JPH01279701A - Production of forged member - Google Patents

Abstract

PURPOSE:To manufacture a forged member having excellent strength and wear resistance by mixing at least one kind of Ni, Cu and Fe powder with Al alloy powder and executing heat treatment after forge-forming into the desired shape. CONSTITUTION:The super fine particle-state of Ni having 200Angstrom average particle size is mixed with the Al alloy powder manufactured by rapid cooled solidifying method at 3-6wt.% and this mixed material is pre-formed by vacuum hot press method. Successively, the pre-formed material is heated and after hot- extruding, machining work is executed to form a raw material for forging, and successively, it is forged at 450Angstrom . Solution treatment is executed to the forged product and after improving the hardness by developing an intermetallic compound between Al and Ni, the finishing machining is applied, to manufacture the forged product having the prescribed shape and excellent strength and wear resistance. In this case, further, Cu and Fe powders besides Ni may be mixed as complexing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of manufacturing a forged member, in which various forged members such as an engine valve upper seat are forged using Al as a main material.

[Conventional technology]

Conventionally, as shown in FIG. 3, a valve upper seat 4, which is attached to an intake or exhaust valve 1 in an engine via a split collet 2 and supports the upper end of a valve spring 3, is usually made of steel. However, this valve upper seat 4 made of steel has a large inertial mass, resulting in poor responsiveness and a problem in that the maximum rotational speed of the engine is also limited. Therefore, in order to reduce the weight, it is considered that the valve upper seat 4 is made of an Al alloy.

By the way, conventionally, when manufacturing various Al alloy members such as the above-mentioned valve upper seat 4, a Ni porous body is
A method of casting with L alloy is known, but this method has the disadvantage that the compound is too large and sufficient strength cannot be obtained. Furthermore, when using the so-called powder metallurgy method, in which Al alloy powder is molded into a desired shape and then sintered, microporosity, or tiny cavities, occur within the product, resulting in poor strength. There was a problem.

Therefore, a method for manufacturing a Ni-Al alloy member has been proposed in which an Al alloy containing 0.5 to 4.0% by weight of Ni is formed as is or by forging after preforming (especially (Refer to JP-A-62-44540).

[Problem to be solved by the invention]

However, when the above manufacturing method is adopted, although the product has excellent strength and wear resistance, the Ni-Al alloy has extremely poor elongation, so there is a problem that forging formability is poor. Therefore, cracks easily occur in the cold, making forging practically difficult, so in the above manufacturing method, forming such as forging is performed hot at a temperature of 500° C. or lower.

[Means to solve the problem]

The method for manufacturing a forged member according to the present invention solves the above problems and ensures good forging formability.
I! After mixing the alloy powder with at least one of Ni powder, Fe powder, or Cu powder, it is forged into a desired shape, and then heat-treated to reduce Al and N l %.
This is characterized in that an intermetallic compound is formed between Fe and Cu.

[Function] According to the above configuration, at the stage of forging, the rapid solidification A
7! Since the alloy powder is only mixed with Ni powder, Fe powder, or Cu powder, and Ni, Fe, or Cu does not form an alloy with 8L, a mixture of these powders, for example, Even in the cold, it can be forged into a desired shape relatively easily.

Further, since an intermetallic compound is generated between Aff and Ni, Fe, or Cu after forging, the completed forged member has excellent strength and wear resistance.

〔Example〕

An embodiment of the present invention will be described below based on FIGS. 1 and 2.

Here, we will describe the manufacturing procedure for manufacturing a forged member such as an engine valve upper seat using rapidly solidified alloy powder and ultrafine Ni powder as raw materials.

First, ultrafine Ni powder is produced by heating and evaporating Ni in an atmosphere of an inert gas such as He or Ar whose pressure is regulated to several to several hundred Torr, and depositing it on the cooling surface of a water-cooled device, etc. .

