ O ~ _, . _ _ _ _ _ _ _ _. _ _ _ _ _ _ _ _ ~_ ~ _ _ _ O O O O O O O O O O O O O O O O O O O O O O
O O O O O O O O O ,._ O O O O O O ~_ O O O O O
)- ~_ I_ O ~ I_ O ~_ I_ ~ O V) ~1 O O O ~- ~ )- 1-' t- ~-~ ~ ot ~O cn ,_ o~ v w v) o~ ~1 o ~ tD ~ O~ ~ a~ ~ w ~
. _ _ _ - - - - - 1- - - - - - - - -- - - - - - -O O O O O O O O O O O O O O O O O O O O O O
O O O O O O O O O O O O O O O O O O O O O O O
O O O O O O O O O O O O O O O O O O O O O O
_ I_ ~ O ~_ ~_ 1~ I ~ _ ~ ~ )- ~ t~ ~ ~ ~ )~ O I_ O
~ O r~ o~ oo _) O V C~ V) O _ t~ O O O o O C~7 ,_ o7 _ ~ ~
rt rt r~ rt r~ rt rt ot rt r~ . . rt rt rt . . . rt rt rt r~ ~
~ ,,~ '1 ~ '1 '1 ~ ~ ~ ~ W O t~ ~ '1 O~ O O ~ ~ ~ 't 1~.
. . . _- . . . . . o C~ . . . W V) ~_ _- . . _ r~
/
_ _ _ _ _ _ _ _ ~ _ _ ~ _ _ _ ~_ _ _ _ _ ,_ ~:
~: !--O CD O~ ~ O) CJI ~ C~ _ _ O _ _ _ r cn _ _ _ _ o . O _ _ _ _ __ _ _ _ _ rt ~,. ~1 ~, ,rJ rJ~ ~u t~ ~1 ~ ~! ~ c1~ ~ cn ~:) Æ) ~ O ~ ~ t~ ~ c~ ~ ~ (D
H ~ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ~ _ _ ~:
~...
.. ~_ ~_ ~_ ~_ ~_ ~_ ~_ ~_ ~_ I_ ~_ ~_ ,--~_ ~ Y ~ ~_ ,_ ,_ ~_ ~_ ,_ _ ~ ,_ ,_ ~ ,- ~ ,_ ,_ o ,_ ,_ ,_ ~ o o ,_ ,_ o o ,_ ~_ ,_ ~ _ t~ ~) O O O O O O O O O O O O O O O O O ~n o o o o ~
X ~ o o o o o o o o o o o o o o o o o o o o o o ~_ _ 3~ _ _ _ _ _ _ _ _ _ _ ------------------ - - - l ~a ~ ~ ~ ,_ c~ .~ _, cn ~ ~ crl ~ cn cn ~ ~ cn ~ _~ ~ a~ ~
O co C~ ~ tO ~ ~ ~ ~ ~ ~ ~ ~ ~ -a ~ o~ c:n r~ _~ o ~ ~D
~h rt o o o _J o o ~ co o o cn o o _l o ~ o ~ o o o o n ~D o o o o o o o o o o o o o o o o o o o o o o D~
rt 3 o o o o o o o o o o o o o o o o o o o o o o - - - - - - - - - - - - - - - - - - - - - -rt o o o o o o o o o o . o o o o o o o o o o o O ~
tD ~1 ~ ~ ~ ~ ~ ,_ ,_ ,_ c~ u~ v- ~ .P ,_ ,_ ,_ ~ ~ ~ ,_ ,_ ,_ t~ ~
(D ~ r~ c~ a~ _~ ID r~ ~o ~o o ~ _~ v ~ o~ co ~ o ~ ~ r~ ~ ~_ rt U~
O-'`' _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ --~ ~_ ,_ )--~_ ~ ,_ ~_ ~_ ,_ ~_ )--~ ~_ ~_ ~ ~_ ~ --: ~ CA~ ~ ~ C`~ W C.~ ~ O ~_ C~ O ~ ~ ~ C~ C~ ~ C~ ~ C.
