EP1475450A1 - High strength soft magnetic Iron-Cobalt-Vanadium alloy. - Google Patents

Abstract

Soft magnetic alloy contains (in weight %) 35.0-55.0 cobalt, 0.75-2.5 vanadium, 0.3-1.5 zirconium, not more than 5.0 nickel, 0-1.0 (tantalum + 2 x niobium), and a balance of iron and impurities.

Description

The invention relates to a high-strength soft magnetic iron-cobalt-vanadium alloy, in particular for electrical Generators, motors and magnetic bearings used in aircraft can be. Electric generators, motors and magnetic Bearings in aircraft must be next to one as possible Small size also have the lowest possible weight. Therefore soft magnetic iron-cobalt-vanadium alloys are used for these applications used, which has a high saturation induction exhibit.

The binary iron-cobalt alloys with a cobalt content between 33 and 55 wt.% are extremely brittle, resulting in the formation of an ordered superstructure at temperatures below 730 ° C is due. The addition of about 2 % By weight of vanadium impairs the transition into this superstructure, so that a relatively good cold workability after Quenching to room temperature from the temperatures above 730 ° C can be achieved.

As a ternary base alloy is therefore an iron-cobalt-vanadium alloy known, the 49 wt.% Iron, 49 wt.% Cobalt and 2% by weight of vanadium. This alloy has been around long known and is described, for example, in R. M. Bozorth, Ferromagnetism, van Nostrand, New York (1951) "in detail described. This vanadium-containing iron-cobalt alloy is characterized by its very high saturation induction of about 2.4 T from.

A further development of this ternary vanadium-containing cobalt-iron base alloy is known from US 3,634,072. There is a quenching in the production of alloy strips of the hot-rolled alloy strip from a temperature above the phase transition temperature of 730 ° C described. This process is necessary to allow the alloy is sufficiently ductile for subsequent cold rolling. With Quenching is suppressed the order setting. However, quenching is very critical in terms of manufacturing technology as it is very easy to do in the so-called cold rolling passes Band breaks can come. That's why considerable efforts have been made to increase the ductility of the alloy ribbons increase and thus increase manufacturing reliability.

US 3,634,072 therefore proposes as ductility-enhancing additives an addition of 0.02 to 0.5 wt.% of niobium and / or 0.07 to 0.3 wt.% zircon.

Niobium, which by the way is replaced by the homologous tantalum Not only has in the iron-cobalt alloy system the property of strongly suppressing the degree of order, what for example, R.V. Major and C.M. Orrock in "High saturation ternary cobalt-iron based alloys ", IEEE Trans. Magn. 24 (1988), 1856-1858, but it also inhibits grain growth.

The addition of zirconium in those proposed in US 3,634,072 Amounts of at most 0.3% by weight also inhibits grain growth. Both mechanisms significantly improve ductility the alloy after quenching.

In addition to this known from US 3,634,072 high-strength niobund zirconium-containing iron-cobalt-vanadium alloys are the Further still zirconium-free alloys from US 5,501,747 known.

There are proposed iron-cobalt-vanadium alloys, their application in high-speed aircraft generators' and find magnetic bearings. The US 5,501,747 is based on the teaching of US 3,364,072 and limits the niobium content taught there to 0.15-0.5% by weight. Furthermore, there is a special magnetic annealing recommended in which the Alloy not longer than about four hours, preferably not longer than two hours, at a temperature of not above 740 ° C can be tempered to an object to produce a yield strength of at least about 620 MPa. This is very restrictive and very much unusual, since usually the soft magnetic iron-cobalt-vanadium alloys at temperatures above 740 ° C and annealed below 900 ° C.

1. Wird die Legierung bei einer höheren Temperatur geglüht, so erhält man ein gröberes Korn und damit gute weichmagnetische Eigenschaften. Die dabei erzielten mechanischen Eigenschaften sind in der Regel jedoch relativ schlecht.

2. Glüht man die Legierung hingegen bei niedrigeren Temperaturen, so erzielt man bessere mechanische Eigenschaften aufgrund eines feineren Korns. Das feinere Korn jedoch bewirkt schlechtere magnetische Eigenschaften.

With the annealing temperature, the magnetic and mechanical properties can be adjusted. Both properties are crucial for the use of the alloys. However, the simultaneous optimization of these two properties is very difficult because the properties are in opposite directions:

1. If the alloy is annealed at a higher temperature, we obtain a coarser grain and thus good soft magnetic properties. However, the mechanical properties achieved are generally relatively poor.

2. On the other hand, if the alloy is annealed at lower temperatures, better mechanical properties due to a finer grain are achieved. The finer grain, however, causes poorer magnetic properties.

A major drawback to the alloy selection taught in US 5,501,747 lies in the need of the above Short term annealing, which only takes about one to two hours disordered / ordered at a temperature near the phase boundary may be performed to usable magnetic and to achieve mechanical properties.

For a large amount of annealed material is due to different Heating times and due to temperature fluctuations within the annealing good a production security with it only very difficult to realize. It comes on a large scale usually related to intolerable variations in terms on the characterizing the mechanical properties Yield.

Object of the present invention is therefore to provide a new high strength soft magnetic iron cobalt vanadium alloy selection to provide, which is characterized by very good mechanical properties, especially by very high Distinguishing yield points.

The alloys are also intended for longer annealing times of at least two hours with a high level of production reliability Yield strengths of more than 600 MPa, preferably from above 700 MPa.

In addition, the alloys should simultaneously have high saturation induction values and the lowest possible coercive field strengths have, i. an excellent soft magnetic Show behavior.

35,0 ≤ Co ≤ 55,0 Gew.%,

0,75 ≤ V ≤ 2,5 Gew.%,

0 ≤ (Ta + 2 x Nb) ≤ 0,8 Gew.%,

0,3 < Zr ≤ 1,5 Gew.%,

Ni ≤ 5,0 Gew.%, Rest Fe sowie erschmelzungsbedingten und/oder zufälligen Verunreinigungen besteht.

According to the invention this object is achieved by a soft magnetic iron-cobalt-vanadium alloy selection, which essentially consists of

35.0 ≦ Co ≦ 55.0% by weight,

0.75 ≦ V ≦ 2.5% by weight,

0 ≦ (Ta + 2 × Nb) ≦ 0.8 wt%,

0.3 <Zr ≤ 1.5% by weight,

Ni ≤ 5.0 wt.%, Remainder Fe and melting-induced and / or accidental impurities.

The term "consists essentially of" is here and hereinafter understood that the alloy selection according to the invention besides the stated main constituents of Co, V, Zr, Nb, Ta and Fe are merely melting and / or have random contaminants in such an amount can, which has neither the mechanical nor the magnetic properties significantly impaired.

It has surprisingly been found that iron-cobalt-vanadium alloys with zirconium contents above 0.3% by weight much better mechanical properties with simultaneous Achieving excellent magnetic properties have as the aforementioned alloys from the State of the art.

This can be attributed to the fact that it is due to the addition of zirconium in amounts above 0.3% by weight within the structure to form a previously unknown hexagonal Laves phase between the individual grains, the one very positive influence on the mechanical and magnetic Properties takes. This hexagonal Laves phase is from the Viewpoint of metallurgy and crystallography not with the cubic Laves phase described in US 5,501,747 to be confused. There is only a name part identity. This significant addition of zirconium effects in particular in the Interplay with niobium and / or tantalum is a significant improvement in ductility.

In a preferred embodiment, the inventive soft magnetic iron-cobalt-vanadium alloy one Zirconium content of 0.5 ≤ Zr ≤ 1.0 wt%, ideally one Zirconium content of 0.6 ≤ Zr ≤ 0.8 wt.% To.

Typically, the cobalt content is 48.0 ≦ Co ≦ 50.0 Wt.%. But also with alloys whose cobalt content is between 45.0 ≤ Co ≤ 48.0% by weight, very good results can be achieved. The content of nickel should be Ni ≦ 1.0 wt%, ideally Ni ≤ 0.5 wt.%.

In a typical embodiment of the present invention has the soft magnetic iron-cobalt-vanadium alloy according to the invention a vanadium ion content of 1.0 ≦ V ≦ 2.0 % By weight, ideally a vanadium content of 1.5 ≤ V ≤ 2.0 % By weight.

