JPH1081941A - Corrosion resistant soft magnetic iron-nickel-chromium alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop a soft magnetic Fe-Ni-Cr alloy for relay parts high in saturation magnetic flux density, small in a coercive force and excellent in corrosion resistance by incorporating specified amounts of Ni and Cr into Fe. SOLUTION: An ingot of an alloy having a compsn. contg., by mass, 38 to 42% Ni, 7.5 to 9.5% Cr, <1.0% Mn, <0.3% Si, and the balance Fe is subjected to blooming, hot rolling and cold rolling to work into a band material. This band material is annealed at 1100 deg.C for 6hr in a pure hydrogen atmosphere, is thereafter subjected to furnace to furnace cooling to 450 deg.C and is successively cooled in the air. The soft magnetic Fe-Ni-Cr alloy as the magnetic core material and yoke material for an electromagnetic relay having >=0.75T saturation magnetic flux density and <=2.5A/m coercive force and having excellent corrosion resistance to moisture in the air can be obtd. at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a corrosion-resistant soft magnetic iron-nickel-chromium alloy particularly for relay parts.

[0002]

2. Description of the Related Art It is well known to use a soft magnetic iron-nickel alloy as a magnetic core material and a yoke material of an electromagnetic relay. The main requirements for the magnetic core material and yoke material of the electromagnetic relay are high magnetic permeability and narrow hysteresis loop. It is necessary that the hysteresis loop be narrowed with a high magnetic permeability and a low coercive magnetic field strength. This is because, when the strength of the magnetic field in the air gap is low, that is, when the exciting current is low, a high magnetic flux density is generated and the attractive force to the armature increases. Further, if the coercive magnetic field strength is low, it becomes easy to open the relay during interruption of the exciting current.

FIG. 1 (Table 1) shows a conventional technique of a soft magnetic iron-nickel alloy used as a magnetic core material and a yoke material of an electromagnetic relay in terms of magnetic characteristics. The source in Table 1 is a group of nickel alloys of DIN17405 standard “Soft magnetic material for DC relay”.

The following materials are included in the DIN 17745 standard "worked alloys made of nickel and iron": NiF for RNi5 type
e16CuCr (2.4511), NiFe16CuM
o (2.4531), and NiFe15CuMo (2.
4551), and for the RNi2 type, NiFe16
CuCr (2.4515), NiFe16CuMo
(2.4535), NiFe15Mo (2.4555)
Is stipulated. FIG. 2 (Table 2) shows DIN standard 1774
This is an excerpt from 5.

From these descriptions, RNi5 and RNi2
Type iron-nickel material has a saturation magnetic flux density Bs of about 0.75T
And Mo and / or C
It can be seen that u and Cr are added. NiFe
In the case of 16CuCr, the chromium content is 1.5 to 2.5
Note that it is only mass%. Apart from this, Table 1 also lists RNi24, RNi12 and RNi8 with 36 or 50% by weight of Ni respectively.

[0006] These latter types differ from alloys with a high nickel content in that they have a low nickel content and do not contain other significant alloying elements. Is higher at a magnetization intensity of 4000 A / m, which corresponds to Both high nickel content alloys and moderately nickel second class iron-nickel materials are susceptible to corrosion due to atmospheric moisture, especially coastal climates.

[0007]

Accordingly, the present invention provides a novel soft coating that combines very low coercivity and the saturation flux of high nickel alloys with good corrosion resistance, especially with respect to atmospheric moisture. The aim is to find a magnetic iron-nickel material.

[0008]

SUMMARY OF THE INVENTION According to the present invention, the above objectives (in wt.%) Are: 38 to 42% nickel, 7.5 to 9.5% chromium, 1.0% manganese maximum, 1.0% silicon maximum. Achieved by alloys with 3% balance iron and unavoidable impurities.

Surprisingly, the iron-nickel-chromium alloy according to the invention has almost reached the reference values for the relay materials RNi5 and RNi2. Due to the low nickel content,
Magnetic properties similar to RNi 8, 12, and 24 according to Table 1 can be expected well, but the fact is not. The saturation magnetic flux density Bs of the Fe—Ni—Cr alloy according to the present invention is about 0.7.
9T. At about 1.5 A / m, the coercive force Hc is RNi2
It is less than the upper limit of 2.5 A / m specified in the DIN17405 standard for the mold material. These values are for a belt thickness of 1 mm
Was determined by static magnetization measurement of the punched ring.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The Fe--Ni--Cr alloy according to the present invention
It was melted under industrial conditions in a ton-arc furnace, and cold rolled at a subsequent stage after the lumping and hot rolling to obtain a strip having a test thickness of 1.0 mm.

Before measuring the magnetic properties, the test ring was annealed in a pure hydrogen atmosphere at 1100 ° C. for 6 hours, cooled in a furnace to about 450 ° C., and then cooled in air.

FIG. 3 (Table 3) shows the chemical composition of the alloy according to the present invention, and FIG. 4 (Table 4) shows its magnetic properties in comparison with RNi2 and RNi5 type materials representing the prior art.

Due to the high chromium content, the Fe--Ni--Cr alloy according to the invention has a lower nickel content and better corrosion resistance than Fe--Ni alloys without chromium. Its corrosion resistance is comparable to Fe-Ni alloys with a high nickel content. When the Fe—Ni—Cr alloy according to the present invention is compared with a soft magnetic iron-nickel alloy having a high nickel content, the nickel content is remarkably low, the magnetic properties are the same, and the cost is low.

[Brief description of the drawings]

FIG. 1 is a table (Table 1) showing the magnetic properties of iron-nickel relay materials according to DIN 17405.

FIG. 2: NiFe15Mo, NiFe16CuMo and Ni as relay materials according to DIN 17745 standard
4 is a chart (Table 2) showing the composition of Fe15CuMo.

FIG. 3 is a table showing the composition of the alloy according to the present invention (Table 3).
It is.

FIG. 4 Fe—Ni—Cr alloy according to the present invention “Invention”
Magnetic properties and the prior art materials RNi2 and RNi
5 is a table (Table 4) showing the magnetic properties of Sample No. 5;

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ulrich Hoebner Germany, Day 5891 Belldor, Borghellerstrasse 28 (72) Inventor Wolfgang Mettgen Germany, Day 58515 Lüdenscheid, Nietenbergerbeek 14

Claims (2)

[Claims] 1. A corrosion-resistant soft magnetic iron-nickel-chromium alloy having a saturation magnetic flux density of greater than 0.75 T and a coercive force of at most 2.5 A / m: (in mass%): from Ni38 to 42% from Cr7.5 9.5% Mn maximum 1.0% Si maximum 0.3% Corrosion resistant soft magnetic iron-nickel-chromium alloy characterized by containing the balance iron and unavoidable impurities. 2. Use of the corrosion resistant soft magnetic iron-nickel-chromium alloy of claim 1 as a yoke and armature of an electromagnetic relay exposed to a corrosive medium.