The ultrafine Ni powder produced by the above method is black in color and has a face-centered cubic lattice (FCC) crystal structure.
It has a particle size distribution as shown in the figure. If the average particle size of this ultra-fine Ni powder is 200, the apparent density is 0.4 g/
cm3, and the specific surface area is 69.4 m2/g. Furthermore, if the average particle size of the ultrafine Ni powder is 500, the apparent density is 0.1 g/cm3, and the specific surface area is 18.9 m3.
2/g. In addition, when producing a forged member, ultrafine Ni powder having an average particle diameter of about 200 to several 100 particles is usually used. In other words, if the average particle size of the Ni powder becomes too large, the rate at which Al penetrates between the Ni particles and combines with Ni becomes too large during the heat treatment described below, and as a result, it becomes powdered and mixed with the Ni powder. It is preferable that the average particle diameter of the Ni powder is approximately several hundred particles or less, since this may cause the Al master alloy raw material to become brittle.

On the other hand, rapidly solidified A7! The alloy powder is obtained by melting the Al master alloy raw material, and then forming the powder of the Al master alloy raw material by a gas atomization method using Ar gas at 104°C/s.
It is manufactured by cooling at a rate of about EC. In this case, usually about 70% of the produced rapidly solidified Al alloy powder has a particle size of 0 to 50 μm, and the remaining about 30% has a particle size of 50 μm or more.

Examples of the above-mentioned Al master alloy raw materials include A (1-Cu-Mg alloy whose composition is shown in Table 1), A1-Si-Cu-Mg alloy whose composition is not shown in Table 2, etc. In addition, in the column of Ni in Tables 1 and 2, the weight of the ultrafine Ni powder added to the rapidly solidified Al alloy powder produced from the above-mentioned Al master alloy raw material with respect to the entire mixed powder can be used. The ratio is shown, and Ni is not included as an alloying component in the above A4 master alloy raw material.Also, the values shown in the columns of Si, Cu... in Tables 1 and 2 are the same as above. The weight ratio of each component to the entire mixed powder is shown.

Table 1 (unit: % by weight) Table 2 Next, the manufacturing procedure of a forged member using rapidly solidified Al alloy powder and ultrafine Ni powder will be described.

As shown in FIG. 1, first, the rapidly solidified Al alloy powder described above and ultrafine Ni powder with an average particle size of 200 mm are mixed (S2), and then the mixed powder is preformed (S2).
). This preforming is performed, for example, by a vacuum hot press method at a temperature of about 350° C. and a pressure of about 1 to 2 tons and 7 cm” for about one hour.

Next, the preform was heated to a temperature of about 350°C and 1:
After performing hot extrusion S3) at an extrusion ratio of about 15,
By performing machining (S4), a forging material is formed (S5), and subsequently, forging is performed on the forging material (S5).
6). If the forging temperature is set to 450° C. or higher, a compound may be formed between Al and Ni, resulting in poor forging formability, so the forging temperature is set lower than 450° C.

Subsequently, by applying heat treatment (solution treatment) to the forged product, Aj? , :! : Generate an intermetallic compound with Ni (S7). In this case, (i) 450 to 55
When heat treated at 0°C for 1 to 4 hours, A7! The compound formed between Ni and Ni is mostly NiAl, with trace amounts of Ni and Aj! is generated. The hardness of the forged product heat-treated under the above conditions is 400 on the Vickers scale.

Also, (ii) when heat treatment is performed at a temperature of 550°C or higher for 1 to 4 hours, AI! The compound produced between Ni and Ni is Niz Al 3, and in this case, the hardness of the forged product is 850 on the Pinkers hardness.

When the heat treatment is completed, the forged product is then subjected to final machining (S8), and a predetermined forged member is completed (S9).
. In addition, after the above heat treatment, aging treatment (
Tempering) may also be performed.

In the above-described method for producing a forged member, since AI and Ni do not form an alloy or a compound at the forging stage, good forging formability can be obtained, thereby ensuring that the desired shape is obtained. It becomes possible to manufacture forged parts. Furthermore, by generating an intermetallic compound between AN and Ni after forging, it is possible to impart sufficient strength and wear resistance to the completed forged member.

The present inventor conducted a test to compare the forging formability between the method of the present invention and the conventional method. According to the test results, the first
After preforming a mixed powder of rapidly solidified A/alloy powder produced from Al master alloy raw material having the composition shown in the table and ultrafine Ni powder into a cylindrical shape, free forging was performed at room temperature using the method of the present invention. The upsetting rate, that is, the maximum increase in cross-sectional area without cracking when compressed in the axial direction, is 60%, while the Al master alloy raw material with the composition shown in Table 1 has the same Aj containing Ni as an alloy component in advance in the proportion shown in the table! When a cylindrical body made of -Cu-Mg-Ni alloy was subjected to free forging at room temperature, the upsetting rate was 40%.