To achieve particularly good ductilities are according to the vorliegnden Invention niobium and / or tantalum contents of 0.04 ≤ (Ta + 2 x Nb) ≦ 0.8 wt%, ideally, 0.04 ≦ (Ta + 2 x Nb) ≤ 0.3% by weight.

Cu ≤ 0,2, Cr ≤ 0,3, Mo ≤ 0,3, Si ≤ 0,5, Mn ≤ 0,3 und Al ≤0,3; vorzugsweise von:

Cu ≤ 0,1, Cr ≤ 0,2, Mo ≤ 0,2, Si ≤ 0,2, Mn ≤ 0,2 und Al ≤ 0,2; idealerweise von :

Cu ≤ 0,06, Cr ≤ 0,1, Mo ≤ 0,1, Si ≤ 0,1, Mn ≤ 0,1; auf.

The soft-magnetic high-strength iron-cobalt-vanadium alloys according to the invention also have a content of melting-induced and / or incidental metallic impurities of:

Cu ≦ 0.2, Cr ≦ 0.3, Mo ≦ 0.3, Si ≦ 0.5, Mn ≦ 0.3, and Al ≦ 0.3; preferably from:

Cu ≦ 0.1, Cr ≦ 0.2, Mo ≦ 0.2, Si ≦ 0.2, Mn ≦ 0.2 and Al ≦ 0.2; ideally of:

Cu ≤ 0.06, Cr ≤ 0.1, Mo ≤ 0.1, Si ≤ 0.1, Mn ≤ 0.1; on.

P ≤ 0,01, S ≤ 0,02, N ≤ 0,005, O ≤ 0,05 und C ≤ 0,05; vorzugsweise im Bereich von:

P ≤ 0,005, S ≤ 0,01, N ≤ 0,002, O ≤ 0,02 und C ≤ 0,02; idealerweise im Bereich von:

S ≤ 0,005, N ≤ 0,001, O ≤ 0,01 und C ≤ 0,01.

Furthermore, non-metallic impurities typically range from:

P ≤ 0.01, S ≤ 0.02, N ≤ 0.005, O ≤ 0.05 and C ≤ 0.05; preferably in the range of:

P ≤ 0.005, S ≤ 0.01, N ≤ 0.002, O ≤ 0.02 and C ≤ 0.02; ideally in the range of:

S ≤ 0.005, N ≤ 0.001, O ≤ 0.01 and C ≤ 0.01.

The alloys of the invention can be prepared by means of various Process be melted. Basically all are common techniques, such as the melting at the Air or production via vacuum induction melting (VIM = Vacuum Induction Melting) possible.

For the production of soft magnetic iron-cobalt-vanadium alloys according to the invention however, the VIM procedure is used preferred since the relatively high zirconium contents to adjust better are. When melting in the air have zirconium-containing Alloys burn to high, leaving unwanted Form zirconium oxides and other impurities.

Overall, when using the VIM method, the zirconium content is better to adjust.

The alloy melt is then poured into molds. After solidification of the melt block is turned off and then rolled at a temperature between 900 ° C and 1300 ° C to a slab.
Alternatively, it is also possible to dispense with twisting off the oxide skin on the surface of the melt blocks. Instead, then the slab must be processed accordingly on their surface.

The resulting slab is then at similar temperatures, that means at temperatures above 900 ° C, to one Hot rolled strip. The then obtained hot-rolled alloy strip is too brittle for another cold rolling process. As a result, The hot-rolled alloy strip becomes of a temperature ordered above the phase transition / disordered, which known to be at a temperature of about 730 ° C in Water, preferably quenched in ice-salt water.

By this treatment, the alloy ribbon is now sufficient ductile. After removal of the oxide skin on the alloy strip, which take place, for example, by pickling or blasting For example, the alloy ribbon becomes a thickness cold-rolled of about 0.35 mm.

Subsequently, from the cold-rolled alloy strip, the manufactured desired shapes. This form processing is done usually by punching. Further methods are laser cutting, Wire eroding, water jet cutting or the like.

After this shaping, the important magnetic takes place Final annealing, whereby by the variation of the annealing time and the annealing temperature the magnetic properties and the mechanical Properties of the final product precisely set can be.

The invention will be explained below with reference to exemplary embodiments and comparative examples. The differences of the individual alloys with regard to their mechanical and magnetic properties are illustrated by _FIGS . 1 to 8, which each show the coercive force H _c as a function of the yield strength R _p0,2 .

All embodiments and all comparative examples were prepared by melting under vacuum in flat molds were poured off. The oxide skin present on the fused blocks was then milled off.

Subsequently, the melting blocks were at a temperature hot rolled at 1150 ° C together with a thickness of d = 3.5 mm.

The resulting slabs were then from a temperature T = 930 ° C quenched in ice water. The quenched, hot-rolled Slabs were finally on a thickness d '= 0.35 mm cold rolled. Subsequently, tensile specimens and Punched rings. At the resulting tensile specimens and rings were the respective magnetic final annealing performed.

All alloy parameters, magnetic measurement results and Mechanical measurement results are shown in Tables 1 to 26.

To investigate the mechanical properties, tensile tests were carried out in which the elastic modulus E, the yield strength R _p0.2 , the tensile strength R _m , the elongation at break A _L and the hardness HV were measured. An essential mechanical parameter considered to be the yield strength R _p0.2 .

The magnetic properties were examined on the stamped rings. At the punched rings, the static BH new curve and the static coercive field H _{c were} determined.

Tabelle 1:

Eigenschaften von Sonderschmelzen der Chargen 93/5964 bis 93/6018 nach einstündiger Schlussglühung bei 720°C unter H₂

Tabelle 2:

Eigenschaften von Sonderschmelzen der Chargen 93/6278 bis 93/6289 nach einstündiger Schlussglühung bei 720°C unter H₂

Tabelle 3:

Eigenschaften von Sonderschmelzen der Chargen 93/6655 bis 93/6666 nach einstündiger Schlussglühung bei 720°C unter H₂

Tabelle 4:

Eigenschaften von Sonderschmelzen der Chargen 93/5964 bis 93/6018 nach zweistündiger Schlussglühung bei 720°C unter H₂

Tabelle 5:

Eigenschaften von Sonderschmelzen der Chargen 93/6278 bis 93/6289 nach zweistündiger Schlussglühung bei 720°C unter H₂

Tabelle 6:

Eigenschaften von Sonderschmelzen der Chargen 93/6655 bis 93/6666 nach zweistündiger Schlussglühung bei 720°C unter H₂

Tabelle 7:

Eigenschaften von Sonderschmelzen der Chargen 93/6278 bis 93/6289 nach vierstündiger Schlussglühung bei 720°C unter H₂

Tabelle 8:

Eigenschaften von Sonderschmelzen der Chargen 93/6655 bis 93/6666 nach vierstündiger Schlussglühung bei 720°C unter H₂

Tabelle 9:

Eigenschaften von Sonderschmelzen der Chargen 93/6278 bis 93/6289 nach einstündiger Schlussglühung bei 730°C unter H₂

Tabelle 10:

Eigenschaften von Sonderschmelzen der Chargen 93/6278 bis 93/6289 nach zweistündiger Schlussglühung bei 730°C unter H₂

Tabelle 11:

Eigenschaften von Sonderschmelzen der Chargen 93/6278 bis 93/6289 nach einstündiger Schlussglühung bei 740°C unter H₂

Tabelle 12:

Eigenschaften von Sonderschmelzen der Chargen 93/6655 bis 93/6666 nach einstündiger Schlussglühung bei 740°C unter H₂

Tabelle 13:

Eigenschaften von Sonderschmelzen der Chargen 93/6278 bis 93/6289 nach zweistündiger Schlussglühung bei 740°C unter H₂

Tabelle 14:

Eigenschaften von Sonderschmelzen der Chargen 93/6655 bis 93/6666 nach zweistündiger Schlussglühung bei 740°C unter H₂

Tabelle 15:

Eigenschaften von Sonderschmelzen der Chargen 93/5964 bis 93/6018 nach vierstündiger Schlussglühung bei 740°C unter H₂

Tabelle 16:

Eigenschaften von Sonderschmelzen der Chargen 93/6278 bis 93/6306 nach vierstündiger Schlussglühung bei 740°C unter H₂

Tabelle 17:

Eigenschaften von Sonderschmelzen der Chargen 93/6655 bis 93/6666 nach vierstündiger Schlussglühung bei 740°C unter H₂

Tabelle 18:

Eigenschaften von Sonderschmelzen der Chargen 93/6278 bis 93/6289 nach einstündiger Schlussglühung bei 750°C unter H₂

Tabelle 19:

Eigenschaften von Sonderschmelzen der Chargen 93/6278 bis 93/6289 nach einstündiger Schlussglühung bei 770°C unter H₂

Tabelle 20:

Eigenschaften von Sonderschmelzen der Chargen 93/6278 bis 93/6289 nach zweistündiger Schlussglühung bei 770°C unter H₂

Tabelle 21:

Eigenschaften von Sonderschmelzen der Chargen 93/5964 bis 93/6018 nach vierstündiger Schlussglühung bei 770°C unter H₂

Tabelle 22:

Eigenschaften von Sonderschmelzen der Chargen 93/6278 bis 93/6284 nach vierstündiger Schlussglühung bei 770°C unter H₂

Tabelle 23:

Eigenschaften von Sonderschmelzen der Chargen 93/6655 bis 93/6666 nach vierstündiger Schlussglühung bei 770°C unter H₂

Tabelle 24:

Eigenschaften von Sonderschmelzen der Chargen 93/5964 bis 93/6018 nach vierstündiger Schlussglühung bei 800°C unter H₂

Tabelle 25:

Eigenschaften von Sonderschmelzen der Chargen 93/6278 bis 93/6306 nach vierstündiger Schlussglühung bei 800°C unter H₂

Tabelle 26:

Eigenschaften von Sonderschmelzen der Chargen 93/6655 bis 93/6666 nach vierstündiger Schlussglühung bei 800°C unter H₂

Tabelle 27:

Gefügezustand der Sonderschmelzen 93/7179 bis 93/7183 nach Abschrecken von verschiedenen Temperaturen

Tabelle 28:

Eigenschaften der Chargen 93/7180 bis 93/7184 sowie 74/5517 und 99/5278 nach einstündiger Schlussglühung bei 720°C unter H_2; Dicke: 0,35 mm

Tabelle 29:

Ummagnetisierungsverluste von Sonderschmelzen der Chargen 93/7180 bis 93/7184 sowie 74/5517 und 99/5278 für verschiedene Aussteuerungen und Frequenzen nach einstündiger Schlussglühung bei 720°C unter H₂; Dicke: 0,35 mm

Tabelle 30:

Eigenschaften der Chargen 93/7180 bis 93/7184 sowie 74/5517 und 99/5278 nach zweistündiger Schlussglühung bei 750°C unter H_2; Dicke: 0,35 mm

Tabelle 31:

Ummagnetisierungsverluste von Sonderschmelzen der Chargen 93/7180 bis 93/7184 sowie 74/5517 und 99/5278 für verschiedene Aussteuerungen und Frequenzen nach zweistündiger Schlussglühung bei 750°C unter H₂; Dicke: 0,35 mm

Tabelle 32:

Eigenschaften der Chargen 93/7180 bis 93/7184 sowie 74/5517 und 99/5278 nach vierstündiger Schlussglühung bei 840°C unter H_2; Dicke: 0,35 mm

Tabelle 33:

Ummagnetisierungsverluste von Sonderschmelzen der Chargen 93/7180 bis 93/7184 sowie 74/5517 und 99/5278 für verschiedene Aussteuerungen und Frequenzen nach vierstündiger Schlussglühung bei 840°C unter H₂; Dicke: 0,35 mm

Hereinafter, comparative examples and embodiments of the present invention will be discussed in detail with reference to Tables 1 to 33 and Figs. Showing:

Table 1:

Properties of special melts of batches 93/5964 to 93/6018 after one hour final annealing at 720 ° C. under H ₂

Table 2:

Properties of special melts of batches 93/6278 to 93/6289 after one hour of final annealing at 720 ° C. under H ₂

Table 3:

Properties of special melts of batches 93/6655 to 93/6666 after one hour of final annealing at 720 ° C. under H ₂

Table 4:

Properties of special melts of batches 93/5964 to 93/6018 after two hours of final annealing at 720 ° C. under H ₂

Table 5:

Properties of special melts of batches 93/6278 to 93/6289 after two hours' final annealing at 720 ° C. under H ₂

Table 6:

Properties of special melts of batches 93/6655 to 93/6666 after two hours' final annealing at 720 ° C. under H ₂

Table 7:

Properties of special melts of batches 93/6278 to 93/6289 after four hours of final annealing at 720 ° C. under H ₂

Table 8:

Properties of special melts of batches 93/6655 to 93/6666 after four hours of final annealing at 720 ° C. under H ₂

Table 9:

Properties of special melts of batches 93/6278 to 93/6289 after one hour final annealing at 730 ° C. under H ₂

Table 10:

Properties of special melts of batches 93/6278 to 93/6289 after two hours' final annealing at 730 ° C. under H ₂

Table 11:

Properties of special melts of batches 93/6278 to 93/6289 after one hour of final annealing at 740 ° C. under H ₂

Table 12:

Properties of special melts of batches 93/6655 to 93/6666 after one hour final annealing at 740 ° C. under H ₂

Table 13:

Properties of special melts of batches 93/6278 to 93/6289 after two hours' final annealing at 740 ° C. under H ₂

Table 14:

Properties of special melts of batches 93/6655 to 93/6666 after two hours' final annealing at 740 ° C. under H ₂

Table 15:

Properties of special melts of batches 93/5964 to 93/6018 after four hours of final annealing at 740 ° C. under H ₂

Table 16:

Properties of special melts of batches 93/6278 to 93/6306 after four hours of final annealing at 740 ° C. under H ₂

Table 17:

Properties of special melts of batches 93/6655 to 93/6666 after four hours of final annealing at 740 ° C. under H ₂

Table 18:

Properties of special melts of batches 93/6278 to 93/6289 after one hour final annealing at 750 ° C. under H ₂

Table 19:

Properties of special melts of batches 93/6278 to 93/6289 after one hour final annealing at 770 ° C. under H ₂

Table 20:

Properties of special melts of batches 93/6278 to 93/6289 after two hours' final annealing at 770 ° C. under H ₂

Table 21:

Properties of special melts of batches 93/5964 to 93/6018 after four hours of final annealing at 770 ° C. under H ₂

Table 22:

Properties of special melts of batches 93/6278 to 93/6284 after four hours of final annealing at 770 ° C. under H ₂

Table 23:

Properties of special melts of batches 93/6655 to 93/6666 after four hours of final annealing at 770 ° C. under H ₂

Table 24:

Properties of special melts of batches 93/5964 to 93/6018 after four hours of final annealing at 800 ° C. under H ₂

Table 25:

Properties of special melts of batches 93/6278 to 93/6306 after four hours of final annealing at 800 ° C. under H ₂

Table 26:

Properties of special melts of batches 93/6655 to 93/6666 after four hours of final annealing at 800 ° C. under H ₂

Table 27:

Microstructure state of the special melts 93/7179 to 93/7183 after quenching of different temperatures

Table 28:

Properties of Batches 93/7180 to 93/7184 and 74/5517 and 99/5278 after one hour of final annealing at 720 ° C under H _2; Thickness: 0.35 mm

Table 29:

Re-magnetization losses of special melts of batches 93/7180 to 93/7184 as well as 74/5517 and 99/5278 for different outputs and frequencies after one-hour final annealing at 720 ° C under H ₂ ; Thickness: 0.35 mm

Table 30:

Properties of lots 93/7180 to 93/7184 and 74/5517 and 99/5278 after two hours of final annealing at 750 ° C under H _2; Thickness: 0.35 mm

Table 31:

Re-magnetization losses of special melts of batches 93/7180 to 93/7184 and 74/5517 and 99/5278 for different outputs and frequencies after two hours of final annealing at 750 ° C. under H ₂ ; Thickness: 0.35 mm

Table 32:

Properties of Batches 93/7180 to 93/7184 and 74/5517 and 99/5278 after four hours of final annealing at 840 ° C under H _2; Thickness: 0.35 mm

Table 33:

Remagnetization losses of special melts of batches 93/7180 to 93/7184 as well as 74/5517 and 99/5278 for different outputs and frequencies after four hours of final annealing at 840 ° C under H ₂ ; Thickness: 0.35 mm

Comparative examples:

It was under the designations Batches 93/5973 and under the designations Lot 93/5969 and 93/5968 Alloy according to manufactured in the prior art. The batch corresponds to 93/5973 an alloy, such as those mentioned above US 3,634,072 (Ackermann) is removable, d. H. So one high strength, soft magnetic iron-cobalt-vanadium alloy with a low zirconium addition below 0.3 wt.%.

The zirconium additive was exactly 0.28% by weight.

Batches 93/5969 and 93/5968 were alloys such as the aforementioned US 5,501,747 (Masteller) correspond. These were high-strength, magnetically soft iron-cobalt-vanadium alloys, which were zircon free.

The properties of these alloys are shown in Tables 1, 4, 15, 21 and 24 can be seen.

These tables give the properties of the molten alloys under different final annealing again.

The duration of the final annealing and the Annealing temperatures varies. The annealing temperatures were from 720 ° C up to 800 ° C varies. The duration of the final anniversaries was varied from one hour to four hours.

A graphic summary of the results found in these three prior art alloys are provided by _FIGS. 1, 2 and 3. As can be seen from these figures, these alloys have a high yield strength, ie a yield strength R _p0.2 above 700 MPa only achievable if appreciable losses in soft magnetic behavior are accepted. All three alloys already exhibit a semi-hard magnetic behavior in the range of 700 MPa and higher, ie a coercive force H _c of more than 6.0 A / cm.

EXAMPLES

As exemplary embodiments according to the present invention five different alloy batches were produced, the under the batch designations 93/6279, 93/6284, 93/6285, 93/6655 and 93/6661 in Tables 2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 22, 23, 25 and 26 are listed are.

For the alloys, the zirconium content was varied on the one hand, On the other hand, the zirconium content together with the other alloying components responsible for ductility Niobium and tantalum vary.

Even with these alloy batches, both the annealing temperatures at the magnetic annealing as well as the Final annealing times varies. The closing times were between one hour and four hours varied. The final annealing temperatures were varied between 720 ° C and 800 ° C.

A graphic summary of the individual results can be taken from FIGS. 4 to 8. In these figures, too, the coercive force H _{c is shown} as a function of the yield strength R _p0,2 . In contrast to the prior art alloys discussed above under Comparative Examples, the alloys according to the present invention exhibit very high yield strengths with very good soft magnetic behavior.

This can be seen in particular in FIGS. 7 and 8. The Alloys shown there point in the yield point Values above 700 MPa at coercivities of approximately 5.0 A / cm.

In particular, from Figure 3 it can be seen that during use of zirconium contents below 0.30% by weight, as described in US Pat 3,634,072 teaches, in fact, not really high strength alloys can be produced.

Compared to the composition 49.2 Co; 1.9V; 0.16 Ta; 0.77 Zr; Residual Fe was the V content of 0-3% and the Co content varies from 10-49% in batches 93/7179 to 93/7184. These embodiments are in Figures 9 to 15 and tables 26 to 32 summarized. The batch 74/5517 99/5278 is a comparative alloy of the prior art.

Table 26 shows the examination of the appropriate ironing temperature for the special melts try the batches 93/7179 to 93/7183. Only the batch 93/7184 was without quenching cold-rolled. After quenching at each specified Temperatures, see Table 26, let the bands cold roll to final thickness.

Figures 9 to 11 show the relationship between induction and Field strength for lots 93/7179 to 93/7184 after one Final annealing under different annealing parameters. induction values are air flow corrected according to ASTM A 341 / A 341M and IEC 404-4. These results as well as the results of the tensile tests are listed in Tables 27, 29 and 31.

The ratio between Co content or V content and yield strength R _p0.2 is shown graphically in _FIGS . 12 and 13.

Tables 28, 30 and 32 show the resistivity as well as the core loss losses for lots 93/7179 to 93/7184. The relationship between specific electrical resistance ρ _e1 and Co and V content for different annealing parameters is shown graphically in FIGS. 14 and 15.

The alloys according to the present invention are particularly suitable for magnetic bearings, in particular for the rotors of magnetic bearings, as described in US 5,501,747, and as a material for generators and for engines.

