JPH02247356A - Cast parts made of alloys based on Fe-Mn-Al-Cr-Si-C - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION 1 To the helmet 11 Cast members that can withstand high temperatures can be preferably used in incinerators, blast furnaces, nuclear reactors, steel refining furnaces, and the like. The temperatures generated in such applied light can be as high as 1100°C. The design of cast parts suitable for such applications requires (1) maintenance of excellent mechanical properties at high temperatures;
and (2) in accordance with the essential requirements of maintaining hot corrosion resistance.

The cost, security of supply, or even availability of the alloying components of the cast member are primary considerations.

Mechanical failure of cast parts at high temperatures is primarily caused by softening and creep of the part at such temperatures. Additionally, hot corrosion reactions induced by the unfavorable atmosphere further accelerate the progression of mechanical failure.

The need for cast parts to have good mechanical properties at elevated temperatures varies widely depending on the desired application optical function and configuration. For example, in the case of cast parts used as gas turbine blades, it is important that they meet very high standards of mechanical properties such as resistance to stress, erosion and wear. On the other hand, in static applications such as boiler shells or boiler linings, the standards for mechanical properties are not as high. However, even though the need for good mechanical properties varies from application to application, it is always of critical importance that cast parts can be resistant to hot corrosion that can occur in unfavorable atmospheres.

As is known to those skilled in the art, aluminum, chromium and/or silicon are often used as alloying components in order to improve the hot corrosion resistance of alloys used at high temperatures. The effectiveness of these elements is similar to that of aluminum oxide (Al
203), chromium oxide (CrzOs) and/or silicon oxide (Si(h)) at relatively low temperatures. Nickel oxide (Nip) on the surface
) Nickel may be used in the alloy to provide relatively weak protection against hot corrosion by forming a coating. Nickel oxide coatings do not provide the same level of hot corrosion resistance that aluminum, chromium, and silicon provide.

However, nickel is still often considered an important alloying element in the design of alloys for use at high temperatures, as it can have the additional benefit of improving the mechanical properties of the protected materials.

In the 1920's and 1930's, Fe-Cr-Al1 alloys were primarily preferred for high temperature applications. However, this alloy is rarely used today because of the disadvantages of poor mechanical properties inherent in its ferritic or body-centered cubic (BCC) structure.

Recently commercially available alloys for high temperature applications are mainly
It is characterized by containing 30% by weight of chromium. As mentioned above, chromium forms a Cr2O3 protective film by reaction with oxygen in the atmosphere. However, at temperatures higher than 1000° C., Cr20= is further oxidized to Cry, which evaporates during the reaction, and the oxide film finally disappears. For this reason, the use of this type of alloy is usually limited to temperatures below 1000°C. Also, such a high chromium content precipitates the σ phase in the alloy, making it brittle. In order to overcome this drawback, it is necessary to add some component that suppresses the formation of the σ phase. However, while other types of alloys often use relatively inexpensive carbon for this purpose, Fe-Cr alloys such as those mentioned above are sensitive to carbon contents above about 0.04% by weight; Carbon cannot be used in alloys.

If carbon is not used, nickel is used instead because nickel can suppress the formation of the sigma phase and at the same time stabilize the austenite phase and improve the toughness and other mechanical properties of the alloy. Depending on the purpose, Fe-
Various alloys based on Cr-Ni have been developed. For example, alloys for high temperature applications on the market today include the Ni-based superalloy In-conet-718 and the Fe-Ni
Processing alloys such as base stainless steel ^l5I310 as well as Ni-based superalloy Incone l-738
and F such as SAE 80410 (JIS 5C) I-1) and 5AE60446 (JIS 5C11-2).
e-Cr based alloys and SAE 80442 (JIS
5CH-11), SAE 60316 (JIS SC
I+-12), SAE 80312 (JIS 5C11
-13), SAE 60309 (JIS 5CH-14
) and SAE 60310 (JIS 5C) l-15)
Cast alloys such as Fe-Ni based alloys are included. Table I summarizes the composition of the foreshortening alloys.6 As is clear from Table 1, all of these alloys contain relatively large amounts of nickel and/or chromium. All of the above alloys are very expensive since nickel and chromium are rare and expensive elements. Moreover, nickel and chromium are considered strategic materials in most countries, so they are not easily available to countries that do not have these as resources. As a result, the price of these alloys is extremely high, reaching tens or even hundreds of times the price of carbon steel. This is why the alloys are priced per kilogram rather than per ton. Clearly, the high cost precludes the use of these alloys in large quantities. Furthermore, high nickel or chromium contents also lead to difficulties in explosive welding and therefore to increased manufacturing costs of the component.

m J 口塙Meng几U Discussion 1+conel-73861,0 ^IS1310 19~22 SAE 60410 <1.0 SAE 60446 16.0 24~26 12~15 25~28 0.17 3.4 1.7 <0 .08 0.2~0.4 <0.5 CH-I CH-2 SAE 60312 11~1424~29 0.2
~Q, 5 SCI! -13SAE 6030
9 18-2224-28 0.3-Q, 13
5CH-14SAE 60310 33~
37 13~17 0.35~0.75
5CH-15 In the face of the economic and availability problems mentioned above, an attempt was made to find substitutes for chromium and nickel. As a result, aluminum was used in place of chromium to provide the necessary hot corrosion resistance. In order to stabilize the austenitic phase so that a high degree of toughness could be achieved, manganese and carbon were used together in place of Ni-Nokel.

In particular, it has been found that the combination of manganese and carbon can stabilize the austenite phase more effectively than nickel. However, the above two objectives are incompatible. If such alloys contain too much carbon or manganese, the hot corrosion resistance of aluminum oxide is severely impaired. In many cases, hot corrosion resistance can be reduced to 1150. An effective method for resolving this conflict between chemical properties and mechanical properties has not yet been reported. Another problem with this type of alloy is that aluminum oxide is not as effective as chromium oxide in protecting against hot corrosion. To overcome this drawback, α-Al, which contributes most to hot corrosion resistance,
□0. Silicon was added to promote the formation of . However, silicon only functions at temperatures around 1100° C., and adding silicon at lower temperatures does not have any substantial effect. In conclusion, the prior art does not disclose alloys that simultaneously have sufficient hot corrosion resistance and sufficient mechanical properties in the temperature range from ambient to high temperatures such as 1100°C and are relatively inexpensive. do not have.

In previous research on alloys based on Fe-Mn-Al, Kos16r and Tonn in 1934 attempted to construct part of the three-element phase diagram of Fe-Mn-^I.
Kos16r & H, Tonn, ^re Eisen
huet16nw, 7.365 (1933)), which was later revised in 1959 by 5chaIatz (D, J,
Schwarz.

Trans, ^IME, 215.112-114
(1959)), Chakrabar Li in 1977
c is ([1, J, Chakrabartic, Ne
tall.

Trans,, 8B, 121-123 (1
977)), and in 1983 V, G, Rivli
n is (V, G, Rivlin, In16rnat
ionalMetals Reviews, 28.
No. 6.309-337 (1983)). However, these studies are limited to a small temperature range around 1000° C., and many regions of the phase diagram are still unclear. For example, the solidus line in the phase region around 20 wt% Mn and 6 wt% Al has not yet been elucidated, Fe-Mn-81
The four-element phase diagram for c has not yet been created and remains C).

U.S. Pat. No. 3,201,230, issued in 1965 to Mitchell et al.
4-35% manganese and 3.5-8.75% by weight
of aluminum, 4.5 to 8.75 wt% chromium, 0.25 to 1.0 wt% silicon, 0.25 to 1
．． An alloy consisting of 0% by weight carbon and the balance iron is disclosed. The alloy of this patent contains relatively large amounts of chromium and therefore would be relatively expensive if commercially available. In fact, this patent was not enforced even after its protection period expired. The contents of this patent are inconsistent with several metallurgical theories, and it is believed that the disclosed alloys may not exhibit the desired effectiveness, particularly when designed for use at temperatures between 400 and 1000C. The reason is as follows.

(1) The manganese content range of 14-35% by weight in this patent is too wide because in 1934 Kos16
As taught by R and Tonn (L Kos16
r & H, Toon, ^rc Eisen
hueL16nw, 7. 3651933), this is because when the manganese content of the alloy of this patent exceeds 31% by weight, β-Mn precipitates around the grain boundaries of the alloy at temperatures of 300 to 1000°C. Also, if the manganese content is less than 20% by weight, relatively large Fe3^IC0 carbides are formed, making the alloy brittle and consuming aluminum in the alloy. F
e3^IC, the consumption of aluminum by the formation of carbides clearly reduces the hot corrosion resistance and makes the alloy unsuitable for use at high temperatures.

(2) Chromium contained in a large amount easily reacts with carbon at the applicable temperature, resulting in chromium carbide (Cr2.Ci or Cr7).
C5). The alloy thus becomes sensitive and its mechanical properties deteriorate. Moreover, the temperature exceeds 800℃,
And when the chromium content is between 5 and 8.75% by weight, the chromium contained in the alloy reacts rapidly and extensively with nitrogen in the atmosphere, resulting in acicular aluminum nitride (^IN).

As a result, the aluminum content is insufficient to form an oxide protective film. However, Mitchell's patent does not disclose a solution to this problem; therefore, Nat.
ional Chin-hwa IJnivers
iLy, Taiwan's Ma16real 5ci
ence Re5earch In5titu16 L
Transmission scanning electron microscopy (STE) by Wang et al.
Aluminum nitrite was mistakenly thought to be an internal oxide of aluminum until research using M) broke the misconception in 1987. A report on the discovery of HgI2 etc. is published in Journal of Ma16real 5
science of Great Br1tain in
Hay, 1988.

The present invention is superior to any of the above-mentioned prior art in the following points.

(1) Limiting the manganese content within a specific range found to be effective over the range of desired application temperatures. β-Mn or F near the limits of the manganese content range
In order to suppress the formation of e3^IC, other alloying elements are added to control the morphology and position of the precipitates.

(2) Silicon is added to improve hot corrosion resistance.

(3) Adding auxiliary elements to further enhance the mechanical properties of the cast member through a precipitation hardening mechanism at high temperatures.

(4) By appropriately controlling the relative ratios of alloying elements, the addition of chromium may not necessarily be necessary depending on the application.
Or even become unnecessary.

As a result, the cost of the cast parts of the invention is significantly reduced.

(5) The oxidation weight gain of the cast member of the present invention at high temperatures was lower than that of any of the prior art mentioned above.

SUMMARY OF THE INVENTION The object of the present invention is to provide a ready-to-apply cast member having excellent hot corrosion resistance and mechanical properties over the entire temperature range from ambient temperature to 1100'C. shall be.

The present invention also provides a ready-to-applicable cast member that satisfies the above-mentioned needs where the inclusion of expensive or rare elements such as chromium and nickel is essential. purpose.

A further object of the invention is to provide a ready-to-apply cast part which can be modified to meet the specific needs of a particular application by the addition of auxiliary elements.

The present invention discloses a new, ready-to-apply cast component made of an alloy based on Fe-No-Al-Cr-Si--C, as well as a method for manufacturing the same. In particular, the present invention
Essentially 20-35% by weight of manganese, 5-13% by weight of aluminum, 0-5% of chromium, and 0-2% of chromium.
．． A new, ready-to-applicable cast member consisting of 5% by weight silicon, 0.5-1.4% by weight carbon, and the balance iron. Such cast parts can be used even at high temperatures, such as 1100'C, without sacrificing the excellent mechanical properties of the part.

The cast members of the present invention contain small amounts of boron, tungsten, and
Molybdenum, niobium, titanium, vanadium, nitrogen, copper,
It can also be made from alloys containing other elements such as nickel, yttrium, scandium, hafnium and tantalum.

While the features of the invention are clearly set out in the claims, it is believed that the invention can be better understood from the following detailed description and examples.

The ready-to-apply cast parts of the invention contain, in addition to iron, mainly five alloying elements, each of which is detailed below.

Manganese Manganese is used in the present invention as an austenite stabilizing substance to stabilize the austenite structure of the alloy and improve the toughness of the alloy. Manganese can be easily oxidized at temperatures above 750°C. This problem can be avoided by adding silicon as described later.

As mentioned earlier, conventional alloys suffer from poor corrosion resistance if the manganese mold is too high. This problem could be solved in the present invention by adjusting the relative ratios of manganese, carbon and aluminum.

Ready-to-apply cast parts of the invention contain 20-35% by weight
, preferably 20-32% by weight, most preferably 24-32% by weight
Contains 30% by weight of manganese.

Carbon Carbon is also used in the present alloy as an austenite stabilizing material to improve the mechanical properties of the present alloy. When adding optional carbide forming materials such as niobium and molybdenum, the carbon content must be increased proportionately.

As mentioned earlier, in conventional alloys, too high a carbon content reduces corrosion resistance. This problem could be solved by adjusting the relative proportions of manganese, carbon and aluminum.

The cast parts of the invention, which are ready to apply, have a thickness of 0.5 to 1.
It contains 4% by weight carbon, preferably 0.5-1.2% by weight, most preferably 0.5-1.1% by weight.

AluminumAluminum can oxidize at high temperatures to form an aluminum oxide film, providing the primary hot corrosion resistance.Aluminum also functions as a ferrite former in the alloys of the present invention, thus combining aluminum with manganese and other alloying elements. An extremely effective aluminum oxide protective film can be obtained by appropriately determining the relative ratios of other elements, and F in the base material must be appropriately balanced.
It is also possible to form carbides regularly to further strengthen the alloy.6 Cast members according to the invention, which can be applied immediately, contain from 5 to 13% by weight, preferably from 8 to 12% by weight. , most preferably 8-1
Contains 1% by weight aluminum.

Chromium Chromium can be oxidized at high temperatures to form a chromium oxide film, further increasing thermal corrosion resistance. The corrosion resistance provided by chromium oxide is more effective at room temperature. Chromium is both a ferrite former and an effective carbide former. The relative proportions of chromium must be carefully adjusted to prevent the adverse effects of chromium on the mechanical properties of the alloy.

The ready-to-apply cast parts of the invention contain from 0 to 5% by weight of chromium, preferably from 1 to 5% by weight, most preferably from 2 to 4% by weight.

silicon Silicon can naturally form a silicon oxide overcoat.

The oxidation rate and dissociation pressure of silicon oxidation are manganese oxide (Mn
O), silicon is used in the alloys of the invention primarily as an inhibitor of manganese oxidation and manganese oxide nucleation and growth. As a result, the chances of aluminum oxide formation are greatly increased. However, since silicon is a strong ferrite-forming material and will greatly reduce the likelihood of blast contact in the cast part, the relative proportions must be carefully set to take this into account.

The ready-to-apply cast parts of the invention contain 0 to 2.5% by weight.
, preferably 0.5-2% by weight, most preferably 0.5
Contains ~1.5% by weight silicon.

Auxiliary Elements The cast parts of the present invention incorporate the main alloying elements listed above with minor amounts of boron, tungsten, molybdenum, niobium, titanium, vanadium, nitrogen, copper, nickel, and yttrium to meet the special needs of various specific applications. Other elements such as , scandium, hafnium and tantalum can also be added and alloyed. The addition of auxiliary elements as described above is well known to those skilled in the art, and the individual auxiliary elements mentioned herein are described below to illustrate other aspects of the invention.

Boron The addition of boron lowers the surface free energy of the grain boundaries, resulting in further reduction of carbide precipitation at the grain boundaries. With the addition of boron, better mechanical properties are achieved due to uniform precipitation in the matrix.

Cast members of the present invention may optionally contain 50 to 200 ppm boron.

Tungsten, Molybdenum and Niobium These elements are used in the alloys of the present invention to produce fine carbide reinforced alloys, increase erosion resistance, inhibit carbon diffusion, and prevent damage to the oxide overcoat due to decarburization. Used for prevention.

Cast parts of the invention may optionally contain 0.1-1.0% by weight tungsten.

Cast parts of the invention may optionally contain 0.1 to 2.1% by weight of molybdenum.

Cast parts of the invention may optionally contain 0.1 to 1.0% by weight of niobium.

Titanium and Vanadium Titanium and vanadium function similarly to tungsten, molybdenum and niobium. Moreover, titanium and vanadium form little nitride, which can prevent damage caused by nitriding and can aid in surface hardening.

Cast parts of the invention may optionally contain 0.1 to 2.0% by weight of titanium.

Cast parts of the invention may optionally contain 0.1 to 1.0% by weight vanadium.

nitrogen Nitrogen is also a strong austenite former.

By adding nitrogen, the austenitic phase can be stabilized with less carbon, resulting in better hot corrosion resistance.

Cast parts of the invention may optionally contain 0.605 to 0.2% by weight nitrogen.

Copper can be used to increase corrosion resistance at relatively low temperatures.

Copper can also be used to form compounds with residual phosphorus in cast parts to prevent thermal embrittlement caused by residual phosphorus.

Cast parts of the invention may optionally contain 0.5-1.5% by weight copper.

Nickel Compounds of phosphorus and copper, such as those mentioned above, still lead to thermal brittleness depending on the temperature. Nickel can be used to avoid such problems. Nickel can also be used to improve the shine of the alloy. Excess nickel forms a metallic compound γ' phase with aluminum that is detrimental to the alloy. The amount of nickel and copper added must be carefully adjusted according to the residual phosphorus content.