C17 O W _1 V~ ~_ V~ Vl .t:. ~ ~ ~_ _~ O Oo O~ V~ Vl t~ W --~ r~ o o o o o o o o o o o o o o o o o o o o o o o _~
O'' o o o o o o o o o o o o o o o o o o o o o o 3': _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ~ ~D ~ l- ~- ~ 1- ~- )- 1- ~' ~- 1- ~- ~- '- - ~ ~ ~- '- ~ ~-' ~ ~ C~ ~ C.~ ~ C~ ~ V- ~ C.~ ~ ~ ~P ~ ~ ~ ~ Cl~ C.
~1 ~D ~n o tD ~ ~ ,_ ,_ a- ~D rJ~ ~_ oo ~> ~ ~ Vl Cl~ I_ CO t~ tl~ C~ ~_ O (L~ o o o o o o o o o o o o o o o o o o o o o o 30 (D. o o o o o o o o o o o o o o o o o o o o o o ~H~ _ _ _ . _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ .
~ ~ ,- ~- ,- ,- ,- ,- ,- ,- --~- ,- ,- ,- ,- ,- ,- ,- ,- ~ ~- ~ ,-rt l't V7 rJ~ rJ~ v~ v7 r~ r o v- rJ7 ~ v7 r v7 r~ Vl V~ V7 Vl C V~ n r.7 td ~- (D o o o o o o o o o o o o o o o o o o o o o o ~' u~
(~ O O O O O O O O O O O O O O O O O O O O O O
3~t __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ~
~ n~ ~_ ~ ~~ O ~ c~ ~ ~ O O O ~ ~_ ~ ~ ~_ ~ ~ w ~ ~ ~ _~ ~
~ Vl ~ V~ O O ~Jl C~l ~ W O O Ln O C~1 O V~ O O V- CJ~ ~l _ ~' _ _ _ _ _ _ _ _ _ ~- _ _ _ _ _ _ _ _ _ _ __ _ _ ~J. .
N H O . H ( ) H ( ) ~
a ~ <~ ~0, ~ ~7 ~ . ~ ~ 3 ~ ~, ~ ::, ~, :, ~ ~ :, ~ . ;
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . .
- 20 - 2~
INDUSTRIAL APPLICABILITY
The present invention may be applied to production of soft magnetic materials, for example, electromagnetic cores or magnet~
5~,'e Id J~
~ r~in~ materials which require high DC magnetization propertles.
Claims (8)
1. A method of producing soft magnetic ferrous materials characterized by heating higher than 700°C but lower than 1300°C
a steel piece or a cast piece composed of C: not more than 0.004 wt%, Si: not more than 0.5 Wt%, Mn: not more than 0.50 wt%, P: not more than 0.015 wt%, S: not more than 0.01 wt%, sol.Al:
0.5 to 2.0 wt%, N: not more than 0.005 wt%, oxygen: not more than 0.005wt%, and the rest being Fe and unavoidable impurities, accomplishing a hot working at temperatures of higher than 700°C, and finally annealing at temperature of 900 to 1300°C, thereby to obtain a soft magnetic ferrous material having a coercive force of lower than 0.4 Oe and the magnetic flux density of more than 10000 G at the magnetic field of 0.5 Oe.
a steel piece or a cast piece composed of C: not more than 0.004 wt%, Si: not more than 0.5 Wt%, Mn: not more than 0.50 wt%, P: not more than 0.015 wt%, S: not more than 0.01 wt%, sol.Al:
0.5 to 2.0 wt%, N: not more than 0.005 wt%, oxygen: not more than 0.005wt%, and the rest being Fe and unavoidable impurities, accomplishing a hot working at temperatures of higher than 700°C, and finally annealing at temperature of 900 to 1300°C, thereby to obtain a soft magnetic ferrous material having a coercive force of lower than 0.4 Oe and the magnetic flux density of more than 10000 G at the magnetic field of 0.5 Oe.
2. The method as defined in claim 1, wherein C+N is not more than 0.007 wt%.
3. A method of producing soft magnetic ferrous materials characterized by heating higher than 700°C but lower than 1300°C
a steel piece or a cast piece composed of C: not more than 0.004 wt%, Si: not more than 0.1 Wt%, Mn: not more than 0.15 wt%, P: not more than 0.015 wt%, S: not more than 0.01 wt%, sol.Al:
0.5 to 2.0 wt%, N: not more than 0.005 wt%, oxygen: not more than 0.005wt%, and the rest being Fe and unavoidable impurities, accomplishing a hot working at temperatures of higher than 700°C, and finally annealing at temperature of 1000 to 1300°C, thereby to obtain a soft magnetic ferrous material having a coercive force of lower than 0.4 Oe and the magnetic flux density of more than 10000 G at the magnetic field of 0.5 Oe.
a steel piece or a cast piece composed of C: not more than 0.004 wt%, Si: not more than 0.1 Wt%, Mn: not more than 0.15 wt%, P: not more than 0.015 wt%, S: not more than 0.01 wt%, sol.Al:
0.5 to 2.0 wt%, N: not more than 0.005 wt%, oxygen: not more than 0.005wt%, and the rest being Fe and unavoidable impurities, accomplishing a hot working at temperatures of higher than 700°C, and finally annealing at temperature of 1000 to 1300°C, thereby to obtain a soft magnetic ferrous material having a coercive force of lower than 0.4 Oe and the magnetic flux density of more than 10000 G at the magnetic field of 0.5 Oe.
4. The method as defined in claim 3, wherein C+N is not more than 0.007 wt%.
5. A method of producing soft magnetic ferrous materials characterized by heating higher than 700°C but lower than 1300°C
a steel piece or a cast piece composed of C: not more than 0.004 wt%, Si: not more than 0.5 Wt%, Mn: not more than 0.50 wt%, P: not more than 0.015 wt%, S: not more than 0.01 wt%, sol.Al:
0.5 to 2.0 wt%, N: not more than 0.012 wt%, oxygen: not more than 0.005 wt%, Ti: 0.005 to 1.0 wt% and the rest being Fe and unavoidable impurities, accomplishing a hot working at temperatures of higher than 700°C, and finally annealing at temperature of 900 to 1300°C, thereby to obtain a soft magnetic ferrous material having a coercive force of lower than 0.4 Oe and the magnetic flux density of more than 10000 G at the magnetic field of 0.5 Oe.
a steel piece or a cast piece composed of C: not more than 0.004 wt%, Si: not more than 0.5 Wt%, Mn: not more than 0.50 wt%, P: not more than 0.015 wt%, S: not more than 0.01 wt%, sol.Al:
0.5 to 2.0 wt%, N: not more than 0.012 wt%, oxygen: not more than 0.005 wt%, Ti: 0.005 to 1.0 wt% and the rest being Fe and unavoidable impurities, accomplishing a hot working at temperatures of higher than 700°C, and finally annealing at temperature of 900 to 1300°C, thereby to obtain a soft magnetic ferrous material having a coercive force of lower than 0.4 Oe and the magnetic flux density of more than 10000 G at the magnetic field of 0.5 Oe.
6. The method as defined in claim 5, where C+N is not more than 0.014 wt%.
7. A method of producing soft magnetic ferrous materials characterized by heating higher than 700°C but lower than 1300°C
a steel piece or a cast piece composed of C: not more than 0.004 wt%, Si: not more than 0.1 Wt%, Mn: not more than 0.15 wt%, P: not more than 0.015 wt%, S: not more than 0.01 wt%, sol.Al:
0.5 to 2.0 wt%, N: not more than 0.012 wt%, oxygen: not more than 0.005 wt%, Ti: 0.005 to 1.0 wt% and the rest being Fe and unavoidable impurities, accomplishing a hot working at temperatures of higher than 700°C, and finally annealing at temperature of 1000 to 1300°C, thereby to obtain a soft magnetic ferrous material having a coercive force of lower than 0.4 Oe and the magnetic flux density of more than 10000 G at the magnetic field of 0.5 Oe.
a steel piece or a cast piece composed of C: not more than 0.004 wt%, Si: not more than 0.1 Wt%, Mn: not more than 0.15 wt%, P: not more than 0.015 wt%, S: not more than 0.01 wt%, sol.Al:
0.5 to 2.0 wt%, N: not more than 0.012 wt%, oxygen: not more than 0.005 wt%, Ti: 0.005 to 1.0 wt% and the rest being Fe and unavoidable impurities, accomplishing a hot working at temperatures of higher than 700°C, and finally annealing at temperature of 1000 to 1300°C, thereby to obtain a soft magnetic ferrous material having a coercive force of lower than 0.4 Oe and the magnetic flux density of more than 10000 G at the magnetic field of 0.5 Oe.
8. The method as defined in claim 7, wherein C+N is not more than 0.014 wt%.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP155,025 | 1989-06-17 | ||
| JP1155025A JP2682144B2 (en) | 1988-10-24 | 1989-06-17 | Method for manufacturing soft magnetic steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2019187A1 true CA2019187A1 (en) | 1990-12-17 |
Family
ID=15597026
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002019187A Abandoned CA2019187A1 (en) | 1989-06-17 | 1990-06-18 | Method of producing soft magnetic steel materials |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0431167B1 (en) |
| JP (1) | JP2682144B2 (en) |
| KR (1) | KR960014944B1 (en) |
| CN (1) | CN1048236A (en) |
| CA (1) | CA2019187A1 (en) |
| DE (1) | DE68927174T2 (en) |
| WO (1) | WO1990015886A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0499819A (en) * | 1990-08-15 | 1992-03-31 | Nkk Corp | Production of mild magnetic steel products |
| DE4293604C2 (en) * | 1991-10-14 | 1997-04-03 | Nippon Kokan Kk | Soft magnetic steel material and process for its manufacture |
| KR100915199B1 (en) * | 2007-09-07 | 2009-09-02 | 하미란 | Manufacturing method for steel articles having soft magnetic property by hot forging and housing and core manufactured by the method |
| CN102796948B (en) * | 2011-05-27 | 2014-03-19 | 宝山钢铁股份有限公司 | Non-oriented electrical steel plate with extremely low content of Ti and smelting method for non-oriented electrical steel plate |
| WO2013072124A1 (en) * | 2011-11-14 | 2013-05-23 | Nv Bekaert Sa | Steel wire for magnetic field absorption |
| CN104139167A (en) * | 2014-07-31 | 2014-11-12 | 攀钢集团工程技术有限公司 | Iron core, electromagnetic inductor with same and electromagnetic stirring device |
| KR101977507B1 (en) * | 2017-12-22 | 2019-05-10 | 주식회사 포스코 | Steel sheet for magnetic field shielding and method for manufacturing the same |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3971678A (en) * | 1972-05-31 | 1976-07-27 | Stahlwerke Peine-Salzgitter Aktiengesellschaft | Method of making cold-rolled sheet for electrical purposes |
| JPS60208417A (en) * | 1984-03-30 | 1985-10-21 | Sumitomo Metal Ind Ltd | Production of hot-rolled high magnetic permeability iron sheet |
| JPS6345443A (en) * | 1986-08-11 | 1988-02-26 | Toyota Motor Corp | Abnormality deciding method for air-fuel ratio controller |
-
1989
- 1989-06-17 JP JP1155025A patent/JP2682144B2/en not_active Expired - Fee Related
