Classifications

• • 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
  • C22C38/004—Very low carbon steels, i.e. having a carbon content of less than 0,01%
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/26—Methods of annealing
• • 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
  • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/008—Ferrous alloys, e.g. steel alloys containing tin
• • 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
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
• • 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
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/10—Ferrous alloys, e.g. steel alloys containing cobalt
• • 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
  • C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur

Definitions

• the present invention relates to a cold rolled magnetic laminated steel excellent in magnetic properties and a method of manufacturing the same.
• Cold-rolled magnetic laminated steel is an important metal soft magnetic material, also known as semi-process electrical steel. It is mainly used to manufacture iron cores for motors and transformers. After cold-rolled steel coils are softened and annealed by steel mills, they are not coated with insulation. The coating is supplied directly to downstream users, who perform chipping and magnetic annealing. Its basic production process includes the following steps: steel mill: smelting ⁇ hot rolling ⁇ (normalization, optional, only for high-grade products) ⁇ cold rolling ⁇ softening annealing ⁇ temper rolling ⁇ finishing, no insulation coating on the steel surface , no oil or a small amount of special anti-rust oil, users: steel strips ⁇ punching ⁇ magnetic annealing and blue annealing.
• the cold-rolled magnetic laminated steel is magnetically annealed to reach the target value of iron loss and magnetic induction of the iron core, and the surface is blued to form an insulating layer, which improves the performance of the iron core and can satisfy most of the motor iron.
• Core application requirements Cold rolled magnetic laminated steel is widely used in motor cores and transformer cores in the United States. The market scale is several times that of non-oriented electrical steel in the whole process. In recent years, the proportion of use has been further expanded. More and more motor and compressor users in the domestic market are beginning to pay attention to the use of this material.
• Chinese patent CN1974820A discloses a method for producing semi-process electrical steel.
• the chemical composition of the semi-process electrical steel casting blank is: C: 0.001-0.020%, Si: 0.15-1.40%, Mn: 0.15-1.20%, P: 0.0015 -0.10%, S: 0.005-0.020%, Al: 0.15-0.80%, N: 0.0015-0.0080%, Sb: 0.015-0.12%, Sn: 0.015-0.12%, the balance being iron and inevitable impurities, using thin slab
• the hot-rolled sheet is continuously cast and rolled, and then obtained by pickling, cold rolling, annealing and secondary cold rolling, wherein the secondary cold rolling reduction rate is 2-10%.
• the technology is characterized by the use of thin slab continuous casting and rolling technology to obtain favorable texture structure and achieve magnetic improvement.
• the secondary cold rolling process requires a high reduction ratio and requires special cold rolling flattening equipment.
• Chinese patent CN1864879A discloses a method for producing semi-process cold-rolled silicon steel by thin slab continuous casting and rolling.
• the Si content is 0.2-1.0%
• the Mn content is 0.20-0.8%
• the P content is 0.02-0.07%.
• the continuous casting billet with acid-soluble aluminum content of 0.04-0.30% and Sb content of 0.02-0.06% is then subjected to hot rolling, pickling cold rolling, annealing, and 2-18% elongation flat transformation to obtain a cold-rolled sheet after magnetic annealing.
• the iron loss is less than 6.5W/kg.
• the manufacturing method also adopts a large elongation flatness and a high iron loss.
• the Chinese patent CN101306434A discloses a low carbon low silicon aluminum-free semi-process non-oriented electrical steel preparation method, which is characterized in that the composition does not contain alloying elements such as Al, Sn, Sb, Cu, Cr, Ni and rare earth.
• the steel sheet does not contain Al and there is no addition of the internal oxidation inhibiting alloy, when the steel sheet is annealed under complicated furnace conditions, especially when the dew point is higher than 0 ° C, it is easy to cause internal oxidation in the surface layer, resulting in magnetic deterioration, which limits Application range.
• Chinese patent CN101654757A also discloses a semi-process non-oriented electrical steel plate and a manufacturing method thereof.
• the chemical composition of the steel plate is: C: ⁇ 0.003%, Si: 1.00-2.30%, Mn: 0.20-1.00%, P: 0.01-0.10% , S: ⁇ 0.005%, Al: 0.20-0.80%, N: ⁇ 0.005%, the rest is iron and inevitable impurities, the production process includes slab continuous casting, hot rolling, pickling cold rolling, annealing, which is characterized by After annealing, the surface of the steel plate is coated with an insulating coating, and there is no flat deformation.
• the Si content is 1.15%
• the iron loss P 15/50 after magnetic annealing is about 4.2 W/kg.
• the technical problem to be solved by the present invention is to obtain a cold-rolled magnetic laminated steel which can suppress internal oxidation behavior and has excellent soft magnetic properties by reasonable composition design and process control under low flat pressure conditions.
• the object of the present invention is to provide a cold-rolled magnetic laminated steel excellent in magnetic properties and a method for producing the same, the cold-rolled magnetic laminated steel having excellent magnetic properties and good processing property, and magnetically annealed after cold-rolled magnetic laminated steel, iron Loss P 15/50 ⁇ 3.9W/kg, magnetic induction B 50 ⁇ 1.68T.
• the chemical composition weight percentage is: C ⁇ 0.010%, Mn: 0.20 to 0.50%, S ⁇ 0.0050%, P ⁇ 0.030%, 0.4% ⁇ Si, and the Si and Al contents are satisfied. : 0.65% ⁇ Si + 1.2Al ⁇ 1.5%, one or more components of B, Zn, Co, Sn, Sb, Cu, Bi, the amount of addition is controlled at 0.020-0.10%, and the rest is Fe and unavoidable impurities.
• the iron loss P 15/50 i.e., the iron loss under the condition of a frequency of 50 Hz and a magnetic induction of 1.5 T
• the cold rolled steel of the present invention can be used to produce laminated steel.
• the iron loss and magnetic induction test standards are carried out in accordance with the Chinese standard GB/T 3655.
• Si Silicon element can significantly improve the electrical resistivity, strength and hardness of steel, reduce iron loss and improve the processing performance of the chip. Therefore, the chemical composition of the present invention controls the silicon content to be not less than 0.40%.
• Si+Al increasing the content of Si and Al can increase the electrical resistivity of steel, thereby reducing iron loss, but at the same time deteriorating the magnetic induction.
• the invention optimizes the composition of silicon and aluminum to satisfy the relationship: 0.65. % ⁇ Si+1.2Al ⁇ 1.5%.
• Si+1.2Al content is less than 0.65%, the iron loss improvement after magnetic annealing is limited and the performance deviation is small under the condition of small elongation.
• Si+1.2 When the Al content exceeds 1.5%, the magnetic induction deteriorates severely, and the alloy cost increases.
• Carbon is a harmful element that is not conducive to magnetism. If the carbon content is too high, it will cause an increase in iron loss, magnetic aging, and difficulty in decarburization. Therefore, the content should not exceed 0.010%.
• Mn Manganese can increase the electrical resistivity, improve the hot rolling plasticity and grain structure, and is beneficial to the improvement of magnetic properties. The addition of less than 0.2% or more than 0.5% is not conducive to performance improvement.
• S Sulfur is a magnetically harmful element, and when fine MnS precipitates are formed with Mn, grain growth during annealing is inhibited, and iron loss is deteriorated.
• the S content of the present invention is not more than 0.0050%.
• P Phosphorus element is easily segregated along the grain boundary, resulting in poor processing performance, especially for products with low carbon content and high Si+Al content. If the phosphorus content is too high, embrittlement is likely to occur after annealing. P ⁇ 0.030%.
• the method for producing cold-rolled steel excellent in magnetic properties according to the present invention comprises the following steps:
• the finishing temperature F and the Si content satisfy the relationship: 830 ⁇ F ⁇ 860 + exp (112 ⁇ ⁇ + 2.8), wherein ⁇ represents the Si content, F unit ° C; the coiling temperature is controlled at 650-740 ° C, the thickness of the hot rolled sheet 2.2-2.8mm;
• the core of the manufacturing method of the present invention is chemical composition design and hot rolling process.
• the Si content is ⁇ 1.7%
• austenite ⁇ ferrite ⁇ wherein the Si content in the steel is opposite to the Ar 3 transformation point
• the Si content increases, and the temperature of the Ar3 phase transition point rises sharply.
• the deformation resistance between the austenite and ferrite phases is large, and the deformation resistance of the hot rolling process fluctuates greatly, which makes hot rolling. Plate type and thickness control are difficult.
• the highest content of Si element in the steel component of the invention does not exceed 1.5%, and austenite ferrite transformation occurs in the finish rolling process.
• the present invention controls the finish rolling temperature below the Ar3 phase transition temperature; for different silicon contents, the finish rolling temperature Control: 830 ⁇ F ⁇ 860 + exp (112 ⁇ ⁇ + 2.8), ⁇ represents the Si content, to ensure that the last or second pass of the finishing rolling is outside the two-phase zone, that is, a single ferrite phase zone rolling, The deformation resistance fluctuation is reduced, the rolling stability and the plate shape control are increased, and the finish rolling temperature is prevented from being too high, resulting in an inner layer of the surface layer of the hot rolled plate.
