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
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/06—Surface hardening
  • C21D1/09—Surface hardening by direct application of electrical or wave energy; by particle radiation
• • 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

Definitions

• the present invention relates to the field of ferrous metallurgy, in particular to the production of cold rolled anisotropic electrical steel used for the manufacture of large magnetic circuits with low energy losses for magnetization reversal.
• laser processing is proposed to be carried out in a magnetic field oriented along the rolling direction.
• the absorption capacity of the insulating layer increasing with increasing wavelength, leads, in the case of using a CO 2 laser, to local overheating of the coating material and the formation of visible processing marks. With increasing ⁇ , the task of forming a sharply focused spot becomes more complicated. Finally, difficulties in the operation and tuning of the optical scheme, special cooling conditions make the practical use of CO 2 lasers ineffective.
• the implementation of the proposed method is based on the use of radiation with a relatively low (from 10 W) output power.
• the need for the formation of a sharply focused beam with a spot diameter at the focal point of up to 0.01 mm is due in this case to the choice of a single-mode radiation mode. at which a radiation power of more than 1 kW cannot be achieved.
• Irradiation of a metal surface with a focused beam with a small cross-sectional area leads to the creation of high temperature gradients in the area affected by the spot. In this case, the depth of heating of the metal and the observed width of the line of action of the beam are no more than 20 ⁇ m.
• the problem to which the technical solution is directed is to reduce the magnetic loss of cold-rolled strips of anisotropic electrical steel while maintaining a high level of magnetic induction and the resistance of the electrical insulation coating. This ensures a reduction in the cost of production and additional profit from its sale.
• anisotropic electrical steel sheet including steel smelting, continuous casting, hot rolling.
• decarburizing annealing degreasing
• applying a protective coating high-temperature annealing
• applying an electrical insulating coating rectifying annealing and electromagnetic exposure to the surface of a moving strip with a scanning non-circular laser beam elongated along the scanning direction.
• electromagnetic exposure is carried out under an adjustable tension of the strip, creating an internal voltage in the metal in the range of 5-80 N / mm 2 .
• continuous multimode laser radiation is used with a ratio of radiation power to scanning speed P / V in the range of 0.015-0.050 J / mm, while in the non-circular section of the beam its ratio length to width in the rolling direction is 0.005-0.075; and the magnitude of the strip tension during laser processing is determined by the following formula:
• k is the proportionality coefficient equal to 0.002-0.010 depending on the chemical composition and mechanical properties of the treated steel.
• a comparative analysis of the proposed technical solution with the prototype shows that the claimed method differs from the well-known topics.
• the electromagnetic effect on the surface of the moving strip is carried out under controlled tension, which creates an internal voltage in the metal in the range of 5-80 N / mm 2 , and continuous electromagnetic multimode laser radiation of a non-circular cross section is used as the electromagnetic effect with the ratio of the radiation power to the scanning speed P / V in range 0.015-0.050 J / mm. while in the elongated along the scanning direction non-circular section of the beam, the ratio of its length to width in the rolling direction is 0.005-0.075.
• the claimed method meets the criteria of the invention of "Novelty.”
• a comparative analysis of the proposed solution not only with the prototype, but also with other technical solutions showed that methods for the production of anisotropic electrical steel sheet, including continuous casting, hot rolling, single or double cold rolling, decarburizing annealing, degreasing, applying a protective coating, high-temperature annealing, applying an insulating coating, rectifying annealing and electromagnetic effects on the surface of a moving strip with a scanning laser beam A cross section elongated along the scanning direction is widely known.
• Figure 1 presents the implementation diagram of the proposed method. The method is as follows.
• the strip -1 of steel in the treatment zone is transported by an iodine with adjustable tension - N -, which creates an internal voltage in the metal in the range of 5-80 N / mm 2 , and the ratio of the radiation power to the scanning speed P / V of the laser beam is 2 - support in the range of 0.015 - 0.050 J / mm, while in the elongated along the scanning direction -R- non-circular section - 3 - of the beam - 2 - the ratio of its length - s - to width - b - in the rolling direction -T- is 0.005 - 0.075.
• a multimode fiber laser -4- with a generation wavelength of 1070 nm and an output power of 1.5 - 3.5 kW is used as a source of laser radiation.
• the processing of strip -1- is carried out with a spot - 3 -, which have different sizes in the sweep direction and in the transverse direction to it.
• This is achieved through the use of a special optical system, which is a set of cylindrical lenses located along the line of scanning the beam.
• the time of laser exposure, the temperature of heating of the surface layer and the depth depend on the geometric shape and size of the spot -3- penetration of heat into the metal.
• the width of the spot-b- laser radiation determines the time of laser exposure to the surface of the strip. Accordingly, when forming a spot elongated along the scanning line, it is possible to provide both sharp heating of the local zone of the surface with a maximum temperature gradient at its boundary, and smooth heating with a spot with a width of -b- 20-30 mm. providing deep warming up. Obviously, an increase in the extent of the spot is accompanied by a proportional decrease in the radiation density at each point of exposure.
• the performed calculations for the sweep speed m / s and the total radiation power of 2.5 kW show that an increase in the width of the spot -b- from 3.5 mm to 25 mm with a length of -s- 100-300 ⁇ m corresponds to a change in the depth of heating of the metal from 30 up to 100 microns.
• the depth of heating refers to the distance from the surface at which the temperature, expressed in degrees Celsius, is reduced by 2 times.
• B and d are the width and thickness of the strip (mm), respectively.
• Processing the strip with an internal voltage in the metal in the range of more than 80 N / mm 2 is accompanied by a sharp decrease in the magnitude of the magnetic induction below the permissible value.
• the ratio of the radiation power to the scanning speed P / V is more than 0.050 J / mm, the insulating coating on the steel surface is destroyed, which is unacceptable, since it worsens the appearance of the product and can lead to a decrease in the resistance value of the electrical insulation coating.
• a decrease in the ratio of length to width of the non-circular beam cross section less than 0.005 under the existing power limitations of modern fiber-optic lasers leads to a decrease in the density of laser radiation and, as a consequence, insufficiently deep heating of the metal in the laser irradiation zone, which excludes the possibility of using the applied tension to further reduce specific magnetic losses.
• a laser beam with an output power of 2.5 kW having a non-circular cross section with a length of 150 ⁇ m along the scanning direction and a width of 20 mm in the direction of movement of the strip, and a tension in the processing section of 18 N / mm
• the use of the proposed method for the production of anisotropic electrical steel sheet allows not only to reduce magnetic losses while maintaining a high level of magnetic induction, but also to reduce the cost of production and get additional profit from its sale.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Electromagnetism (AREA)
• Manufacturing & Machinery (AREA)
• Manufacturing Of Steel Electrode Plates (AREA)

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• 2009
  • 2009-08-03 RU RU2009129819/02A patent/RU2405841C1/ru active
• 2010
  • 2010-07-27 BR BR112012001806-0A patent/BR112012001806B1/pt active IP Right Grant
  • 2010-07-27 WO PCT/RU2010/000414 patent/WO2011016758A1/ru not_active Ceased
  • 2010-07-27 PL PL398130A patent/PL218343B1/pl unknown
  • 2010-07-27 CZ CZ2012-30A patent/CZ306162B6/cs unknown

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