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Production method for sintered component made of stainless steel with high corrosion resistance

a technology of stainless steel and production method, which is applied in the field of production method of sintered components made of stainless steel with high corrosion resistance, can solve the problems that the perovskite composite oxide powder is not easily agglomerated, and achieve the effects of high corrosion resistance, increased corrosion resistance, and high corrosion resistan

Inactive Publication Date: 2005-05-05
HITACHI POWDERED METALS COMPANY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0008] The invention aims to provide a production method for a sintered component made of stainless steel with high corrosion resistance in which corrosion resistance is increased without parts of decreasing Cr concentration and precise production processes and process control are not necessary.
[0012] In the sintered component made of stainless steel with high corrosion resistance mentioned above, the rare earth element is dispersed with a transition metal element and oxygen as a perovskite composite oxide in a matrix of the stainless steel. Therefore, corrosion resistance is increased without parts of decreasing Cr concentration. That is, the Cr amount in the matrix of the sintered stainless steel with high corrosion resistance obtained by using the production method of the present invention is substantially uniform.
[0013] When a content of the rare earth element in the overall composition is less than 0.1 mass %, oxide coating in the matrix is not effectively strengthened. On the other hand, when the content is more than 12 mass %, perovskite composite oxide in the matrix is excessive, whereby the amount of the matrix is low, resulting in decreasing strength and wear resistance of the component.
[0014] According to the present invention, corrosion resistance can be increased by no part of decreasing the concentration of the transition metal element in the matrix. Moreover, in the present invention, cumbersome processes to uniformly disperse the rare earth element are not necessary, and the problem in which cracks are formed in the green compact does not occur even in the case of having a pause between compacting and sintering.

Problems solved by technology

Moreover, the powder of the perovskite composite oxide is not easily agglomerated, and the powder is stable, whereby the above-mentioned hydration reaction is not generated.

Method used

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  • Production method for sintered component made of stainless steel with high corrosion resistance
  • Production method for sintered component made of stainless steel with high corrosion resistance
  • Production method for sintered component made of stainless steel with high corrosion resistance

Examples

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example 1

(Practical Example 1)

[0030] SUS310 powder which was defined by the JIS (Japan Industrial Standards) and was equal to 310 defined by the AISI (American Iron and Steel Institute) was prepared as a stainless steel powder forming a matrix, and LaCrO3 powder and La2O3 powder which had average grain diameters of 5 μm were prepared as a rare earth-oxygen composite powder. These powders were dispensed at a rate shown in Table 1, and were mixed, whereby a raw powder was obtained. The raw powder was compacted into a cylindrical shape (diameter: 10 mm, height: 10 mm) and to a square block having a square cross-section (width: 60 mm, depth: 10 mm, height: 10 mm), in order to set the green density to be 6.7 g / cm3, obtained green compacts were sintered in a hydrogen atmosphere at a sintering temperature of 1250° C. for 1 hour, whereby samples shown by sample Nos. 1 to 12 were produced.

[0031] In the samples having the cylindrical shape, each sample was set in a crucible made of aluminum per test ...

example 2

(Practical Example 2)

[0038] LaCrO3 powder and La2O3 powder used in the Practical Example 1 were added to the stainless steel powder shown in the Table 2, in order to set the La content in the overall composition to 2 mass %, whereby a mixed raw powder was obtained. Test pieces were produced by using the raw powder in the same process of Practical Example 1, and oxidation testing was performed. The results are also shown in Table 2 and are shown in FIG. 3 as a graph. Additionally, SUS304 (JIS) is a steel type equal to 304 defined by the AISI, and SUS430 (JIS) is a steel type equal to 430 defined by the AISI.

TABLE 2rare earthcomposition rate (mass %)elementincreasestainless steelrare earth-oxygencontent inin weightpowdercomposite powderthe overallbysamplesteeladditionadditioncompositionoxidationnumbertypeamounttypeamount(mass %)(g / m2)04SUS310balanceLaCrO33.442.0018811SUS310balanceLa2O32.352.0025416SUS304balanceLaCrO33.442.0033517SUS304balanceLa2O34.692.0040718SUS430balanceLaCrO33.44...

example 3

(Practical Example 3)

[0040] Perovskite composite oxide powder having an average grain diameter of 5 μm shown in Table 3 was added to the stainless steel powder (SUS310 powder), in order to set rare earth metal element content in the overall composition to 2 mass %, and these powders were mixed, whereby a mixed raw powder was obtained. Test pieces were produced by using the raw powder in the same process of Practical Example 1, and oxidation testing was performed. The results are also shown in Table 3 and are shown in FIG. 4 as a graph.

TABLE 3rare earthcomposition rate (mass %)elementincreasestainless steelrare earth-oxygencontent inin weightpowdercomposite powderthe overallbysamplesteeladditionadditioncompositionoxidationnumbertypeamounttypeamount(mass %)(g / m2)04SUS310balanceLaCrO33.442.0018811SUS310balanceYCrO34.252.0019516SUS304balanceCeCrO33.432.0019617SUS304balanceLaFeO33.502.0021018SUS430balanceLaNiO33.532.0019919SUS430balanceLa2O32.352.00254

[0041] As shown in the Table 3 and...

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Abstract

A production method for a sintered component made of stainless steel with high corrosion resistance has steps of preparing a perovskite composite oxide powder made of rare earth element, transition metal element and oxygen, and a stainless steel powder or a mixed powder having a stainless steel composition, mixing the perovskite composite oxide powder and the stainless steel powder or the mixed powder, whereby a raw powder in which the rare earth element is 0.1 to 12 mass % is prepared, compacting the raw powder in a predetermined shape, whereby a green compact is obtained, and sintering the green compact. The sintered component obtained by the production method is a component in which corrosion resistance can be increased without parts of decreasing Cr concentration and precise production processes and process control are not necessary.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The invention relates to an improvement in a sintered component made of stainless steel with high corrosion resistance, and specifically relates to a production method for a sintered component made of stainless steel with high corrosion resistance having the following property; oxidation and corrosion do not easily occur even when the sintered component is exposed to corrosive atmospheres in a high temperature. [0003] 2. Related Art [0004] As a sintered component made of stainless steel with high corrosion resistance mentioned above, for example, a sintered component disclosed in Patent Document No. 1 (Japanese Published Unexamined Application No. 10-183315: sections [0014] and [0015]) is known. In the Patent Document No. 1, a Fe—Cr based sintered alloy, in which Cr is 14 to 35 mass %, compound of at least La and Y including O is a predetermined mass % of multiplying the Cr mass % by a coefficient “a” (range of the ...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): B22F1/00C22C32/00C22C33/02C22C38/00C22C38/18C22C38/60
CPCC22C32/0089C22C38/18C22C33/0228
Inventor YOSHIHIRO, TATSUAKICHIKAHATA, KATSUNAO
Owner HITACHI POWDERED METALS COMPANY
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