- 1989-12-08 EP EP90900339A patent/EP0431167B1/en not_active Expired - Lifetime
- 1989-12-08 WO PCT/JP1989/001231 patent/WO1990015886A1/en active IP Right Grant
- 1989-12-08 KR KR1019910700177A patent/KR960014944B1/en not_active IP Right Cessation
- 1989-12-08 DE DE68927174T patent/DE68927174T2/en not_active Expired - Fee Related
- 1989-12-08 CN CN89109230A patent/CN1048236A/en active Pending
-
1990
- 1990-06-18 CA CA002019187A patent/CA2019187A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| KR960014944B1 (en) | 1996-10-21 |
| CN1048236A (en) | 1991-01-02 |
| EP0431167A4 (en) | 1993-02-24 |
| KR920700301A (en) | 1992-02-19 |
| DE68927174D1 (en) | 1996-10-17 |
| JPH02213421A (en) | 1990-08-24 |
| JP2682144B2 (en) | 1997-11-26 |
| EP0431167B1 (en) | 1996-09-11 |
| WO1990015886A1 (en) | 1990-12-27 |
| EP0431167A1 (en) | 1991-06-12 |
| DE68927174T2 (en) | 1997-03-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR100753940B1 (en) | Non-oriented magnetic steel sheet excellent in magnetic characteristic in rolling direction, and method for producing the same | |
| WO1996000306A1 (en) | Method of manufacturing non-oriented electromagnetic steel plate having high magnetic flux density and low iron loss | |
| WO2019105041A1 (en) | Non-oriented electrical steel sheet with excellent magnetism and manufacturing method therefor | |
| CA2019187A1 (en) | Method of producing soft magnetic steel materials | |
| KR20010100866A (en) | Low iron loss non-oriented electrical steel sheet excellent in workability and method for producing the same | |
| US20020062885A1 (en) | Co-Mn-Fe soft magnetic alloys | |
| US4948434A (en) | Method for manufacturing Ni-Fe alloy sheet having excellent DC magnetic property and excellent AC magnetic property | |
| JP2007031754A (en) | Method for manufacturing non-oriented electromagnetic steel sheet to be aged | |
| JP3835227B2 (en) | Non-oriented electrical steel sheet and manufacturing method thereof | |
| EP0429651A1 (en) | Iron base, soft magnetic steel material | |
| US5019191A (en) | Magnetic steel plate for use as a magnetic shielding member and a method for the manufacture thereof | |
| CN112030076A (en) | High-strength electrical steel for high-speed motor and preparation method thereof | |
| JP4303431B2 (en) | Ultra high magnetic flux density non-oriented electrical steel sheet and manufacturing method thereof | |
| CN114875318B (en) | Dispersed delta phase strengthened low-density high-strength and high-toughness steel and manufacturing method thereof | |
| JP4422220B2 (en) | Non-oriented electrical steel sheet with high magnetic flux density and low iron loss and method for producing the same | |
| CN102264922B (en) | Non-oriented electrical steel sheets having high workability for client companies and manufacturing method thereof | |
| JP3430794B2 (en) | Non-oriented electrical steel sheet excellent in magnetic properties and method for producing the same | |
| JP3037878B2 (en) | Non-oriented electrical steel sheet excellent in iron loss after strain relief annealing and method for producing the same | |
| CN109097679B (en) | Marine low-magnetic steel and preparation method thereof | |
| Kubota et al. | Magnetic properties of high-efficiency core materials NC-M3 and NC-M4 | |
| KR101246456B1 (en) | High strength steel sheet and method of manufacturing the high strength steel sheet | |
| JP2006124809A (en) | Nonoriented magnetic steel sheet having excellent iron core after stress relieving annealing and its production method | |
| KR101110257B1 (en) | Non-oriented electrical steel sheet with high magnetic flux density and manufacturing method thereof | |
| JP3280959B1 (en) | Low iron loss non-oriented electrical steel sheet with good workability and method for producing the same | |
| CN113166880A (en) | Non-oriented electrical steel sheet and method for manufacturing the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |