CA1050863A - Steels for electromagnetic applications - Google Patents
Steels for electromagnetic applicationsInfo
- Publication number
- CA1050863A CA1050863A CA236,029A CA236029A CA1050863A CA 1050863 A CA1050863 A CA 1050863A CA 236029 A CA236029 A CA 236029A CA 1050863 A CA1050863 A CA 1050863A
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- CA
- Canada
- Prior art keywords
- strip
- temperature
- anneal
- steel
- range
- 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.)
- Expired
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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
- 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
- C21D8/1261—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 following hot rolling
-
- 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
- C21D8/1205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties involving a particular fabrication or treatment of ingot or slab
-
- 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
- C21D8/1255—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 with diffusion of elements, e.g. decarburising, nitriding
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Crystallography & Structural Chemistry (AREA)
- Thermal Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Electromagnetism (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing Of Steel Electrode Plates (AREA)
- Soft Magnetic Materials (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A process for producing grain oriented silicon steel for electromagnetic applications comprising producing by a conventional refining process a steel yielding a slab having a carbon content of up to 0.08% by weight and a silicon content lying between 2.5%
and 3.5% hot rolling the slab to strip which is annealed at a temperature within the range 850°C to 1050°C, cold rolling the annealed strip to substantially final gauge, subjecting the cold rolled strip to a decarburising anneal at a temperature within the range 850°C to 1050°C so as to reduce carbon concentration to less than 0.005% and subjecting the strip to a final anneal at a temperature up to 1200°C.
A process for producing grain oriented silicon steel for electromagnetic applications comprising producing by a conventional refining process a steel yielding a slab having a carbon content of up to 0.08% by weight and a silicon content lying between 2.5%
and 3.5% hot rolling the slab to strip which is annealed at a temperature within the range 850°C to 1050°C, cold rolling the annealed strip to substantially final gauge, subjecting the cold rolled strip to a decarburising anneal at a temperature within the range 850°C to 1050°C so as to reduce carbon concentration to less than 0.005% and subjecting the strip to a final anneal at a temperature up to 1200°C.
Description
~01~63 This invention relates to the production o~ grain oriented silicon steel sheet or strip of low core loss which is used as magnetic core material in electric machines such as transormers and the like. Such material has a preferred grain orientation or texture defined in Miller indice~ as ~110) 001, that is to say the individual grains making up the sheet or strip have their (110) crys-tallographic planes predominantly parallel to the sheet or trip surface and their 001 crystallographic directions predominantly paralle:L to the rolling diréction of the sheet or stripO
.. According to one aspect of the present invention a procéss for producing grain oriented silicon steel for ; electromagnetic applicati.ons comprises producing by a conven-tional refining process a steel yielding a slab having a carbon content of up to 0.08% by weight and a silicon content lying between 2~5% and 3.5%, hot rolling the slab to strip, which is annealed at a temperature lying within the range 8S0C to 1050C, cold rolling the annealed strip to sub-stantially final gauge, subjecting the cold rolled strip to a decarburising anneal at a temperature within the range 850C -to 1050C so as to reduce carbon concentration to less than 005% and subjecting the strip to a final anneal at a temperature up to 1200C. .
; Preferably the slab is reduced to hot band within the thickness range 1.5mm - 3.0mm.
The final anneal conveniently is a box anneal which preferably is within the range 1150C to 1200C.
.In one embodiment of the invention the steel of the slab suitably contains manganese and sulphur which subse~uent--~ 30 ly combine to produce manganese sulphide precipitates in the . hot rolled sheet or strip, such manganese sulphide precipita-;~ tes subsequently acting as a grain growth inhibitor effective 1C~5~38~3 to produce material displaying good core loss characteristics.
The manganese sulphide is obtained by adding manganese in concentrations of up to 0.1% by weight to the steel melt at any suitable stage up to casting of the ingot for slabbing. -In this embodiment of the invention the ingot may be derived from a melt produced by any conventional steel-making process and typically having a composition adjusted to 0.02% to 0,035% carbon, 2.8% to 3.5% silicon, 0~02% to 0.03% sulphur, and 0.05% to 0.09% manganese, the balance being iron and incidental impurities. Slabs obtained from such a melt either by ingot casting and hot rolling or directly by continuous slab casting are reheated at a temperature within the range 1350C to-1400C and hot rolled into strip conveniently of about 1.9mm thickness. The hot rolliny parameters may be those conventionally used in the art.
The hot band so produced may be annealed at between 850C to 1000C typically for a few minutes and then cold ~
rolied to substantially final gauge without intermediate , ;, annealing. The cold rolled strip is then continuously annealed in wet hydrogen or other decarburising atmosphere, -~
preferably between 900C to 1000C although any temperature within the range 850C to 1050C may be used. ;
The decarburising temperature whi~h is higher than that conventionally used may be maintained substantially ;~
constant during the period the strip or sheet remains in the ;~
annealing furnace. However the annealing furnace may be arranged to heat the strip through two distinct temperature ranges respectively effective to reduce carbon concentration and to develop the final magnetic characteristics required~
`30 Conveniently the strip is heated in a typical annealing furnace over two temperature plateaux extending batween 800C to 850C and between 900C to 1000C. The sequence .
.. According to one aspect of the present invention a procéss for producing grain oriented silicon steel for ; electromagnetic applicati.ons comprises producing by a conven-tional refining process a steel yielding a slab having a carbon content of up to 0.08% by weight and a silicon content lying between 2~5% and 3.5%, hot rolling the slab to strip, which is annealed at a temperature lying within the range 8S0C to 1050C, cold rolling the annealed strip to sub-stantially final gauge, subjecting the cold rolled strip to a decarburising anneal at a temperature within the range 850C -to 1050C so as to reduce carbon concentration to less than 005% and subjecting the strip to a final anneal at a temperature up to 1200C. .
; Preferably the slab is reduced to hot band within the thickness range 1.5mm - 3.0mm.
The final anneal conveniently is a box anneal which preferably is within the range 1150C to 1200C.
.In one embodiment of the invention the steel of the slab suitably contains manganese and sulphur which subse~uent--~ 30 ly combine to produce manganese sulphide precipitates in the . hot rolled sheet or strip, such manganese sulphide precipita-;~ tes subsequently acting as a grain growth inhibitor effective 1C~5~38~3 to produce material displaying good core loss characteristics.
The manganese sulphide is obtained by adding manganese in concentrations of up to 0.1% by weight to the steel melt at any suitable stage up to casting of the ingot for slabbing. -In this embodiment of the invention the ingot may be derived from a melt produced by any conventional steel-making process and typically having a composition adjusted to 0.02% to 0,035% carbon, 2.8% to 3.5% silicon, 0~02% to 0.03% sulphur, and 0.05% to 0.09% manganese, the balance being iron and incidental impurities. Slabs obtained from such a melt either by ingot casting and hot rolling or directly by continuous slab casting are reheated at a temperature within the range 1350C to-1400C and hot rolled into strip conveniently of about 1.9mm thickness. The hot rolliny parameters may be those conventionally used in the art.
The hot band so produced may be annealed at between 850C to 1000C typically for a few minutes and then cold ~
rolied to substantially final gauge without intermediate , ;, annealing. The cold rolled strip is then continuously annealed in wet hydrogen or other decarburising atmosphere, -~
preferably between 900C to 1000C although any temperature within the range 850C to 1050C may be used. ;
The decarburising temperature whi~h is higher than that conventionally used may be maintained substantially ;~
constant during the period the strip or sheet remains in the ;~
annealing furnace. However the annealing furnace may be arranged to heat the strip through two distinct temperature ranges respectively effective to reduce carbon concentration and to develop the final magnetic characteristics required~
`30 Conveniently the strip is heated in a typical annealing furnace over two temperature plateaux extending batween 800C to 850C and between 900C to 1000C. The sequence .
- 2 -~. . ; -~OS0~363 of low temperature and high temperature plateaux may h~wever be reversed if so required.
