JPH09137265A - Nonferrous metal molten metal member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a member having excellent erosion resistance to nonferrous molten metal by forming a moisture-contg. oxidized film or a moisture-contg. nitrided film on the surface of an Fe base material. SOLUTION: For example, at the time of heating the stock of an Fe base material at 400 to 1200 deg.C in an oxidizing atmosphere in which steam is present, a dense oxidized film hard to peel is formed on the surface. The formed oxidized film is extremely excellent in erosion resistance to nonferrous molten metal, particularly, to aluminum and zinc molten metal, and is most excellent in the resistance to aluminum molten metal above all. Other than the Fe base material, an Fe-Cr base alloy may be used. The content of Cr in the alloy is regulated to 5 to 40wt.%. The stock is composed of the Fe-(Al or Si) base allay and is subjected to oxidizing treatment, nitriding treatment or oxygen nitriding treatment. Thus, it makes a large contribution toward the field of nonferrous metal casting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-ferrous metal melt, and more particularly, to a non-ferrous metal melt hardly damaged by a non-ferrous metal melt such as aluminum, zinc, and copper.

[0002]

2. Description of the Related Art Conventionally, ceramics or nitrided steel materials are generally used for non-ferrous metal melt members, that is, members that are immersed in the melt, such as thermocouple protection tubes, and members that contact the melt, such as molds. Ceramics are often used for immersion members, and nitrided steel is often used for contact members. A disadvantage of these materials is that ceramics are expensive and are easily broken, and nitrided steels are liable to be damaged by molten metal.

[0003]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to use a steel material as a raw material and notably for molten metals such as aluminum, zinc and copper. A novel molten metal member having excellent melting resistance is provided.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have obtained the following findings. That is, 1. When the member is made of a Fe-based material and a wet oxide film or wet oxynitride film is formed on the surface, aluminum, zinc,
Demonstrate outstanding erosion resistance against molten metal such as copper. 2. Among Fe-based materials, Fe-Cr based alloys are particularly preferable. 3. The Cr content of the above alloy is preferably in the range of 5 to 40 wt%. And 4. Melt resistance is particularly effective against molten aluminum. Also, 5. When a member is formed of an Fe- (AL, Si) -based alloy and subjected to an oxidation treatment, a nitriding treatment, or an oxynitriding treatment, it exhibits remarkable erosion resistance against molten metals such as aluminum, zinc, and copper. Furthermore, 6. Fe- (AL, Si) -Cr based alloys are more preferable. 7. The Cr content of the above alloy is preferably in the range of 5 to 40 wt%. The above findings were obtained. The present invention has been made based on the above findings.

[0005]

In the present invention, the wet oxide film means an oxide film that has been oxidized in an atmosphere containing moisture, that is, water vapor. An atmosphere containing water vapor is an atmosphere in which water vapor is added to the atmosphere,
And an atmosphere in which water vapor is generated by a reaction in the atmosphere, for example, hydrogen contained in the atmosphere is burned to generate water. The combustion atmosphere of oil and natural gas corresponds to this.

When the Fe-based material is heated to a temperature of 400 to 1200 ° C. in an oxidizing atmosphere in the presence of water vapor, a dense oxide film which is difficult to peel off is formed on the surface. The formed oxide film has extremely excellent erosion resistance against non-ferrous metal melt, and is most excellent against aluminum, zinc melt, especially aluminum melt.

The heating atmosphere is not necessarily limited to the atmosphere, and even in a nitriding atmosphere in which ammonia, nitrogen, etc. exist, or a so-called reducing gas atmosphere such as hydrogen, carbon monoxide, etc., steam is allowed to coexist in these atmospheres. As a result, a weakly oxidizing atmosphere is formed and an oxide film or an oxynitride film is formed.

The composition of the oxide film is such that an MO-based oxide film typified by FeO is formed in contact with the member,
Furthermore, M ₃ O ₄ system represented by Fe ₃ O ₄ or M ₂ O ₃ represented by Fe ₂ O ₃ is further formed thereon.
A system oxide film may be formed. This MO-based oxide film is a film that has excellent peeling resistance and crack resistance with respect to the member.