Cast parts of the invention may optionally contain 0.5 to 2.5% by weight of nickel.

Yttrium, scandium, hafnium and other substances should not be considered as limiting. Because these rare elements have a strong latent oxidizing power,
By guiding oxidation within the alloy and absorbing the vacancies generated during oxide film formation, a key mechanism is realized, and an intermediate layer mechanism is realized, which improves the adhesion of the oxide film while the temperature repeatedly rises and falls. It can be added to prevent the oxide film from peeling off easily.

Cast members of the invention may optionally contain 0.01 to 1.0% by weight of yttrium.

Cast parts of the invention may optionally contain 0.1 to 1.0% by weight of scandium.

Cast parts of the invention may optionally contain 0.01 to 0.5% by weight hafnium.

Cast parts of the invention may optionally contain 0.01 to 0.8% by weight tantalum.

The following examples are presented to assist in the understanding of the invention; all parts and percentages are by weight, unless these examples limit the scope of the invention.

(The following is a blank space) Back 1''LL This example shows an example of the method for manufacturing a cast member of the present invention.

A mixture of iron, manganese, aluminum, silicon and carbon was melted in a high frequency induction furnace to prepare a melt of known composition. The obtained melt was cast using multiple types of molds made of different materials to produce multiple types of cast members having different surface conditions.

Melting was achieved in a high-frequency induction furnace with a capacity of 20 kg.The ratio, form, and weight of the 0 alloying elements are shown in Table 3.

Aluminum 101゜5 Commercially available pure aluminum until it becomes No. 1008 coil winding wire The iron and silicon iron were charged into the furnace while cold.

Furnace power was set to 20 kHz and maintained for 10 minutes, then power was adjusted to 40-. After 7 minutes, at about 1550°C, the iron and silicon iron were completely melted. Next, the power was adjusted to 20 - and 2.25 kg of manganese and the entire amount of chromium were added, and then the power was adjusted back to 40 kl. After the added manganese and chromium were melted, the remaining manganese 2.25 kg was added. 2
5 kg and 0.15 kg of carbon were added. After 10 minutes, the slag was removed. 1.5 kg of aluminum was added.

Slag generation and removal operations were performed after aluminum melting. The supernatant of the melt was taken into a 30 kg capacity ladle after the temperature reached 1580° C. and cast in four separate molds of different materials after the temperature decreased to 1480° C. The molds of 4111i1 are shell molds, sand molds, ceramic molds and compound molds, each with a capacity of 4 kg.

The surface condition of the obtained cast member was observed. Regarding the shape of the product, the best results were obtained with shell molds, followed by sand molds, ceramic molds, and compound molds. In terms of surface smoothness, good results were obtained in the order of compound mold, shell mold, ceramic mold, and sand mold. but,
Both cast members are considered to be within the acceptable range for the application.

A cast member cast in a ceramic mold was homogenized at 1200°C for 4 hours, and a sample for chemical analysis was taken with a drill.The results of the analysis are shown in Table 3.

A series of cast members within the scope of the present invention were manufactured in the same manner as in Example 1, and the mechanical properties (tensile strength, elongation and hardness) of the alloy were tested and A comparison was made with cast members for high-temperature applications.

Seventeen cast members consisting of Fe-Nn-1c based alloys with optional additions of other alloying elements such as niobium, molybdenum and nitrogen were produced in the same manner as described in Example 1.

The melt was cast in a ceramic mold to obtain a cylindrical ingot having a diameter of 80 mm, a length of 250 mm, and a weight of about 15 kg. The ingot was cut into cylinders with a height of 4 cm and then forged at 1200° C. to reduce the height to 20 −.

The forged ingots were cooled to room temperature and cut into tensile property test specimens with an average length of 1 inch. The tensile strength, elongation and hardness of the test samples were tested and the results were recorded as shown in Table 3. --like deformation was observed in all samples throughout the test. For comparison, Table V shows typical mechanical properties of some of the conventional high temperature application castings listed in Table 1, which have relatively low necking rates. As is clear from a comparison between Table 1 and Table V, the mechanical properties of the cast members of the present invention are superior to those of conventional cast members for high temperature applications on the market. In particular, the cast members of the present invention exhibit higher elongation and toughness than those specified by ISI 310, a processing steel for high temperature applications.

Clothes-■ Iki-Tim Nono-type t JIS SCI! -12>70
Horn Horn JISSCH-13>70j)
n JIS 5CH-14>65 Horn Horn JISSCH-15>57 nol
H was observed using an optical microscope. The improvement of mechanical properties is achieved by a small amount of F.
It was observed by microscopic structure analysis that this was the result of the formation of e-^I-C carbide (Fea^Ic).