The use of a decarburising anneal temperature of up to 1050C which is higher than that conventionally employed allows good secondary recrystallisation to occur during subsequent box annealing which conveniently is for about 24 hours at a temperature of up to 1190C. It is believed that such secondary recrystallisation would not occur with single stage cold rolled material which is decarburised within the normal temperature range of between 800C to 850CC at present employed in conventional processes for producing grain ; oriented silicon steels.
In an alternative embodiment of the invention the steel may include aluminium nitride as a grain growth inhibitor in addition to manganese sulphide. In this case the aluminium nitride is pro-/
/
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~ ' ~ - 3 -. .
Sg~863 duced ~y inoculating the steeL with aluminium at any stage up to casting of the ingot so that the final concentration of acid solu-ble aluminlum is up to ~.065% by weight. In this alternative em-bodiment the steel again is produced from a melt arising rom any conventional steelmaking process and typically adjusted to contain 0.02% to 0.06% carbon, 2.5% to 3.5% silicon~ 0.01% to 0.06% acid soluble aluminLum, 0.05% to 0;1% manganese and 0.02% to 0.03% sul-phur, the balance being iron and other incidental impurities.
After casting lnto ingots and rolling to slabs, the slabs are re-heated wlthin the temperature range 1350C to 1400C and hot rolled to strip of about 2.8mm thickness.
In accordance with the present invention the hot band so pro~
duced is annealed at a temperature between 850C to 1000C that is to say at a considerably lower temperature than conventional r~15 finishing processes involving aluminium nitride as a grain growth --inhibitor and is after picking cold rolled directly to substan-tially final gauge.
The cold rolled strip is subject to a decarburisation anneal at a temperature wit~in the range 850C to 1050C and is subse~
quently box annealed for about 24 hours at about 1190C. As previou~ly, the annealing may be achieved in a suitable furnace ;~
which may display a temperature gradient including two temperature plateaux.
It is believed that ~he non-conventional comblnation of hot . . . . . .
~5 band annealing and decarburisation temperature produces grain ' orlented material having magnetic characteristics at least equi-.. ; , , .
:~ .
'', ~
- ' .", r_~
. ~ . , ' ' . . . ' .
~5D8~;3 valent to those produced by more costly alternative processes.
Embodiment of the invention will now be particularly described by way of the following examples.
An open hearth steel of pit analysis 0.~29%C, 0.079/~Mn, 0.028%S, 3.18%Si, 0.007%P, 0.0065/~, 0.116%Cu, 0 . 044~Ni ~ and 0.018%Sn was cast into ingots which were sub-sequently rolled into slabs. The slabs after reheating to about 1400C were rolled on a continuous hot strip mill to produce hot rolled strip 1.92mm thlck. Sheets of this hot rolled strip were annealed at 910C for a total residence time of 5 minutes. After pickling these sheets were cold rolled to 0.337mm thick in several passes without intermediate annealing. The cold rolled sheets were then decarburisation annealed at 950C for about 5 minutes in hydrogen with a dewpoint of 60C. After coating with magnesia the decarburi~ed sheets were annealed at about 1190C for about 24 hours.
Epstein samples cut from the annealed material gave, after stress relief annealing, core loss values of 1.03 to 1.09 W/kg at 1.5T and 50Hz. These values are all within the M6 grade specification of l.llW/kg for this thickness of material.
A basic oxygen converter, vacuum degassed melt was cast into ingots which were subsequently hot rolled into slabs. The slabs after reheating to about 1400C were rolled on a continuous hot strip mill to produce hot rolled strip 2.97mm thicko The hot rolled strip analysed 0.041%C~ 0.080/~n, ; 2.94%Si~ 0.024%S, 0.013%P, 7/~2' and 0.025% acid soluble ` Al. Sheets of this hot rolled strip were annealed at 900C
to 910C for a total residence time of 5 minutes. After pickling these sheets were cold rolled to 0.337mm thick in several passes without intermediate annealing. The cold .. ' ~ .
' ~ ~' '' ' . , ~
~ 08~;3 :~ `
rolled sheets were then decarburisation annealed at 950C
for about 5 minutes in hydrogen with a clewpoint of 60C.
After coating with magnesia the decarburised sheets were annealed at about 1190C for about 24 hours~ The material thus produced had excellent orientation of the (110) 00~ ;
type and gave the following magnetic test results:-Core loss at 1.5T, 50Hz - 0.91 to 1.00 W/kg, mean 0.96 W/kg Core loss at 1.7T, 50Hz - 1.16 to 1.36 W/kg, mean 1.28 W/kg B at H = lkA/m - 1.90 to 1.94T, mean 1.92T
An open hearth steel pit analysis 0.024%C, 0.087/~Mn, 0.027%S, 3.08%Si, 0.008YoPl 7/~2' 0.142%Cu, 0.0580/oNil 0.018%Sn were cast into ingots which were subsequently rolled to slabs. After reheating to 1400C the slabs were rolled on a continuous hot strip mill to produce hot rolled strip 2.28mm thick. Sheets of this hot rolled strip were annealed at ~-, 1000C for a to-tal residence time of 5 minutes. After pickli~g, ~`
- these sheets were cold rolled to 0.337mm thick in several passes without intermediate annealing. The cold rolled sheets were then decarburised at 900C for about 5 minutes in hydrogen ~dewpoint + 60C). After coating with magnesia the decarburised sheets were annealed at about 1190C for 24 hours. Epstein samples cut from the annealed material gave, after stress relief annealing, core loss values of 1.06 to 1.07 at 1.5T
and 50Hz and permeabilities of B = 1.78 to 1.81 at H = lkA/m.
, . . .
A basic oxygen converter, vacuum degassed melt was cast into ingots which were subsequently hot rolled in slabs.
The slabs after reheating to about 1400C were rolled on a continuous hot strip mill to produce hot rolled strip 2.03 mm : .
-` thick. The hot rolled strip analysed 0.029%C, 3.14%Si, O.02S%S, 0.008%P, 0.067~/~Mn, O.015~i, 0.042%Cu, 0.008%Sn, ` - 6 -' .
~L~5~ 3 0.0042%N, 0.004f~1. This hot rolled strip was processed through a work continuous annealing furnace at 900C for a total time in furnace of 5 minutes~ After pickling, the .
strip was cold rolled to 0.354mm in several passes without intermediate annealing. The cold rolled sheets were then decarburisation annealed in a continuous annealing line at 950C for about 5 minutes in hydrogen (dewpoint + 60C).
After magnesia coating the decarburised strip was coiled and annealed at 1190C for 24 hours. The material thus ~.
produced had an excellent orientation of the (110) 001 type and gave the following magnetic test results after stress relief annealing:-Core loss at 1.5T, 50Hz - 1.03 - 1.13 mean 1.07 Core loss at 1.7T, 50Hz - 1.47 - 1.61 mean 1.53 Permeability B at H = lkA/m 1.76 - 1.82 mean 1.79 ~o significant variation of magnetic properties was detected ~:
between those embodiments in which the strip was or was not allowed to cool toward ambient between the decarburisation anneal and the final anneal.
, ' ' ~'~
.
,
The use of a decarburising anneal temperature of up to 1050C which is higher than that conventionally employed allows good secondary recrystallisation to occur during subsequent box annealing which conveniently is for about 24 hours at a temperature of up to 1190C. It is believed that such secondary recrystallisation would not occur with single stage cold rolled material which is decarburised within the normal temperature range of between 800C to 850CC at present employed in conventional processes for producing grain ; oriented silicon steels.
In an alternative embodiment of the invention the steel may include aluminium nitride as a grain growth inhibitor in addition to manganese sulphide. In this case the aluminium nitride is pro-/
/
': / ' /
''~ ' ' / '''', ':
.,~
~' / ' .
'' / ~ .:
~ ' ~ - 3 -. .
Sg~863 duced ~y inoculating the steeL with aluminium at any stage up to casting of the ingot so that the final concentration of acid solu-ble aluminlum is up to ~.065% by weight. In this alternative em-bodiment the steel again is produced from a melt arising rom any conventional steelmaking process and typically adjusted to contain 0.02% to 0.06% carbon, 2.5% to 3.5% silicon~ 0.01% to 0.06% acid soluble aluminLum, 0.05% to 0;1% manganese and 0.02% to 0.03% sul-phur, the balance being iron and other incidental impurities.
