TWI737475B - Matian bulk iron series stainless steel plate and matian bulk iron series stainless steel components - Google Patents

Abstract

The present invention provides a Asada scattered iron-based stainless steel plate and components used in the manufacture of Western tableware knives, looms, tools, disc brakes, etc., which have excellent corrosion resistance even if they are air-cooled and quenched. The Mattian scattered iron series stainless steel plate is calculated by mass%, C: 0.100~0.170%, Si: 0.30~0.60%, Mn: 0.10~0.60%, Cr: 11.0~15.0%, Ni: 0.05~0.60%, Cu: 0.010 ~0.50%, V: 0.010~0.10%, Al: 0.05% or less, N: 0.060~0.090%, C+1/2N: 0.130~0.190%, the γp shown in formula (1) is 120 or more; among them, After the aforementioned Asada scattered iron-based stainless steel plate is quenched and tempered, at this time, the area ratio of δ Fe iron (δFe) existing in the center of the steel plate thickness in the plate thickness section will be 0.1 to 1%.

Description

Matian bulk iron series stainless steel plate and matian bulk iron series stainless steel components

Field of invention The invention relates to a Matian scattered iron-based stainless steel plate and a Matian scattered iron-based stainless steel component with excellent corrosion resistance after quenching. In more detail, the present invention relates to a Asada loose iron stainless steel used for manufacturing Western tableware knives, looms, tools, disc brakes, etc., which has excellent corrosion resistance even if it is air-cooled and quenched.

Background of the invention As for Western tableware knives (table knives) or scissors, looms, calipers and other tools, Asatine scattered iron stainless steel plates such as SUS420J1 and SUS420J2 steel are generally used. In this application, it is difficult to plate or paint, and use anti-rust oil, and the material itself is required to have rust resistance. In addition, it is also important that it is not easy to wear, so it must be high hardness.

In the manufacturing steps such as Western tableware knives, the knives are usually made by die-cutting from the steel plate, heating and quenching, and then going through the grinding step. The quenching step is mostly carried out at the degree of air cooling, which is also related to the characteristics of the Asada scattered iron stainless steel plate with excellent hardenability.

Document 1 (Japanese Patent Application Laid-Open No. 2008-163452) discloses an Asada bulk iron-based stainless steel having excellent corrosion resistance when quenched by air cooling. Among them, as an element to improve corrosion resistance, N is added to about 0.06%.

Document 2 (Japanese Patent Laid-Open No. 2005-163176) discloses a steel to which N is further added. In addition, Document 3 (Japanese Patent Laid-Open No. 2005-248263) discloses a steel that uses special equipment to further increase N.

In recent years, with Europe as the center, the requirements for the corrosion resistance of Western tableware have gradually increased. As a result, in the rust resistance evaluation test, rust was seen everywhere in the center of the back or tip of the knife, and the handle, and it is required to improve this situation.

Summary of the invention In recent years, with Europe as the center, as the requirements for the corrosion resistance of Western tableware have increased, the requirements for improving the rust at the center of the back or tip of the knife and the handle in the strict corrosion resistance test have gradually increased. In the present invention, the object is to provide an Asada loose iron-based stainless steel plate and an Asada loose iron-based stainless steel member, which has sufficient durability for the use of Asada loose iron-based stainless steel such as table knives and other Western tableware. Hardness and corrosion resistance are also excellent.

In order to achieve the above-mentioned object, the inventors of this case first investigated the rust condition of the table knife in detail. As a result, it became clear that the rusted area would start from the end face of the steel plate, or in detail, the center of the thickness of the steel plate would be the starting point. It was also confirmed that the δ Fe grain iron phase (δFe phase), which would cause macrosegregation, was formed, and it was also clear that the δFe grain boundary would become the accumulation point of carbides, and the carbides would be melted by heating during quenching, and During the subsequent cooling, the grain boundaries are precipitated, and as a result, sensitization and corrosion of the grain boundaries occur, which is the mechanism of rust.

It was also found that the rust was also related to the cooling rate during quenching. Although the cooling rate varies with the height of the quenching equipment, if the average cooling rate is evaluated from the quenching temperature to the temperature at which carbide precipitation is almost completed, that is, 600°C, it is understood that the permeable quenching can obtain a value greater than 100°C. /s cooling rate, it will inhibit the precipitation of carbides and hardly rust. However, for air cooling, which is mostly used in the manufacturing process of table knives, the cooling rate is only about 5°C/s, which cannot suppress the precipitation of carbides. Prone to rust.