That is, it has been found that the mechanical properties of the cast members of the present invention can be improved by controlling the morphology of precipitates at high temperatures.

Then, six forged ingots of alloy #10 of Example 2 produced by the same method were cold rolled to reduce the thickness by 90% to 0.2 cm. The material obtained by rolling was heated to 1050°C.
Solution treated for hours and quenched to room temperature in gear oil. 6
Five of the rolled members were aged at 550° C. for different periods of time. Six rolled members were tested for tensile strength, elongation, and hardness, and the results shown in Table ■ were obtained.
As can be seen, the tensile strength increased significantly, the elongation decreased to a limited level, and the hardness increased. Aging of these rolled members at 550℃ for 1 hour 138
．． 5 39.6 64.5Ra Aging at 550℃ 16 hours 151.7 44.0 65. O
Ra 夾1j1L This example illustrates the hot corrosion resistance of the alloy of the present invention.

A plurality of cast members made of alloys having the compositions shown in Table 1 were melted at fIi 1200 as described in Examples 1 to 3.
It was produced by forging at 1050°C and homogenizing for 8 hours at 1050°C. The obtained member was cut to prepare a test sample with a size of 2 x 4 x 8 mm. The surface of the test sample was coated with No. 1200 Si.
Polished with C abrasive paper. The polished sample was passed through a thermogravimetric analyzer (T
C^), and its oxidation weight gain was investigated. T.G.
The drying air flow rate was 100 cc/sin, the temperature was 700.900°C and 1100°C, and the experimental time was 24 hours. The oxidation weight gain of the test samples is shown in Table ■.

#20 10.0 0.52 Cloth-1 KaikariUlZunhengCviewσ #19 1.19 0.46 0.
89#20 <0.05 0.29
As is clear from Tables 1.22 and 2, the addition of aluminum can suppress the negative effect of carbon on the corrosion resistance of the cast member of the present invention. This example validates the present disclosure that the corrosion resistance of carbon-containing alloys can be controlled by the addition of aluminum.

E111 A plurality of cast parts of alloys having the compositions shown in Table IM were manufactured in the manner described in Examples FAI and 2. The resulting cast member was treated as described in implementation PA4 and placed in a tube furnace set at 400-700'C^IS1.
It was installed with a cast member consisting of 304. Dry air was introduced into the tube furnace at a flow rate of 200 cm37 sin to oxidize the test member. After oxidizing for 24 hours, the test member was air cooled to room temperature, and the surface condition of the test member was observed. ^IS
The color of 1304 becomes darker as the temperature increases, and when the temperature is 600
It was observed that when the temperature exceeded ℃, it completely turned black. In contrast, the cast member of the present invention did not lose its luster, although it became yellowish at relatively high temperatures. As the temperature rises,
The color of the cast part of the invention changed from yellow to brown. No delamination was observed in either the cast parts of the present invention or the cast parts made of ISI 304.

Repeat the same operation as above, this time at a temperature of 1100°C. No peeling was observed on the surface of the cast member of the present invention,
Further, no significant oxide formation was observed.The color of the cast member of the present invention was a glossy brown. In contrast, ^
A black captive oxide film was observed on the I81304 surface,
Cracks were also observed after cooling to room temperature. This example demonstrates the point 15 of the disclosure of the present invention that excellent IK corrosion resistance can be achieved even with a very high carbon or manganese content by adjusting the composition of the alloy. It proves that.

A plurality of chromium-containing cast parts of alloys having the compositions shown in Table X were manufactured as in Examples 1 and 2;
After that, the thickness of the part is reduced by 90% by cold rolling, and 2-
I made it one. The resulting part was homogenized at 1150° C. for 50 hours to completely eliminate processing stresses and promote complete growth of crystal grains. The rolled members were cut, ground, and polished to 0.05B aluminum oxide powder to provide samples for oxidation testing. The oxidation test was carried out using the same operation and equipment as described above, except that the oxidation temperature was set at 1050°C and the rate of temperature rise from room temperature was 100°C per minute. Thermal lightning analysis was carried out at 1050° C. for 48 hours. The overall oxidation weight gain increased by 0.42 B/cmff.

