WO1998042882A1 - Procede de fabrication d'une tole d'acier electrique a grains orientes pour la fabrication notamment de circuits magnetiques de transformateurs - Google Patents
Procede de fabrication d'une tole d'acier electrique a grains orientes pour la fabrication notamment de circuits magnetiques de transformateurs Download PDFInfo
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- WO1998042882A1 WO1998042882A1 PCT/FR1998/000540 FR9800540W WO9842882A1 WO 1998042882 A1 WO1998042882 A1 WO 1998042882A1 FR 9800540 W FR9800540 W FR 9800540W WO 9842882 A1 WO9842882 A1 WO 9842882A1
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/12—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
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/12—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
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- 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
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
- C21D8/1277—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties involving a particular surface treatment
- C21D8/1288—Application of a tension-inducing coating
Definitions
- the present invention relates to a method of manufacturing an electric steel sheet with oriented grains for the production in particular of magnetic circuits of transformers comprising, successively:
- an annealing separator mainly consisting of MgO magnesia, - an annealing of secondary recrystallization and purification in a coil
- the texture ⁇ 1 1 0 ⁇ ⁇ 001> gives grain oriented electrical steel sheets good magnetic properties in the rolling direction.
- the fine precipitates MnS, AIN and CuS alone or in combination, with an average diameter of less than 1 00 nm are inhibitors of the normal growth of primary grains not having the orientation ⁇ 1 1 0 ⁇ ⁇ 001>.
- the hot rolling conditions are controlled so as to obtain in the hot rolled strip:
- Reheating the oriented steel slab at a temperature above 1350 ° C for a sufficiently long time has the serious disadvantage of favoring the formation of liquid oxides which accumulate in the form of slag in the reheating oven and requires the periodic shutdown of the oven for its cleaning. This results in a loss of productivity and a high maintenance cost.
- the AIN precipitates are re-dissolved during reheating of the slab is incomplete, a nitriding of the decarburized sheet being carried out to form the main inhibitor (AI, Si) N in the form of fine particles before the start of recrystallization. secondary.
- the sulfur content is limited and less than 0.01 2%.
- the manganese sulphides MnS are not put back into solution during the reheating of the slab and do not participate in the inhibition because they remain in the form of coarse particles in the rolled sheet hot.
- the aluminum nitrides AIN are only redissolved in a small proportion and do not participate in the inhibition either since they are in the form of coarse particles in the hot-rolled sheet, in an amount equal to at least 60% of the total nitrogen content.
- the inhibition is essentially carried out by the fine particles of copper sulphide which are formed during the annealing of the hot-rolled sheet.
- the steel is hot rolled so as to precipitate all of the sulfur in the form of fine particles.
- the steel is hot rolled so as not to precipitate nitrogen in the form of fine AIN particles.
- Steel hot rolled is annealed so as to precipitate nitrogen in the form of fine AIN particles which constitute the main inhibitor.
- at least one sulfur-containing and / or nitrogen-containing compound which allows additional inhibition can be added to the magnesia used as an annealing separator.
- the object of the present invention is to manufacture a sheet of electric steel with oriented grains ensuring an improvement in the magnetic quality of the sheet when the reheating of the slab or the strip is carried out at a temperature below 1350 ° C. before hot rolling.
- the subject of the present invention is a method of manufacturing a sheet of electrical steel with oriented grains for the production in particular of magnetic circuits of transformers comprising, successively:
- an annealing of primary recrystallization and decarburization in the parade in a humid atmosphere containing N2 and H2 an application on the two faces of the decarburized sheet of an annealing separator consisting mainly of MgO magnesia, - annealing of secondary recrystallization and purification in a coil,
- the other characteristics of the present invention are:
- the slab or the strip contains in particular in composition by weight: 0.02% ⁇ carbon ⁇ 0.07%
- the slab or strip also contains from 0.08% to 0.20% tin, the mass percentage of sulfur not precipitated in the form of coarse particles with an average diameter equal to or greater than 300 nanometers (nm) being greater than 0.004% in hot rolled sheet.
- the slab or strip additionally contains less than 0.08% tin, the mass percentage of sulfur not precipitated in the form of coarse particles with an average diameter equal to or greater than 300 nanometers (nm) being greater than 0.006% in the hot rolled sheet.
- the mass percentage of non-precipitated sulfur in the form of coarse particles with an average diameter equal to or greater than 300 nanometers (nm) is greater than 0.006% and preferably greater than 0.008%
- the mass percentage of sulfur precipitated in the form of fine particles with an average diameter of less than 100 nm is greater than 0.006
- Annealing includes maintaining the temperature of the sheet between 900 ° C and 1150 ° C for at least 50 seconds, followed by rapid cooling.
- the annealing is carried out before cold rolling in a single step until final thickness.
- the annealing is an intermediate annealing, carried out after a first cold rolling of the hot-rolled sheet or of the strip during a cold rolling in two stages, the annealing being followed by rapid cooling.
- Annealing is carried out before cold rolling and after a first cold rolling of the hot rolled sheet or strip during a cold rolling in two stages, the annealing being followed by rapid cooling.
- the cold rolling preceding the primary recrystallization and decarburization annealing is carried out with a reduction rate greater than 70%.
- Magnesia contains, in addition to the optional addition of titanium dioxide, alone or in combination, boron or a boron compound, sulfur or one or more sulfur compounds, one or more nitrogen compounds, one or more sulfur compounds and nitrogen, antimony chloride, tin sulfate.
- the decarburized sheet is subjected to gaseous nitriding in an atmosphere containing ammonia.
- the invention also relates to an electrically oriented grain steel sheet obtained by the method.
- FIG. 1 shows the mass percentage of the non-precipitated sulfur, in the form of coarse particles with a diameter greater than or equal to 300 nm, of the hot-rolled sheet before annealing, as shown in curve A and of the hot-rolled sheet after annealing , as shown in curve B, the mass percentage of the non-precipitated sulfur being a function of the mass percentage of the total sulfur contained in the slab heated to 1300 ° C.
- Figures 2a, 2b, 2c show the magnetic characteristics of the sheet, sheet to the final thickness 0.285mm after cold rolling, coated with an insulating coating inducing a tensile stress, the slab having been reheated to 1300 ° C. , as a function of the percentage by mass of sulfur not precipitated in the form of coarse particles with a diameter equal to or greater than 300 nm from the hot-rolled sheet before annealing.
- FIG. 3 shows the induction B800 of the final product to the thickness 0.285 mm after cold rolling as a function of the temperature of the annealing of the hot-rolled sheet, the slab having been reheated to 1300 ° C.
- FIG. 4 shows the mean diameter, in microns, of the grain after the primary recrystallization and decarburization annealing as a function of the mass percentage of the sulfur of the slab heated to 1300 ° C., the thickness of the hot rolled strip being 2.3 mm and 2 mm.
- FIG. 5 shows the magnetic characteristics of the final product, at a thickness of 0.285 mm, as a function of the percentage of grains having a diameter greater than 1 5 ⁇ m, after annealing of primary recrystallization and decarburization, the reheating of the slab being carried out at 1,300 ° C.
- FIGS. 6a, 6b, 6c show the magnetic characteristics of the final product, at a thickness of 0.285 mm, as a function of the percentage of grains having a diameter of less than 5 ⁇ m, after annealing of primary recrystallization and decarburization, the reheating of the slab being carried out at 1300 ° C.
- FIG. 7 shows the losses at 1.7 T and 50 Hz of the final product, at a thickness of 0.285 mm, as a function of the mass percentage of soluble aluminum of the slab reheated to 1300 ° C.
- FIGS. 8a, 8b, 8c show the magnetic characteristics of the final product at the thickness 0.285 mm as a function of the percentage by mass of tin of the slab reheated to 1300 ° C. and of the mass percentage I of the sulfur not precipitated in the form of coarse particles. of diameter equal to or greater than 300 nm, of hot-rolled sheet before annealing.
- the mass percentage I of non-precipitated sulfur in the form of coarse particles of the hot-rolled sheet is equal to the difference between the mass percentage of the total sulfur of the steel slab, determined by chemical analysis, and the mass percentage of the precipitated sulfur in the form of coarse particles of hot-rolled sheet, determined using a scanning electron microscope.
- the precipitates containing sulfur with an average diameter equal to or greater than 300 nm were taken into account.
- Crossings with contiguous fields were made on a micrographic section, from the upper face to the lower face of the sheet, with a magnification of 1000 and with an electron acceleration voltage of 15 kV.
- the surface fraction of the sulfur-containing precipitates is equal to the total area of the sulfur-containing precipitates over the total area examined.
- the surface fraction of the precipitates is equal to the volume fraction of the precipitates.
- the steels whose compositions are presented in Table 1 are continuously cast in the form of steel slabs with a thickness of 210 mm.
- the slabs are then subjected to: - reheating to the core at a temperature of 1300 ° C., the core of the slabs being maintained for 50 minutes above 1250 ° C., including 30 minutes above 1280 ° C.,
- the temperature of the start of the hot finish rolling being between 1060 ° C and 1075 ° C and the temperature of the end of the hot finish rolling being between 925 ° C and 935 ° C.
- the hot roughing and finishing rolls are carried out continuously, by successive passage in, for example, the twelve stands of a rolling mill, the successive reduction rates being 21, 39, 20 and 25% for the rolling of roughing and 53, 38, 43, 38, 26, 1 8 and 4% for finish rolling.
- Hot rolled sheet annealing is carried out with a temperature rise of 1100 ° C in 1 00 seconds, maintenance at 1100 ° C for 160 seconds, cooling to 800 ° C in 30 seconds and quenching at 65 ° C in 10 seconds.
- the hot rolled and annealed sheet is then subjected to a cold rolling to the thickness of 0.285 mm in a step comprising six passes corresponding to successive reduction rates of approximately 30% and to an overall reduction rate of 87.6%, the rolling temperature exceeding more than 150 ° C for at least one pass.
- the cold-rolled sheet is subjected to a primary recrystallization and to a decarburization comprising in particular a rise in temperature from 700 ° C in approximately 1 5 seconds, a rise from 700 ° C to 820 ° C in approximately 1 00 seconds, holding at 820 ° C for 40 seconds in a humid N2 / H2 atmosphere.
- the decarburized sheet is coated with a milk of magnesia containing 1 50 g of magnesia MgO per liter of water, 6 g of Ti ⁇ £ per 1 00 g of MgO, 0.04% of antimony chloride per 1 00 g of MgO , and dried.
- the decarburized sheet coated with magnesia is then subjected to a secondary recrystallization annealing with a rise in temperature of
- the purified sheet is then subjected to:
- Table 2 Magnetic characteristics obtained at the final thickness 0.285 mm after cold rolling, as a function of the reheating temperature at the core of the slabs:
- Curve A in FIG. 1 shows, unpredictably, that under the conditions of reheating to 1300 ° C. of the continuous casting slab and hot rolling according to the invention, the mass percentage of the non-precipitated sulfur in the form coarse particles from the hot-rolled sheet not annealed increases as the mass percentage of total sulfur in the slab increases.
- FIGS. 1 shows, unpredictably, that under the conditions of reheating to 1300 ° C. of the continuous casting slab and hot rolling according to the invention, the mass percentage of the non-precipitated sulfur in the form coarse particles from the hot-rolled sheet not annealed increases as the mass percentage of total sulfur in the slab increases.
- Steel No. 2 whose slab contains 0.01 5% of total sulfur and whose hot-rolled sheet has a mass percentage of sulfur not precipitated in the form of coarse particles greater than 0.006%, has a slightly magnetic quality lower than that of steels 3, 4 and 5, the hot-rolled sheets of which are characterized by a percentage by mass higher sulfur not precipitated as coarse particles.
- Figure 3 shows, the slab having been reheated to 1300 ° C, that as soon as one deviates strongly from the optimal annealing temperature, close to 1100 ° C, of the hot rolled sheet corresponding to l steel n ° 2, the magnetic quality represented by the B800 induction is greatly degraded, in particular when the annealing temperature is equal to 1050 and 1150 ° C., the thickness of the final product being 0.285 mm after rolling to cold.
- a steel slab No. 3 was reheated in another example, to the core, to 1,250 ° C, the core of the 21 0 mm thick slab being maintained 45 minutes above 1200 ° C, including 32 minutes above 1230 ° C.
- the temperature at the end of the rough rolling for roughing is 1075 ° C.
- the temperature at the start of the hot rolling finish is 1030 ° C.
- the temperature at the end at the finish hot rolling is 950 ° C.
- the winding temperature is 525 ° C.
- the annealing of the hot-rolled sheet was carried out at 1100 ° C.
- the use of a longer reheating time of the slab or strip makes it possible to increase, in the hot-rolled sheet or in the strip, the mass percentage of the non-precipitated sulfur in the form of coarse particles of equal or equal diameter. greater than 300 nm.
- the core of a steel slab n ° 3 was reheated to 1300 ° C under the following conditions: maintenance of 65 minutes above 1250 ° C, including 45 minutes above 1280 ° C. Under these conditions, the mass percentage I of sulfur not precipitated in the form of coarse particles is 0.01 3% in the hot-rolled sheet, instead of 0.008% (Table 2).
- the annealing of the hot-rolled sheet, according to the invention must be carried out under conditions such that there is no increase in the percentage of sulfur precipitated in the form of coarse particles with an average diameter equal to or greater than 300 nm.