Claims (20)

High-strength, soft magnetic iron-cobalt-vanadium alloy consisting of 35.0 ≦ Co ≦ 55.0% by weight, 0.75 ≦ V ≦ 2.5% by weight, 0 ≤ (Ta + 2 x Nb) ≤ 1.0 wt%, 0.3 <Zr ≤ 1.5% by weight, Ni ≤ 5.0% by weight, Remainder of Fe as well as melting and / or accidental impurities. High strength, soft magnetic iron-cobalt-vanadium alloy according to claim 1, wherein the zirconium content is 0.5 ≤ Zr ≤ 1.0 wt.%. High strength, soft magnetic iron-cobalt-vanadium alloy according to claim 2, wherein the zirconium content is 0.6 ≤ Zr ≤ 0.8 wt.%. High strength, soft magnetic iron-cobalt-vanadium alloy according to any one of claims 1 to 3, wherein the cobalt content between 45.0 ≦ Co ≦ 50.0 weight%. High strength, soft magnetic iron-cobalt-vanadium alloy according to claim 4, wherein the cobalt content is between 48.0 ≤ Co ≤ 50.0% by weight. High strength, soft magnetic iron-cobalt-vanadium alloy according to any one of claims 1 to 5, wherein the vanadium content between 1.0 ≦ V ≦ 2.0% by weight. High strength, soft magnetic iron-cobalt-vanadium alloy according to any one of claims 1 to 6, wherein the vanadium content between 1.5 ≦ V ≦ 2.0% by weight. High strength, soft magnetic iron-cobalt-vanadium alloy according to any one of claims 1 to 7, wherein the content of niobium and / or tantalum between 0.04 ≤ (Ta + 2 x Nb) ≤ 0.8 % By weight. High strength, soft magnetic iron-cobalt-vanadium alloy according to claim 8, wherein the content of niobium and / or Tantalum between 0.04 ≤ (Ta + 2 x Nb) ≤ 0.5 wt.% Is. High strength, soft magnetic iron-cobalt-vanadium alloy according to claim 9, wherein the content of niobium and / or Tantalum between 0.04 ≤ (Ta + 2 x Nb) ≤ 0.3 wt.% Is. High strength, soft magnetic iron-cobalt-vanadium alloy according to any one of claims 1 to 10, wherein the nickel content Ni ≤ 1.0 wt.%. High strength, soft magnetic iron-cobalt-vanadium alloy according to claim 11, wherein the nickel content Ni ≤ 0.5 % By weight. High-strength, magnetically soft iron-cobalt-vanadium alloy according to one of claims 1 to 12, wherein the content of melting-induced and / or accidental metallic impurities
Cu ≦ 0.2, Cr ≦ 0.3, Mo ≦ 0.3, Si ≦ 0.5, Mn ≦ 0.3, and Al ≦ 0.3. High-strength, soft magnetic iron-cobalt-vanadium alloy according to claim 13, wherein the content of melting-induced and / or accidental metallic impurities
Cu ≦ 0.1, Cr ≦ 0.2, Mo ≦ 0.2, Si ≦ 0.2, Mn ≦ 0.2, and Al ≦ 0.3. High-strength, soft magnetic iron-cobalt-vanadium alloy according to claim 14, wherein the content of melting-induced and / or accidental metallic impurities
Cu ≤ 0.06, Cr ≤ 0.1, Mo ≤ 0.1, Si ≤ 0.1 and Mn ≤ 0.1. High strength, soft magnetic iron-cobalt-vanadium alloy according to any one of claims 1 to 15, wherein the content of melting and / or random non-metallic Impurities P ≤ 0.01, S ≤ 0.02, N ≤ 0.005, O ≤ 0.05 and C ≤ 0.05. High strength, soft magnetic iron-cobalt-vanadium alloy according to claim 16, wherein the content of melting-related and / or random non-metallic contaminants P ≤ 0.005, S ≤ 0.01, N ≤ 0.002, O ≤ 0.02 and C ≤ 0.02. High strength, soft magnetic iron-cobalt-vanadium alloy according to claim 17, wherein the content of melting-related and / or random non-metallic contaminants S ≤ 0.005, N ≤ 0.001, O ≤ 0.01 and C ≤ 0.01. Use of a high-strength, soft magnetic iron-cobalt-vanadium alloy according to one of claims 1 to 18, as a material for magnetic bearings. Use of a high-strength, soft magnetic iron-cobalt-vanadium alloy according to one of claims 1 to 18, as a material for rotors.

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