JPS58197256A - High toughness high-mn steel with superior weather and rust resistance - Google Patents

Abstract

PURPOSE:To obtain a high-toughness high-Mn steel with superior weather and rust resistances, by adding specified amounts of C, Mn, Si, Cr, Cu, Al and N to steel so as to regulate the weather and rust resistance index, AR value to a specified value or above. CONSTITUTION:To steel are added, by weight, 0.1-1% C, 16-35% Mn, 0.2-3% Si, 0.5-18% Cr, 0.01-2% Cu, 0.01-7% Al and <0.3% N, and the weather and rust resistance index, AR value represented by the equation is regulated to >=3wt%. It is preferable to add <1.5% Sn or one or more among <1% Co, <1% Mo, <2% Ti and <2% Zn besides said components.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention provides a tube toughness iQ with excellent weather resistance and rust resistance.
Regarding Mn steel, we propose an improved 1'-good alloy design that can improve the corrosion resistance in polluted atmospheric environments and salt spray test conditions, along with the toughness at room temperature and in cryogenic closed regions. This is what I am trying to do.

In recent years, there has been a strong demand for inexpensive non-magnetic steel, which is less affected by magnetic fields, for the structural components of electromagnetic equipment, transformers, and related equipment, including nuclear fusion facilities and magnetic levitation high-speed trains. . ! (・Furthermore, recently, non-magnetic steel has been used not only at room temperature, but also at low temperature.
In particular, there is an increasing demand for use in extremely low temperature ranges such as the liquid helium temperature (77K) and lower liquid helium temperatures (4.2K).

Among these, structural materials used at extremely low temperatures are generally used repeatedly at near room temperature and in the extremely low temperature range, and in this case they are usually used without surface rust prevention treatment such as paint. In such a usage environment, when the temperature returns from an extremely low temperature to room temperature, the frost on the surface of the steel material melts and becomes moist, resulting in an alternating dry-wet usage environment, which can lead to rusting. The fear is high.

It has excellent ductility and toughness even at extremely low temperatures, and at the same time has excellent magnetic and rust resistance.

This is why there is a need to develop non-magnetic steel for cryogenic use that has both excellent properties. In addition, even with structural steel used near room temperature, materials attached to equipment such as transformers and motors, and materials such as scientific instruments that are sensitive to magnetic influences, it has excellent toughness and durability.・(7) It is highly desirable to develop materials that are compatible with magnetism and rust resistance.

Conventionally, austenitic stainless steel has been commonly used as non-magnetic steel, but this steel contains a large amount of expensive nickel, has unstable magnetic properties when processed or heat treated, and has poor strength. When used as a material, it has drawbacks such as low yield strength.

Therefore, we focused on high-Mn I11 non-magnetic steel as a low-cost steel that can maintain stable non-magnetic properties even during processing and heat treatment.

However, conventional high M steel, which is generally used as non-magnetic steel,
N steel, for example, standard 18% In steel, has the disadvantage that its rust resistance and weather resistance are significantly inferior to that of stainless steel, and its ductility and toughness in the cryogenic range are severely reduced15.

The object of the present invention is to eliminate and improve the deficiency of conventional high-Mn steel, and to provide a high-toughness high-Mn steel that has excellent weather resistance and rust resistance.

The inventors especially stabilized the austenite phase!・Si, Or to improve weather resistance and rust resistance for high Mn steel with Mn: 16 to 351% by weight (hereinafter simply expressed as %) to obtain high toughness.

It has been found that significant effects can be obtained by adjusting au, ht, C, and N to appropriate compositional ranges.

Based on the results of repeated experiments on this point, the following formula (1) % formula % () (1) By setting the weather resistance and induction resistance indices A and R, values of 8% or more, Improved weather resistance and rust resistance can be obtained. Furthermore, it has been found that by adjusting the components in this way, high 1° toughness can be obtained even at extremely low temperatures such as liquid ♦ elementary temperature and liquid helium temperature.

The steel composition of the present invention is compatible with the common purpose according to the above findings through each of the following component series, and the individual properties can be further enhanced for each component series.

1, O: 0.10-1.00%, Mn: 16-8
5%.

Si: 0.2 to 8.0%, Or
20.5 to 18.0% Qu
: 1 (3, old ~ 2.00%, AZ:O, old ~ 7.0
0% and N: 0.3% or less at a weather resistance, induction resistance index A, R, value of 8% or more calculated by the above formula (]), and the remainder substantially consists of iron. 0: 0.10~1.00%, Mrl: 16~
35%.

st: 0.2~a, o%, Or: 0.5~1
8.0%, Ou: 0.01-2,00%, AL:
0.01 to 7.00% and N: 0.3% or less, weather resistance and attraction resistance index A, R, value 3, calculated using the above formula (])
Component composition 3 containing 1'□ and 1.5% or less of Sn, with the remainder substantially consisting of iron, O: 0.10-1.00%, Mn: 16-.
115%.

si,: 0.2~3.0%, Or: 0.5~
18.0%, Ou: 0.01-2.00%, At
: U, 01 to 7.00% and N: 0.8% or less, weather resistance and induction resistance index A, R calculated using the above formula (1)
, containing at a value of 8% or more and 1.0% or less Co
, 1. ．． 0% or less MO, 2% or less Ti and 2
Includes at least one building selected from zr below %,
The remainder is essentially composed of iron! ··composition.

4, O: 0.10-1.00%, Mn: 16-3
5%.

8i: (1.2~8.0%, Or: 0.5~
18.0%, CU: 0, old ~ 2.00%, A7
: 0. IJ]~7.00% and N: 0.3% or less'
i, n1] Contains weather resistance, rust resistance index A, R, value 3 or more of 1 to 5 according to formula (1), and 4.0
% or less Ni, 2.0% or less v, and 2.0
% or less of Nb, and the remainder is substantially iron.

5. O: 0.10-1. (10%+Mn::
16-85%, 1(1Si: 0.2-8.0%,
Or: o, 5-18. o%, Ou; 0.01-2
．． 00%, At: 0. Old ~7.00% and N: (
J, 3% or less, weather resistance, resistance index A, R, value 8% or more determined by the above formula (1), L, and 1.5
% or less Sn, 1.0% or less Co, 1.0% or less MO, 2.0% or less T1, and at least one selected from 2.0% or less Zr. , with the remainder essentially consisting of iron.

6, 0: fJ, 10~1.00%2Mn;]6~
35%.

Si: L2~3.0%, Or: 0.5~18
．． 0%, Ou: 4. .

0, Q~2.00%, At: 0.01~7.00%
and N: 10.8% or less at a weather resistance and resistance index A, R, value of 3% or more calculated by the formula ( ), 5% or less Sn, and 4.0% or less. % or less N1.2
．． 0% or less of V and 2.0% or less of Nb, and the remainder is substantially iron.

7, (E: 0.10-1.00%, Mn:]6
~85%.

Si: U, 2~LO%, Cr: o, 5~18
．． 0%, Cu: 0, old ~ 2.00%, At: 0
．． 01 to 7.00%, and N: 0.8% or less, weather resistance and induction resistance index A, R determined by the above formula (1)
, Contains at a value of 3% or more, Ga], 00 below θ
, 1.0% or less MO+ 2.0 or less Ti.

and at least one vertebra selected from zr of 2.0% or less, and at least one vertebra selected from 4.0% or less oNi, 2.0% or less ov+i, and 2.0% or less Nb.
The composition includes seeds, with the remainder essentially consisting of iron.

8, 0: 0.10-1.00%, Mrl: 16-
85%.

si,: 0.2~3.0%, Or: 0.5~
18.0%, Ou: 4. .

0.01-2.00%, At: 0.01-7.00
% and N: 10.8% or less, according to the above formula ( ]) [and containing Schiff in weather resistance, resistance index A, R, value of 8% or more], 5% or less Sn, 1. 0% or less
0.1.0% or less M (1,,2,0% or less Ti,
and at least one selected from 5zr of 2.0% or less, and a small amount selected from ml of 4.0% or less, ■ of 2.0% or less, and Nb of 2.0% or less. ] seeds, with the remainder essentially consisting of iron.

The reason for limiting the component elements of this invention will be explained below.

Mn: 16-85% Mn is an essential element to stabilize the austenite phase and make it non-magnetic steel, and it must be at least 1.16% to maintain good toughness not only at room temperature but also at low temperatures. Requires. However, if it exceeds 85%, manufacturing difficulties will arise, so it is limited to a range of 16 to 85%.

0! The presence of 0.10 to 1.00% 0 stabilizes the austenite phase and makes it non-2...
.

It is effective in making it magnetic and has a large effect on forced increase, but 0. ] If it is less than 00%, there is a risk of a decrease in strength and magnetic instability, while if it exceeds 1.00%, carbides are likely to be formed and the toughness in extremely low temperature ranges will decrease. Therefore, '・0.10~1,00%
limited within the range of

si: 0.2-3.0% Sl is an effective element as a deoxidizing element, and also QM
In n steel, it is an element that has a particularly large effect on improving weather resistance and induction resistance.

For these purposes, it is necessary to add at least 0.2% or more, and the effect increases as the amount added increases.
．． If it exceeds 0%, cracks will occur during cold rolling, so it was limited to a range of 0.2 to 3.0%.

Qr: 0.5-18.0% Or has a great effect on improving induction resistance and weather resistance,
The effect is further enhanced by adding S11 in combination with Ou and Aja, which will be discussed later.

In order to fully exhibit the desired effect, it is necessary to add at least 0.5% of Cr, and the effect increases as the amount of Cr increases, but if it exceeds 18.0%, it may cause the contamination of the δ phase. 0.5 to 18.0 because it causes an increase in magnetic permeability.
% range.

Qu: tl, 01 to 2.00% When O is combined with the above-mentioned Si and Or and the below-mentioned At, the weather resistance and induction resistance are significantly improved. It is necessary to add at least 0.01% to this,
If it exceeds 2.00%, it increases the cracking susceptibility of the steel ingot and reduces manufacturability, so it is limited to a range of 0.01 to 2.00%.

At: 0.01 to 7.00% AJa has a remarkable effect on improving weather resistance and induction resistance by adding it in combination with Si, Or, and CU mentioned above.
.

Although it is necessary to add at least 0.01%, the effect remains the same even if it exceeds 7.00%, but using a large amount will increase the cost, so it is necessary to add at least 0.01% to 7.0%.
It was limited to a range of 0%.

(15) N: 0.3% or less N has a large effect of stabilizing the austenite phase and making it non-magnetic, and also produces solid solutions and nitrides, making a large contribution to the increase in force. If it exceeds this, the induction resistance will deteriorate, so it is limited to 0.3% or less.

A, R, value: 8% or more Weather resistance, attraction resistance index A, R, value needs to be 3% or more to obtain good weather resistance and attraction resistance, so it is 8% or more. limited to.

Although the basic components have been described above, the following subcomponents are advantageously utilized for the purposes of addition described below in order to further enhance the effects aimed at by this invention.

Sn: 1.5% or less Sn is useful for further improving weather resistance and induction resistance by adding Si', Or, Ou, and At in combination with the effect of li, but 1.5% If the content exceeds 1.5%, the hot workability decreases and the manufacturability of the steel becomes difficult, so the content was limited to 1.5% or less.

Co: 1.0% or less 211 (
]6) No.: 1.0% or less Ti-: 2.0% Zr: 2.0% or less These elements have the effect of solid solution and precipitation, respectively.
The functions and effects are the same in that they increase strength and are also effective in improving weather resistance and - resistance.

Since MO is an expensive element, it is set to below 0% and 0%, respectively, in order to suppress the cost increase, and Ti
, For Zr, if it exceeds 2.0%, low C
) Since the toughness at high temperatures decreases, the content is limited to 2.0% or less.

Ni: 4. o% or less V: 2.0% or less Nb: 2.0% or less These elements each have the effect of increasing strength without adversely affecting weather resistance and induction resistance due to solid solution and precipitation effects. The effect is the same in that respect.

However, since Ni is an expensive element, the cost will increase -1,1
The content of V and Nt is limited to 4.0% or less in order to suppress the content, and 1 is limited to 2.0% or less since the toughness at low temperatures decreases if the content exceeds 2.0%.

An example will be explained.

Table 1 shows conventional steels (A, B, O)', invention steels (1 to 29) and comparative steels (a+b+C+d, e, f) as test materials.
The composition and A, R, values of 1g) are shown.

(21) Here, conventional steel (A) is standard 18% In steel, and (B) is 10% In steel.
r't 24% Mn steel with 5% addition, (0) is 80% I
It is n steel. Furthermore, invention steels 1 to 4 are 18% Mn@ containing 0.6% in 01, and steels 5 to 28 are 0.2 to 0.
．． It is a 24% In steel containing 8% In, and 24 to 26" is C
Nos. 27 to 29 are 30% In steels containing 0.2% C'i.

On the other hand, comparative steel a and d are 24% Mn containing 0.6% 0.
steel, and e and f are 18% In containing 0.2% C.
85% steel containing 0.8% gVia
)(n steel, but (a) does not contain CU, (b) does not contain At, and (0) contains less than 0.2% Si, and (C
1) to (g) have weather resistance, resistance index A, and R01 [of less than 3%, and all of them are outside the composition range of the present invention.

Each of these test steels was melted in a vacuum melting furnace, then bloomed at a temperature of 1200°C to 800°C, and then hot-rolled at a temperature of 200°C to 700°C. A tensile test using a round bar tensile test piece (JIS No. 14A) and a J
We conducted a Sha2...Ruby impact test using an IS No. 4 test piece and measured magnetic permeability using a vibrating sample magnetometer.
In addition, an induction resistance test using a salt spray test based on JIS Z 237 and a weather resistance test using an atmospheric exposure test in a factory area were conducted.

In addition to room temperature, the Charpy impact test was performed at liquid nitrogen temperature (-
196°C) and liquid helium temperature (-269°C). The results are shown in Table 2.

The weather resistance test shown in Table 2 was conducted in an industrial area for six months to two years of atmospheric exposure. and 6 minutes.

As can be seen from the table, the magnetic permeability of the invented steel is 1.
．． 002 exhibits good non-magnetic properties and has excellent weather resistance and induction resistance.

Next, the absorbed energy of the invented steel was significantly improved at -196°C and especially at -269°C compared to the conventional steels (A) and CG), and showed a value of 1·l that was superior to that of the steel (B). It has high toughness not only at room temperature but also at extremely low temperatures.

On the other hand, the salt spray test results also showed that the invented steel was better than the conventional steel. Furthermore, in the atmospheric exposure test, the corrosion weight loss of the invented steel was significantly improved compared to the conventional steel1.

I understand that.

However, it can be seen that all of the comparative steels that fall outside the scope of the invention are inferior in induction resistance and weather resistance to the invention steel.

Some of these results and the results of separate tests and ・1゜(
26) are summarized and shown in Figure 1.

In the figure, the horizontal axis is 1.5 (G (%) + N (%)) + U
, IIn (%) is 1. The vertical axis is Si (%) +30rC%)
Corrosion loss m9/cTn2 after one year weather resistance test of each test steel by taking +20u (%) +8 At (%) respectively.
The value of ◎ for the evaluation of 5 salt spray tests for 6 minutes.
, ○, and X marks are also shown in the plot.

Here, all salt spray test results are evaluated as ◎, ○, or ×, and the evaluation criteria are as follows.

◎ mark: Very good 9 rust rate less than 5% I+・○
Mark: Good 2 Rust rate 5% or more, less than 30% × mark:
Defective 9 Rust rate 30% or more In Figure 1, the boundary where the evaluation is divided into ○ mark and )+20u(%) +8 A2
C%)-1,5(0(%)10N(%))-0,1Mn(
%) = 3(%), which is the weather resistance company rust index A, R
, indicates that the value is 3%.

That is, weather resistance and rust resistance 2.1 (
27) The properties are significantly different, and the compositions located above this line, that is, the weather resistance and resistance index A, R, value are 3% or more, the weather resistance and resistance to resistance are significantly better, and this line It is shown that the weather resistance and induction resistance are inferior to the invention steel in the lower compositions, that is, the A and R values are less than 8%.