• the recrystallized grain structure ratio of the hot rolled sheet exceeds 70%, thereby achieving the purpose of improving the final product magnetic induction.
• Si and Al element ratio design According to the rational design of the content of Si and Al elements, the magnetic induction is also improved while obtaining low iron loss.
• microalloying one or more microalloyings are selected from elements such as B, Zn, Co, Sn, Cu, Sb, and Bi.
• segregation of alloying elements at grain boundaries can be utilized to improve weaving. Structure, improve magnetic properties; on the other hand, improve the environmental adaptability of laminated steel during magnetic annealing, and suppress internal oxidation in the annealing environment with dew point higher than 0 °C, thereby preventing deterioration of magnetic properties.
• the invention improves the grain structure and the plate type quality of the hot rolled plate by designing the hot rolling process, and combines the softening annealing and the deformation process under the uniform pressure to obtain the cold rolled magnetic laminated steel excellent in magnetic properties.
• the flattening process of the present invention adopts a low elongation of 1.0-2.0%.
• the rolling capacity of the leveling machine is low, the rolling force is small in the leveling process, and the energy consumption is low. It can be produced by using an ordinary leveling machine, and no special high-power leveling mill equipment is needed. Additional equipment investment is small.
• Table 1 shows the mass percentages of the main elements of the cold-rolled magnetic laminated steel excellent in magnetic properties of Examples A0 to A10, the balance of which is Fe and other unavoidable impurities.
• Table 2 lists the final rolling temperatures, coiling temperatures, softening annealing processes, and leveling process parameters for the specific examples A0-A10.
• Table 3 lists the magnetic performance results of the samples of Examples A0-A10 after magnetic annealing under different conditions, wherein:
• Magnetic annealing I annealing temperature 760 ° C, heat preservation 2.5 hr, atmosphere 10% H 2 , 90% N 2 , dew point 26 ° C;
• Magnetic Annealing II Annealing temperature 790 ° C, holding for 1 hr, atmosphere 20% H 2 , 80% N 2 , dew point 13 ° C.
• the cold rolled magnetic laminate steel of Examples A0-A10 was obtained by the following process steps:
• the casting billet heating temperature is 1080-1160 ° C
• the hot rolling finishing rolling temperature is controlled at 830 ° C -890 ° C
• the coiling temperature is 650-740 ° C
• the hot rolled sheet thickness is 2.5 mm;
• A0-A8 number corresponds to rolling thickness 0.50-0.51mm
• A9 corresponds to rolling thickness 0.475-0.48mm.
• softening annealing process annealing temperature 650-780 ° C, holding time 60-100 s;
• the flattening elongation is 1.0-2.0%, of which A0-A8 corresponds to the final thickness of strip steel of 0.50mm, and A9 and A10 correspond to strip thickness of 0.47mm.
• Example Finishing temperature (°C) Coiling temperature (°C) Softening annealing process Flattening elongation (%) A0 890 650 780°C+60s 2.0 A1 880 700 720°C+90s 2.0 A2 875 680 750°C+90s 1.9 A3 855 690 730°C+80s 1.9 A4 860 720 710°C+80s 1.5 A5 855 685 650°C+70s 1.8 A6 870 660 670°C+70s 1.8 A7 880 680 690°C+70s 1.6 A8 850 740 650°C+100s 1.0 A9 875 690 720°C+90s 1.9 A10 860 685 760°C+70s 2.0
• the cold-rolled magnetic laminated steel obtained by the present invention has a magnetic loss P 15/50 of less than 3.9 W/kg and a magnetic induction B 50 of more than 1.68 after magnetic annealing in different processes. T.
• the cold-rolled magnetic laminated steel obtained by the present invention has excellent soft magnetic properties such as low iron loss and high magnetic induction.
• Table 4 lists the respective chemical element mass percentages of the comparatively baked B1-B6 cold rolled magnetic laminated steel.
• Table 5 lists the final rolling temperatures, coiling temperatures, softening annealing processes, and leveling process parameters for Comparative Examples B1-B6.
• Table 6 lists the magnetic performance results of the comparative B1-B6 samples after magnetic annealing under different conditions, among which:
• Magnetic annealing I annealing temperature 760 ° C, heat preservation 2.5 hr, atmosphere 10% H 2 , 90% N 2 , dew point 26 ° C;
• Magnetic Annealing II Annealing temperature 790 ° C, holding for 1 hr, atmosphere 20% H 2 , 80% N 2 , dew point 13 ° C.

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• 2017
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