JPH06330714A - Manufacture of heat resistance aluminum alloy made valve body - Google Patents

Abstract

PURPOSE:To form a valve body without deteriorating strength of heat resistance aluminum alloy. CONSTITUTION:Rapid cooling coagulation powder of particle dispersion type heat resistance aluminum alloy having component of al-7, 7Fe-2, 5V-0, 5Mo-0 and 4Zr is manufactured, and it is push-formed so as to form a cylindrical push casting billet 15. The push casting billet 15 is arranged on the push plate 13 of a container 11 bottom part as shown in figure (a), and dies 17 on which a valve body mold 17a is formed are arranged. The dies 17 are pressed forcibly and pushed down by a punch 19 as shown in figure (b) so as to form a valve body (an intake valve) for an internal combustion engine having a shaft part 1a and an umbrella part 1b by a push casting method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a heat-resistant aluminum alloy valve body used for an intake valve of an internal combustion engine, and particularly to forming a valve body without deteriorating the strength of the heat-resistant aluminum alloy. The present invention relates to a method of manufacturing a valve body that can be used.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, an intake valve P1 and an exhaust valve P3 provided in an internal combustion engine each have a shaft portion P.
5 and a bulge portion P7, they serve to send the combustion gas regularly into the cylinder chamber P9 and exhaust it, as is well known.

At present, iron and steel materials such as SUH3 and SUH11 are mainly used for the intake valve P1 and the exhaust valve P3. A process (up-set method) of forming a bulky portion by embedding is mainly used. That is, FIG.
As shown in (a), the end P13 of the small diameter rod P11 is heated and compressed by the upsetting punch P15,
As shown in (b), the end portion P13 is pushed open to form the umbrella portion P17.

By the way, recently, in order to improve the output, fuel efficiency and responsiveness of the internal combustion engine, it is particularly required to reduce the size and weight of the intake / exhaust valve. Is comparatively low up to about 300 ° C., so weight reduction using a heat-resistant aluminum alloy is being studied. Examples of the heat-resistant aluminum alloy include metals such as Fe, V, Mo, Zr, Ti, and Cr as disclosed in JP-B-63-10221, JP-B-63-10222, or JP-A-1-147037. It has been attempted to use a particle-dispersed aluminum alloy containing a predetermined amount of.

[0005]

However, when a valve body is manufactured using the heat-resistant aluminum alloy as described above, high temperature heating is required if the valve body is molded by the up-set method applied to the conventional steel material. Therefore, there is a problem in that the strength is lowered in the bulky portion and the strength after molding becomes lower than the strength required for the valve body.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for manufacturing a valve body made of a heat-resistant aluminum alloy, which can form the valve body without deteriorating the strength of the heat-resistant aluminum alloy. To do.

[0007]

In order to achieve the above object, the invention of claim 1 is a method of manufacturing a valve body made of a heat-resistant aluminum alloy, which has a shaft portion and a bulk portion and is used for an intake valve of an internal combustion engine. It consists of the heat resistant aluminum alloy,
After manufacturing a bar material having a diameter substantially equal to the outer diameter of the bulge portion, the bar material is arranged on the bulge portion side of the valve body mold formed in a die, and the rod material is heated and extrusion-forged by A gist is a method for manufacturing a valve body made of a heat-resistant aluminum alloy, which is characterized in that a valve body having the shaft portion and the cap portion is manufactured.

The composition of the heat-resistant aluminum alloy is not particularly limited.
A metal selected from Fe, V, Mo, Zr, Ti, Cr, Co, Ce and the like, as disclosed in Japanese Patent Publication No. 3-10221, Japanese Patent Publication No. 63-10222, Japanese Patent Laid-Open No. 1-147037, and the like. A particle-dispersed aluminum alloy containing a predetermined amount of can be used.

The rod is made of the heat resistant aluminum alloy. More specifically, it can be obtained, for example, by manufacturing a rapidly solidified material of the above-mentioned particle dispersion type heat-resistant aluminum alloy by an air atomizing method or the like and molding it into a rod shape by plastic working such as extrusion.
It is also possible to obtain this rapidly solidified material by molding it into a rod shape by compression processing such as hot isostatic pressing (HIP) or cold isostatic pressing (CIP). Furthermore, after this rapidly solidified material is once molded by extrusion or pressing,
The bar may be obtained by performing other processing such as turning.

The term "valve element type" refers to a space having the shape of a valve element formed in a die.

[0011]

According to the first aspect of the present invention, first, a bar member made of a heat-resistant aluminum alloy and having a diameter substantially equal to the outer diameter of the bulk portion of the valve body to be manufactured is manufactured. Then, this bar is placed on the side of the valve body mold formed on the die,
The rod body is heated and extrusion-forged to manufacture a valve body having a shaft portion and a bulk portion.

When the valve body is manufactured by such extrusion forging, the temperature for heating the heat-resistant aluminum alloy at the time of forming the valve body (that is, at the time of extrusion forging) is lowered as compared with the conventional upsetting method. The valve body can be manufactured without suppressing the strength of the alloy.

[0013]

EXAMPLES Examples embodying the present invention will be described below together with comparative examples. [Examples] (1) First, as a particle-dispersed heat-resistant high-strength aluminum alloy, Al-7.7Fe-2.5V-0.5Mo-0.4Zr was used.
(Fe: 7.7%, V: 2.5%, Mo: 0.5%, Z
An alloy having a composition of r: 0.4% and the balance being Al) was melted, and a rapidly solidified powder having an average particle diameter of 60 μm was manufactured by an air atomizing method.

(2) The rapidly solidified powder was
After enclosing in an aluminum container having a height of 300 mm and performing vacuum degassing treatment at 400 ° C., the powder was densified by compressing the mold together with the container at 400 ° C. Then, the outer container is turned and removed, and the inner molded body (diameter 90 mm, height 150 m
m) got. This was used as an extrusion billet used in the next extrusion step.

(3) This extrusion billet was indirectly extruded at 400 ° C. to obtain an extrusion rod having a diameter of 30 mm (extrusion ratio 10). Then, this was cut into a length of 22 mm to obtain an extrusion forging billet (bar material) used in the following extrusion forging step. (4) This extrusion forging billet is heated to 380 ° C.,
Extrusion forging was performed as described below to prepare a valve body (intake valve) 1 having a shaft portion 1a and a bulge portion 1b as shown in FIG.

That is, first, as shown in FIG. 2 (a), the extrusion forging billet 15 is arranged on the lower push plate 13 of the cylindrical container 11, and the valve body mold 17a is formed thereon. The die 17 was placed. That is, the extrusion billet 15 was arranged on the side of the bulb portion 17b of the valve body die 17a of the die 17. Then, as shown in FIG. 2 (b), the die 17 was strongly pressed and pushed down by the punch 19, and the shaft portion 1 a was pushed out to form the valve body 1.

Next, a strength test conducted to confirm the strength of the valve body 1 manufactured as described above will be described. First, a tensile test was performed at 250 ° C. on the extruded rod formed in the above step (3). The results are shown in Table 1 below.

Next, with respect to the valve body 1 obtained by extrusion forging, a tensile test piece is prepared from the shaft portion 1a, and a tensile test is carried out at 250 ° C. as in the case of the above-mentioned extruded rod, and the shaft portion 1 And the Rockwell hardness of the umbrella portion 3 was measured. The results are shown in Table 1 below.

[0019]

[Table 1]

As is clear from Table 1, the valve body 1 molded by the manufacturing method of the example has the same yield strength (stress that causes permanent elongation of 0.2%), tensile strength and elongation before forging. The result is equivalent to that of the extruded rod, and it can be seen that the extruded rod retains sufficient high temperature strength even after being formed into a valve body by extrusion forging. Also, regarding Rockwell hardness, there was no difference in hardness between the shaft portion and the bulk portion, which was very preferable.

As described above, according to the method of manufacturing the valve body of this embodiment, there is a remarkable effect that the valve body having the shaft portion and the bulk portion can be formed without deteriorating the strength of the heat-resistant aluminum alloy. . [Comparative Example] Next, a comparative example in which a heat-resistant aluminum alloy valve body is manufactured by upsetting (up-set method) used for a current material (steel material) will be described.

First, the round bar having a diameter of 30 mm obtained in the step (3) of the above-mentioned embodiment is machined into a diameter of 8 mm by carving, and a cap portion is formed at one end of this bar material by upsetting. I tried. That is, a round bar is placed in a molding die, one end of the round bar is energized via an electrode, and one end of the material is heated by Joule heat by this, and then a load is applied to the one end to set it up. By doing so, an attempt was made to form the bulky portion. The heating temperature was changed from 350 ° C to 460 ° C.

As a result, the heating temperature of the material is 350 ° C.-4.
In the case of 50 ° C, cracking occurred in the overhanging portion of the bulky portion during upsetting, and molding was impossible. On the other hand, when the heating temperature of the material was 460 ° C., upsetting was possible without causing cracks in the bulk.

Then, a tensile test piece was prepared from the shaft portion of the valve body (referred to as the valve body 2) obtained by the upsetting at this high temperature, and a tensile test at 250 ° C. was conducted in the same manner as in the example. The Rockwell hardness of the shaft and the bulk was measured. The results are also shown in Table 1 above.

As is clear from Table 1, the valve body 2 of the comparative example
The tensile strength of was almost the same as that of the round bar material of the example. However, in the valve body 2, it was found that the Rockwell hardness (85) of the bulge portion was lower than the value (91) of the shaft portion, and the bulge portion was deteriorated by the heat effect due to the electric heating.

From the results of the above comparative examples, it was found that it is not easy to form the bulky part by upsetting in the particle-dispersed heat-resistant aluminum alloy. Although the embodiments have been described above, the present invention is not limited to the above embodiments and can be implemented in various modes.

[0027]

As described above, according to the manufacturing method of the present invention, a bar made of a heat-resistant aluminum alloy and having a diameter substantially equal to the outer diameter of the bulk part of the valve body to be manufactured is manufactured and then formed into a die. A valve element is manufactured by arranging a rod member on the side of the formed valve body mold on the bulge portion and heating the rod member for extrusion forging. Therefore, there is a remarkable effect that the valve body can be molded without deteriorating the strength of the heat-resistant aluminum alloy and the heat resistance such as the strength required for the valve body can be maintained even after the molding.

[Brief description of drawings]

FIG. 1 is a front view showing a valve body of an embodiment.

FIG. 2 is an explanatory view showing a method for manufacturing the valve body of the embodiment.

FIG. 3 is an explanatory diagram showing a conventional technique.

FIG. 4 is an explanatory diagram showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Valve body 1a ... Shaft part 1b ... Bulk part 15 ... Extrusion billet (bar material) 17 ... Die 17a ... Valve body type

Claims (1)

[Claims] 1. A method for manufacturing a valve body made of a heat-resistant aluminum alloy, comprising a shaft portion and a bulk portion, which is used for an intake valve of an internal combustion engine, comprising the heat-resistant aluminum alloy, and having an outer diameter substantially equal to that of the bulk portion. After manufacturing the rod having the same diameter, the rod is arranged on the side of the valve body mold formed in the die, and the rod and the bar are heated and extrusion-forged to form the shaft and the bulb. A method of manufacturing a valve body made of a heat-resistant aluminum alloy, which comprises manufacturing a valve body having the same.