Based on these findings, the inventors of the present invention reviewed the improvement method and found that by adding N to the steel sheet composition, the rust can be suppressed for the cutlery cutlery after forming and heat treatment.

After that, a more detailed review was conducted to complete the invention. that is: (1) A Matian scattered iron series stainless steel plate, characterized in that it has the following steel composition: Calculated by mass%, C: 0.100~0.170%, Si: 0.25~0.60%, Mn: 0.10~0.60%, P: 0.035% or less, S: 0.015% or less, Cr: 11.0~15.0%, Ni: 0.05~0.60%, Cu: 0.010~0.50%, V: 0.010~0.10%, Al: 0.05% or less, N: 0.060~0.090%, C+1/2N: 0.130~0.190%, The remainder is composed of Fe and impurities, Γp represented by the following formula (1) is 120 or more; where, After holding the aforementioned Asada scattered iron stainless steel plate at 1050°C for 30 minutes, it is air-cooled and quenched, and then tempered at 150°C for 30 minutes. At this time, the δ Fe grain iron (δFe) present in the center of the plate thickness is The area ratio in the plate thickness profile will be 0.1~1%; γp=420C+470N+30Ni+7Mn+9Cu-11.5Cr-11.5Si-12Mo-23V-47Nb-52Al+189...Equation (1) The element symbol in the formula (1) means the content (mass %) of the element.

(2) The Asada scattered iron-based stainless steel plate of the present invention further contains one or more of the following in terms of mass% in place of part of the aforementioned Fe: Mo: 0.01~1.0%, Ti: 0.005~0.050%, Nb: 0.005~0.050%.

(3) The Asada scattered iron-based stainless steel plate of the present invention further contains one or two of the following in terms of mass% to replace part of the aforementioned Fe: Sn: 0.01~0.10%, Bi: 0.01~0.20%.

(4) A stainless steel component of Asada scattered iron series, characterized by having the steel composition of the present invention, wherein: Let γp shown in the following formula (1) be 120 or more; In addition, the area ratio of δ Fe grained iron (δFe) existing in the center of the plate thickness in the plate thickness section is 0.1~1%; γp=420C+470N+30Ni+7Mn+9Cu-11.5Cr-11.5Si-12Mo-23V-47Nb-52Al+189...Equation (1) The element symbol in the formula (1) means the content (mass %) of the element.

The Asada loose iron-based stainless steel plate of the present invention retains sufficient hardness to withstand the use of Asada loose iron-based stainless steel for western tableware such as table knives, and has excellent corrosion resistance, especially excellent end surface corrosion resistance. . Therefore, when using Asada scattered iron-based stainless steel members as Western tableware cutlery, etc., the effect of improving corrosion resistance and prolonging product life can also be expected.

According to the present invention, it is possible to produce a kind of Asada scattered iron stainless steel components with excellent corrosion resistance on the back end of air-cooled quenching with good productivity, and the corrosion resistance of Western tableware knives manufactured by using the same can be improved, which is very useful in industry. .

Embodiments of the present invention Give further details. <Chemical composition of steel plates and steel members> (% means mass%.) C: 0.100~0.170%

Both C and N are elements that determine the quenching hardness. In order to obtain the required hardness of Western tableware knives, it must be more than 0.100%. It should be above 0.110% and above 0.120%. On the other hand, when excessive addition, the quenching hardness will increase more than necessary, in addition to increasing the load during grinding, the toughness will also decrease. In addition, even according to the present invention, Cr carbides are likely to precipitate during air quenching to impair the corrosion resistance, so it is set to 0.170% or less. It should be less than 0.155%. Si: 0.25~0.60%

In addition to being necessary for deoxidation in steel making, Si can also effectively inhibit the formation of oxide film after quenching heat treatment, so it contains more than 0.25%. When it is less than 0.25%, excessive oxide film will be formed and the final polishing load will increase. However, excessive addition suppresses the formation of austenitic iron and impairs hardenability, so it is set to 0.60% or less. Mn: 0.10~0.60%

Mn is a stable element of austenitic iron, which is necessary to ensure the hardness and the amount of scattered iron during quenching. Therefore, it contains 0.10% or more. However, since it promotes the formation of an oxide film during quenching and increases the subsequent polishing load, it is set to 0.60% or less. In addition, when excessively added, MnS is formed in a large amount and corrosion resistance is also reduced. P: Below 0.035%

P is an element contained as an impurity in alloys such as melt milling of raw materials and ferrochrome. Since it is an element harmful to the toughness of the steel sheet after hot rolling and annealing, its content is set to 0.035% or less. When it is added excessively, hot workability and corrosion resistance will decrease. S: 0.015% or less

S has a low solid solubility for the austenitic iron phase, and it will segregate at the grain boundary and cause the hot workability to decrease. Therefore, the content is set to 0.015% or less. In addition, when excessively added, MnS is formed in a large amount and corrosion resistance is also reduced. Cr: 11.0~15.0%

Cr must be at least 11.0% or more in order to maintain the corrosion resistance of Western tableware knives. On the other hand, since it also has the effect of narrowing the stable temperature of austenitic iron, it is set to 15.0% or less. It should be more than 12.0%. The upper limit is preferably 14.0% or less. The range should be set to 12.0~14.0%. Ni: 0.05~0.60%

Ni, like Mn, is a stable element of austenitic iron, which is necessary to ensure the hardness during quenching and the amount of scattered iron. In addition, it also has the effect of improving corrosion resistance. Therefore, it contains 0.05% or more. However, Ni is set to 0.60% or less due to its higher price than other elements. Cu: 0.010~0.50%

Cu, like Mn and Ni, is a stable element for austenitic iron, and it is also an element that improves corrosion resistance. Although it is also an element that is unavoidably mixed from scrap during steelmaking, it contains more than 0.010% in order to improve corrosion resistance. On the other hand, excessive content is made to be 0.50% or less because the hot workability and the like will decrease. Although it is cheaper than Ni, it is still relatively expensive, so it is to minimize the added elements. V: 0.010~0.10%

V is an element that is unavoidably mixed in most of alloy elements, such as ferrochrome. It is difficult to reduce the amount, but it contains more than 0.010%. However, excessive content will narrow the austenitic iron formation temperature range, so it is set to 0.10% or less. In addition, when excessively added, VN is formed and N is fixed, resulting in a decrease in hardness and corrosion resistance, which is not suitable. Al: 0.05% or less

Although Al is a very effective element for deoxidation, excessive content will generate CaS which is a soluble inclusion during hot rolling and reduce the corrosion resistance, so its content is set to 0.05% or less. May not contain Al. N: 0.060~0.090%

Both N and C are elements that determine the quenching hardness, and at the same time, it also improves the corrosion resistance and is an important element in the present invention. Therefore, in the present invention, the content is 0.060% or more. It should be above 0.065%. However, when N is contained excessively, bubble defects are likely to occur in the steel billet, and the manufacturing cost is increased in the secondary refining with VOD or the like, so its content is set to 0.090% or less. It should be less than 0.085%. C+1/2N: 0.130~0.190%

The elements that determine the hardness of the Asada scattered iron phase in steel are C and N, and their total contributes to the hardness. According to the review of the inventor of this case, N's contribution to hardness is half of C. In order to obtain the necessary hardness for Western tableware knives, C+1/2N must be more than 0.130%. It should be more than 0.150%. On the other hand, when C+1/2N is excessive, the quenching hardness becomes too high and the toughness of the product or the intermediate material (cast slab, etc.) in the production process is impaired, so it is set to 0.190% or less. It is preferably 0.180% or less, and can also be set to 0.175% or less.

In addition, in order to stably exhibit hardness at the time of quenching, it is necessary to adjust each other so that γp described in the above formula (1) becomes 120 or more. When γp is less than 120, unevenness in hardness increases with quenching conditions. In addition, δFe in steel also increases. In the present invention, γp may be adjusted to 130 or more, or 140 or more. In the present invention, it may be 170 or less, or may be 150 or less.