- the annealing conditions according to the invention must favor the partial dissolution of precipitates with an average diameter equal to or greater than 300 nm and the precipitation of sulfur in solid solution, on cooling, in the form of fine particles with an average diameter of less than 1 00 nm.
- 1 shows examples, according to the invention, of the mass percentage of non-precipitated sulfur in the form of coarse particles of average diameter equal to or greater than 300 nm, that is to say in solid and precipitated solution essentially in the form of fine particles with an average diameter of less than 1 00 nm, after annealing of the hot-rolled sheet.
- the mass percentage of sulfur in solid solution and precipitated in the form of fine particles, after annealing the hot rolled sheet, is greater than 0.010% for steels 3, 4 and 5.
- the process according to the invention allows the precipitation of sulfur in solid solution in the form of fine particles of mean diameter less than 100 nm during the annealing carried out before or / and after the first cold rolling, during the decarburization annealing, during the secondary recrystallization annealing and in particular before the start of the secondary recrystallization.
- the annealing of the hot-rolled sheet or strip, according to the invention, must also be carried out under conditions such that there is significant precipitation of nitrogen, with more than 60% of the mass percentage of nitrogen. total, in the form of fine particles with an average diameter less than or equal to 1 00 nm.
- the principle of the method for measuring the percentage by mass of precipitated nitrogen is as follows: dissolving the matrix using a bromine-methanol mixture, separation of the precipitated aluminum by filtration through a membrane, dissolution of aluminum nitride by dilute sodium hydroxide, determination of aluminum by ICP emission spectrometry and calculation of the corresponding nitrogen.
- Tables 3 and 4 present typical values of the percentage by mass of nitrogen precipitated before and after annealing of the hot-rolled sheet. Transmission electron microscopy has been verified that the average diameter of the nitrogen-containing particles is less than 100 nm, before and after annealing of the hot-rolled sheet.
- conditions for annealing the hot-rolled sheet or strip simultaneously promoting the reduction in the mass percentage of sulfur precipitated in the form of coarse particles with an average diameter equal to or greater than 300 nm and the precipitation of nitrogen in the form of fine AIN particles, alone or combined with sulfur, with an average diameter of less than 1,00 nm.
- the above examples correspond to an annealing cycle, according to the invention, comprising the rise in temperature, the maintenance at a given temperature and rapid cooling, and in particular comprising a maintenance between 900 ° C. and 1150 ° C. d '' at least 50 seconds.
- More complex cycles can be used, for example a rise in temperature up to 800 ° C in 50 seconds, from 800 ° C to 1100 ° C in 40 seconds, a holding of 50 seconds between 1100 ° C and 1 1 25 ° C, cooling from 1 1 25 ° C to 900 ° C in 30 seconds, maintaining at 900 ° C for 1 60 seconds, cooling from 900 ° C to 1 00 ° C in less than 40 seconds.
- losses at 1.7 Tesia and 50 Hz of 1.01 W / kg, losses at 1.5 Tesia and 50 Hz of 0.75 W / kg and a B800 induction of 1.94 Tesia have were obtained from a steel slab n ° 3 reheated to 1300 ° C for a final thickness of 0.285 mm after cold rolling in a step, the final product being coated with an insulating coating inducing a tensile stress.
- FIGS. 2a, 2b, 2c show an example of magnetic characteristics of the final product at the thickness 0.285 mm after cold rolling in one step, coated with an insulating coating inducing a tensile stress: energy losses W (1, 5/50), W (1, 7/50) in Watt / kg at a frequency of 50 Hz and for a work induction of 1, 5 Tesia and 1, 7 Tesia respectively and B800 induction acquired under a magnetic field of 800 A / m as a function of the percentage by mass of the sulfur not precipitated in the form of coarse particles of the hot-rolled sheet (before annealing), the slab having been reheated to 1300 ° C.
- a soluble aluminum content equal to 0.020%
- a sulfur content equal to 0.01 8%
- the losses W (1.5 / 50) are less than 0.92 W / kg, the W losses (1, 7/50) are less than 1.25 W / kg and the B800 is greater than 1.86 T.
- the losses W (1.7 / 50) at the thickness 0.335 mm are equivalent to those obtained at the thickness 0.285 mm.
- the absence of voluntary addition of tin facilitates decarburization.
- a rate of cold reduction greater than 70%, before the annealing of primary recrystallization and decarburization makes it possible to obtain a B800 induction greater than 1.84 Tesia and possibly exceeding 1.90 Tesia if the mass percentage of non-precipitated sulfur in the form of coarse particles with an average diameter equal to or greater than 300 nm is greater than 0.006% before the primary recrystallization annealing and decarburization.
- cold rolling will preferably be carried out in two stages, with intermediate annealing.
- a reduction rate in the second cold rolling step, after intermediate annealing, greater than 70% makes it possible to obtain a B800 induction greater than 1.84 Tesia and possibly exceeding 1.90 Tesia if, in hot-rolled sheet, the mass percentage I of the non-precipitated sulfur in the form of coarse particles is greater than 0.006%, the slab containing less than 0.08% of tin, or greater than 0.004%, the slab containing more than 0.08% of tin .
- the mass percentage of the non-precipitated sulfur in the form of coarse particles with a diameter equal to or greater than 300 nm from the hot-rolled sheet before annealing may be less than 0.006% but must be greater than
- Annealing of the hot-rolled sheet or strip before cold rolling in one step and intermediate annealing before the second cold rolling in cold rolling in two stages comprise maintaining at least 50 seconds at 900 ° C. and 1150 ° C, followed by rapid cooling.
- the hot-rolled sheet or strip can be annealed before the first cold rolling.
- Such annealing favors obtaining a good magnetic quality.
- This annealing includes maintaining at least 50 seconds between 900 ° C and
- the sheet is maintained at a temperature above 1550 ° C. for at least one pass from the rolling step to cold preceding the primary recrystallization and decarburization annealing, the cold rolling taking place in one or two stages. Raising the temperature of the sheet above 150 ° C. during several passes promotes the obtaining of good magnetic quality, in particular if the rate of cold reduction is greater than 70%.
- the non-precipitated sulfur in the form of coarse particles has an influence on the size of the grains formed by primary recrystallization, the average grain diameter after primary recrystallization and decarburization being according to the invention less than 15 microns.
- the conditions according to the invention are not met, and in particular when the mass percentage of sulfur not precipitated in the form of coarse particles is less than 0.006% before the annealing of primary recrystallization and decarburization, certain primary grains have a diameter greater than 1 5 microns due to an insufficient quantity of sulfur in solid solution and precipitated in the form of fine particles with an average diameter less than 1 00 nm. This results in poor secondary recrystallization and a degradation of the magnetic quality.
- Figure 4 shows the influence of the mass percentage of sulfur of the slab on the average diameter expressed in ⁇ m of the grain after annealing of primary recrystallization and decarburization.
- the average grain diameter primary decreases as the mass percentage of total sulfur in the slab increases.
- the average diameter of the primary grain changes little as a function of the mass percentage of the total sulfur of the slab which is bound the mass percentage of the non-precipitated sulfur in the form of coarse particles with an average diameter equal to or greater than 300 nm from the hot-rolled sheet by the relationship of FIG. 1.
- the use of a thickness of the hot-rolled strip of 2 mm appears preferable to improve the magnetic quality.
- the improvement is 6%, 5% and 1% respectively for the losses and B800 when the thickness of the hot-rolled strip is 2 mm rather than 2.3 mm, cold rolling being carried out in one step.
- FIGS. 5 and 6 show that, in the case of the example above, for the thicknesses of the hot and cold rolled strips of 2.00 mm and 0.285 mm respectively, the best magnetic quality, losses at 1, 5 T and at 1.7 T the lowest and B800 the highest, is obtained when the percentage of primary grains with a diameter greater than 1 5 ⁇ m is less than 25%, and preferably less than 20%, and when the percentage primary grains with a diameter of less than 5 ⁇ m is greater than 10%, the average diameter of the grain after the annealing of primary recrystallization and decarburization is close to 1 0 ⁇ m.
- magnesia In addition to the optional addition of titanium dioxide the addition to magnesia, alone or in combination, of boron or a boron compound, sulfur or one or more sulfur compounds, one or more sulfur and nitrogen compounds, antimony chloride, a tin compound improves the magnetic quality.
- magnesia additives enhance the inhibition of normal growth of the primary grains during the secondary recrystallization annealing.
- magnesium sulfate, manganese sulfate, sodium thiosulfate, ammonium sulfate, ammonium thiosulfate, amidosulfuric acid (or sulfamic acid), urea, thiourea, sulfate tin can improve the magnetic quality.
- the mass percentage of the sulfur of the slab or of the strip continuously cast must be greater than 0.006% in order to obtain in the hot-rolled sheet or the strip a mass percentage of the non-precipitated sulfur in the form of coarse particles with an average diameter equal to or greater than 300 nm, greater than 0.006%. It will preferably be less than 0.05% so that the desulfurization during the purification annealing is complete. It will preferably be less than 0.035% to avoid the formation of edge cracks during the hot rolling of the slab or the strip.
- the percentage by mass of nitrogen of the slab or of the continuous casting strip must be greater than 0.004% in order to obtain a sufficient quantity of fine AIN particles which constitute the main inhibitor. It is less than 0.01 2% and preferably 0.009% to avoid the formation of blisters (blistering phenomenon) on the surface of the sheet.
- the percentage by mass of soluble aluminum in the slab or strip continuously cast must be greater than 0.008% in order to obtain a sufficient quantity of fine AIN particles which constitute the main inhibitor and in order to have sufficient availability of aluminum free no combined, in the case of nitrogen addition by gaseous nitriding after decarburization or by addition of one or more nitrogen compounds to magnesia. It is less than 0.04% and preferably less than 0.03% in order to obtain the dissolution of the AIN precipitates during the reheating preceding the hot rolling.
- Increasing the S content from 0.023% to 0.029% reduces losses.
- the mass percentage of manganese in the slab or continuous casting strip must be greater than 0.02% in order to obtain a sufficient quantity of fine MnS particles which reinforce inhibition and in order to have sufficient manganese availability free, not combined, in the case of supply of sulfur by addition of sulfur or one or more sulfur-containing compounds to magnesia.
- the percentage by mass of copper in the slab or strip continuously cast must be greater than 0.02% in order to limit the precipitation of sulfur in the form of coarse particles in the sheet hot rolled. It is less than 0.50% and preferably less than 0.030% to avoid pickling problems.
- the percentage by mass of tin of the slab or of the strip continuously cast must be greater than 0.02% to have a significant beneficial influence on the magnetic quality. It is limited to 0.20% in order to avoid pickling and decarburization problems.
- FIG. 8 illustrates the beneficial influence of the increase in the tin content of the slab on the magnetic quality, the slab having been heated to 1300 ° C., hot rolled and annealed, the thicknesses of the hot rolled strips and cold being 2.3 mm and 0.285 mm respectively.
- the mass percentage I of sulfur not precipitated in the form of coarse particles of the hot-rolled sheet metal not annealed is specified in FIG. 8.
- the beneficial effect of tin is only fully exerted if the mass percentage I is equal to or greater than 0.006%. In the voluntary absence of addition of tin, the percentage I should preferably be equal to or greater than 0.008%.
- the percentage I may be less than 0.006%, but this results in a magnetic quality which is not optimal.
- the percentage by mass of silicon of the slab or of the strip continuously cast is greater than 2.5% to have low magnetic losses. The higher this percentage of silicon, the lower the losses, but increasing the percentage of silicon above 4% makes cold rolling difficult.
- the percentage by mass of carbon of the slab or of the strip continuously cast is limited to 0.10% and preferably to 0.07% because beyond, decarburization is difficult.
- the percentage of carbon is greater than 0.02% in order to obtain good magnetic quality.
- the increase in the manganese content may exceed 0.20% provided that the mass percentage of the non-precipitated sulfur in the form of coarse particles with an average diameter equal to or greater than 300 nm remains greater than 0.006% before the annealing of primary recrystallization and decarburization.
- This increase in the content of manganese, a gamma element which promotes the formation of austenite can be accompanied by a decrease in the sulfur content and a decrease in the carbon content, gamma element, and or an increase in the content of silicon, alpha-element which favors the formation of ferrite. It is essential to maintain a certain fraction of austenite to dissolve AIN during the reheating of the slab or the strip.
- the method according to the present invention is described for continuous casting slabs of thickness between 1 50 and 300 mm. The greater the thickness of the slab, the longer it takes to reach the target temperature at the heart of the slab. In the case of reheating in the parade, for example, it is preferably necessary to slow down the speed of passage of the slab in the oven when the thickness of the slab goes from 21 0 mm to 240 mm.
- the hot-winding temperature must be such that the mass percentage of non-precipitated sulfur in the form of coarse particles is equal to or greater than 0.004% and preferably 0.006% and such that the mass percentage of nitrogen precipitated only in the form of fines particles is less than 40% of the total mass percentage of nitrogen in the hot-rolled sheet. This temperature is generally less than 700 ° C.
- the method according to the present invention can also be applied to thin strips of thickness between 1 and 10 mm obtained by casting liquid steel between two cooled rollers, the strips being quickly reheated to the core, taking into account the small thickness , at a temperature below 1350 ° C before hot rolling.