In addition, although only the results of hot rolled materials were described in the examples, solution treatment of these high Mn steels often has a negative effect on weather resistance and induction resistance, but the toughness at each warm temperature is further improved. It was recognized that

The invented steel has excellent weather resistance and induction resistance even in polluted atmospheric environments and salt spray environments, has good toughness at room temperature and in the extremely low temperature range, and is completely non-magnetic and stable against processing and heat treatment. Nidamochi, @j5 It is advantageously used as cryogenic steel, as well as general structural steel in applications where the influence of fields is averse, and is particularly useful for cooling structures around superconducting magnets that generate strong magnetic fields, due to its low-temperature toughness, weather resistance, and Since good induction resistance is required, the invention steel is expected to be applied.
・、.

It is also useful as a first side plate for a transformer as a non-magnetic material at room temperature, and as a peripheral material for degaussing devices and precision instruments.

As described above, the present invention can improve the weather resistance, induction resistance, and toughness of high Mn steel.

[Brief explanation of drawings]

FIG. 1 is a graph showing the influence of component balance on the weather resistance and induction resistance of high Hn steel. Patent applicant Kawasaki Steel Corporation Figure 1 11::/rtat+1hA//alA)-pf)/nf,,/Il'□ θ'? /6) A U (Ll /a horn+/V11n/)&I"l
l I/l l /IIノ298-

Claims (1)

[Claims] L O: 0; 10 to 1.00% by weight, Mn:
16-35'wt%, Si: 0.2-8.0wt%, Cr: 0.5-18.0wt%, Gu:
0.01-2.00% by weight. 1: 0.01 to 7.00% by weight and N: 0.
8% by weight or less, with a weathering resistance index A and an R value of 3% by weight or more calculated by the following formula, and the remaining IG has a substantially iron composition. High toughness high Mn steel with excellent conductivity. Note A, R, = Si (%) + acr (%) + 20u (
%)+3At(%)+5-1.5 (0(%) 10N(%)
))-0,1Mn(%)1. 0: 0.10-1.
00% by weight, Mn: 16-35% by weight, si:
0.2-3.0% by weight, Or: 0.5-18.0
Vehicle weight %9, Ou: 0.01-2.00% by weight. At: 0.01-'-7,00% by weight and N:
0. ．． Contains 3% by weight or less of Sn at a weatherability and rust resistance index A, R value of 8% by weight or more calculated by the following formula, and contains 1.5% by weight or less of Sn, with the remainder being substantially A high-toughness high-In steel with excellent weather resistance and induction resistance, characterized by having a composition of iron.・dself A, R, = Si (%) + 80r (%) + 20u (
%) + 8 AA (%) - 1,5 (0 (%) 10 N
(%))-0,1Mn(%)&O: 0.10~1
．． 00% by weight, In: 16-85 111% by weight
, si-: U, 2~a, o weight%, Or: 0
．． 5-18. Oi child%, Ou: 0.01-2.0
0% by weight. At: 0.01-7.00% by weight and N: 0.
Contains 8% by weight or less, weather resistance and resistance index A, R, value 8% by weight or more calculated by the following formula, 1° and 1.
0% by weight or less (30, 1,0% by weight or less) MO, 2,
0 wt% or less Ti, and 2.0 wt% or less zr
A high-toughness, high-Mn steel having excellent weather resistance and induction resistance, characterized in that it contains at least one kind selected from among the above, and the remainder has a composition of substantially iron. Note A, R, = Si (%) 10”13cd: (%) +20
u(%)+3At(%), -1,5(0(%)10N
(%) ) -0,1In (%)4 0: 0.10
~1.00% by weight, Mn: 16-35% by weight, Si
: 0.2 to 3.0% by weight, Or
: 0.5-18.0% by weight, Ou: 0.01
~2.00% by weight. At: 0.01-7.00% by weight and N 20. ．．
8% by weight or less, weather resistance and rust resistance index A, R, value 3% or more calculated by the following formula, and 4.
N1 of 0% by weight or less, ■■ of 2.0% by weight or less, and 2
．． A high-toughness high-In steel having excellent weather resistance and induction resistance, characterized in that it contains at least one selected from Nb of 0.02 ffift% or less, and the remainder has a composition of substantially iron. Note □ A, R, = Si (%) + 30r (%) + 2 (3u
(%) + 3A2 (%) - 1,5 (0 (%) 10N (%)
)-U, IMn (%) 10: 0.10 to 1.00
Weight%, Mn: ] 6-351N amount%, si
: 0.2~a, o weight%, Qr: 11.5~1
8.13% by weight, Ou: 11.1-2.00% by weight. At: tl, 1-7.00 weight% and N: 0.
Contains 3% by weight or less of Sn at a weather resistance, rust resistance, and resistance index A, 'R, value of 3% by weight or more calculated by the following formula, and contains 1.5% by weight or less of Sn and 1.0% by weight or less of Sn. 00
, 1.0% by weight or less of MO, 2.0% by weight or less of Ti, and 2.0% by weight or less of Ti. High toughness and high Mn with excellent weather resistance and side rust resistance, characterized by containing at least one type selected from Zr of 1 ml 1 t% or less, and the remainder being 1.--substantially iron. Steel record A, R, = Si (%) + 8Or (%) +20u
(%)+8At(%)-1,5(0(%)+N(%)
)-0, IMn (%) a, 0: 0.10-1
．． 00% by weight, Mn: 16-35%, Si:
0.2-8.0% by weight, Or: 0.5-18.0
Weight %, 011: 0.01 to 2.00 weight %. AZ: O, 1-7.00% by weight, and N: 0.3
- Weather resistance and resistance when 1% by weight or less is abraded using the following formula. Containing a rustiness index A, R value of 3% by weight or more, and 1.5% by weight or less of Sn, and 4.0% by weight or less of Ni,
2.0% by weight or less ■ and 2.0% by weight or less Nb
At least selected from among. ] A high-toughness high-In steel having excellent weather resistance and induction resistance, characterized in that the remainder has a composition of substantially iron. A, R, = Si (%) + acr (%) + 20u
(%) + 3At (%) - 1,5 (0 (%) 10N (%)
))-0,IMn(%)? , G: U, 10-1
．． 00% precious, Mn: 16-85% by weight, si:
0.2-8.0 heavy lid%, Or: 0.5-18.0
Weight %, Ou: 0.01-2.00 weight %23.
1A7: (1,01-7.00% by weight and N:
Contains 0.8% by weight or less at a weather resistance, attraction resistance index A, R, value of 3% or more calculated by the following formula, and 1
．． 00 of 0% by weight or less, Mo of 1.0% by weight or less,
,, 2.0 military% or less of Ti, and 2.0 weight, 1
, at least 11 types selected from Zr in an amount of % or more, Ni in an amount of not more than 4.0% by weight, and ■ not more than 2.0% by weight.
and 2.0% by weight or less of Nb, with the remainder being essentially iron. High toughness high Mn steel. Note A, R, = Si (%) + aar (%) +20u
(%) +8 AJ! , (%) -1,5 (0 (%) ten N
(%) ) -0,1Mn(%)&C: 0,10
~1.00% by weight, Mn: 16-85% by weight, s, i
: 0.2-3.0% by weight, Qr: 0.5-1
8.0% by weight, Ou: 0.01-2.00% by weight
. Al: U, (11-7.00% by weight and N: 0
．． 8% by weight or less, weather resistance, rust resistance 15
Contains a sexual index A, R value of 8% by weight or more, and 1
．． sn of 5% by weight or less and Co of 1.0% by weight or less,
MO of 1.0% by weight or less, Ti of 2.0% by weight or less,
and 2.0% by weight or less of Zr, and 4.0% by weight 2.・mi below lid%,
2.0% by weight or less ■ and 12.0% by weight or less Nb
A high-toughness high-In steel having excellent weather resistance and induction resistance, characterized in that it contains at least one kind selected from among the above, and the remainder has a composition of substantially iron. Note A, R, = Si (%) + 80r (%) + 20u (%
) + 3A,! (%) -1,5 (0 (%) 10N (%)
) -0,1Mn(%)