JPS58185741A - Alloy with corrosion resistant at high temperature - Google Patents

Abstract

PURPOSE:To enhance the corrosion resistance and strength of the resulting alloy at high temp. and to reduce the cost by substituting Mn for part of Ni in an Ni alloy, adding Nb, Ta and Ti, and reducing the Al content. CONSTITUTION:This alloy with corrosion resistance at high temp. has a composition consisting of, by weight, <=0.15% C, <=1.0% Si, 5.0-15.0% Mn, 35.0- 65.0% Ni, 15.0-35.0% Cr, 1.5-4.0% Ti, <=1.5% Al, 0.5-6.0% Nb and/or 0.5- 6.0% Ta, and the balance essentially Fe or further contg. one or more among 0.0005-0.020% Ca, 0.0005-0.020% Mg, 0.005-0.050% rare earth element, 0.0005-0.010% B and 0.005-0.100% Y, one or more among 0.3-4.0% Mo, 0.1- 3.0% V and 0.3-4.0% W, or 0.005-0.50% Zr and/or 0.005-0.50% Hf.

Description

Detailed Description of the Invention The present invention is a heat-resistant material for gasoline engines and exhaust valves for diesel engines, which has excellent high-temperature corrosion resistance and high-temperature strength, and is inexpensive compared to conventional Ni-based alloys. They are used under harsh conditions, such as being exposed to industrial exhaust gas and moving at high speeds at temperatures of over 800 degrees Celsius. High temperature combustion gas [1st item is CQI! , H2O and residual 02, etc., are present, and are oxidized by these, and the lead oxide, which is added to Gunrif as an anti-knock agent, is lead oxide, which is produced by the combustion of tetramethylene lead. Furthermore, S, Cl, Br-P contained as impurities in fuel
Reaction products (PbSO4, PbBrC1, Pb
÷ (PO4)t, etc.) 1 -] The valve face becomes severely yellowed.

In addition, due to the tension of the spring and the natural force of the valve itself, large tensile stress and bending stress act on the part when the eyebrow is seated. 2L-4N steel (Fe-21Cr-9Mn-4Ni-
0,5C-0,4N).

However, in recent years, high-performance engines have been increasing in output and speed, and under such harsh conditions, the 2L-4N steel lacks high-temperature corrosion resistance and high-temperature strength, making it difficult to withstand use. The situation has also arisen, and there is a demand for the development of an alloy that has high temperature resistance and high temperature strength that are several orders of magnitude better than 2l-4N steel.

In response to this situation, there has recently been a trend to use Ni-based alloys or Nisterite alloy fillet valves for exhaust valves. However, Ni-based alloys are expensive materials, resulting in high valve costs, and also have insufficient corrosion resistance against high-temperature combustion gases containing S in high-load engines.

In addition, the stellite alloy plated valve requires complicated plated work and requires a lot of manpower, resulting in high valve costs, and its performance as an exhaust valve is also insufficient in high-load engines.

The present invention solves the drawbacks of conventional steels, and as a result of various studies conducted by the inventor, a part of Ni in Ni-based alloys has been
By substituting with n and containing 5.0 to 15.0 h of Mn, the combustion products containing S compounds improve the corrosion resistance and further improve the strength at high temperatures. -6.096 Nb, Ta and 1.54.0% +7
) T' Woit 44 Sase, Kak Alk! k
1.5% I'II・(In order to reduce this, N
It has the same corrosion resistance as that of a single-base alloy, and has the same high strength as that of a single-base alloy, and is a much cheaper and more flexible steel alloy.

In addition, the alloy of the present invention has a valve-made crushing effect, and is it similar to stellite metal moldings? J! Conventional 2l-4N without the need for complicated processes
Like the exhaust valve, it can be manufactured in one piece, so it is cheaper and has superior performance compared to stellite alloy metal valves.

As described above, the alloy of the present invention has excellent corrosion resistance, high-temperature oxidation resistance, and high-temperature strength, and is useful for exhaust valves, various one-piece parts, one-needle hot tool materials, high-temperature sliding parts, etc. This can be used widely.

The alloy of the present invention will be explained in detail below.

The first invention alloy has a single pupil ratio of CO of 15% or less.

Si 1.0cm or more 1M115.0~15.0%, N
i85. o ~65.0%, Cr 15. (+
-85.0%, Ti 1.6-4.0%, A11.
5-1 and Nb O, 5-6,0%, Ta (1,5
-1lIj out of 6,0%! The second invention alloy C, the first invention alloy E Ca O,000
5-0,020%, containing two or more types of Mg, further improving the high temperature strength and hot workability of the first invention alloy,
The third invention alloy contains Mo 0.8-4.0% in the first invention alloy.
, VO,1-8,O% VO,a~4.0%
The fourth invention alloy contains one or more of the following and improves the high temperature strength by 1 without significantly deteriorating the high temperature corrosion resistance of the first invention alloy.The fourth invention alloy contains ZrO,005 in the first invention alloy. -0,50%,
The high temperature strength of the first invention alloy was improved without significantly deteriorating the high temperature: 1*L corrosion properties of the first invention alloy. The invented alloy is the second
Invention alloy KMo 0*L-4,0%, VO,1-a,
The sixth invention alloy contains one to 72 or more of Zr0.00% and WO18 to 4.0φ to further improve the high temperature strength of the second invention alloy.
．． 50%H "I If out of 0.005~0.50
This alloy further improves the high-temperature strength of the second invention alloy by containing at least two of them.

Below, the reasons for limiting the components of the alloy of the present invention will be explained.

C partially hardens M to strengthen it, and also forms carbide to strengthen the base material. Strengthening of the matrix by carbides is not effective, but if the amount exceeds 0.15 qb, carbides will precipitate at the grain boundaries, which will significantly impair hot hII kingship, so the upper limit was set at 0.15 qb. . 81 either solidly dissolves in the geology and strengthens it, and also improves high-temperature oxidation resistance, or exceeds LOO-chi, which impairs high-temperature lead oxide corrosion resistance, so the upper limit was set at LOO-chi.

Mu significantly improves the resistance of high Nt alloys to combustion products containing S compounds and other impurities. Figure 1 shows the influence of composite lead oxide (composition equivalent to combustion products) and the influence of Mn on eating habits.
n or 5. It is known that the resistance is significantly improved at VO% or higher. Therefore, the limit of Mu was set to 5.0 inches.

Moreover, when Mu exceeds 15.0%, Ni − has a low melting point.
M.

j (because crystals form and hot workability becomes extremely difficult, the upper limit was set at 15.0 cm).

N1 is necessary to obtain a stable austenite structure and prevent the formation of harmful precipitates that deteriorate mechanical properties such as sigma phase (this is necessary, and Ni3 (is necessary) to improve the corrosion resistance of composite lead oxide.
Since precipitation hardening due to Ni (Al, Ti) and Ni 3 Nb is performed, the lower limit of Ni is set to 85.0%. In addition, even if the content exceeds 65.0%, the effect will not be improved and it will be expensive, so the upper limit should be set at 65.0%.
It was set at 5.0%. Cr is essential for improving composite lead oxide corrosion resistance, and since less than 15.0% is insufficient, the lower limit was set at 15.0%. In addition, even if the content exceeds 85.0%, the effect will not improve much, and harmful precipitates such as sigma phase that deteriorate mechanical properties are likely to appear, so the upper limit should be set at 85.0%.
It was Oqb.

Nb and Ta, like Ti and AI, are elements that improve high-temperature strength.

Fig. 2 Small lead oxide corrosion resistance caused by Nb,
As is known from the effects of Ta, Ti, and AI, Nb is used to prevent Al from severely deteriorating corrosion resistance.

Since Ta and Ti have a small deterioration effect, they are the optimal elements to minimize the deterioration of high-temperature corrosion resistance and strengthen the high eccentric strength. In addition, Nb and Ta form N b QT a C type carbides and strengthen the bond, and excess Nb and Ta form Ni
3Nb, Ni, and Ta are formed and contribute to strengthening the material.

To achieve the performance described in L, Nb and Ta should be added to 0. Since it is necessary to immediately increase La 1, the limit was set at 0.5%.

Furthermore, if the content exceeds 6.0 inches, hot working becomes difficult and high temperature corrosion resistance also deteriorates, so the upper limit was set at 6.0 inches.

Ti forms Ni 3 (AI, Ti) and significantly improves high temperature strength. As is clear from Figure 2, Ti high γ
The deterioration of corrosion resistance of the product is smaller than that of Al, and the high temperature strength σ
j Suitable as a reinforcing element. To exhibit the necessary performance, it is necessary to have a sound level of 1.5*L:J.

Approximately 1,000 inches was set as 1.5 inches.

In addition, if the content exceeds 4.0%, hot processing becomes difficult and high temperature corrosion resistance also deteriorates, so the upper limit should be set at 4.0%.
It was hot.

A1 forms Ni (AI, Ti) and significantly improves high-temperature strength, but as is clear from FIG. 2, it is safe to limit the content to a low level because of the strong deterioration of high-temperature corrosion resistance.

If the A1 content exceeds 1.5 inches, the high-temperature corrosion resistance deteriorates significantly, causing practical problems, so the upper limit was set at 1.5 inches.

The scale of each component element on W, 0.5 to 6.0 inches of Nl
+Ta, 1.5-4.0 inches of Ti, 1.5 inches or less of A
I gold content + 0.0005-0.020%
Ca, 0.0005-0.020% Mg0.0
0.05 to 0.050 of a rare earth element, 0.0005 to 0.05.
If Bo of 0.10 mm and Y of 0.05 to 0.10 mm are added alone or in combination of two or more, high temperature strength can be further increased without significantly deteriorating high temperature corrosion resistance, and hot workability can also be improved. improves. In this case, if each element is contained below the f limit, the effect is small, and if contained above the upper limit, high temperature corrosion resistance or hot workability is deteriorated.

For Mo, ■, W, Mo 0.1-4.0%, V
If O, 1-3.0% and WO, a-4.0% are contained alone or in combination of two or more, high temperature strength can be further increased without significantly deteriorating high temperature corrosion resistance.

In this case, the effect of each element is small below the T limit.

If the content exceeds the L limit, the high temperature corrosion resistance and hot workability will deteriorate.

By adding one or more of Mg, rare phosphorus, B, and Y, an alloy with superior high-temperature strength can be obtained.

Z", Hf k: Rai"CkL, Zr O,005-
0,5096, HlO, 005 ~ 0.50Ll) woshin German Alui 1.121 small wo: N ii]'t it.

High-temperature strength can further improve hot workability without significantly deteriorating high-temperature corrosion resistance. In this case Zr
, Hl are less than 1 limit, the effect is small.

If the content exceeds the upper limit, no reasonable effect can be expected.

Also, Zr 0.0050.50%, H'l'
Containing 0.005-0.50% of 1 or 2 types and IMl or 2 or more of Ca, Mg, rare ↑ phosphorus, B, and Y within the above ranges is the best for high-temperature strength. It is possible to improve hot workability by knitting.

Next, the characteristics of the alloy of the present invention will be clearly explained by comparing it with conventional alloys and comparative alloys with examples.

Table 1 shows the chemical components of the present alloy, conventional alloy, and comparative alloy.

In Table 1, Alloy A is a conventional Ni-based alloy consisting of 78% Ni, 15% Cr, 3% Ti, 1% Nb, and 1% Al, alloys B and C are comparative alloys, and D The -Q alloy is the invention alloy, the D-F alloy is the first invention alloy, and the G and N alloys are the second invention alloy.
Invention alloy, alloy J is the 8th invention alloy, L alloy is the 4th invention alloy, M and N alloys are the 5th invention alloy, P and Q alloys are the 6th invention alloy.
It is an invented alloy.

Table 2 shows the A-Q alloy in Table 1 after forging at 1050℃×
After 1/2h solution heating, water cooling, then 750℃×41+
The weight loss of Ff4 when aged and immersed in lead oxide at 960°C or molten composite lead oxide at 900°C for 1 hour is shown. It was measured using a dragon specimen.

As is clear from Table 2, the mechanical properties of the A-Q alloy, which was immediately heat-treated in accordance with the usage conditions of exhaust valves for gasoline engines, are V, and its hardness is that of the A-Q alloy. Both are H
It is possible to obtain hC80 to 88 and a hardness of 900
The tensile strength at a high temperature of 1 is the conventional alloy A, the comparative alloy B, and the C association 1.
By containing I etc., alloy A has 88 kq/-, B
, C alloy shows a value of 20 to 85 kq/-, and that of the D-Q alloy, which is an alloy of the present invention, shows a value of 81 to 89 kq/-, which is higher than that of conventional Ni-based alloys.

Regarding high temperature corrosion resistance, the amount of lead oxide corrosion resistance of the conventional alloy is 2. It has excellent OSI/dm"h, but the problem with composite lead oxide corrosion resistance is that it does not contain Mn, but instead contains 2.3 Ti and 0.8 Ti, resulting in a food weight loss of 88.4 p. /d, h, which indicates that the Ni-based alloy has insufficient corrosion resistance against high-temperature combustion gas containing S compounds and other impurities.

In addition, alloy B, which is a comparative alloy, has good lead silicate corrosion resistance like conventional alloy A, but the Mn content is 8.
2'1%, which is lower than that of the alloy of the present invention, so when considering the composite lead oxide corrosion resistance, the corrosion loss is as large as 86.7 p/d*,h, which is found to be insufficient.

Furthermore, since the comparative alloy C alloy contained no Nb but 2.4% Ti and 1.8% AI, both lead oxide corrosion resistance and N alloy lead oxide corrosion resistance were insufficient. On the other hand, the D-Q alloy, which is the alloy of the present invention, has reduced lead oxide corrosion due to the essential Mn content. If you get the hang of it, it's 2.8-6, 89/dk,
h and the same corrosion resistance as conventional alloy A, and the corrosion loss of the bleached composite lead oxide corrosion resistance is 11.8 to 24.
．． 8 f/dvl, h, which is significantly superior to conventional alloy A in terms of high-temperature corrosion resistance, which shows that the alloy of the present invention will continue to have excellent corrosion resistance against high-temperature combustion gases containing S compounds and other impurities. I understand that.

As mentioned above, the alloy of the present invention contains 35.0 to 65.0% N.
i, 15.0-35. (For alloys containing l C', 5.0
~15.0% Mn and 0.5-6.0qb) Nb,
Ta, 1.5-4.0 Ti, l, 5% or less AI
and, if necessary, one or more of Ca, Mg, and rare earth elements B and Y, one or more of Mo, V, and W, and one of Zr and H\. By containing one or two species, it has high-temperature strength equal to or higher than that of Ni-based alloys, and superior high-temperature combustion gas corrosion resistance compared to N1-based alloys. It is extremely important that this high-temperature corrosion-resistant alloy, which can be manufactured at a much lower cost than the alloy molding, will contribute to the industry.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the influence of Mo on composite lead oxide corrosion resistance, and FIG. 2 is a diagram showing the influence of Nb, Ta, Ti, and AI on composite lead oxide corrosion resistance. Patent applicant, see)′

Claims (1)

[Claims] 11 weight ratio C0, 15φ or less, Sil, Qqb
F, Mll 5.0-15.0%, Ni 85.
0-65. Oqb, Cr15. O-85,0qb,
Ti 1.5-4.0%, All, 5 Ti or less, Nb
A high-temperature corrosion-resistant alloy characterized by containing one or two of O, 5-6, Oqb, Ta O, 5 to 6.0%, with the balance consisting of Fe and impurity elements. 2. Weight ratio C0.15 or more 1, Si 1.0 or less M ++ 5, 0-15.096, Ni 8
I5.0-6.5.0%, Cr 15.0-35.
0%, Ti 1.5-4.0%, At 1.5% or less, NbO, 5-6.0%, Ta 0, 5-6,
Including 1 or 2 types of 01b, and 1 and E
Ca O, 0005~0.020 L M g 0.0
005~0.020 qb, rare earth elements 0.005~
0.050%, BO, 0005~0.010%, Y
A high-temperature corrosion-resistant alloy characterized in that it contains 1 to 2 or more of O.005 to 0.100 and the remaining percentage is Fe as an impurity element. 3. Weight ratio: C0, IFl or less, Sit, Ochi or less, Mro 580-15.0%, Ni 35.0-
65.0%, Cr 15.0-85.0%, Til,
5 to 4.0 inches, Al l, more than 5 inches and -Nb015 to 6
, 0chi, Ta0.5-6.0chi None/2
Contains a rod, 8 to 460 inches,
A high-temperature resistant alloy characterized by containing one or more of Vo, 1 to 8.0 inches and Wo, 8 to 4.0 inches, with the remainder consisting of Fe and impurity elements. 4. Loading ratio: C0,1596 or more, Si1. Ochi 1', M u 6, O ~ 15.0chi, Ni
85.0~65.0chi, Cr15.0~85.0chi,
Tit, 5 to 4.0 inches, Al 1.5 inches or more, NbO
, 5-6, i, Ta O, 5-6, 0%, 1 rod is missing, 2 kinds, and E Z r O, 005-0
, 50'iy, Hr O, 005-0,501 A high temperature resistant alloy characterized in that it contains 1i4 or 2 of O,005-0,501, and the shallow portion of Fe is an impurity element. 5. Weight ratio V strained CO, 15 inches or more, Si 1
, 0chi or more F1Mn 5.0-15.0%, Ni 8
5.0-65.096, Cr 15.0-85.0 inches, Tit, 5-4.0%, At 1.5 inches or more,
NbO, 5-6, OL Tj+ 0.5-6. O%I
7) U? J 1 hM Naishi 21m, 3, further contains CaO,0005-0,0209b, Mg0.0
006~0. (2) H, rare earth element 0. (105~0.
I0chi, BO,0005~0.010chi, Y O,00
One or more of 5 to 0.100 chi, and Mo
0.8~4.0chi, Vo, 1~8.0%, WO18~
Contains one or more of 4.0% and the remainder F'e
A high temperature corrosion resistant alloy characterized by comprising: and t impurity elements. 6-6 weight/1 ratio CO, 15 or more 7, Si 1. Below Ochi, Mn5. Q~15.0chi, Ni85. O2 65.0
Ca O,0005-0,020 for Crt5.0 et al.
%, Mg 0.0005-0.020%, rare earth elements 0. '005~0.050chi, B O,0005~
One or more of 0.010chi, Yo, 005 to 0.100chi, and ZrO, 005 to 0.50chi, H
A high-temperature corrosion-resistant alloy characterized by containing one or two of f O,005 to 0.50, with the balance consisting of Fe and impurity elements.