The steel plate and steel member of the present invention have the following steel composition: the remainder is composed of Fe and impurities. In addition, in the present invention, in addition to the elements described above, in order to improve rust resistance and corrosion resistance, elements of Mo, Nb, Ti, Sn, and Bi may be added to replace part of the aforementioned Fe. Mo: 0.01~1.0%

Mo is an element that improves corrosion resistance. Adding more than 0.01% will show this effect. However, Mo is also a high-priced element, even if it is added excessively, the effect is not obvious, so 1.0% is set as the upper limit. Ti: 0.005~0.050%

Ti is an element that forms carbonitrides and inhibits sensitization and corrosion resistance degradation caused by the precipitation of chromium carbonitrides in stainless steel. This effect will be displayed above 0.005%. However, when excessively added, the Asada scattered iron phase becomes unstable and the hardness decreases, so 0.050% is set as the upper limit. Nb: 0.005~0.050%

Nb is an element that forms carbonitrides and inhibits the sensitization and corrosion resistance degradation caused by the precipitation of chromium carbonitrides in stainless steel. This effect will be displayed above 0.005%. However, when excessively added, the Asada scattered iron phase becomes unstable and the hardness decreases, so 0.050% is set as the upper limit. Sn: 0.01%~0.10%

Sn is a very effective element for improving the corrosion resistance after quenching, and it should be 0.01% or more, and if necessary, it should be 0.05% or more. However, excessive addition may promote edge cracks during hot rolling, so it is preferably set to 0.10% or less. Bi: 0.01%~0.20%

Bi is an element that improves corrosion resistance. The mechanism is not yet clear, but it is believed that the addition of Bi makes MnS, which is likely to be the starting point of rust, to become finer, and therefore, the effect is that the probability of MnS becoming the starting point of rust is reduced. It will be effective by adding more than 0.01%. Even if the addition is greater than 0.20%, the effect is only saturated, so the upper limit is set to 0.20%. ＜Delta Fertilizer Iron Ratio of Steel Plates and Steel Components＞

The inventors of the present case discovered that the ferrous iron (δFe) present in the center of the thickness of the steel plate greatly affects the corrosion resistance of the steel plate end surface. It is also believed that when the steel plate is quenched by air cooling with a slow cooling rate, the grain boundary between δFe and the parent phase (γ phase) will become the precipitation point of Cr carbide during cooling, and cause sensitization near the precipitated Cr carbide. The corrosion resistance of the end surface is reduced. In addition, for the reason that N improves the corrosion resistance of the end surface, it is presumed that it also has the effect of suppressing the precipitation of Cr carbides.

Therefore, while containing N in the present invention, δFe in steel can be effectively suppressed.

Although it is sufficient that the δFe present in the steel sheet before quenching can be measured, it is difficult to measure the surrounding area because of the ferrous iron phase. Instead, the δFe present in the quenched and tempered steel sheet is surrounded by the Asada scattered iron phase, so it is easier to measure. Therefore, in the steel sheet of the present invention, the δFe content is evaluated after quenching and tempering. . The quenching conditions used in the evaluation were heated to 1050°C and held for 30 minutes, and then set to air cooling conditions, while the tempering conditions were set to 150°C for 30 minutes. When the quenching temperature is too low and the time is too short, the ferrous iron phase will remain and cannot be distinguished from the δFe phase, so it is not suitable; when the quenching temperature is too high and the time is too long, the δFe phase will change and be different from the initial state, so Not suitable. The quenching method is set to air cooling. After the steel plate is quenched and tempered under the above evaluation conditions, it is evaluated by the area ratio in the thickness section of the steel plate. If δFe is 1% or less, good end surface corrosion resistance can be obtained. Although it is less than 0.1%, it will show excellent corrosion resistance regardless of whether it is according to the present invention, but in order to reduce δFe, a long heat treatment is required, and the cost will increase, which is not suitable. In addition, if it exceeds 1%, the corrosion resistance will not be sufficiently improved even according to the present invention, and the hardness will be insufficient, which is not suitable. In addition, a suitable upper limit is 0.5%. The range should be 0.1%~0.5%. ＜Manufacturing method of steel plate＞

The manufacturing method of the steel plate of the present invention uses a normal method. The steel billet with adjusted composition is obtained by melting and casting, hot-rolled and then box-annealed, shot and pickled to produce a product.