After casting lnto ingots and rolling to slabs, the slabs are re-heated wlthin the temperature range 1350C to 1400C and hot rolled to strip of about 2.8mm thickness.
In accordance with the present invention the hot band so pro~
duced is annealed at a temperature between 850C to 1000C that is to say at a considerably lower temperature than conventional r~15 finishing processes involving aluminium nitride as a grain growth --inhibitor and is after picking cold rolled directly to substan-tially final gauge.
The cold rolled strip is subject to a decarburisation anneal at a temperature wit~in the range 850C to 1050C and is subse~
quently box annealed for about 24 hours at about 1190C. As previou~ly, the annealing may be achieved in a suitable furnace ;~
which may display a temperature gradient including two temperature plateaux.
It is believed that ~he non-conventional comblnation of hot . . . . . .
~5 band annealing and decarburisation temperature produces grain ' orlented material having magnetic characteristics at least equi-.. ; , , .
:~ .
'', ~
- ' .", r_~
. ~ . , ' ' . . . ' .
~5D8~;3 valent to those produced by more costly alternative processes.
Embodiment of the invention will now be particularly described by way of the following examples.
An open hearth steel of pit analysis 0.~29%C, 0.079/~Mn, 0.028%S, 3.18%Si, 0.007%P, 0.0065/~, 0.116%Cu, 0 . 044~Ni ~ and 0.018%Sn was cast into ingots which were sub-sequently rolled into slabs. The slabs after reheating to about 1400C were rolled on a continuous hot strip mill to produce hot rolled strip 1.92mm thlck. Sheets of this hot rolled strip were annealed at 910C for a total residence time of 5 minutes. After pickling these sheets were cold rolled to 0.337mm thick in several passes without intermediate annealing. The cold rolled sheets were then decarburisation annealed at 950C for about 5 minutes in hydrogen with a dewpoint of 60C. After coating with magnesia the decarburi~ed sheets were annealed at about 1190C for about 24 hours.
Epstein samples cut from the annealed material gave, after stress relief annealing, core loss values of 1.03 to 1.09 W/kg at 1.5T and 50Hz. These values are all within the M6 grade specification of l.llW/kg for this thickness of material.
A basic oxygen converter, vacuum degassed melt was cast into ingots which were subsequently hot rolled into slabs. The slabs after reheating to about 1400C were rolled on a continuous hot strip mill to produce hot rolled strip 2.97mm thicko The hot rolled strip analysed 0.041%C~ 0.080/~n, ; 2.94%Si~ 0.024%S, 0.013%P, 7/~2' and 0.025% acid soluble ` Al. Sheets of this hot rolled strip were annealed at 900C
to 910C for a total residence time of 5 minutes. After pickling these sheets were cold rolled to 0.337mm thick in several passes without intermediate annealing. The cold .. ' ~ .
' ~ ~' '' ' . , ~
~ 08~;3 :~ `
rolled sheets were then decarburisation annealed at 950C
for about 5 minutes in hydrogen with a clewpoint of 60C.
After coating with magnesia the decarburised sheets were annealed at about 1190C for about 24 hours~ The material thus produced had excellent orientation of the (110) 00~ ;
type and gave the following magnetic test results:-Core loss at 1.5T, 50Hz - 0.91 to 1.00 W/kg, mean 0.96 W/kg Core loss at 1.7T, 50Hz - 1.16 to 1.36 W/kg, mean 1.28 W/kg B at H = lkA/m - 1.90 to 1.94T, mean 1.92T
An open hearth steel pit analysis 0.024%C, 0.087/~Mn, 0.027%S, 3.08%Si, 0.008YoPl 7/~2' 0.142%Cu, 0.0580/oNil 0.018%Sn were cast into ingots which were subsequently rolled to slabs. After reheating to 1400C the slabs were rolled on a continuous hot strip mill to produce hot rolled strip 2.28mm thick. Sheets of this hot rolled strip were annealed at ~-, 1000C for a to-tal residence time of 5 minutes. After pickli~g, ~`
- these sheets were cold rolled to 0.337mm thick in several passes without intermediate annealing. The cold rolled sheets were then decarburised at 900C for about 5 minutes in hydrogen ~dewpoint + 60C). After coating with magnesia the decarburised sheets were annealed at about 1190C for 24 hours. Epstein samples cut from the annealed material gave, after stress relief annealing, core loss values of 1.06 to 1.07 at 1.5T
and 50Hz and permeabilities of B = 1.78 to 1.81 at H = lkA/m.