Similarly, after preforming a mixed powder of rapidly solidified Al alloy powder and ultrafine Ni powder produced from AJ master alloy raw materials having the composition shown in Table 2 into a cylindrical shape, free forging was performed at room temperature using the method of the present invention. The upsetting rate is 55% in the case of A#51-, which contains Ni as an alloy component in advance in the Al master alloy raw material having the composition shown in Table 2 in the proportion shown in the same table.
When a cylindrical body made of a CuMg Ni alloy was subjected to free forging at room temperature, the upsetting rate was 30%.

The above results demonstrate that the method of the present invention significantly improves forging formability.

The inventor also conducted wear tests on pins forged by the method of the present invention and by the conventional method. That is, as shown in Table 3 on the next page, the pin made by the method of the present invention is made by adding 2 ultra-fine Ni powder to rapidly solidified Al alloy powder produced from an Al master alloy raw material containing predetermined amounts of Cu, Mg, and Si. It is forged and formed by the method of the present invention based on a mixed powder obtained by mixing .0% by weight. On the other hand, pins made using the conventional method are made using the rapid solidification AI! It is forged and formed without mixing ultrafine Ni powder with alloy powder. In this case N
i is not contained in the Al master alloy raw material either.

Table 3 Table 4 Then, while rotating the disk formed from A390 alloy whose composition is shown in Table 4 and subjected to T6 treatment, the bottles according to the above-mentioned method of the present invention and the conventional method were attached to the disk. The limit surface pressure at which no seizure occurred was measured. According to this, the limit surface pressure at which seizure does not occur is 100 kg/cm2 for bottles made using the conventional method, while it is 145 kg/cm2 for bottles made using the method of the present invention. was confirmed to have improved. In the above wear test, the sliding speed of the bottle with respect to the disk was 8 m/s, the lubricating oil used was l0W-30 4-cycle gasoline engine oil, and the temperature of the lubricating oil was 100°C.

In the above example, Ni was added to the rapidly solidified AA alloy powder.
A mixture of powders and preforming was used as the forging material, but instead of that, rapidly solidified AI! Mixing Fe powder (hardness: Hv 50) or Cu powder (hardness: Hv 80) with alloy powder, or adding N to rapidly solidified Al alloy powder
A mixture of two or more of I powder, Fe powder, or Cu powder and preforming may be used as the forging material. When Fe powder is used, Hv LOOO is reduced by heat treatment. -Fe and A with hardness of 1200
On the other hand, when Cu powder is used, an intermetallic compound of Cu and Al having a hardness of Hv570 to 730 can be obtained by heat treatment. Similarly, strength and wear resistance can be improved. “[Effects of the Invention] As described above, in the method for manufacturing a forged member according to the present invention, after mixing at least one of Ni powder, Fe powder, or Cu powder into the rapidly solidified/1 alloy powder, the desired AN and Ni are formed by forging into a shape, followed by heat treatment.
This structure is designed to generate an intermetallic compound with Fe or Cu.

As a result, at the stage of forging, only Ni powder, Fe powder, or Cu powder is mixed with rapidly solidified Al alloy powder, and Ni, Fe, or Cu does not form an alloy or compound with Al. Therefore, it is possible to obtain good forging formability.

Further, since an intermetallic compound is generated between Al and Ni, Fe, or Cu after forging, the completed forged member has excellent strength and wear resistance.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, and FIG. 1 is a flowchart showing the manufacturing procedure of a forged member;
FIG. 2 is a graph showing the particle size distribution of ultrafine Ni powder used for manufacturing forged parts, and FIG. 3 is a schematic cross-sectional view showing the pulp drive section of the engine. 4 is a valve upper seat (forged member). Fig. 1 Fig. 2rM Last nine manual sutra [in] Fig. 3

Claims (1)

[Claims] 1. Adding Ni powder, Fe powder or C to the rapidly solidified Al alloy powder
After mixing at least one type of u powder, forging into a desired shape, and then heat treatment is performed to generate an intermetallic compound between Al and Ni, Fe, or Cu. A method for manufacturing a forged member, characterized by: