NON-GRAIN-ORIENTED FLAT METAL PRODUCT, METHOD FOR PRODUCTION THEREOF AND USE

Abstract

The invention relates to a non-grain-oriented flat metal product, which inter alia has comparatively high weight proportions of Mn and Cr. The invention also relates to a method of production and to a use.

Claims

1. A non-grain oriented flat metal product consisting of the components mentioned below in weight percent, abbreviated as: Wt.%: C: 0.0020 to 0.005; Si: 2.6 to 2.9; Al: 0.5 to 0.8; Mn: 1.1 to 1.3; Cr: 0.7 to 1.6; N: 0.0001 to 0.0060; S: 0.0001 to 0.0035; Ti: 0.001 to 0.010; P: 0.004 to 0.060; optional components: 0.001 up to 0.15; remainder Fe and unavoidable impurities.

2. The flat product according to claim 1, having at 28° C. a specific electrical resistance of
0.60 Ωmm.sup.2/m≤ρ.sub.spec≤0.70 Ωmm.sup.2/m.

3. The flat product according to claim 1, wherein
Abs[P.sub.1.0;1000×d/(J.sub.200;1000×([Mn]+[Cr]){circumflex over ( )}2)]<9, and/or
P.sub.1.0;400<16 W/kg, and/or
P.sub.1.0;1000<70 W/kg, and/or
J at 200 A/m and 1000 Hz>1.0.

4. The flat product according to claim 1, wherein at a temperature between 18° C. and 28° C. inclusive, the following applies
2.2≤([Mn]+[Cr]).sup.2×[ρ.sub.spec]≤5.5 where: [Mn]: dimensionless value of the Mn content in wt. %, [Cr]: dimensionless value of the Cr content in wt. %, [ρ.sub.spec]: dimensionless value of the specific electrical resistance in Ωmm.sup.2/m of finally-annealed cold strip.

5. The flat product according to claim 1, wherein in a boundary region to the surface up to a depth of 0.95 μm the ratio of a content in kg/m{circumflex over ( )}3 of the sum of Mn and Cr to a content in kg/m{circumflex over ( )}3 of the sum of Al and Si is 0.2 or greater.

6. The flat product according to claim 1, having a thickness d of
d<0.35 mm.

7. A method for producing a flat product, in particular from an alloy according to claim 1, having the following production steps: A) melting a melt containing an element composition according to claim 1; B) casting the melt to form a rollable preliminary product, in particular a preliminary strip, a slab or a thin slab; C) hot rolling of the preliminary product with a final rolling temperature between 820° C. and 890° C.; D) pickling; E) optionally hot strip annealing; F) cold rolling; G) final annealing.

8. The method according to claim 7, wherein the preliminary product is heated to a preheating temperature of at most 1200° C. at the beginning of the hot rolling.

9. The method according to claim 7, wherein the hot strip is coiled at a coiling temperature of between 500° C. and 750° C. after step C) or after step D).

10. The method according to claim 7, wherein the hot strip annealing of step E) is carried out at a temperature between 700 and 790° C.

11. The method according to claim 7, wherein the cold rolling of step F) is carried out with a total cold rolling degree between 75% and 90%.

12. The method according to claim 7, wherein the final annealing is carried out at a temperature between 930° C. and 1070° C.

13. The flat product obtainable by a method according to claim 7.

14. (canceled)

15. A use of a cutout punched from a flat product according to claim 1 as a lamella of a rotating electrical machine.

16. The flat product according to claim 3, wherein a thickness of the flat product is between 0.19 mm and 0.31 mm.

17. The flat product according to claim 1, wherein at any temperature between 20° C. and 24° C., the following applies
2.2≤([Mn]+[Cr]).sup.2×[ρ.sub.spec]≤5.5 where: [Mn]: dimensionless value of the Mn content in wt. %, [Cr]: dimensionless value of the Cr content in wt. %, [ρ.sub.spec]: dimensionless value of the specific electrical resistance in Ωmm.sup.2/m of finally-annealed cold strip.

18. The flat product according to claim 1, having a thickness d of
0.19 mm<d<0.31 mm.

19. The method according to claim 10, wherein the hot strip annealing of step E) is carried out at a temperature between 700 and 790° C. for a period between 12 h and 36 h.

20. The method according to claim 7, wherein the flat product is rolled with a maximum of four passes and to a thickness between 0.19 mm and 0.31 mm.

Description

DETAILED DESCRIPTION

Examples

[0070] Aspects of the subject disclosure are explained in more detail below with reference to exemplary embodiments.

[0071] Three (3) electrical steel strips according to the subject disclosure were produced, hereinafter referred to as variant 1, variant 2 and variant 3. The compositions of variants 1, 2 and 3 are listed in Table 1. Further variants, referred to as variant Ref. 1, variant Ref. 2 and variant Ref. 3, serve as comparative samples not according to the subject disclosure, the alloy compositions of which are likewise listed in Table 1.

[0072] From the listed alloys, low sulfur and nitrogen contents were adjusted via a ladle furnace and slabs were produced via continuous casting and thin slab casting, respectively. A strip was then produced from each of these by hot rolling, pickling, hot strip annealing, cold rolling and final annealing. In the examples, the material was heated to a maximum of 1200° C. prior to hot rolling, rolled to a hot strip thickness of 1.3-1.9 mm to a final rolling temperature of 820° C.-890° C. and coiling temperature of 500° C.-750° C.

[0073] The hot strips produced are pickled and subsequently annealed at 700-790° C. for 24 hours, wherein this step is not necessarily part of the subject disclosure, i.e., it is optional. The annealed hot strip was formed, at a total cold rolling degree of 75-90%, to a final thickness of 0.19-0.31 mm (+/−8%) with a maximum of 4 passes.

[0074] Final annealing is carried out at a maximum temperature between 930-1070° C.

[0075] The production parameters of variants 1 to 3 and Ref. 1 to Ref. 3 are listed in Table 1.

TABLE-US-00001 TABLE 1 Preheating temperature Hot strip Total Final before hot Final rolling Coiling annealing cold annealing rolling in temperature Hot strip temperature temperature rolling Final Number temperature degrees in degrees thickness in degrees in degrees degree thickness of in degrees Sample Celsius Celsius in mm Celsius Celsius in percent in mm passes Celsius Var. 1 1120 840° C. 1.6 620 740 Different Different 4 Different see Table 4 see Table 4 see Table 4 Var. 2 1120 840° C. 1.6 620 740 see above see above 4 see above Var. 3 1120 840° C. 1.6 620 740 see above see above 4 see above Ref. 1 1120 840° C. 1.6 620 740 see above see above 4 see above Ref. 2 1120 840° C. 1.6 620 740 see above see above 4 see above Ref. 3 1120 840° C. 1.6 620 740 see above see above 4 see above

[0076] The specific electrical resistance of the samples was measured after the final annealing. For this purpose, a Wheatstone measuring bridge according to DIN EN 60404-13:2015-01 was used.

TABLE-US-00002 TABLE 2 Spec. Electrical resistance 2.2 ≤ [ρ.sub.spec] × C Si Mn Al Cr P Ti N S at 28° C. ([Mn] + [Cr]) Var. [wt. %] [wt. %] [wt. %] [wt. %] [wt. %] [wt. %] [wt. %] [wt. %] [wt. %] [Ωmm.sup.2/m] {circumflex over ( )}2 ≤ 5.5 1 0.0038 2.72 1.20 0.77 1.01 0.02 0.0050 0.0026 0.0030 0.626 yes 2 0.0041 2.74 1.20 0.77 1.31 0.02 0.0050 0.0025 0.0030 0.642 yes 3 0.0040 2.70 1.20 0.70 1.60 0.02 0.0030 0.0030 0.0030 0.643 yes Ref. 1 0.0034 3.29 0.16 0.93 0.07 0.03 0.0040 0.0018 0.0020 0.625 no Ref. 2 0.0031 3.22 0.16 0.75 0.02 0.01 0.0040 0.0010 0.0012 0.588 no Ref. 3 0.0023 2.67 0.20 0.74 0.04 0.02 0.0042 0.0010 0.0010 0.525 no

[0077] Table 3 shows properties of the prepared samples 1 to 3 and Ref. 1 to Ref. 3.

[0078] The magnetic values P at 1.0 T and 1000 Hz and J at 200 A/m and 1000 Hz were determined using a 60×60 mm.sup.2 panel according to IEC404-3, wherein a mean value of a longitudinal and a transverse value was formed in each case.

[0079] In particular, it is found that in addition to the very good polarization, at 1000 Hz and a magnetic field strength of 200 A/m, a desirable low magnetic remagnetization loss P occurs at 1.0 T and 1000 Hz, which is approximately in the order of magnitude of the results obtained at the reference samples.

TABLE-US-00003 TABLE 3 P at J at | P(1.0_1000) × d/ 1.0 T 200 A/m (J(200_1000) × 1000 Hz 1000 Hz d ([Mn] + Variant [W/kg] [T] [mm] [Cr]{circumflex over ( )}2) | ≤ 9 Inventive 1 61.83 1.11 0.25 2.85 yes 2 60.86 1.08 0.25 2.33 yes 3 58.04 1.08 0.25 1.78 yes Ref. 1 63.75 0.98 0.27 329.15 no Ref. 2 54.64 1.20 0.25 337.55 no Ref. 3 80.17 0.91 0.35 536.70 no

[0080] Table 4 shows the following properties of the samples 1.1, 2.1, 2.2, 2.3, 3.1 produced from the analyses 1-3 and the samples Ref. 1.1, 1.2, 2.1, 3.1 to 3.5 from the analyses Ref. 1-3; wherein the digits after the dot refer to the fact that a plurality of samples was prepared randomly from one sample for optical analysis to support the robustness of the tests performed. For example, five samples were prepared from reference materials 3, which are numbered 3.1 to 3.5.

[0081] The special feature of the element enrichment of Mn and Cr in the surface layers of the flat product was determined by means of glow discharge spectroscopy according to test specification ISO 11505:2012-12. The measurement is carried out on the upper side (OS) and the lower side (US) of the samples. In addition, measurements were made across the bandwidth at the sample locations edge (R1/R2) and middle (M). From the obtained measurement curves of the mass over the sample depth of 0 to 12 μm, an integral evaluation of the mass density from the surface (0 μm) to a sample depth of 0.95 μm was calculated for Mn, Cr, Al and Si.

TABLE-US-00004 TABLE 4 Ratio of (sum of Mn and Cr contents from surface to a depth of 0.95 μm) to (sum of Al and Si contents Mass density per area from a depth Final integrated over the of 0.95 μm) Cold annealing volume from the surface ∫.sub.0.sup.0.95([Mn] + ∫.sub.0.sup.0.95( [Mn] + rolling temperature to a depth of 0.95 μm [Cr])/∫.sub.0.sup.0.95 [Crl)/∫.sub.0.sup.0.95 Thickness degree Temperature OS/US R1/M/R2 Mn Cr Al Si ([Al] + [Si]) ([Al] + Variant Sample [mm] [%] [° C.] position position [kg/m.sup.3] [kg/m.sup.3] [kg/m.sup.3] [kg/m.sup.3] [ ] [Si]) ≥ 0.2 1 1.1 0.25 84.4 1030 OS M 65 59 127 175 0.408 yes 1 1.1 0.25 84.4 1030 US M 70 61 114 174 0.453 yes 1 1.1 0.25 84.4 960 OS M 47 45 89 157 0.376 yes 1 1.1 0.25 84.4 960 US M 58 63 86 194 0.432 yes 2 2.1 0.35 78.1 1000 OS R1 59 56 126 201 0.353 yes 2 2.1 0.35 78.1 1000 US R1 66 53 142 210 0.340 yes 2 2.1 0.35 78.1 1000 OS M 62 61 127 214 0.361 yes 2 2.1 0.35 78.1 1000 US M 73 57 144 232 0.348 yes 2 2.1 0.35 78.1 1000 OS R2 56 56 117 191 0.363 yes 2 2.1 0.35 78.1 1000 US R2 65 56 134 206 0.355 yes 2 2.2 0.27 83.1 1000 OS R1 52 51 124 185 0.335 yes 2 2.2 0.27 83.1 1000 US R1 56 54 133 195 0.335 yes 2 2.2 0.27 83.1 1000 OS M 54 54 116 193 0.349 yes 2 2.2 0.27 83.1 1000 US M 58 61 111 204 0.375 yes 2 2.2 0.27 83.1 1000 OS R2 61 59 128 199 0.367 yes 2 2.2 0.27 83.1 1000 US R2 57 59 120 194 0.370 yes 2 2.3 0.25 84.4 1000 OS R1 54 44 136 199 0.292 yes 2 2.3 0.25 84.4 1000 US R1 63 63 133 195 0.381 yes 2 2.3 0.25 84.4 1000 OS M 62 62 130 201 0.378 yes 2 2.3 0.25 84.4 1000 US M 65 59 148 213 0.342 yes 2 2.3 0.25 84.4 1000 OS R2 66 61 139 209 0.367 yes 2 2.3 0.25 84.4 1000 US R2 62 63 126 193 0.391 yes 3 3.1 0.25 84.4 1000 OS R1 50 50 149 172 0.310 yes 3 3.1 0.25 84.4 1000 US R1 57 58 175 182 0.323 yes 3 3.1 0.25 84.4 1000 OS M 59 60 162 186 0.343 yes 3 3.1 0.25 84.4 1000 US M 58 57 194 183 0.305 yes 3 3.1 0.25 84.4 1000 OS R2 60 50 208 170 0.291 yes 3 3.1 0.25 84.4 1000 US R2 65 52 195 177 0.313 yes Refer- R1.1 0.27 83.1 1030 OS M 10 2 150 238 0.030 no ence 1 Refer- R1.1 0.27 83.1 1030 US M 10 2 121 243 0.032 no ence 1 Refer- R1.2 0.25 84.4 1030 OS M 9 2 129 236 0.030 no ence 1 Refer- R1.2 0.25 84.4 1030 US M 9 2 118 233 0.031 no ence 1 Refer- R2.1 0.25 84.4 1030 OS M 12 2 98 247 0.040 no ence 2 Refer- R2.1 0.25 84.4 1030 US M 12 2 89 247 0.041 no ence 2 Refer- R3.1 0.35 78.1 1000 OS M 5 1 138 132 0.021 no ence 3 Refer- R3.1 0.35 78.1 1000 US M 4 1 133 117 0.020 no ence 3 Refer- R3.2 0.25 84.4 1030 OS M 12 2 79 212 0.049 no ence 3 Refer- R3.2 0.25 84.4 1030 US M 12 2 82 209 0.050 no ence 3 Refer- R3.3 0.25 84.4 1030 OS M 11 2 91 217 0.044 no ence 3 Refer- R3.3 0.25 84.4 1030 US M 12 3 96 203 0.050 no ence 3 Refer- R3.4 0.25 84.4 1030 OS M 13 2 122 201 0.047 no ence 3 Refer- R3.4 0.25 84.4 1030 US M 10 2 103 223 0.038 no ence 3 Refer- R3.5 0.25 84.4 1030 OS M 12 2 98 207 0.048 no ence 3 Refer- R3.5 0.25 84.4 1030 US M 13 2 103 198 0.051 no ence 3