Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1216—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the working step(s) being of interest
  • C21D8/1222—Hot rolling
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
  • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
  • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
  • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
  • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
  • H01F1/147—Alloys characterised by their composition
  • H01F1/14766—Fe-Si based alloys
  • H01F1/14775—Fe-Si based alloys in the form of sheets
• • 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
  • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
  • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
  • C21D8/0236—Cold 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
  • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
  • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
  • C21D8/0273—Final recrystallisation annealing

Definitions

• the invention relates to a non-grain-oriented electrical sheet or strip and a method for producing such products.
• non-grain-oriented electrical sheet here means electrical sheets falling under DIN EN 10106 (“final annealed electrical sheet”) and DIN EN 10165 (“non-final annealed electrical sheet”).
• more anisotropic grades are included as long as they are not considered grain-oriented electrical sheets.
• electrical sheet and “electrical steel” are used synonymously.
• J2500 or "J5000” in the following denote the magnetic polarization at a magnetic field strength of 2500 A / m or 5000 A / m.
• P 1.5 is understood to mean the loss of remagnetization with a polarization of 1.5 T and a frequency of 50 Hz.
• a non-grain-oriented electrical sheet is finally produced by using ⁇ 0.025% C, ⁇ 0.1% Mn, 0.1 to 4.4% Si and 0.1 to 4.4% Steel material (AI in mass%) is first hot-rolled to a thickness of not less than 3.5 mm.
• the hot strip obtained in this way is then cold-rolled without recrystallizing intermediate annealing with a degree of deformation of at least 86% and subjected to an annealing treatment.
• the band produced according to the known method has a particularly high magnetic polarization of more than 1.7 T with a field strength J 2 soo of 2500 A / m and low magnetic reversal losses.
• SI / cs 020172WO a large-scale production of the necessary safety to produce electrical sheets with a total content of more than 1.4% by mass of Si and Al non-grain-oriented electrical strips or sheets which, measured in the longitudinal direction of the strip, have a magnetic polarization J 2500 of> 1.7 T.
• the values determined for J 2 soo in the transverse direction of the belt and the mixed values of J 2500 are always smaller than the values of J 2 soo measured in the belt direction.
• the object of the invention now is to make starting quality of the above-mentioned prior art non-grain oriented electrical steels, as final annealed as well as can be produced without additional production effort so as not final annealed varieties that they improved a comparison with the previously achievable values have magnetic polarization and reduced magnetic reversal losses.
• a non-grain-oriented electrical steel sheet or sheet with a nominal thickness of ⁇ 0.75 mm made from a steel which, in addition to iron, contains the usual unavoidable levels of impurities (for example S, Ti) and optionally available levels of Mo, Sb, Sn , Zn, W and / or V, (in mass%) C: ⁇ 0.005%, Mn: ⁇ 1.0%, P: ⁇ 0.8%, AI: ⁇ 1%
• the steel used in accordance with the invention is composed in such a way that it does not have a purely austenitic structure at any time when it cools down from 1300 ° C.
• the composition should be selected so that a temperature range is necessary during cooling, within which the steel structure consists of a mixture of ⁇ and ⁇ phases. It is regarded as a tolerable deviation from this regulation in the sense of the invention if pure austenite structure occurs over a maximum temperature range of 50 ° C. This means that in the event that a pure austenite structure is formed, a two-phase mixed structure must be present again after a temperature decrease of another 50 ° C at the latest.
• the temperatures are preferably carried out in such a way that the critical temperature range is avoided.
• the rewarming temperature of the slab in the conventional hot strip manufacturing process or the temperature of the thin slab during casting rolling or thin strip casting before hot rolling can be selected so that it lies above the two-phase area.
• the hot rolling end temperature is> 800 ° C.
• the coiling temperature at which the hot strip is rolled up after the hot rolling process should be ⁇ 650 ° C.
• the hot rolling process usually comprises a final rolling (finished hot rolling) which takes place in a hot rolling mill comprising a plurality of roll stands.
• the overall degree of deformation achieved in the course of the final rolling should be> 75%.
• Electrical sheets that have magnetic polarization J 2 soo values of more than 1.74 T with particularly low losses P ⁇ , 5 of significantly less than 4 W / kg can be produced by the degree of deformation achieved in the course of the final rolling in the two-phase mixing area is at least 35%.
• At least one of the last forming passes is hot-rolled with lubrication.
• Hot rolling with lubrication results in less shear deformation on the one hand, so that the rolled strip as a result obtains a more homogeneous structure across the cross section.
• the lubrication reduces the rolling forces so that a greater decrease in thickness is possible over the respective roll pass. It can therefore be advantageous if all the forming passes in the ferrite area are carried out with roll lubrication.
• the final annealing of the electrical steel that has been cold-rolled from the hot strip can generally be carried out in a continuous process or in a hood furnace (final-annealed electrical steel).
• the annealed strip can be reshaped after the annealing carried out in a continuous or bell-type furnace with a degree of deformation ⁇ 12% and then subjected to a reference annealing at temperatures above 700 ° C, so that a non-final annealed electrical steel strip is then obtained.
• the attached diagram shows the phase diagram of a binary FeSi alloy. Analog diagrams apply to technical alloys, whereby the respective "temperatures” change compared to those in the binary alloy shown.
• the line L 0 marking the lower limit of the sum "% Si + 2% A1" of the Si and Al contents of alloys processed according to the invention over a temperature range T s corresponds to the smaller amounts of the sum "% Si + 2 % A1 "extends the austenite phase region ⁇ in which pure austenite is formed.
• the temperature difference, which lies between the upper intersection T s0 and the lower intersection T su of the line L 0 with the austenite phase region ⁇ , is less than 50 ° C.
• the section A ⁇ cut off from the austenite phase region ⁇ from the line L D in the direction of the line L 0 thus represents the tolerance range enclosed by the two-phase mixing region ( ⁇ + ⁇ ), within which the embodiment of the invention forms pure Austenite may come.
• each alloy according to the invention which has a value of its sum "% Si + 2% A1" lying between the lines L 0 and L 0 , passes through the two-phase mixing range ( ⁇ + ⁇ ) when it is cooled from an initial temperature below 1300 ° C. ,
• the alloy of the steel S1 is chosen so that the structure of the steel S1 does not consist of pure austenite ⁇ at any time when it cools down from 1300 ° C.
• steel S2 on the other hand, in the course of its cooling from the previously two-phase mixed structure ⁇ + ⁇ for a temperature range T s of less than 50 ° C, a briefly purely austentic structure is formed, which immediately changes again into two-phase mixed structure ⁇ + ⁇ when the temperature decreases further.
• the slabs were then pre-rolled and, in the course of four different tests 1 to 4, with a hot-rolling start temperature, ran into a hot-rolling mill comprising seven rolling stands, in which they were each rolled into a hot strip.
• test 1 the hot rolling starting temperature of four slabs Bl.l, B2.1, B3.1, B4.1 cast from steel S1 was so high when it entered the hot rolling mill that the steel had a two-phase mixed structure formed from austenite and ferrite. Are in the hot rolling season
• the slabs Bl.l to Bl.4 were first rolled in the two-phase mixing area.
• the degree of deformation achieved during rolling in the two-phase mixing area was 40% and the degree of forming in the ferrite area was 66%.
• Table 2 shows the slabs Bl.l to B4.1 and the hot strips produced from them
• SI / cs 020172WO had after their structure had previously passed through the two-phase mixing range ( ⁇ + ⁇ ) in the course of its cooling.
• hot rolling in the hot rolling mill has been carried out exclusively in ferrite.
• a total degree of forming Ug ⁇ of 80% was achieved.
• the belt surface was lubricated during the second and third stitch.
• Table 3 shows the final hot rolling temperature ET in ° C, the reel temperature HT in ° C and the reel holding time tH in min as well as the magnetic properties P 1 for the slabs B1.2 to B5.2 and the hot strips produced from them 5 in W / kg, J 250 o and J5000 in T.
• the hot rolling starting temperature in test 3 was so high that the slabs Bl.3, B2.3, B3.3, B4.3 cast from steel S2 had a two-phase mixed structure formed from austenite and ferrite when they entered the hot rolling mill.
• the slabs B1.3 to B .3 were therefore first rolled in the two-phase mixing area.
• the degree of deformation Ug ⁇ / ⁇ achieved during this rolling was 70%.
• Rolling in the two-phase mixing area was followed by rolling with a ferritic structure of the processed steel. In the course of this ferrite rolling, a degree of deformation Ug ⁇ of 33% was achieved.
• the hot rolling starting temperature was chosen such that the three slabs B1.4, B2.4, B3.4 cast from steel S2 had a two-phase mixed structure formed from austenite and ferrite when they entered the hot rolling mill.
• the slabs B1.4 to B3.4 were therefore also rolled in the two-phase mixing area.
• a relatively low degree of deformation Ug ⁇ / ⁇ of 40% was observed.
• Table 5 shows the slabs B1.4 to B3.4 and the hot strips produced from them
• Table 6 shows the magnetic properties P 1 -5 in W / kg and J 2 500 and J5000 in T for two conventionally produced electrical sheets offered by the applicant under the trade names M 800-50 A and 530-50 AP specified, whose alloy with a Si content of 1.3 wt .-% is such that it has a pronounced austenite range in the course of its production.
• the M 800-50 A electrical sheet has undergone standard production, while the 530-50 AP electrical sheet has been subjected to hot strip annealing in addition to the standard production steps.
• Sl / cs 020172WO Hot rolling is carried out at least partially in the two-phase mixing area and an overall shape change ⁇ h of at least 35% is achieved.
• Table 7 shows the magnetic properties P, 5 in W / kg and J 250 o and J5000 for an electrical sheet V.2, which was produced by the process described in DE 199 30 518 AI.
• the special feature of this process is that during hot rolling at least the first forming pass is rolled in the austenite area and then one or more forming passes are carried out in the ferrite area with an overall shape change Sh of at least 45%.

Landscapes

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

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=29413886

Family Applications (1)

Country Status (8)

Cited By (4)

Families Citing this family (10)

Citations (6)

Family Cites Families (6)

• 2002
  • 2002-05-15 DE DE10221793A patent/DE10221793C1/de not_active Expired - Fee Related
• 2003
  • 2003-05-15 KR KR1020047018451A patent/KR101059577B1/ko not_active Expired - Fee Related
  • 2003-05-15 JP JP2004505397A patent/JP2005525469A/ja active Pending
  • 2003-05-15 US US10/514,983 patent/US7501028B2/en not_active Expired - Lifetime
  • 2003-05-15 WO PCT/EP2003/005114 patent/WO2003097884A1/de not_active Ceased
  • 2003-05-15 CN CNB038154463A patent/CN100363509C/zh not_active Expired - Fee Related
  • 2003-05-15 EP EP03752745A patent/EP1506320A1/de not_active Ceased
  • 2003-05-15 AU AU2003232780A patent/AU2003232780B2/en not_active Ceased

Patent Citations (6)

Also Published As

Similar Documents

Legal Events