, . . .
A basic oxygen converter, vacuum degassed melt was cast into ingots which were subsequently hot rolled in slabs.
The slabs after reheating to about 1400C were rolled on a continuous hot strip mill to produce hot rolled strip 2.03 mm : .
-` thick. The hot rolled strip analysed 0.029%C, 3.14%Si, O.02S%S, 0.008%P, 0.067~/~Mn, O.015~i, 0.042%Cu, 0.008%Sn, ` - 6 -' .
~L~5~ 3 0.0042%N, 0.004f~1. This hot rolled strip was processed through a work continuous annealing furnace at 900C for a total time in furnace of 5 minutes~ After pickling, the .
strip was cold rolled to 0.354mm in several passes without intermediate annealing. The cold rolled sheets were then decarburisation annealed in a continuous annealing line at 950C for about 5 minutes in hydrogen (dewpoint + 60C).
After magnesia coating the decarburised strip was coiled and annealed at 1190C for 24 hours. The material thus ~.
produced had an excellent orientation of the (110) 001 type and gave the following magnetic test results after stress relief annealing:-Core loss at 1.5T, 50Hz - 1.03 - 1.13 mean 1.07 Core loss at 1.7T, 50Hz - 1.47 - 1.61 mean 1.53 Permeability B at H = lkA/m 1.76 - 1.82 mean 1.79 ~o significant variation of magnetic properties was detected ~:
between those embodiments in which the strip was or was not allowed to cool toward ambient between the decarburisation anneal and the final anneal.
, ' ' ~'~
.
,
Claims (20)
1. A process for producing grain oriented silicon steel for electromagnetic applications, which comprises producing by a conventional refining process a steel yielding a slab having a carbon content of up to 0.08% by weight and a silicon content lying between 2.5% and 3.5% hot rolling the slab to strip which is annealed at a temperature within the range 850°C to 1050°C, cold rolling the annealed strip to substantially final gauge, subjecting the cold rolled strip to a decarburising anneal at a temperature within the range 850°C to 1050°C so as to reduce carbon concen-tration to less than 0.005% and subjecting the strip to a final anneal at a temperature up to 1200°C.
2. A process as claimed in claim 1, wherein the steel is produced by basic oxygen refining.
3. A process as claimed in claim 1, wherein the steel is produced by open hearth refining.
4. A process as claimed in claims 1, 2 or 3, wherein the steel is adjusted to a composition comprising 0.02% to 0.035%
carbon, 2.8% to 3.5% silicon, 0.02% to 0.03% sulphur and 0.05%
to 0.098 manganese, the remainder being iron and incidental impurities.
carbon, 2.8% to 3.5% silicon, 0.02% to 0.03% sulphur and 0.05%
to 0.098 manganese, the remainder being iron and incidental impurities.
5. A process as claimed in claim 1, wherein the steel is inoculated with manganese.
6. A process as claimed in claim 5, wherein the manganese is inoculated to a concentration of up to 0.10% by weight.
7. A process as claimed in claim 1, wherein the steel is inoculated with aluminium.
8. A process as claimed in claim 7, wherein the steel is adjusted to a composition comprising 0.02% to 0.06% carbon, 2.5% to 3.5% silicon, 0.01% to 0.06% acid soluble aluminium, 0.05% to 0.1% manganese and 0.02% to 0.03% sulphur, the balance being iron and other incidental impurities.
9. A process as claimed in claim 1, wherein the slab is heated to a temperature within the range 1350°C to 1400°C
prior to hot rolling.
prior to hot rolling.
