JPS5913056A - Amorphous iron alloy with high strength and resistance to fatigue, general corrosion, pitting corrosion, crevice corrosion, stress corrosion cracking and hydrogen embrittlement - Google Patents

Abstract

PURPOSE:To obtain an amorphous Fe alloy provided with high strength and resistance to fatigue, general corrosion, pitting corrosion, crevice corrosion, stress corrosion cracking, hydrogen embrittlement, etc., by adding Cr and P, C or B as principal components and necessary secondary components to Fe. CONSTITUTION:This amorphous Fe alloy consists of, by atom, 1-40% Cr and 7-35% one or more among P, C and B as principal components, 0.01-75% in total of one or more groups of secondary components selected from the following groups, and the balance essentially Fe. The groups are 0.01-40% Ni and/or Co, 0.01-20% one r more among Mo, Zr, Ti, Si, Al, Pt, Mn and Pd, 0.01-10% one or more among V, Nb, Ta, W, Ge and Be, and 0.01-0.5% one or more among Au, Cu, Zn, Cd, Sn, As, Sb, Bi and S. The amorphous Fe alloy obtd. by solidifying the blended components by rapid cooling does not cause pitting corrosion, crevice corrosion, stress corrosion cracking and consumption or breaking due to hydrogen embrittlement, and it has high strength and superior fatigue resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an amorphous iron alloy with high strength, fatigue resistance, general corrosion resistance, pitting corrosion resistance, crevice corrosion resistance, stress corrosion cracking resistance, and hydrogen embrittlement resistance.

Ordinary corrosion-resistant iron alloys i.e. stainless steel alloys, e.g.
3% chromium steel, /It-1 stainless steel (304 steel), n-n-CojMo stainless steel (3/L L steel) have excellent weather resistance and corrosion resistance, and are suitable for chemical reaction vessels, vibrators,
It is often used in atmospheric or corrosive environments, such as in cooling equipment for nuclear reactors. However, during long-term use, pitting corrosion, stress corrosion cracking, crevice corrosion, hydrogen embrittlement, etc. can cause sudden destruction or damage, making the equipment unusable and causing serious problems in terms of safety and pollution. is causing. Therefore, many researchers are currently conducting research to solve these corrosion-related problems.

Normally, metals are in a crystalline state in the solid state, but under certain special conditions (alloy composition, rapid solidification), even in the solid state, an atomic structure similar to that of a liquid can be obtained without a crystalline structure.
Such metals or alloys are referred to as fully amorphous metals (or non-crystalline metals).

This amorphous alloy may have significantly higher strength than conventional practical metal materials, but has the disadvantage of poor corrosion resistance. This is thought to be due to the weak bonding force between atoms in amorphous metals. For example, Fe-0-
The corrosion weight loss of P-based and IPa-B-P-based amorphous alloys due to salt spray is about three times that of ordinary carbon steel. On the other hand, when used as a practical metal, it may be used not only at room temperature but also at elevated temperatures. have. When an amorphous alloy crystallizes, it loses its properties as an amorphous alloy. Therefore, when used under such elevated temperature conditions, it is necessary that the crystallization temperature is as high as possible.

The present invention eliminates the disadvantages of stainless steel alloys such as pit corrosion, crevice corrosion, stress corrosion cracking, hydrogen embrittlement, and wear and tear of materials involved in corrosion, and has high strength and fatigue resistance. The purpose is to provide an amorphous iron alloy.

The present invention contains as main components Or/~Q% and 7 to 33% of any one of P, 0, and B or two or more types of Fi, and as subcomponents (1) Ni and 00. Any one type or two types 00O7NqO (2) Mo, Zr, Ti, Si, 'Al
, Pt, Mn, and l, any one or two or more 0
．． 0/-20% (51V, mb, Ta,
w, any one of Ga and Be or [more than J type 0.
01-10 elb (4) Au, Ou, Z
n, Od, an, As, 8b, Bi
and S contains one or more groups selected from the group of cypress or two or more 0,0/-jchi in a total amount of 0.0/~7jchi, The remainder is an amorphous iron alloy obtained by rapidly cooling and solidifying a blended material consisting essentially of IPe, which has high strength, fatigue resistance, general corrosion resistance, pitting corrosion resistance, crevice corrosion resistance, and (4!1) resistance. It has properties such as stress corrosion cracking and hydrogen embrittlement resistance, and can achieve the purpose of the present invention.

In the present invention, the amorphous structure obtained by rapid solidification from a solution having the above composition is a single-phase alloy structure in which each of the above elements is irregularly dissolved in a solid solution in a matrix mainly composed of iron. On the contrary,
Many lattice defects normally exist in crystalline metals, and these become starting points for corrosion, pitting corrosion, stress corrosion cracking, hydrogen embrittlement, etc., so it is necessary to prevent damage to the metal surface and prevent stress corrosion cracking and hydrogen embrittlement. difficult to prevent. Conventionally, corrosion resistance has been improved by adding alloying elements such as chromium and aluminum to form a corrosion-resistant coating. However, improving corrosion resistance by adding alloying elements carries the risk of accelerating pitting corrosion, stress corrosion cracking, etc., and there are limits to the improvement of corrosion resistance. Further, addition of large amounts of elements that can improve corrosion resistance is naturally restricted due to deterioration of the material and difficulty in manufacturing.

On the other hand, amorphous alloys that are rapidly cooled from liquid can have a large amount of corrosion-resistant elements uniformly added to them while maintaining strength and toughness.1. It does not contain any defects that can become a starting point for corrosion.

This is why this alloy has extremely high corrosion resistance without causing pitting corrosion, stress corrosion cracking, or hydrogen embrittlement.

Next, a method for manufacturing the amorphous alloy of the present invention will be explained with reference to the drawings.

The figure is a schematic diagram showing an example of an apparatus for producing the amorphous alloy of the present invention. In the figure, l is a quartz tube having a nozzle at its lower end that ejects water in a horizontal direction, into which raw metal 3 is charged and melted. ≠ is a heating furnace for heating the raw material metal 3, and j is a rotating drum rotated at a high speed, for example, 3000 rpm, by a motor O. This is done in order to minimize the centrifugal force load due to the rotation of the drum. dt is a quartz tube made of a lightweight metal with good thermal conductivity, such as an aluminum alloy, and whose inner surface is lined with a metal with good thermal conductivity, such as a copper plate 7.
In support of moving up and down is King Aviston.

The raw metal is first charged through the inlet port /a of the quartz tube by fluid conveyance, etc., heated and melted at the heating end position, and then transferred to the quartz tube by the air piston so that the nozzle faces the inner surface of the rotating drum j. 1 is lowered to the position shown in the figure, and then at about the same time as it begins to rise, gas pressure is applied to the molten metal 3, causing the metal to be jetted toward the inner surface of the rotating drum. In order to prevent the metal 3 from oxidizing, an inert gas such as argon gas is constantly fed into the inside of the quartz tube to create an inert atmosphere. The metal jetted onto the inner surface of the rotating drum is brought into strong contact with the inner surface of the rotating drum due to the centrifugal force caused by the high-speed rotation, and is cooled at an ultra-high speed to become an amorphous metal.

By the above manufacturing method, the amorphous iron alloy of the present invention,
For example, it can be obtained as a long tape-like wire with a thickness of 0.2mm and a width of /θmm.

In the research of the present invention, an amorphous alloy having the composition shown in Table 1 was prepared using the equipment shown in the figure to a thickness of 0.0 cm and a width/a.
It was fabricated in strips of m.

(7) The mechanical properties of these amorphous alloys are shown in Table 2.

As seen in the same table, the hardness Hv) is 6ri O~/O
It is in the range of jO, and the breaking strength is λriO to 3riOkg.
/- and is comparable to piano wire, which has the highest strength among conventional steels. On the other hand, it has almost no elongation, but unlike so-called brittle materials, it exhibits localized viscous rupture characteristic of amorphous materials. The fatigue limit is in the range of /10~tso kg)7b2, for example, O0j ratio 0 carbon steel 3j4kg/mu
2.1 g-g stainless steel 32. ! Buttocks-2, /7-/
Stainless Steel Evening/. The fatigue limit is significantly higher than that of 6kv/-.

As mentioned above, the fact that the mechanical properties are significantly different from those of practical metal materials is due to the fact that the structure of the alloy of the present invention is an amorphous structure. It has been found that the present inventors have more advantageous mechanical properties than the amorphous iron alloy that does not contain various metals.

Samples were taken from each of these strips and various corrosion tests were conducted. The results are shown in Table 6. For comparison, commercially available chromium steel, TG-G stainless steel (30g curve, /7-/II-2,3Mo stainless steel (3/L,
A similar test was also conducted on L steel.

Corrosion tests were carried out using /N Napl aqueous solution, /M at 30°C.
16 in H2Sa4 aqueous solution and hydrochloric acid aqueous solution at various concentrations.
It was determined by the weight loss per unit area after immersion for g hours.

Pitting corrosion test is 1θ4yθ023・6H2 at word ℃ and J℃
The test was carried out by immersing the sample in 0 solution for 16g for 16 hours and comparing the surface observation and weight loss of the sample. To further clarify this point, a 30°C /N Na0L aqueous solution and a 30°C H2So4+ 0. /Ii The presence or absence of pitting corrosion type 5 position due to anodic polarization in the Na0t aqueous solution was investigated.

Susceptibility to stress corrosion cracking and hydrogen embrittlement was investigated by the amount of elongation of the sample at break in a constant speed tensile test. The elongation in the corrosive liquid is ε, and the elongation in air at the same temperature is ε. Then, the susceptibility to cracking is ε. −ε/6o.

Stress corrosion cracking tests were carried out in a 2% UG, AT2 aqueous solution boiling at l≠3° C. while varying the tensile rate and potential.

On the other hand, in the hydrogen embrittlement test, H2S was added to 0, I NOH0
OONa+0. /H0H3000H(PH!j7
) conducted in liquid.

(73) Table 3 Corrosion test results In the corrosion resistance test in MH2804, the alloy of the present invention did not corrode at all as shown in Table 3. Also, in the corrosion resistance test in /N NaO2 aqueous solution, no weight change due to corrosion was detected in the alloy of the present invention. Furthermore, as can be seen from the test results in an aqueous hydrochloric acid solution (Table 4), the alloy of the present invention does not undergo any general corrosion or pitting corrosion even after /IJ hours, whereas 30≠steel does not undergo any corrosion after 3 hours. Significant general corrosion and pitting have occurred. Rabbit temperature commonly used for pitting corrosion tests
10 'A I! Table 5 shows the results in the eOLs/6H20 solution and the results when the temperature of the solution was raised to +°C. Even in &'C, where pitting corrosion occurs not only in comparative examples but in all stainless steels currently in use, pitting corrosion does not occur in the alloy of the present invention at all, and no weight loss is detected.

The results of anodic polarization in a solution containing at""jk are shown in the sixth section.
Shown in the sky. All of the stainless steels in use today undergo pitting corrosion and exhibit a pitting corrosion potential, but the alloy of the present invention shows no pitting corrosion at all.
In addition, it becomes completely passivated without exhibiting any pitting corrosion potential, and no corrosion loss is detected.

(/j) (/7) Table 7 shows the results in /413°C boiling & 2% MgO12 liquid, which is a typical stress corrosion cracking test liquid. In general, stress corrosion cracking susceptibility increases as the tensile rate decreases, and increases as the anode becomes lower than the natural electrode potential. 3011 steel clearly shows stress corrosion cracking, whereas the alloy of the present invention does not exhibit this at all. In addition, 0.00% containing H2S, which is a typical hydrogen embrittlement test liquid, was used. /N 0
H600ONa +0. /N OH,0OOH(PH4
j. 67) As shown in Table 8, hydrogen embrittlement tests were conducted using the solution, and as shown in Table 8, even mild steel, which does not easily cause hydrogen embrittlement, becomes hydrogen embrittlement when subjected to a constant speed tensile test in this solution. In general, hydrogen embrittlement susceptibility increases as the tensile speed decreases, and increases as the cathode becomes lower than the natural/electrode potential.

However, even under these conditions, the alloy of the present invention does not change at all.

