DE2459604A1 - FERRITIC STAINLESS STEEL HIGH PERMEABILITY - Google Patents

Description

Hamburg, December 13, 1974 169974 IP 49752

Priority: December 17, 1973, Dapan, Pat. 141 538/1973

Applicant:

Citizen UJätch Company Limited

9-18, 1-chome, Nishishinjuku, Shinjuku-ku, Tokyo / Japan

High permeability ferritic stainless steel

The invention relates to a high permeability ferritic stainless steel which is superior in corrosion resistance and has very good magnetic properties.

Ferritic stainless steel is known as a particularly good meichmagnetic material, which is characterized by good corrosion resistance and is used e.g. for the production of electromagnetic valve parts.

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509825/0

Attempts have been made to improve the magnetic properties of ferritic stainless steel by adding Al, Si, or Ti alone or a combination of Al and \ 1 , see, for example, Japanese Patent Publication Sho-46-15213. In such improved stainless steels, the DC magnetic properties reach U values which for the permeability ( LL ) are in the order of magnitude of at most 8,000 and for the coercive force (H) are at most 0.3 Oe. In addition, the corrosion resistance of this known material leaves much to be desired.

For these known alloys, the magnetic properties, namely the permeability LL and the coercive

/ m

force be 1,500 and 3.0 Oe in the order van when the material is subjected to an easy to perform industrial heat treatment, including annealing at less than 1000 ⁰ C. If the annealing temperature is raised to ⁰ C 1.35O, the change Affiliated for ll, and the coercive force on the order of 8,000 and 0.3 Oe, respectively.

Experience has shown that these magnetic properties of the known! Ylagnet materials with reference to the high permeability and the requirements for corrosion resistance are considerable Appear in need of improvement.

The invention therefore aims to provide improved ferritic

9-82670020 ~ ³ ~

to create stainless steels that are comparable to usual Alloy metals are characterized by a superior high permeability and high corrosion resistance.

In order to solve this problem and to realize further advantages, extensive experiments have been carried out, uiobei several preferred alloying elements, namely Ta, Zr, Ge, Sn, Ce, UJ, IYIo, Ti, Si, Al, V and Nb ferritic stainless Base steels containing 12-30 Geiu. ^ Cr were added. When the result was examined, it was found that the addition of Ti, V, Ge, Ce and / or UJ gave the best results to improve permeability and corrosion resistance who brought alloy steels.

These tests have shown that a highly corrosion-resistant alloy according to the invention with high permeability based on a rustproof Fe-Cr steel contains: 12-30 % Cr, up to 0.12% by weight, up to 1 , 0 wt% Si and up to 1.0 wt% IYIn, the balance being Fe. This alloy is particularly characterized by a further addition of 0.2-2.0 Qeui .-% of at least one member from the group consisting of Ti, V, Ge, Ce and UJ.

The invention provides an improved stainless steel based on Fe-Cr, which has a maximum permeability (IL _1n ) of more than 15,000 and a coercive force (Hc) of less than 0.15 Oe and whose corrosion resistance

B Q9 825/0828 ~ ⁴ "

kait at the same time compared to common comparable materials is considerably improved.

Further advantages and features of the invention emerge from the claim and from the following description in which the invention is explained in detail with reference to tables.

In the following Table 1 are several preferred embodiments shown comparatively for the invention,

The underlying here attempts "Ta, Zr, Ge, Sn, Ce, Ui, IYIo, Ti, Si, Al or Nb was added to a ferritic stainless steel on the basis of about 18 wt -.% Cr added.

509825/0 8 28

• Γ *

Table 1

SAMPLE. Admission.
.E lement 0.19
0.31
0.94 Cr C. Si * • Mn Fe (1).
(2)
(3) Ta
Ta
Ta 0.04
Ό.04
0. 15 17.7
17.4
17.9 0.022
0.031
0.022 0.38
0.43
0.42 0.89
0.74
0.68 Rest-
II
It • (4) '
(5)
(6) Zr
Zr
Zr 0.48
Q. 86
1.74
3.23 17.8
17.9
18.-0 0.011
0.012
0.021 0.41
0.32
0.39 0.93
0.76
0.68 Il
Il
Il CO-
fe)
(9)
(10) Ge
Ge
Ge
Ge 'Sn: 0. 39 17.6
17.7
18 January
17 January 0.017
0.016
0.008
0.017 0.37
0.52
0.28
0.41 0.86
0.-77
0.82
0.63 Il
Il
Ii ■,
Il (11) Ce: 0.49
Ce: 1.52
Ce: 2.85 17.4 0.014 0.35 0.75- Il (12)
(13)
(14) W: 0.41
W: 0.86.
W: 1.41 17.6
17.8
17.2 0.018
.0.018
0.015 0.46
0.51
0.43 0.68
0.82
Ö.68 Il
Il
Il (15)
(16)
(17) Mon: 0.70
Mon: 1. 29
Mon: December 2nd 17.3
17.6
17.4 · 0.023
0.016
0. 032 0.42
0.27
0 .. 64 . 0.65
0.81
0. 65 Il
Il
M. (18)
(19)
(20) Ti: 0.43
Ti: 0.75 17.7
17.7
17.3 0.013
0.009
0.013 .0.45
0.56
0.43 0.72
0.63
0. 69 Il
Il
Il (21)
(22) Si: 0.37
Si: 0.74
Si ^ 1.52 17.4
17.5 0.016
0.014 0.39
• 0.25 0.82
0.96 M.
Il (23)
(24)
(25) Al: 0.15
Al: 0.43 17.6
17.7
17.7 0.013
0.032
0.021 0.37
0.74
1.52 0.62
0.73
0.69 Il
Il
Ii (26)
(27) V: 0.51
V: 0.92
V: 1.73 17.6
17.4 · 0.014
¹ 0.011 0.35
Ö.43 0.81
0.75 It
ι Γ (28)
(29)
(30) Nb: 0. 58 17.6
17.6
17.5 ■ 0.018
Q. 012
. 0.012 0.33
0.'70 ■
0.35 0.82
0.83
0.96 Il
Il
ι · '' Il (31) Ge: 0.26
Ce: 0.37 17.4 0.010 0.31 0.65 I! (32) V: ü. 51
W: 0 ·. 27 17.3 0.031 0.45 Ό.65 ti '(33) 17.9 0.022 0.38 0.72 ti

ANNOTATION:

Taballenuiarta are Gq \ u,%

5G9825 / 0828

These samples or Examples 1 -, were as shown in Table 2 below 33, annealed ziuei hours in a gaseous UJasserstoffatmosphäre uon 800 C over 900 C and 1000 ⁰ C to 1100 ⁰ C, then treated with a Abkühlungsgeschuiindigkeit of 100 ° C / Chilled to 600 ^{ºC for} an hour and finally quickly air-cooled. Several physical properties such as the maximum permeability ( LL ), coercive force (H), corrosion resistance and the degree of Vickers hardness of the samples thus treated are also shown in the same Table 2.

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509825/0828

, Taballa 2

sample Additional ele
ment,, ^; '
% Glow
te nap. ,
⁰ C '1,700
1,360
1.720 K in oe.
C. .Corrosion
\ feetigkei s Vickers
t hardness (1)
(2) '
(3) Ta: 0.19 ¹
Ta: 0.31
Ta: 0. 94 1., 0OO '
1,000
1,100 . "." 3.63 0 '
2.920
2, 680 , 1.85
. 2.75
2.03 ' ■ '' 3.5 · '
^1st 3. 5. '. ■
5 "■ 126
128
146 (4)
(6) Zr: 0.04
Zr-: 04-04
Zr: 0.15 1,100
'L, 000
1,000 5,170 '
2, 840.
2, 140
3,900 0.88. '
'1.00.
l.io "■ ···. 5. ■
■ · '3 • 116
■ 118
119 '. (7)
(8th)
'(9)
(10) . Ge: 0.48
'Ge: 0.86
Ge: 1.74
Ge: 3 ". 23 1,100 '
1.0OQ
800
ι, .ιοο 1.620 0.80
0.90
2.60
0.68 . '' · '' 3.5
■ '..' 3.5
'3.5.
: '"4.5 124
. '"128
'142
155: (11) Sn: 0.39 1,000 . 1,960
■ 1,800
2, 180 • 2.50 ' '. '■■ 5 ■ "■ ■, 149 - (12)
(13)
(14) Ce: 0.49
Ce ': 1.52
Ce: 2.85 ■ '. '' 80O
1,000-.
800 2.940
■ 4.030
2,400 3.05
2.05
2.55 ■ .2.5.
.- .. · 4 '■■
. · 4 ' 142
116.
.157 (15).
(16),
(17) YT: 0.41
. W: 0.86
W: 1.41 1,000-
■ 1.100.
I ₁ 000th . ". 1.680
■ 5,500
'1.760 • l.io
- 0.98
3.35 -:; ■: 4. '"■
■ - '3 "' ■■". 117
109
'157 (18)
(19).
(20) Mon: 0.70 '
Mon: 1.29
Mon: 2.17 800
■ 1.100. "
800 .. 4,670
■ 2,100 . , 2. 35 ■
■ Ό.65 ■
2.05 • '^; - ^: 3. 5 '. *'.
. '"■'. 'Δ · · ■''
- '■■■ 3.5'; 151
• 135 ■
170 (21)
(22) Ti: 0.43
Ti: 0.75 1.1 Oo ':
1,000 2, 060
• 1.780
• 3,640 0.80.
1.45 : ^; . W. * ■ ■. . ·.
■ ·: "■ 4.5. • 120
143r (23)
(24)
(25) Si 0. 37.
Si: 0.74
Si · 1. 52 ■ ". 800 ■ ·.
: 800 ..; -
1,100 ! .4,030 2.75
■ 3.20
. 0.88 .. ·· - ν ^:! 3 '· ^:. · Ν.- "'
• · -: 3 '■'. " . ·. .141 ■ '
⁷ 152
· - ■ 153 . (26)
• (27) Al: 0.15
Al-: '0.43 * 1,100 ' / • ■■ '3,900
· '. 6,050
3.060 / ■; 0.68. '■' ■ ' ² · ■■' ■ ·. . 133 (28)
(29)
(30) V: 0.51
V: 0.92
V: 1.73 ■ 1,000 '.
UlOO
1,100 ' 1,440 ■ '. 1.00
■ .'0.58
, 1.23 ■ "., ''. '"' - '4'S'- ?.
■■ '.: "■ : &:"'. '■'
"· -. ' s -ν ' '.' ■ ' 150 ;
126
. 136 (31) ..Nb: .0.58 1,100 4,600 ;; 2.50 ^; ; - - .4.5 '■ · ¹ ; 'l32 ■ (32) .Ge: Ό. 26th
Ce: 0.37 Ii100: "y5, .2 00 -v;: o.; "82 ':' - '..' ■ ':' 'K *' - '' '■ ··, ·· ■ 141 ' (33) V: 0.51
W: 0.27 • 1,100 ■ Γ 0 ^ 76 '. • '■ ^; V125 '
■■ - '■

-8th-

To determine the degree of corrosion resistance, the surface of each sample was polished using emery paper No. 220, degreased with acetone and ethyl alcohol, immersed in a container with city water and finally sprayed with a 5% aqueous NaCl solution at 35 ° C. for 24 hours. The surface treated in this way was then tested and classified into one of the following five classes 1-5 according to the extent of the corrosion and discoloration that had occurred.

Table 3

Examination Extent of corrosion and
Discoloration 5 no corrosion and no discoloration 4th less than three rust spots with ver
coloring 3 more than three rust spots and less
corroded as 1/4 of the surface
and v / colored 2 1/4 - 1/2 of the surface is corroded
and discolored 1 more than half the surface is corrosive
dated and discolored

509825/0828

When-the identifying data specified in the foregoing Table 2 are included, with regard to the magnetic properties and the corrosion resistance are classified, in order to emphasize the overall effect of the additional element, the following table 4 results: ■

Table 4

• Corr.- ^;
• - ^ strength above
"4.5- 4 ' 3.5 uienigar al ».
3 atiua same
or larger
alö: 4,000 3. 23% Ge
1.29% Mon
0.92% V
0.51% v
0.27% W 0.43% Ti
0.51% V 0.48% Gc
0.26% Ge
0.37% Ce 0. & 6% W
1. 52% Si atuja same
3,000 0.04% Zr '
1.73% V 0.41% W 0.86% Gc
0.04% Zr 0.15% Zv about the same
• ·. 2,000 0.75% Ti 1.52% Ce
2.85% Ce 1.74% Ge
2.17% Mon
0.74% Si. 0.49% Ce
0.37% Si *
1.41% W about the same
1,500 0.94% Ta
1.41% W '
0. 58% Nb 0.19% Ta
0.31% Ta
0.70% Mon ι *

Note: * means SUS 430 or 3IS-A1S1-430, i.e. a Alloy steel substantially the same as 18 Cr stainless steel and used as a standard of judgment is used for all samples listed.

509825/0828 ORIGINAL INSPECTED

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Tables 2 and 4 show in connection with the results of annealing treatments that can easily be carried out industrially at temperatures up to a maximum of 1,100 ° C that the addition of at least one member of the group consisting of V, Ge and Ti, the magnetic and corrosion resistant properties improved to a noticeable extent.

The following Table 5 shows the particularly favorable properties, which result from the same samples 1-33, luenn the annealing temperature in the first-35O ⁰ C luird increased. The annealing treatment was carried out at the specified temperatures in a hydrogen gas atmosphere for two hours, followed by rapid cooling at a cooling rate of 100 ° C./hour to 600 ° C. and from there further rapid cooling with air.

Table 5 shows that significant improvements are achieved by adding at least one member of the group consisting of V, Ge, Ce and LU, according to which LL is greater than 15,000, the coercive force H is less than 0.15 Oe and the corrosion resistance is greater than 4.5. These results mean that the alloys made therewith actually show almost no corrosion and discoloration.

From the above experimental analysis, it can be seen that by adding in particular Ti, V and Ge, considerable improvements in the [Ylagnetisierungs- and dsn Corrosion-

509825/0828

-11-

The strength properties of the alloys considered here are achieved after the material has been subjected to an annealing treatment with industrially easily manageable temperatures of less than 1.1OD ⁰ C and also in areas above it.

According to the invention, the improved, particularly economical ferritic stainless steel alloy based on · Fe-Cr to a considerable extent are used for the purposes for the previously expensive permalloy alloys based on Fe-Ni used will. For the alloys improved according to the invention, accordingly there is a wide field of application.

If the CR content to less than 12 wt -.% Is decreased, the corrosion resistance decreases significantly. On the other hand, if the Cr content is reduced to mshr than 30 Gbw .- $! is increased, the magnetic properties deteriorate accordingly.

The addition of C is preferably kept as low as possible in view of the magnetic and corrosion properties of the alloys to be produced. C may be up to a maximum of 0.12 weight in the alloy, however - be% by weight..

Si and IYIn are added as reducing agents and can be used to be contained less than 1.0 wt%.

509825/0828 -1.2-

The alloying elements Ti, Ge, Ce and UJ mentioned here
can be contained individually or together to improve the magnetization and corrosion properties of the alloys produced and with at least 0.2 wt . An addition of these elements with more than 2 % in total leads to a deterioration in the positioning properties.
The proportion of these alloy elements should therefore be selected in the total range from 0.2 to 2 % by weight .

509825/0828 -13-

Table 5

SAMPLE, Additional ele
ment, Geiü »% 0.19
0.31:
0. 94 Incandescent
temp.
^β C ' 10,500
13,600
7.700 H _c in oe. Corrosion *
strength Vickcrs
hardness (1)
(2)
(3) Ta
Ta
Ta 0. 04
0.04
0.15 1,300
1,300
1,300 7,600
11.200
4.030 0.22
0.22
0.36 ■ 3. 5
3.5
. 4th 114
120
131 (4)
(5)
(6) Zr
Zr.
Zr 0.48
0. 86
1.74
3.23 1,300
1,300
1,300 1.4, 500
16,500
9,800
6,400 0.32
0.23
O.9O 2
4th
. .2.5 110
107
111 (7)
(8th)
(9)
(10) Ge
Ge
'Ge
Ge Sn: 0.39 1,300
1,300
1,300
1,300 5, 600 0.15
0.14
0.41
0.19 4.5
3.5
2
2 114
119 '
149 (11) Ce: 0.49
Ce: 1.52
Ce: 2.85 1,300 20,000
13, 100-
10,600 0.14 5 - (12)
(13)
(14) W: 0.41
W: 0.86
W: 1.41 '1,300
1,300
1,300 ' 15,500
7,500
15,300 0.16
0. 15
0. 15 • 4.5
5
4th 111
116
126 . (15)
. (16)
(17) Mon: 0.70
Mon: 1.29
Mon: December 2nd 1,300
1,200
1,300 11,700
5, 500
8,900 0.19
0.39
0. 14 4.5
2.5
5 124
106
124 (18)
(19)
(20) Ti: 0.43
Ti: 0.75 1,300
1.1.00
• 1,200 6,100
■ 2,200 0.14
0.65
0.28 5
5
2 119
135
144 (21)
(22) Si: 0.37
Si:. 0.74
Si: 1.52 1,300
■ 1,200 14,600
12,300
10,000 0.60
•1. 08 • 4
5 118
124 (23)
(24)
(25) Al: 0.15
Al: 0.43. 1,300
1,300
1,300 . 4.030
1,560 0.13
0.15
0.25. 5 '
5
5 ^m 110
117 -
147 (26)
(27) V: 0.5t
V: 0.92
V: 1.73 1, 100
900 17,400
24,600
10.200 0.68
2nd 15th t *
• 2 133
149 (28)
(29)
(30) Nb: 0. 58 1,300
l, 300 ",
1,300 . 5,900- 0.11
0.11
0.14 4.5
• 4.5
4.5 114
117
127 (31) Ge :: 0.26
Ce: 0.37 Ί.200 17,600 1.25 4.5 130 (32) V: 0.51
W: 0.27 1,300 18,600 0.13 3.5 120 (33) 1,300 0.11 ¹ 4 118

509825/0828

- "PATENT CLAIM -

Claims (1)

PATENT TO APPLICATION Highly corrosion-resistant ferritic stainless steel of high permeability with 12 - 30 Gem .- ^ Cr, up to 0.12 wt. % C, up to 1.0 Geuj .- / S Si, up to 1.0 Geiu .- ^ IYIn, while the remainder is Fe, characterized by an addition of 0.2-2.0 Geu /.- fo in total of at least one member of the group consisting of Ti , Ge, Ce and UI. 509825/0828