- the number of hot rolling passes is a function of the initial thickness of the slab or strip and the thickness of the hot rolled sheet. If the thickness of the slab or the continuously cast strip is sufficiently small, the hot rolling for roughing can be eliminated.
- Reheating and hot rolling of the continuously cast thin strip can be omitted if the mass percentage of non-precipitated sulfur in the form of coarse particles with a diameter of 300 nm or more is greater than 0.006% and if the mass percentage d nitrogen precipitated only in the form of fine particles is less than 40% of the total mass percentage of nitrogen in the raw sheet metal between two rolls.
- the thin strip is then subjected to at least one annealing according to the invention.
- the sheet obtained by the process has an induction B under a field of 800A / m equal to or greater than 1.86 Tesia and losses at 1.7 Tesia and 50 Hertz less than 1.30 W / Kg for a final thickness greater than 0.30 mm.
- the sheet obtained by the process has an induction B under a field of 800 A / m equal to or greater than 1.86 Tesia and losses at 1.7 Tesia and 50 Hertz less than 1.25 Watt / Kg.
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- 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)
- Manufacturing Of Steel Electrode Plates (AREA)
- Soft Magnetic Materials (AREA)
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP54511998A JP2001506704A (ja) | 1997-03-21 | 1998-03-18 | 変圧器の磁気回路の製造で用いられる配向粒子を有する電気鋼板の製造方法 |
DE69823771T DE69823771T2 (de) | 1997-03-21 | 1998-03-18 | Verfahren zum herstellen von kornorientierten elektrostahlblechen insbesondere für magnetkerne von transformatoren |
PL98330039A PL330039A1 (en) | 1997-03-21 | 1998-03-18 | Method of making electrical steel sheets having oriented crystallite structure in particular for magnetic cores |
AT98914939T ATE266742T1 (de) | 1997-03-21 | 1998-03-18 | Verfahren zum herstellen von kornorientierten elektrostahlblechen insbesondere für magnetkerne von transformatoren |
EP98914939A EP0912768B1 (fr) | 1997-03-21 | 1998-03-18 | Procede de fabrication d'une tole d'acier electrique a grains orientes pour la fabrication notamment de circuits magnetiques de transformateurs |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR97/03451 | 1997-03-21 | ||
FR9703451A FR2761081B1 (fr) | 1997-03-21 | 1997-03-21 | Procede de fabrication d'une tole d'acier electrique a grains orientes pour la fabrication notamment de circuits magnetiques de transformateurs |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1998042882A1 true WO1998042882A1 (fr) | 1998-10-01 |
Family
ID=9505038
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/FR1998/000540 WO1998042882A1 (fr) | 1997-03-21 | 1998-03-18 | Procede de fabrication d'une tole d'acier electrique a grains orientes pour la fabrication notamment de circuits magnetiques de transformateurs |
Country Status (10)
Country | Link |
---|---|
EP (1) | EP0912768B1 (fr) |
JP (1) | JP2001506704A (fr) |
KR (1) | KR20000011149A (fr) |
CN (1) | CN1220704A (fr) |
AT (1) | ATE266742T1 (fr) |
CZ (1) | CZ375398A3 (fr) |
DE (1) | DE69823771T2 (fr) |
FR (1) | FR2761081B1 (fr) |
PL (1) | PL330039A1 (fr) |
WO (1) | WO1998042882A1 (fr) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106319174A (zh) * | 2016-09-23 | 2017-01-11 | 武汉钢铁股份有限公司 | 提高低温铸坯加热高磁感取向硅钢底层质量的退火隔离剂 |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1162280B1 (fr) * | 2000-06-05 | 2013-08-07 | Nippon Steel & Sumitomo Metal Corporation | Procédé de fabrication d'une tôle d'acier électrique à grains orientés presentant d'excellentes caracteristiques magnétiques |