However, in order to control δFe, the steel billet is preheated. The heating conditions at this time should preferably set the heating at 1100~1150°C to a soaking time of 1 hour or more and 50 hours or less. When the heating temperature is greater than 1150°C, the two-phase (γ+δ) will become stable and the amount of δFe will increase rapidly, which is not suitable. In addition, the sharply increased δFe will remain in a large amount in the subsequent steps, and consequently the hardness will decrease. On the other hand, if it is less than 1100°C, δFe will not decrease even if it is heated for a long time, which is not suitable. Since the amount of δFe is less than when it is greater than 1150°C, the hardness can sometimes be maintained depending on the subsequent steps. In addition, if it is less than 1 hour, δFe becomes too much and unsuitable, and if it exceeds 50 hours, the cost becomes high and unsuitable.

This preheating is performed as the heating of the steel billet before hot rolling, and it can also be directly used for hot rolling. ＜Manufacturing method of steel member＞

In the present invention, punching, quenching, and tempering are performed on the obtained steel sheet, and the steel sheet is polished to form a member. After punching, forging is performed and the shape is adjusted. In addition, the quenching and tempering bars are preferably as follows. The quenching temperature should be 1000~1150℃. If it is less than 1000℃, the austenitic iron phase will decrease at high temperature and the hardness will be lower after quenching, so it is not suitable; if it is greater than 1150℃, the δ phase and stable austenitic iron phase will increase, and the hardness will also be at this time. Will decline, so it is not suitable. In addition, the holding time during quenching is preferably 1 minute to 1 hour. If it is less than 1 minute, the austenitic iron phase will decrease at high temperature and the hardness will be lower after quenching, so it is not suitable; if it is longer than 1 hour, the stable austenitic iron phase will increase, and the hardness will also decrease at this time. Therefore, it is not suitable. As for the cooling rate during quenching, the average cooling rate from the quenching temperature to 600°C should be 1°C/sec or more. If it is smaller than this, the hardness will decrease, which is not suitable. The quenching is air-cooled, so that the aforementioned suitable cooling rate can be achieved. The tempering should be 100℃~250℃. When the temperature is less than 100°C, the tempering effect is not good, and when the temperature is greater than 250°C, the hardness drops too much and is unsuitable. Example

Hereinafter, although examples are used to illustrate the effects of the present invention, the present invention is not limited to the conditions used in the following examples.

In this embodiment, first, the steels with the composition shown in Table 1 and Table 2 are smelted and cast into a steel blank with a thickness of 250 mm. Secondly, preheat these steel blanks and perform heat treatment at 1150°C for 40 hours, and set the amount of δFe within a certain range. However, for A2 steel, it is preheated at 1175°C for 40 hours and 950°C for 40 hours to make A2' steel and A2" steel respectively.

[表2]

＜實施例1＞ After that, it is heated to 1150°C and hot-rolled to form a hot-rolled steel sheet with a thickness of 3-8mm. Next, annealing of the hot-rolled steel sheet is performed by box annealing. The maximum heating temperature is set to a temperature range above 800°C and below 900°C. Shot blasting is used to remove scale on the surface of the annealed steel sheet and pickled. [Table 1]

[Table 2]

<Example 1>

In order to evaluate the steel plate produced, a sample for evaluation was cut out from the steel plate, and the sample was heated to 1050°C and kept for 30 minutes as a quenching and tempering treatment, then air-cooled and tempered at 150°C for 30 minutes . After that, the amount of δFe and the hardness were measured, and each evaluation of the end surface corrosion resistance was performed. The results obtained are shown in Table 3. [table 3]

The amount of δFe is measured after polishing the end surface of the sample to a mirror surface and etching it to reveal the structure. Although the etching solution can also display δFe with aqua regia, etc., if you use the reagent described in Document 4 (Journal of the Japanese Society of Metals, 1962, Vol. 26, No. 7, pages 472-478), it is called a modified Murakami reagent. , Then δFe will be etched into a darker brown color, which is suitable for evaluation. A representative example is shown in Figure 1.

The tissue revealed by the modified Murakami reagent was observed through a microscope, and a photograph of δFe was taken from a total thickness of a certain width (2mm in this example), and the δFe area was calculated from the image analysis, and then calculated from this Area ratio (δFe area (mm ² )/2mm×total thickness (mm)×100(%)). If the steel component of the composition of the present invention is to exhibit excellent corrosion resistance, this value must be 0.1 to 1%. More preferably, it is 0.1%~0.5%. δFe area ratio: 0.1~1% is regarded as qualified (A), and above this is regarded as unqualified (X).