10. A process as claimed in claim 1, wherein strip is hot rolled to a thickness with the range 1.5 mm to 3.0 mm.
11. A process as claimed in claim 1, wherein the hot rolled strip is annealed at about 900°C.
12. A process as claimed in claim 1, wherein the cold reduced strip is decarburisation annealed at a temperature within the range 900°C to 1000°C.
13. A process as claimed in claim 1 or 12, wherein the decarburising anneal is in an atmosphere of wet hydrogen.
14. A process as claimed in claim 1, wherein the decarburising anneal is preceded or followed by an anneal at a temperature within the range 800°C to 850°C.
15. A process as claimed in claim 14, wherein the preceding or following anneal is a decarburising anneal.
16. A process as claimed in claim 14, wherein the two annealing stages are produced in a continuous annealing furnace having respective temperature plateaux.
17. A process as claimed in claim 16, wherein the respective temperature plateaux lie within the ranges 800°C to 850°C and 900°C to 1000°C.
18. A process as claimed in claim 1, wherein the final anneal is at a temperature of about 1190°C.
19. A process as claimed in claim 1 or 18, wherein the final anneal is a box anneal.
20. A process as claimed in claim 1, wherein the strip temperature falls to ambient between the decarburising and final anneal.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB41353/74A GB1521680A (en) | 1974-09-23 | 1974-09-23 | Steels for electromagnetic applications |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1050863A true CA1050863A (en) | 1979-03-20 |
Family
ID=10419301
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA236,029A Expired CA1050863A (en) | 1974-09-23 | 1975-09-22 | Steels for electromagnetic applications |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS6041132B2 (en) |
| BE (1) | BE833649A (en) |
| CA (1) | CA1050863A (en) |
| DE (1) | DE2542173A1 (en) |
| FR (1) | FR2285462A1 (en) |
| GB (1) | GB1521680A (en) |
| IT (1) | IT1047423B (en) |
| SE (1) | SE7510579L (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4054471A (en) * | 1976-06-17 | 1977-10-18 | Allegheny Ludlum Industries, Inc. | Processing for cube-on-edge oriented silicon steel |
| DE2841961A1 (en) * | 1978-10-05 | 1980-04-10 | Armco Inc | METHOD FOR PRODUCING GRAIN-ORIENTED SILICON STEEL |
| JPS61117215A (en) * | 1984-10-31 | 1986-06-04 | Nippon Steel Corp | Manufacture of grain oriented magnetic steel sheet of low iron loss |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1252220B (en) * | 1963-04-05 | 1968-04-25 | ||
| US3636579A (en) * | 1968-04-24 | 1972-01-25 | Nippon Steel Corp | Process for heat-treating electromagnetic steel sheets having a high magnetic induction |
| JPS5037009B2 (en) * | 1972-04-05 | 1975-11-29 | ||
| JPS5224499B2 (en) * | 1973-01-22 | 1977-07-01 |
-
1974
- 1974-09-23 GB GB41353/74A patent/GB1521680A/en not_active Expired
-
1975
- 1975-09-19 BE BE160234A patent/BE833649A/en not_active IP Right Cessation
- 1975-09-22 IT IT69346/75A patent/IT1047423B/en active
- 1975-09-22 SE SE7510579A patent/SE7510579L/en unknown
- 1975-09-22 DE DE19752542173 patent/DE2542173A1/en active Granted
- 1975-09-22 CA CA236,029A patent/CA1050863A/en not_active Expired
- 1975-09-23 JP JP50115453A patent/JPS6041132B2/en not_active Expired
- 1975-09-23 FR FR7529125A patent/FR2285462A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| DE2542173A1 (en) | 1976-04-08 |
| IT1047423B (en) | 1980-09-10 |
| JPS6041132B2 (en) | 1985-09-14 |
| GB1521680A (en) | 1978-08-16 |
| DE2542173C2 (en) | 1987-09-24 |
| FR2285462A1 (en) | 1976-04-16 |
| SE7510579L (en) | 1976-03-24 |
| BE833649A (en) | 1976-01-16 |
| JPS5159719A (en) | 1976-05-25 |
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