JP4272557B2 (ja) * | 2004-02-12 | 2009-06-03 | 新日本製鐵株式会社 | 磁気特性に優れた一方向性電磁鋼板の製造方法 |
WO2006132095A1 (fr) * | 2005-06-10 | 2006-12-14 | Nippon Steel Corporation | Feuille d’acier magnétique à grains orientés ayant une propriété magnétique extrêmement élevée et procédé pour la fabriquer |
JP4823719B2 (ja) * | 2006-03-07 | 2011-11-24 | 新日本製鐵株式会社 | 磁気特性が極めて優れた方向性電磁鋼板の製造方法 |
CN103878175A (zh) * | 2012-12-21 | 2014-06-25 | 鞍钢股份有限公司 | 一种低牌号冷轧硅钢热轧工序中的热轧方法 |
DE102014112286A1 (de) * | 2014-08-27 | 2016-03-03 | Thyssenkrupp Ag | Verfahren zur Herstellung eines aufgestickten Verpackungsstahls |
KR101696627B1 (ko) * | 2014-11-26 | 2017-01-16 | 주식회사 포스코 | 방향성 전기강판용 소둔 분리제 조성물, 및 이를 이용한 방향성 전기강판의 제조방법 |
CA3004286C (fr) * | 2015-12-04 | 2021-05-04 | Jfe Steel Corporation | Methode de production de tole electrique a grain oriente |
CN111020140A (zh) * | 2019-12-17 | 2020-04-17 | 无锡晶龙华特电工有限公司 | 一种磁性优良取向硅钢氧化镁退火隔离剂及其涂覆工艺 |
CN111996354B (zh) * | 2020-08-27 | 2022-04-19 | 上海实业振泰化工有限公司 | 一种取向硅钢用液体添加剂的制备方法 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2506784A1 (fr) * | 1981-05-30 | 1982-12-03 | Nippon Steel Corp | Procede de fabrication d'une tole en acier electromagnetique a grain oriente ayant une haute densite de flux magnetique |
EP0619376A1 (fr) * | 1993-04-05 | 1994-10-12 | Thyssen Stahl Aktiengesellschaft | Procédé pour la fabrication de tôles électriques à grains orientés et à perte dans le fer améliorée |
EP0732413A1 (fr) * | 1995-03-14 | 1996-09-18 | USINOR SACILOR Société Anonyme | Procédé de fabrication d'une tÔle d'acier électrique à grains orientés notamment pour transformateurs |
-
1997
- 1997-03-21 FR FR9703451A patent/FR2761081B1/fr not_active Expired - Fee Related
-
1998
- 1998-03-18 JP JP54511998A patent/JP2001506704A/ja active Pending
- 1998-03-18 CZ CZ983753A patent/CZ375398A3/cs unknown
- 1998-03-18 PL PL98330039A patent/PL330039A1/xx unknown
- 1998-03-18 WO PCT/FR1998/000540 patent/WO1998042882A1/fr not_active Application Discontinuation
- 1998-03-18 KR KR1019980709309A patent/KR20000011149A/ko not_active Application Discontinuation
- 1998-03-18 CN CN98800332A patent/CN1220704A/zh active Pending
- 1998-03-18 AT AT98914939T patent/ATE266742T1/de active
- 1998-03-18 DE DE69823771T patent/DE69823771T2/de not_active Expired - Lifetime
- 1998-03-18 EP EP98914939A patent/EP0912768B1/fr not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2506784A1 (fr) * | 1981-05-30 | 1982-12-03 | Nippon Steel Corp | Procede de fabrication d'une tole en acier electromagnetique a grain oriente ayant une haute densite de flux magnetique |
EP0619376A1 (fr) * | 1993-04-05 | 1994-10-12 | Thyssen Stahl Aktiengesellschaft | Procédé pour la fabrication de tôles électriques à grains orientés et à perte dans le fer améliorée |
EP0732413A1 (fr) * | 1995-03-14 | 1996-09-18 | USINOR SACILOR Société Anonyme | Procédé de fabrication d'une tÔle d'acier électrique à grains orientés notamment pour transformateurs |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106319174A (zh) * | 2016-09-23 | 2017-01-11 | 武汉钢铁股份有限公司 | 提高低温铸坯加热高磁感取向硅钢底层质量的退火隔离剂 |
CN106319174B (zh) * | 2016-09-23 | 2018-10-16 | 武汉钢铁有限公司 | 提高低温铸坯加热高磁感取向硅钢底层质量的退火隔离剂 |
Also Published As
Publication number | Publication date |
---|---|
EP0912768A1 (fr) | 1999-05-06 |
CZ375398A3 (cs) | 1999-07-14 |
ATE266742T1 (de) | 2004-05-15 |
EP0912768B1 (fr) | 2004-05-12 |
FR2761081B1 (fr) | 1999-04-30 |
FR2761081A1 (fr) | 1998-09-25 |
DE69823771D1 (de) | 2004-06-17 |
PL330039A1 (en) | 1999-04-26 |
DE69823771T2 (de) | 2005-05-12 |
JP2001506704A (ja) | 2001-05-22 |
KR20000011149A (ko) | 2000-02-25 |
CN1220704A (zh) | 1999-06-23 |
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