It was noted that an increase in oxidation weight gain was observed only during the first 3 hours, and no increase in oxidation weight gain was observed thereafter. Analysis on an X-ray analyzer and an electronic micro-tube revealed that under the above test conditions the aluminum oxide crystals were completely grown during the first 3 hours. When the test sample was air-cooled to room temperature and observed, the oxide had not peeled off and the color of the test sample had changed to a brownish silver color.

This example proves that by appropriately adding chromium to the cast member of the present invention and appropriately controlling the rate of temperature rise, a perfect aluminum oxide protective film that does not peel off after cooling can be obtained.

Cast parts made of Fe--Mn--Al based alloys having the compositions shown in Table X1 were manufactured in the same manner as described in Example 1. The obtained cast member was homogenized at 1200°C for a period of time and then hot rolled at 900-1000'C. The rolled member was solution treated at 1050° C. for 1 hour and then quenched in oil. Next, the parts are 8x8xlO
Cut to the desired size and polish with 1200 No. SiC abrasive paper.
A test member for a hot corrosion test was obtained by Jf@. The cast samples or test members were made essentially [taCI□, KCI and L
Soak for 268 hours in commercially available Q-6 heat treated salt solution containing iCl. A hot corrosion test was conducted according to the following.

It was observed that the thickness of the corrosion product in the joint 〇N4 was 30H, and that the corrosion progressed along the ferrite phase.

This example demonstrates that the cast members of the present invention exhibit hot corrosion resistance.

#24 30.8 9.8 1. On dog 1”1
1. In areas where waste separation is not widespread, all types of waste, including both acidic and basic waste, are sent to waste incinerators. Analysis of samples taken from garbage incinerators in Taiwan revealed that on average, 56 pieces of garbage are sent to the incinerators.
% water, 15% dust, 15% carbon, 11% oxygen, 0.1% sulfur, and other unidentified substances. Due to the high moisture content, garbage in such areas can burn on its own, and therefore the garbage is often sprayed with fuel to facilitate incineration. The environment within the incinerator in such cases poses a significant threat to alloys for high temperature applications.

Fe-Mn-M-C having the composition shown in Table 1 is produced by melting the pure electrolyte material in a high-frequency induction furnace with a capacity of 500 ml and casting the resulting melt in a sand mold to obtain the desired base plate. -Multiple types of cast members made of Cr-Si based alloys, i.e. incinerator grate (gra16s)
was manufactured. Two types of incinerator grate were manufactured: a fixed grate that receives the incinerator residue, and a movable grate that supports the burning waste and improves the passage of hot air. Both of these two types of grates are subject to significant loads in corrosive atmospheres at combustion temperatures.

Moreover, these grates must withstand constant erosion caused by the loading and unloading of trash. The movable grate weighing 12.5 kg has a length of 39 Ehm and a width of 245 mfi. Dimensions 60IIIll x 1
21I11 rectangular holes are evenly drilled throughout the grate, these holes allow the incinerator residue to fall during incineration as well as the passage of hot air. The dimensions of the fixed grate, which has a similar shape to the movable grate, are 398 cm in length and 28911 II11 in width. The operating temperature of these grates is 700-950°C. These grates were tested in an incinerator for 60 days and 1.5 years, during which the incinerator was loaded with a constant amount of waste each day, ie 200 tons. The thickness of the reaction product film after the test period was as shown in Table x■. Table X III shows the Fe-
It has been demonstrated that an incinerator grate made of a Mn-Alc based alloy meets the quality standards of an incinerator grate made of high chromium cast steel. The properties of the grate can be further improved by adding more chromium, silicon or titanium.

Raw alloy number of 1 portion plate 1st sample 2nd sample #24 70n 1
A 15 kg ingot of Fe-Mn-Al-C based alloy having the composition shown in Table XIV was melted in a high frequency induction furnace and cast in a ceramic mold. Manufactured by. All of the materials melted are in the form of pure electrolyte materials, except that the manganese may be obtained by low carbon manganese iron (marked with 3 in Table XIV). The manufactured ingot was cut and the hardness of the cut surface was measured. Cut a further portion of the ingot to obtain a sample for tensile strength testing as performed in Example 2. The hardness and tensile strength values of the test results are listed in Table X■.

According to Table XV, the alloy constituting the cast member of the present invention is
Even in ingot form, it was proven to exhibit higher tensile strength and hardness than commercially available Al5I stainless steels. In addition, the cast member of the present invention has 1 part in the processing process.
Shows measured toughness. For example, in order to drill a hole in the cast member of the present invention, a suitable combination of a tungsten carbide drilling head, a high-power drilling machine, and a suitable drilling oil is required. In the test, a saw made of a JIS SK alloy was used to cut the alloy #31 of this example, but the saw wore out after making only 51 cuts.

From this phenomenon, it is clear that it is almost impossible to further process the cast member of the present invention as a casting.

Table XV Alloy number Hardness (Re) Tensile strength (ksi) 32.8±09 31.2±0.8 30.5±0.7 30.4±1.0 31.4±0.4 30.4 ±1.0 30.1±2.3 375±0.8 35.7±0.9 36.2±2.1 115±338.0
±1.4 80±536.7±0.8
84±431.1±1.2
Although the present invention has been described based on several preferred embodiments, the scope of the invention is not limited by these embodiments, but only by the claims.

Claims (17)

[Claims] (1) Fe-Mn-Al-C suitable for use at high temperatures
Cast parts based on r-Si-C, comprising essentially 20-35% by weight manganese, 5-13% by weight aluminum, 0-5% by weight chromium, 0-2.5% by weight A cast part consisting of % by weight silicon, 0.5-1.4% by weight carbon and the balance iron. (2) essentially 20-32% by weight manganese and 8-1% manganese;
2% by weight aluminum, 1-5% by weight chromium,
Suitable for use at high temperatures according to claim 1, characterized in that it consists of 0.5-2% by weight of silicon, 0.5-1.2% by weight of carbon and the balance iron. Fe-Mn-Al
- Cast parts based on Cr-Si-C. (3) essentially 24-30% by weight manganese and 8-1
1% by weight aluminum, 2-4% by weight chromium,
2. A method according to claim 1, characterized in that it consists of 0.5-1.5% by weight of silicon, 0.5-1.1% by weight of carbon and the balance iron. Suitable Fe-Mn-
A cast member based on Al-Cr-Si-C. (4) Further containing one or more auxiliary elements selected from the group consisting of boron, tungsten, molybdenum, niobium, titanium, vanadium, nitrogen, copper, nickel, yttrium, scandium, hafnium, and tantalum. A cast member based on Fe-Mn-Al-Cr-Si-C suitable for use at high temperatures according to claim 1. (5) A cast member based on Fe-Mn-Al-Cr-Si-C suitable for use at high temperatures according to claim 1, characterized in that it further contains 50 to 200 ppm of boron. (6) The Fe-Mn-Al-Cr-Si-C suitable for use under high temperatures according to claim 1, further containing 0.1 to 1.0% by weight of tungsten. Cast member used as base. (7) Fe-Mn-Al-Cr-Si-C suitable for use at high temperatures according to claim 1, further containing 0.1 to 2.1% by weight of molybdenum. Cast member used as base. (8) The Fe-Mn-Al-Cr-Si-C suitable for use under high temperatures according to claim 1, further containing 0.1 to 1.0% by weight of niobium. Cast member used as base. (9) Fe-Mn-Al-Cr-Si-C suitable for use at high temperatures according to claim 1, further containing 0.1 to 2.0% by weight of titanium. Cast member used as base. (10) The Fe-Mn-Al-Cr-Si-C suitable for use under high temperatures according to claim 1, further containing 0.1 to 1.0% by weight of vanadium. Cast member used as base. (11) Fe-Mn-Al-Cr-Si-C suitable for use at high temperatures according to claim 1, further containing 0.05 to 0.2% by weight of nitrogen. Cast member used as base. (12) Fe-Mn-Al-Cr-Si-C suitable for use at high temperatures according to claim 1, further containing 0.5 to 1.5% by weight of copper. Cast member used as base. (13) Fe-Mn-Al-Cr-Si-C suitable for use at high temperatures according to claim 1, further containing 0.5 to 2.5% by weight of nickel. Cast member used as base. (14) Fe-Mn-Al-Cr-Si-C suitable for use under high temperatures according to claim 1, further containing 0.01 to 1.0% by weight of yttrium. Cast member used as base. (15) Fe-Mn-Al-Cr-Si-C suitable for use at high temperatures according to claim 1, further containing 0.01 to 1.0% by weight of scandium. Cast member used as base. (16) Fe-Mn-Al-Cr-Si-C suitable for use at high temperatures according to claim 1, further containing 0.01 to 0.5% by weight of hafnium. Cast member used as base. (17) Fe-Mn-Al-Cr-Si-C suitable for use at high temperatures according to claim 1, further containing 0.01 to 0.8% by weight of tantalum. Cast member used as base.