KR100384768B1 - Soft magnetic nickel iron alloy with low coercive field strength, high permeability and improved resistance to corrosion - Google Patents

Abstract

The present invention relates to soft magnetic iron nickel alloys containing 35-65 mass% nickel, one or several rare earth cerium, lanthanum, praseodymium or niobium (rare earth sum is 0.003-0.05 mass%) and impurities introduced upon melting .

Description

Soft magnetic nickel iron alloy with low coercive field strength, high permeability and improved resistance to corrosion}

The present invention relates to soft magnetic nickel iron alloys.

Carl Heck's book "Magnetische Werkstoffe und ihre technische Anwendung" (magnetic materials and their technical uses), Huetig Verlag, Heidelberg 1975, p. 349, below, armature and relay of relays.繼 鐵: soft magnetic material used as yoke) is known.

The material requires high saturation flux density and high permeability in order to obtain high magnetic holding force at low energy, and thus high magnetic flux density as well as a low magnetic field. Intensity (i.e., low excitation current) can occur in the air gap, so that high attraction force acts on the armature. The low coercive field strength allows the relay to open easily when the excitation current is reduced.

In addition to the magnetic conditions, the relay must operate properly under any meteorological conditions, so the relay material is required to be corrosion resistant under alternating climate test. Insufficient corrosion resistance materials can further cover the finished part to form a corrosion resistant layer to meet such conditions.

The contact surface between the armature and the iron should contain as small a gap as possible to increase the permeability of the circular circuit of the iron and armature. The contact surface will not be damaged by relay operation because the current emitted from the relay will change.

Similar conditions are required for other molding and stamping parts of soft magnetic materials.

The magnetic conditions of the relay material are described in DIN 17405 “Weichmagnetische Werkstoffe fuer Gleichstromrelais” (soft magnetic material for DC relays). Table 1 below is taken from DIN 17405.

DIN 17745 "Knetlegierungen aus Nickel und Eisen" ("nickel wrought iron alloy") describes alloys Ni48 (material numbers 1.3926 and 1.3927) as the base material of the RNi12 and RNi8 (see Table 2). Alloy Ni36 (material number 1.3911) is the base material for RNi24.

In the smelting of nickel iron alloys, in addition to the necessary alloying elements, deoxidation and / or desulfurization elements such as manganese, silicon and aluminum are required. In addition, when it is desirable to manufacture the alloy using conventional steel mill technology, the cost is reduced so that oxygen, sulfur, phosphorus, carbon, calcium, magnesium, chromium, molybdenum, copper and cobalt in small amounts Can be mixed. The smelting of the alloys here uses conventional steelmaking techniques, which are subjected to sequential ladle metallurgy and / or vacuum oxidative decarburization for deoxidation, deactivation and degassing in an open arc furnamce. I understand. After the block or continuous casting slab (continuous casting slab) is a high-temperature manufacturing in one or two steps with a thickness of 4mm, then low temperature to the final thickness using intermediate annealing (intermediate annealing) if necessary. For example, the magnetic properties deteriorate by mixing with carbon, nitrogen, oxygen, sulfur and solid nonmetallic inclusions as described in German patent 196556556 A1. Non-metallic impurities are generated by treating the molten reactants prior to casting with the necessary deoxidation and / or desulfurization. Depending on the deoxidizer and / or desulfurization agent, the impurities may be calcium oxide, magnesium oxide or aluminum oxide.

In order to avoid such a problem, soft magnetic materials are actually selected using pure vacuum materials, using vacuum techniques that follow the highest conditions of the state of the art, as clearly described in DE-A 3910147 and DE-C 1259367. To manufacture. As is known in the literature, a very expensive electroslag remelting technique is possible in the vacuum or in the presence of a protective gas, as described in DE-A 4105507, which is either vacuum or protective. Dissolution under gas is preceded.