The material of the molten metal member of the present invention can be used in a wide range of Fe-based materials in general, that is, ordinary ordinary carbon steel, ordinary cast iron to alloy steel, and alloy cast iron. When the film and the moist oxynitride film are formed, the erosion resistance of the effect of the present invention is exhibited. In particular, a material containing Cr, Si, AL as an alloy element has a remarkable effect.
Cr, Si, AL are films (oxide film or oxynitride film)
The effect of improving the compactness, adhesiveness, and crack resistance is remarkable. Cr is preferably in the range of 5 to 40 wt%. When Cr is added at 5% or more, the improvement effect becomes remarkable, while 40%
Even if it exceeds, the effect itself does not change, and further addition is uneconomical.

When Si and AL are added alone, the improving effect becomes remarkable from 4% or more, and when Si and AL are added at the same time, the improving effect becomes remarkable from 4% or more in total. Cr5
When added in an amount of -40 wt%, Si and AL are effective when added in an amount of 1% or more. Therefore, Fe-Cr- (Si, AL)
Is the best combination. When Si and AL are added, the oxidation treatment does not have to be steam oxidation and may be performed in normal air. The heating temperature is effective when it is 400 ° C. or higher, but most preferably 700 to 1250 ° C.

The matrix structure of the material may be any structure of austenite, ferrite, martensite, and a mixed structure thereof. It may be appropriately selected according to the intended use. The base structure can be adjusted metallurgically by adjusting the heat treatment conditions or by adding an alloying element, but in the present invention, the base structure can be freely adjusted by using a usual metallurgical technique. You can adjust it. All metallurgical techniques commonly employed for these purposes are applicable. Regarding the addition of alloying elements other than Cr, Si, and AL, there is no problem in adding the amount in the range that those skilled in the art normally add for the purpose of material science. It is well known that the addition of a rare earth element such as Y is extremely effective in improving the adhesion of the oxide film, but the addition of a rare earth element such as Y is also effective in the present invention.
It may be added in the range of approximately 0.1 to 2%.

Most preferably, the thickness of the oxide film is in the range of 10 to 500 microns. When the thickness exceeds the upper limit, one coating film is likely to peel off. If it is less than the lower limit, the erosion resistance effect on the molten metal is small.

The molten metal member of the present invention is a generic term for a member that is directly immersed in the molten metal, and a member that is not directly immersed in the molten metal but is in contact with the surface of the molten metal. Typical examples of the former are a thermocouple protector, a heater tube, and a strainer, and the latter are a die cast cylinder, a piston head, a die cast mold, a melt transfer officer, a melt pump, and a lining of a melt kiln.

[0014]

【Example】

Example 1 The following steel types were examined for erosion resistance to molten aluminum. Sample shape φ20 × 200mm round bar Oxidation condition 9 Excluding some (No. 4, 5, 8, 9, 10)
After steam oxidation at 00 ° C. for 1 hour, the furnace was cooled. Note that N
o. Nos. 4 and 5 were steam-oxidized at 1000 ° C. for 1 hour, allowed to cool in the atmosphere, tempered at 750 ° C. Nos. 8, 9, and 10 were oxidized in the atmosphere at 1100 ° C. for 1 hour and then cooled in a furnace. Conditions of Melting Resistance Test A sample was immersed in a molten aluminum held at 750 ° C. for 10 hours to examine the melting condition of the sample. The component composition of the sample is shown in the table below. A comparison was made between the oxidization-treated product of the present invention, the oxidization-treated product in normal air, and the non-oxidized product. The results are shown in the table below. The temperature conditions of the atmospheric oxidation treatment were the same as those of the treatment of the present invention. The numerical values in the table are the wall thickness reduction values. From the above results, it was found that the oxide film of the present invention has a remarkable anti-melting effect. Further, when AL and Si were present, a remarkable erosion resistance effect was recognized even in the oxidation in the atmosphere.

Example 2 (Test of Cr Content and Crack Resistance, Peeling Resistance) Changes in crack resistance and peeling resistance were investigated by changing the Cr content. Cr content is 0, 5, 10, 20, 30, 40, 5
Two types were prepared, one with 0% Y and the other without 0.1%. Other elements are unchanged. Crack resistance and peel resistance 750 ° C
The operation of taking out what was dipped in the heated aluminum melt in the atmosphere and forcibly cooling it by air was repeated, and the number of times until cracking or peeling occurred was evaluated. The presence or absence of cracks was inspected with a penetrant called "color check". The results are shown in FIG. From the results of FIG. 1, it was found that the addition of 5% or more of Cr had a remarkable effect on crack resistance and peeling resistance. It was also found that the addition of Y further improves the crack resistance and peeling resistance.

Example 3 The same steel type as in Example 1 was examined for erosion resistance to molten zinc. Sample shape φ20 × 200mm round bar Oxidation condition 1 Excluding some (No.4, 5, 8, 9.10)
After oxynitriding with a mixed gas of NH _{3 and} steam for 1 hour at 000 ° C., the furnace was cooled. No. Samples 4 and 5 were oxynitrided with NH ₃ + steam mixed gas at 1050 ° C. for 1 hour, then left to cool in the air and tempered at 650 ° C. No. 8, 9, and 10 were heated in the atmosphere at 900 ° C. for 1 hour and cooled in the furnace. Conditions of Melt Resistance Resistance Test Samples were immersed in a molten zinc held at 650 ° C. for 20 hours and examined for melting condition. <Results> Oxidation treatment of the present invention, oxidation treatment in normal atmosphere, and oxidation A comparison was made for those not treated. The results are shown in the table below. The temperature conditions of the atmospheric oxidation treatment were the same as those of the treatment of the present invention. The numerical values in the table are the wall thickness reduction values. From the above results, it was found that the oxide film of the present invention has a remarkable erosion resistance effect on the molten zinc. Also, AL, Si
It was found that even with oxidation in the atmosphere, there was a remarkable erosion resistance effect on the molten zinc.

Example 4 No. 4 of Example 1 was examined for erosion resistance to molten brass. Sample shape φ20 × 200mm round bar Oxidation condition: Steam oxidation at 1000 ℃ for 1 hour, cooling in air, 750 ℃
Tempered. Conditions of Melting Resistance Test A sample was immersed in a molten aluminum held at 1100 ° C. for 2 hours to examine the melting state of the sample. For comparison, it was compared with one without oxidation treatment. <Results> Oxidation treated product of the present invention: No melting loss No treatment: Melted and disappeared.

[0018]

As described in detail above, the present invention has excellent erosion resistance against molten metal of non-ferrous metal (aluminum, zinc, brass) and makes a great contribution to the field of non-ferrous metal casting. It is a thing.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the Cr content (%), crack resistance, and peel resistance of the member of the present invention.

Claims (9)

[Claims] 1. A non-ferrous metal melt member characterized in that the material is an Fe-based material, and a wet oxide film or wet oxynitride film is formed on the surface. 2. A non-ferrous metal melt member, characterized in that the material is made of an Fe—Cr alloy, and a wet oxide film or wet oxynitride film is formed on the surface. 3. The molten metal member according to claim 2, wherein the alloy contains Cr in an amount of 5 to 40 wt%. 4. A non-ferrous metal melt member, characterized in that the material is an Fe— (AL, Si) -based alloy and is subjected to an oxidation treatment, a nitriding treatment, or an oxynitriding treatment. 5. A non-ferrous metal melt member characterized in that the material is an Fe— (AL, Si) —Cr alloy and is subjected to an oxidation treatment, a nitriding treatment, or an oxynitriding treatment. 6. The molten metal member according to claim 5, wherein the Cr content of the alloy is 5 to 40 wt%. 7. The molten metal member according to claim 1, wherein the molten metal is an aluminum melt. 8. The molten metal according to claim 1, which is a molten zinc.
The molten metal member according to any one of to 6. 9. The molten metal according to claim 1, which is a molten copper.
6. The molten metal member according to any one of 6.