(lji) In the alloy of the present invention, the pitting corrosion resistance, crevice corrosion resistance, stress corrosion cracking resistance, and hydrogen embrittlement resistance are extremely improved by the addition of Or, and the alloy has excellent performance that is incomparable to current stainless steels. This performance is derived from the atomic structure unique to this alloy. By adding the above various metals to the present alloy, the mechanical properties of the amorphous base itself can be influenced, and, for example, in the above manufacturing method, the quenching conditions for forming an amorphous structure can be changed.

In the amorphous alloy of the present invention, the effects of the alloying elements as the subcomponents are as follows.

1) All of these subcomponent alloying elements do not impair the amorphization of the alloy structure and improve corrosion resistance.

2) The element that stabilizes the amorphous structure (among others) is N.
l, Oo, Mo, 81, At
, Pt, Pd, Go, Be.

Au, As, Sb, Bi, 8,
3) The element that improves general corrosion resistance, pitting corrosion resistance, crevice corrosion resistance, stress corrosion cracking resistance, and hydrogen embrittlement resistance is Ni.

Mo, Zr, Ti, Si,
kl, Pt, car\eagle\Pd, V
,Nb,Ta,W,Au,,Ou,
Zn, 0 (1°" As, Sb); 4) Mo is an element that improves high strength and fatigue resistance.

Zr, Ti, 'Si, 'kt, Mn
, V, Nb, Ta', W, (i(L"1
3e, Sn.

Next, the reason for limiting the content of each component in the present invention will be explained.

Regarding Or, if it is made l-atom soft, general corrosion resistance, pitting corrosion resistance, crevice corrosion resistance, stress corrosion cracking resistance, and hydrogen embrittlement resistance deteriorate, and it also exceeds the ψ atomic ratio and becomes a stone and amorphous structure. Since it is difficult to do so, it is necessary to keep it within the range of I-% atoms, and a range of j to 3S atoms is preferable.

P, O, and B are elements that help form an amorphous structure, and the content of at least seven of these is 7.
If it is less than 3s atoms, it will be difficult to manufacture an amorphous alloy, and if it exceeds 3s atoms, it will be difficult to manufacture an amorphous alloy as well, and the alloy will become brittle.
In manufacturing an amorphous alloy, it is best to set it in the range of the s atomic range, and about the atomic range.

Ni and 0oFi are each less than the p-atom ratio, and Ni.

When 00 is included, the reason why the total value should be less than the W atomic ratio is that even if it exceeds the Q atomic ratio, no improvement in the above-mentioned properties is expected.

Mo, Zr, Ti, Si, At, P
The reason why each of t, Mn, and P(l is set to be below the atomic ratio, and the sum of two or more of these is set to be below the atomic ratio is that it becomes difficult to manufacture an amorphous alloy if the I atom exceeds qb.

V, Wb, Ta, W, Go, Be
The reason why each of these is set to be 10 atomic units or less, and the total of these two or more types is set to 70 atomic units or less is that if the number exceeds 10 atomic units, it becomes difficult to manufacture an amorphous alloy. IAu, , Ou, Zn, 06,
The reason why each of Sn, As, Sb, Bi, and S is set to be less than j atoms, and the sum of two or more of these is set to be less than j atoms, is that it is difficult to manufacture an amorphous alloy when the number exceeds j atoms. It is.

Examples of the alloy of the present invention will be described.

i Button 1, 4 CrlO atom%, P1313 atom 107 atom%, Ni'
A blended material consisting of 10 atomic %, Mar atomic %, Nb] atomic %, Cu, and 2 atomic % balance Pe was heated, melted, and cooled at an ultra-high temperature using the equipment and pre-smelting method shown in the figure to obtain an amorphous alloy (sample A31) was obtained. These amorphous and as-alloys are very easy to manufacture in terms of composition, and have excellent properties in the various tests shown in Table 2-t. It turns out that 73
It exhibits pitting corrosion resistance, crevice corrosion resistance, stress corrosion cracking resistance that is incomparably superior to that of %Or steel, 304 steel, and 616L steel, and incomparably superior hydrogen embrittlement resistance compared to mild steel. It was found to have the following properties: 〇Furthermore, the mechanical properties are also significantly superior compared to the above-mentioned steel types◎Or 20 at%, P10 at%, C7 at%, Ni1
A blended material consisting of 0 atomic % Mol, 2 atomic % As and the balance Fe was heated using the illustrated apparatus and the method described above, and then cooled at an ultra-high speed after melting to form an amorphous alloy 19. Sample A34)
I got it.

, this amorphous alloy is compositionally very easy to manufacture;
Also, like Sample A81 of Example 1, it was extremely excellent in corrosion resistance and mechanical properties.

Example 8 0r 8 atomic%, PIG atomic%, B7 atomic%, Ni2O
Examples 1 and 2 were prepared using an amorphous alloy (sample A35) consisting of 5 atomic % No, 8 atomic % W, and the balance Fe.
Manufactured by the same method as. This alloy is compositionally very easy to manufacture, and alloy A 81 of Examples 1 and 2,
Like A84, it had excellent corrosion resistance and mechanical properties.

Example 4 Fe-1ar-xMo-15PL5 (3, Fe-acr
-xMo-14P-50, Fe-5Cr-xMFe-5
Cr-x alloy and Fe-xor-1 as a comparative example
8P-70 alloy (the number before each element indicates the content of each element in atomic percent, X is a variable, and the remainder is iron) was heated by the apparatus shown in the figure and the method described above.
After melting, an amorphous alloy was obtained by ultra-high-speed cooling. Corrosion tests were conducted on these alloys in IN Hej.

The results are shown in Figure 2. In both alloy systems, the corrosion rate decreases as the No content increases.

Furthermore, these alloys do not suffer from pitting corrosion and dissolution at all even when anodic polarization occurs, and furthermore, even when these alloys are sandwiched between two Teflon plates and anodic polarized to a high potential, no increase in anode current due to crevice corrosion is observed. .

For example, current 304 stainless steel undergoes severe pitting corrosion just by being immersed in 1 (27 N Hel), with an average corrosion rate of 20 N Hel. The material was wrapped around a bar and immersed in a pH 3 I N NaO7 solution for 3 months while being subjected to different constant stress (strain), but stress corrosion cracking and hydrogen embrittlement failure did not occur.

Example 5 Concentrations of V, Nb, W, and Ta X'fi: lO
Fe-1Or-xV-13P changed within the range of atomic% or less
-70°Fe -3Or -xNb -18P -70
, Fe-5Cr-XW-]3P-20-8B-
23i, Fe5Or-XTa-18P-30-5B alloy (the number before the valley element is the concentration of each element in atomic %) was heated in the equipment shown in the figure, melted, and then cooled at an ultra-high speed to obtain an amorphous alloy. Ta. For these alloys INH
The results of the j-meal test conducted in C7 are shown in FIG.

Addition of any of V, Nb, W, and Ta reduces the corrosion rate.

In addition, even when these alloys are anodic polarized (28), they do not undergo any pitting corrosion dissolution, and furthermore, even when these alloys are sandwiched between two Teflon plates and anode polarized to a high potential, the anodic current increases due to crevice corrosion. It is not allowed. For example, current 304 stainless steel undergoes severe pitting corrosion just by being immersed in IN Hel, and the average corrosion rate is over 20 years.

On the other hand, the alloy of the present invention was wrapped around glass pellets of various thicknesses and immersed in an I N NaOz solution of pH 8 for 8 months while being loaded with different constant stresses (strains). No destruction occurred.

Example 6 Fe-1Or-XOO-14P-6B in which the concentration X of CO and N1 was varied within a range of 40 atomic % or less.

Fe -a cr -xco -15P -7B I
Fe-1cr-xNi-14P-6B, F
e -8Or -xNi -15P -5B alloy (the number in front of each element is the concentration of each element in atomic %; the remainder is Fe) was heated using the device shown in the figure and the method described above, and after melting was cooled at an ultra-high speed. An amorphous alloy was obtained. The results of corrosion tests conducted on these alloys in IN Hel are shown in FIG. Corrosion resistance is improved when Fe is replaced with CO or N1.

In addition, these alloys do not suffer from pitting corrosion and dissolution at all even when anode polarized, and furthermore, even when these alloys are sandwiched between two Teflon plates and anode polarized to a high potential, no increase in anode current due to crevice corrosion is observed. do not have. In addition, for example, the current use 304
Stainless steel undergoes severe pitting corrosion simply by immersion in IN Hel, with average corrosion rates up to 20 mny'j4.

On the other hand, an uninvented alloy was wrapped around glass pellets of various thicknesses, and a constant stress (strain) was applied to the I.
Immersed in NHaC7 solution for 3 months, stress 1
Fracture due to hydrogen embrittlement and hydrogen embrittlement did not occur.

Example 7 20 atomic % or less of Pd, Pt, Zr or T
Fe containing i -I Cr -40Ni -xPd -
15P-50.

ve-1Or-4ONi-XPt-14F-2B,F
e-1cr-40Ni-xZr-16P-30,
Fe-10r-40Ni-xTi-12P-2B
-ISi alloy and Fe-1(3r-20Ni-XOu-15P) containing Cu or Iu at 5 atomic % or less
, Fe-10r-2ONi-xAu-13P alloy (the number before each element is the concentration of each element in atomic %, the remainder is Fe) was heated using the equipment shown in the figure and the method described above, and after melting An amorphous alloy was obtained by rapid cooling.

The results of corrosion tests conducted on these alloys in IN Hej are shown in FIG. Ti, Zr, Pt,
Pcl.

It has been shown that the addition of Ou and Au is effective in improving corrosion resistance.

Furthermore, these alloys do not suffer from pitting corrosion at all even when anode polarized, and furthermore, even when these alloys are sandwiched between two Teflon plates and anode polarized to a high potential, no increase in anode current due to crevice corrosion is observed. . For example, the current 804 stainless steel is l N HOJ! ! Just by being immersed in it, it undergoes severe pitting corrosion, with an average corrosion rate of up to 20 IIwf.

On the other hand, the alloy of the present invention was wrapped around glass pellets of various thicknesses, and while different constant stresses (strains) were applied, I
Although it was immersed in a N 2 NaO 7 solution for 3 months, no reaction corrosion cracking or hydrogen embrittlement failure occurred.

The amorphous alloy of the present invention can be manufactured as thin strips or wide plates, and has high strength and corrosion resistance that cannot be obtained with conventional practical metal materials.

Therefore, the amorphous alloy of the present invention can be used for seawater resistance, nuclear reactors, chemical plants, etc., or as composite materials and component materials. For example, equipment used in the atmosphere, seawater or freshwater, hydraulic power, thermal power, nuclear power and other types of energy glands, chemical industrial plants, etc. that are particularly resistant to general corrosion,
Suitable for parts that require pitting corrosion resistance, crevice corrosion resistance, stress corrosion cracking resistance, and hydrogen embrittlement resistance, rubber for vehicle tires and belts, reinforcing cords embedded in plastic products, cords embedded in concrete, etc. It is suitable for use as a gantry material for filter screens, filaments for blending with fibers, etc.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an example of an apparatus for manufacturing the amorphous alloy of the present invention, and Figs. 2 to 5 show the alloy of the present invention and the amount of added alloying elements and corrosion when various subcomponent elements are added thereto. It is a characteristic curve diagram showing the relationship with speed. 1... Quartz tube, 2... Nozzle, 8... Raw metal,
, 4... Heating furnace, 5... Rotating drum, 6. ...Motor, 7...Copper plate, 8...Air piston, 9...
・Argon gas.

Claims (1)

[Claims] Contains as a main component 7 to 35% of any seven or two or more of Or/-ψ, p, a, and B as atomic absorption,
and as subcomponents: (1) one or two of ml and Go; ,0/
~Shunchi, (2) Mo, Zr, Ti, Si,
Any 7 or 2 or more of At, Pt, Mn, and Pa 0.0/~20 q6, (5) V, Nb
, any 7 or 2 or more of Ta, W, Ge, and Be 0.0/~70%, (4) Au, Ou +' Zn, Od,
Any one of Sn, As, Sb, Bi and S
A species or two or more species. , 0/~! O, oi~7 in total amount of any 7 or more groups selected from the group A! %
with high strength, the remainder being substantially composed of Fe,
Amorphous iron alloy with fatigue resistance, full surface resistance, corrosion resistance, pitting corrosion resistance, crevice corrosion resistance, stress corrosion cracking resistance, and hydrogen embrittlement resistance.