JP-A 07166281 is made of Fe and at least 75% by weight of Ni, and relates to a magnetic alloy for a magnet head in which Nb, Pr or Sm is added. The problems underlying the present invention are the aforementioned magnetic and corrosion resistance and Melting of soft magnetic iron nickel alloys that meets wear resistance conditions and is used in a series of preferred applications as soft magnetic components.

This task can be achieved with a soft magnetic iron nickel alloy consisting of 35-65 mass% nickel component and one or more rare earth cerium, lanthanum, praseodymium or niobium and impurities by melting, with a total of rare earths of 0.003-0.05 mass% The total fraction (mass%) of rare earth cerium, lanthanum, praseodymium or niobium is at least 4.4 factors higher than the sulfur component (mass%).

Other embodiments suitable for the object of the present invention can be identified from the dependent claims below.

The alloy of the invention is preferably produced by smelting using sequential ladle metallurgy and / or VOD treatment (vacuum oxidative decarbonization) using steelmaking techniques, ie for deoxidation, desulfurization and outgassing in open arcs. The block or continuous cast slab is then hot-pressed to one or two steps with a thickness of 4 mm, and then cold to the final thickness by intermediate annealing to adjust the hardness required to manufacture the part into the strip, if necessary. .

After the manufacture of parts made of the alloy, it is possible to anneal these parts at 800-1150 ° C. to achieve coercive forces of less than 8 A / m through the parts.

Preferred uses of the alloys according to the invention are in particular relay components such as armatures and yokes.

In addition, iron nickel alloys can be used for:

-Valve bonnet and valve pot of solenoid valve

-Armatures of iron or pole pieces or pole shoes or pole sheet matal and non-operating magnets and electromagnets;

Stator of inductor core and pulse motor and stator and rotor of electric motor

-Molded and pressed parts of sensors, position transmitters and receivers

Magnetic head and head screen

Screening such as, for example, motor screens, screening cans for indicators and screens for cathode ray tubes.

Flat samples were cut from 1.2 mm thick strips prepared using the steelmaking technique, annealed at 1080 ° C. for 4 hours under hydrogen and then cooled to 300 ° C. in a furnace. These samples were subjected to 28 climate tests for 8 hours at 55 ° C./90-96% air humidity and 16 hours at 25 ° C./95-99% air humidity as described in DIN 50017. Alloys consisting of 36-81 mass% nickel components and additives such as chromium, copper and / or molybdenum were tested (see Table 3). All alloys with a nickel content of 55% or less by mass are apparently more corrosive after change climate testing than alloys containing 75% or more nickel (B. Gehrmann, H. Hattendorf, A. Kolb-Telieps, Material and Corrosion 48, 535-541 (1997) by W. Kramer, W. Moettgen) does not meet the corrosion resistance requirements for relay materials without further measures to improve corrosion resistance. On the other hand, the magnetism required by DIN 17405 was met as indicated by the coercive force Hc described in the example of Table 3 (current technology).

After a change climate test, SEM / EDX was used to find sulfur at the corrosion point of these samples.

According to the present invention, the corrosive action is improved by desulfurizing nickel iron alloy containing 35-65% by mass of the nickel component with cerium. This is preferably done using a composition metal consisting of rare earth cerium and / or lanthanum and / or praseodymium and / or niobium whose chemical behavior is very similar. There must be enough rare earth atoms present to bond all sulfur safely. In this case, when there are more cerium atoms than sulfur atoms, formation of cerium sulfide CeS with a high cerium fraction is expected, for example.

Therefore, to fully bind sulfur with cerium, the cerium content (mass%) must be 4.4 factor higher than the sulfur content (mass%). This principle also applies to other rare earth lanthanum, praseodymium and / or niobium and all rare earths.

As already mentioned above, by adding strong deoxidizers and desulfurizing agents, for example cerium, the reaction product remains in the material, which can weaken the magnetism. [A. Hoffmann, Ueber den Einfluss von verschiedenen Desoxidationselementen auf die Verformung und Anfangspermeabilitaet von Ni-Fe-Legierungen (on the effect of different deoxidation factors on the decomposition and initial permeability of Ni-Fe alloys), Z. angew, Physik 32, p236- 241]. Surprisingly, rare earths can be quantified and added so that the coercive force and permeability values are within the normal deviations of the molten charges by current technology.

It is known that residues of deoxidation remain on the surface after breaking the relay contact surface, which can destroy the final polished contact surface due to the strong hardness of the deoxidation residue, ie oxidative residue, during the relay operation. . Thus, the relay material is only allowed to contain small amounts of solid nonmetallic inclusions according to DIN 50602 (method M). In the deoxidation using a metal composition consisting of cerium or rare earth cerium, lanthanum, praseodymium, niobium, the maximum value of the sulfide inclusion SS in the streak form is less than 0.1 or 1.1, and the oxide inclusion OA in dissolved form Aluminum oxide) is less than 2.2 or 3.2 or 4.2, the maximum value of the oxidized inclusion OS (silicate) in the streak form is less than 5.2 or 6.2 or 7.2, the maximum value of the oxidized inclusion (OG) in the spherical form is 8.2 or Less than 9.2.

A very similar composition (T4392, T5405, and T5406) containing about 48% nickel and a small amount of manganese and silicon was melted in a 30 ton arc furnace using steelmaking technology to add rare earth equivalents of the current technology. Compared. Table 4 shows the correct composition.

A minimum amount of boron may be added to improve punching properties, such as charges T4392, T5405, T5406 and E5407. The content (mass%) of cerium in the inventive charges E5407 and E0545 is at least 4.4 factor higher than the sulfur content (mass%).

After melting, it was bloomed and then hot strip rolled to about 4 mm, followed by cold deformation finally to a thickness of 1.0 mm.

A circular sample of 25.5 mm diameter was punched out from above. All charges except E0545 were performed as above. Thereafter, a cast sample piece of about 15 mm x 15 mm x 5 mm is used, the surface being finely polished. All samples were washed and a portion of the sample was annealed at 970 ° C. for 6 hours under hydrogen and then cooled to 300 ° C. or below in a furnace. The other part of the sample was annealed at 1030 ° C. for 2 hours under hydrogen and then cooled to 300 ° C. or lower in a furnace. All samples were subjected to a two-day short-term climate test with temperature / humidity changes from 25 ° C. and 55% air humidity to 55 ° C. and 98% air humidity at 3 hour intervals. At this time, each sample was placed flat on the glass plate, exposing the bottom to much more severe crack corrosion conditions. The results are shown in Table 5.

Samples of the inventive charges E5407 and E0545 were not corroded while each sample of the two comparative charges T5405 and T5406 showed corrosion points on both sides.

With the addition of strong deoxidizers and desulfurizers such as cerium, the reaction product may remain in the material and weaken magnetism as described above. Surprisingly, the coercive force and permeability exhibited by the inventive charges E5407 and E0545 are within the normal deviation range of the molten charge according to the current technology, as shown in Table 6.

Table 6 measures the magnetic values of the charges according to the current technology (T) and the invention (E) for samples of 1 mm thickness after annealing at 1080 ° C. for 4 hours under hydrogen and cooling to 450 ° C. in a furnace. Table 4 shows the composition of the charge.

Secondly, the behavior during blooming and hot strip rolling of the charges of the two compositions listed in Table 7 by current technology was observed.

The two charges differ only in that the rare earth content is substantially different.

In the case of the charge T0626 with a total rare earth content of 0.054%, the block broke after cracking during high temperature formation. Such high content rare earths cause poor high temperature formation behavior. In contrast, the charge T0624 could be rolled into both blocks and hot strips 4 mm thick. Rare earths exhibit similar chemical behavior, so the contents of rare earth cerium, lanthanum, praseodymium and niobium should be limited to a maximum of 0.05 mass% according to the present invention to avoid high temperature formation problems.

Table 8 shows the content analysis of the solid base metal inclusions according to DIN 50602 in the different charges according to the current technology (T) and in the charges according to the invention (E).

The charge T2536 has a maximum value of 2.7 for the oxidized inclusion (method M) in the form of streaks. This value is too high to use the charge as a relay component material. This wears off the contact surface of the relay and impairs its operability. Therefore, the content of the solid nonmetallic inclusion of the present invention should be limited as follows.

The maximum value of the sulfided inclusions SS in the form of streaks according to DIN 50602 is 0.1 or 1.1 or less, and the maximum value according to DIN 50602 of the oxide inclusions OA (aluminum oxide) in the dissolved form is 2.2 or 3.2 or 4.2 or less, streak form The maximum value according to DIN 50602 of the phosphorus inclusion OS (silicate) is below 5.2 or 6.2 or 7.2 and the maximum value according to DIN 50602 of the oxidized inclusion OG in spherical form is 8.2 or 9.2 or less. All other charges listed in Table 8 meet the content requirements for solid base metal inclusions.

Claims (15)

Soft magnetic iron nickel alloy containing 35-65 mass% nickel content and one or more rare earth cerium, lanthanum, praseodymium, niobium and impurities resulting from melting, having a sum of rare earths of 0.003-0.05 mass% and rare earth cerium, lanthanum, praseodymium, An alloy having a total fraction (mass%) of niobium at least 4.4 factor higher than the sulfur content (mass%). 2. The soft magnetic alloy of claim 1, wherein the alloy comprises a cerium content of at most 0.05 mass%. 3. The alloy of claim 1, wherein the alloy comprises at most 0.5 mass% manganese, at most 0.5 mass% silicon and at most 0.002 mass% magnesium, 0.002 mass% calcium, at most 0.010 mass% aluminum, at most 0.004 mass%. Sulfur, a mixture of oxygen of up to 0.004 mass% and a small amount of mixture resulting from melting as a deoxidation and / or desulfurization adduct. The soft magnetic alloy of claim 1, wherein the alloy contains 0.002 mass% or less of boron. A method of producing the soft magnetic iron nickel alloy of claim 1, characterized by melting the alloy by sequential ladle metallurgy and / or VOD treatment in an open arc furnace for deoxidation, desulfurization and outgassing. The method of claim 5 wherein the parameters of the molten alloy are as follows: The maximum value of sulfide inclusions in the form of streaks is less than 0.1 or 1.1; The maximum value of the oxide inclusion OA (aluminum oxide) in dissolved form is 2.2 or less than 3.2 or 4.2; The maximum value of the oxidation inclusion OS (silicate) in the form of streaks is less than 5.2 or 6.2 or 7.2; The maximum value of the spherical oxidation inclusion OG is less than 8.2 or 9.2. A method for producing the soft magnetic iron nickel alloy of claim 1, wherein the component is manufactured from an alloy and the component is annealed at 800-1150 ° C. to obtain a coercive force of less than 8 A / m. The soft magnetic iron nickel alloy of claim 1, which is used as a material for relay parts. 2. The soft magnetic iron nickel alloy of claim 1, which is used as a material for valve bonnets and valve ports of solenoid valves. 2. The soft magnetic iron nickel alloy according to claim 1, which is used as an armature material for yoke or pole portions or pole pieces or ultra thin metal and non-operating magnets and electromagnets. 2. The soft magnetic iron nickel alloy of claim 1, which is used as an inductor core, a stator of a pulse motor, and a rotor and stator material of an electric motor. 2. The soft magnetic iron nickel alloy of claim 1, which is used as a material for molded parts and pressed parts of sensors, position transmitters and receivers. 2. The soft magnetic iron nickel alloy of claim 1, which is used as a material for magnetic heads and head screens. 2. The soft magnetic iron nickel alloy of claim 1, which is used as a shielding material. delete