The hardness is the surface hardness (quenching hardness) evaluated by the Rockwell hardness tester C scale (scale C) according to JIS Z 2245 after the surface of the sample is ground with #80, and 50 or more is regarded as a pass (A). Otherwise, it is regarded as unqualified (X).

The corrosion resistance of the end surface is evaluated by grinding the sample surface and end surface with #600, then swinging the end face up as the evaluation surface, and performing the salt spray test for 24 hours (JIS Z 2371 "Salt spray test method"), and then calculate the rust. point. 2 points or less is regarded as qualified (A), and those greater than this are regarded as unqualified (X). In particular, the one with zero rust point is regarded as pass (S). In addition, even if the salt spray test is carried out for more than 24 hours, rust of this degree will rarely continue to occur, so the 24-hour result is used to judge the corrosion resistance of the end surface.

Each steel plate of the present invention is not only excellent in end surface corrosion resistance, but also excellent in other characteristics, and is suitable as a steel plate for Western tableware cutlery. In contrast, among the comparative steels, it is obvious that either the end face corrosion resistance is poor or other properties are poor, and it is not suitable as a steel plate for Western tableware cutlery. <Example 2>

A member was cut out from the produced steel plate, and the member was quenched and tempered under the conditions shown in Table 4 to form a steel member. Quenching is performed by heating at 1050~1150°C. After that, the cooling rate from the quenching temperature to 600°C is controlled to the cooling rate described in Table 4 for cooling. Furthermore, the tempering treatment is carried out at 150~250℃ for 1~2h to make steel components. In addition, A2' steel and A2" steel are also treated in the same way.

The δFe content measurement, hardness measurement, end surface corrosion resistance evaluation, and heat treatment conditions of the obtained steel components are listed in Table 4. In addition, the evaluation method and evaluation criteria are the same as in Example 1. [Table 4]

Each steel member of the present invention is not only excellent in end surface corrosion resistance, but also excellent in other characteristics, and is suitable as a steel member for Western tableware cutlery. On the other hand, in the comparative steel, it is obvious that either the end surface corrosion resistance is poor or other properties are poor, and it is not suitable as a steel member for Western tableware cutlery.

Figure 1 shows a representative example of the cross-sectional structure of the steel plate of the present invention after etching with modified Murakami reagent.

(without)

Claims (4)

A kind of Matian scattered iron series stainless steel plate, which is characterized in that it has the following steel composition: Calculated by mass%, C: 0.100~0.170%, Si: 0.25~0.60%, Mn: 0.10~0.60%, P: 0.035% or less, S: 0.015% or less, Cr: 11.0~15.0%, Ni: 0.05~0.60%, Cu: 0.010~0.50%, V: 0.010~0.10%, Al: 0.05% or less, N: 0.060~0.090%, C+1/2N: 0.130~0.190%, The remainder is composed of Fe and impurities, Γp represented by the following formula (1) is 120 or more; where, After holding the aforementioned Asada scattered iron stainless steel plate at 1050°C for 30 minutes, it is air-cooled and quenched, and then tempered at 150°C for 30 minutes. At this time, the δ Fe grain iron (δFe) present in the center of the plate thickness is The area ratio in the plate thickness profile will be 0.1~1%; γp=420C+470N+30Ni+7Mn+9Cu-11.5Cr-11.5Si-12Mo-23V-47Nb-52Al+189...Equation (1) The element symbol in the formula (1) means the content (mass %) of the element. For example, the Matian scattered iron-based stainless steel plate of claim 1, which further contains one or more of the following in terms of mass% to replace part of the aforementioned Fe: Mo: 0.01~1.0%, Ti: 0.005~0.050%, Nb: 0.005~0.050%. For example, the Matian bulk iron stainless steel plate of claim 1 or claim 2, which further contains one or two of the following in terms of mass% to replace part of the aforementioned Fe: Sn: 0.01~0.10%, Bi: 0.01~0.20%. A kind of Matian loose iron series stainless steel component, characterized by having the steel composition as described in any one of claim 1 to claim 3, wherein: Let γp shown in the following formula (1) be 120 or more; In addition, the area ratio of δ Fe grained iron (δFe) existing in the center of the plate thickness in the plate thickness section is 0.1~1%; γp=420C+470N+30Ni+7Mn+9Cu-11.5Cr-11.5Si-12Mo-23V-47Nb-52Al+189...Equation (1) The element symbol in the formula (1) means the content (mass %) of the element.

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