JPS60205070A - Connecting rod made of aluminum alloy - Google Patents

Abstract

PURPOSE:To aim at improvements in abrasion resistance, strength and load resistance, by controlling the grain size of both primary crystal Si and eutectic crystal Si particles in an aluminum matrix and their distributed conditions to come into a specific range. CONSTITUTION:In an aluminum matrix made of an aluminum alloy which contains 16-30wt% of Si and 0.3-7wt% of Cu as well as 0.3-2wt% of Mg and the rest is aluminum substantially, primary crystal Si particles of 40-80mum in particle size each accounting for more than 60% of the total primary crystal Si particle area are made to be uniformly distributed. And, using such a material that eutectic crystal Si paticles of less than 10mum in particle size accounting for more than 60% of the total eutectic crystal Si particle area are uniformly distributed, a connecting rod is manufactured. With this constitution, the connecting rod can be made into a thinned type without necessitating any reinforcing ribs.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a connecting rod used in reciprocating gas pressure engines, automobile engines, and the like.

(Prior art) A connecting rod that connects a piston and a crankshaft and converts reciprocating motion in the former and rotational motion in the latter creates severe sliding friction between the crankshaft and the piston pin, and also Large alternating stresses are generated by each load, such as buckling and compression due to high gas pressure (liquid compression force), tension due to the inertia of the piston, and bending stress due to the inertia of the rod itself. Therefore, high abrasion resistance I11 is required for the sliding friction part of A, and f'l''> iJ: 10 is required for high-speed operation.
In order to minimize the vibration of the compressor and engine by minimizing the vibration force, it is desirable to install the compressor at a maximum of 161.

Heretofore, mold castings or die castings of aluminum alloy have generally been widely used as the material for NEXTE rods, particularly in relatively small compressors and the like. That is, Si is L) to 10W (containing about % i
AQ-8i series aluminum alloy castings such as JISAC2B1ΔC3Δ were often used.

<Problems with the prior art> However, since the conventional aluminum alloy connecting rods are aluminum alloy castings or die-cast products, coarse primary and l crystal SI particles are generally dispersed in the C aluminum matrix. The drawback was that there were large variations in strength and abrasion resistance. In addition, since the material itself does not have sufficient wear resistance, it is necessary to separately cast a wear-resistant bearing base metal into the crankshaft and I joint J8 part, and furthermore, the material itself cannot have sufficient wear resistance. In order to compensate for this, it was necessary to form stiff reinforcing ribs, which caused the problem of increased stress and increased inertia due to the larger shape.

(Objective of the Invention) The object of the present invention is to solve the above-mentioned problems. In other words, due to the improved U iff due to the aluminum alloy components and its alloy structure, it has extremely excellent wear resistance by itself, has excellent strength, has good four-way properties, and has excellent ductility and machinability. The purpose of this invention is to provide an aluminum alloy connecting rod that is easy to manufacture by improving the properties of the aluminum alloy.

(Structure of the Invention) The present invention is characterized in that the material of the connecting rod is a high-silicon aluminum base metal containing 3i in the hypereutectic region, and moreover, the material is a high-silicon aluminum base metal containing 3i in the hypereutectic region. The general idea is to use eutectic 3, in which the particle size distribution of one particle is set within a specific range.
0 wt%, CI 0.3-7. Contains Qwt%, or further contains Mg from 0.3 to 2. □ wt %, the balance being substantially aluminum aluminum, wherein primary 3i grains with a grain size of 40 to 80 tt tn are all primary crystals in the j' aluminum matrix of the alloy. The eutectic 3i particles occupy more than 60% of the area of the 3i particles and are evenly divided, and the eutectic 3i particles with a particle size of 10 μTn or more occupy more than 60% of the area of the entire ξ crystal 81. An IR connecting rod made of an aluminum alloy made of a material having uniform molecular weight is provided.

(Specific explanation and operation of 4FJ formation) The aluminum alloys used in the connecting rod of this invention are generally used to form ingots that are #1 missed by known casting methods. , and further hot extrusion J, especially J, has a structure (!) that is manufactured by controlling it within a specific range.

First, the reasons for limiting the range of each component of the alloy used in this invention are as follows.

Needless to say, Sl, which is the main additive element, is effective in improving the wear resistance of the alloy. Therefore, in general, the wear resistance improves as the u5+ content increases, but the ρ-3i alloy used in this invention contains a large amount of St in the hypereutectic region, and the aluminum matrix contains a large amount of St. It is necessary to disperse a relatively large number of primary 3i particles. Therefore, the content of $1 must be at least 15 wt%, and if it is less than 15 wt%, the material itself cannot provide the abrasion resistance necessary for the connecting l'rad. As is clear from this, in many cases, the connecting rod according to the present invention eliminates the need to separately cast a wear-resistant bearing alloy in the sliding contact portion with the crankshaft, thereby simplifying its manufacture. The Si content can be increased to as much as CX by selecting the manufacturing conditions of the alloy within a special range, but when it exceeds 30 wt%, the casting process becomes significant. Since the content of 14J and NKB is low, there is an acceptable range of less than that, and the most suitable content is about 18 to 20 wt%.

CO and MQ contribute to improving the strength of the alloy, and if Q is less than 3 wt%, it is difficult to impart the necessary mechanical strength to the connecting L1. However, when the CLI exceeds 7wt% (th4 food habits become extremely sad), when the MCI exceeds 2wt%, the above effects are greatly increased, and rather, the formation of crystallized substances The most suitable i group of Cυ obtained from the experimental results is about 3 to 5 wt%, which is 1.1, riM!+ (1) 3 right ffH, 10, 4
It is about 5 to 0.65 wt%.

(rQ additive elements, etc.) of the pond, preferably, for example, S
r and/or P are added.

All of these elements are equivalent in that they act as refining agents to refine the primary 3i particles during casting, and it is sufficient that either one contains at least -, /J.
If each is less than 0.005 wt%, the above effects are poor,
Even if it exceeds 0.1 wt%, no particular increase in effect can be expected.

Furthermore, Ni can be used as an optional additional element.
, l''e, and Mn.

All of these elements effectively contribute to improving the heat resistance of the alloy, and in terms of this effect, they are all equivalent, and at least ILF! Or contains 2 or more types 1
However, if the amount of each component is less than 0.5 wt%, it is difficult to realize the above effects, and conversely, if it exceeds 3 wj%, the machinability becomes unreliable.

Alloy '4A according to the present invention having the above-mentioned composition range
The slant is manufactured through an extrusion process after casting in order to bring its structure into a specific range 11. IIp et al. first produced an aluminum base metal ingot by melting and casting the above aluminum alloy according to a conventional method. The primary crystal S1 particles contained in the ingot produced by this casting process (1! It should be noted that the particle size of A is still quite large, including some that reach 100 μm.
The eutectic 3i particles are also quite large, including those with a particle size of about 30 μTrL, and have the form b! I
It is a tree that shows the shape of a tree.

Therefore, these relatively coarse primary crystals and eutectic S1 particles are further added to 350 to 420'CP[! It is extruded at a high temperature. By this hot extrusion, a part of the coarse primary 3i grains contained in the alloy is destroyed, and almost all of the grains (1111 in the range of 10 to 80 μTrL) are destroyed.
And, the eutectic 3i particles are refined to a range where the particles of 40 μm or more F occupy an area ratio of 60% or more of the total primary 3i particle area, and the molecules li are made uniform, and the eutectic 3i particles are
The 11-shape V7 product was divided into 11i in the length direction to make the shape granular, and almost all of the JL grains had a particle size of 15 μyn or less, and the particles with a diameter of 10 μm or less accounted for 60% of the eutectic S1 particle area. Refinement u to a range that occupies the area ratio of
I'll give you something that's closed. In the above, almost all of the above are intended to allow inclusion of particles outside the above particle size range in very rare cases, but the preferred manufacturing conditions are 1.
When χ is used, it can be said that primary 3i particles and eutectic Si particles outside the above particle size range are practically not included at all.

Such preferable production conditions include, in particular, extrusion conditions such as billet 1-3 (350-420°C, ram speed I).
f: 0.03-0.2m/sin, extrusion: 10
It is preferable to use an extrusion die with a bearing quality of 5 to 15 #Il+.

By the way, the reason why the primary crystal 3i particles in the alloy structure are limited to occupying an area ratio of 60% or more in the range of 40 to 80 μm as described above is that if the alloy structure contains many particles smaller than 40 μm, If the desired excellent wear resistance cannot be obtained and, on the contrary, the material contains many coarse particles exceeding ε30 μm, the (min/li) becomes unsuitable and coarse.
This is because it makes uneven splicing of J I (f wear 1'U) difficult and reduces machinability.In addition, eutectic Si particles (y15μm or less and 10μm or less in area) It is limited to containing 60% or more of the primary Si particles (by reducing the grains to the above-mentioned range, they are inevitably refined to the 2-range IQ+). Therefore, if I were to point out the effect of -, I would say that at least many of the 3i particles remain as coarse particles exceeding 15 μm (7 particles are those that at least cause defects in machinability). Therefore, the opposite effect can be cited as the effect of improving machinability.

(Effect of the invention) The connecting rod according to the present invention has the above-mentioned Jζ
Because it is made of a high-silicon aluminum alloy with a similar composition and structure, it has extremely excellent wear resistance as a material, and does not require casting of bearing metal or separate installation. I can write things. In addition, it is also extremely good at mechanically strong melon (Jj
Not only does it have sufficient load-carrying properties required for a connecting rod, but it can also be made thin and compact without the need to form large reinforcing ribs. Therefore, it is possible to provide a connecting rod with excellent characteristics such as small inertia force and low inertia force while reducing manufacturing costs.

[Margin below] (Implementation 1-) 1st+, an example for this light is shown.

Table 1 Regarding the aluminum-based alloys with the phase formation shown in Table 1 above,
In the material of the present invention, the alloy is first melted and cast into #A single series.
This was made into a billet with a diameter of 120#II+, and then extruded at 4115°C, 1111 mm, +5
Diameter 30I under the condition of speed IQO, 1Ill/l1lin
The extruded round bar of IIIR was subjected to T6 heat treatment to obtain a connecting rod material specimen.

In the specimen of the present invention material, all of the primary 3i particles contained therein belong to the particle size range of 10 to 80μ711, and those in the range of 40 to 80μrn are clearly free of primary Si. There were some particles that occupied an area ratio of 00% or more to the particle surface (^).

In addition, the eutectic Si particles are also miniaturized, and all of them are in the particle size range of at least 15 μm rL or less, making the eutectic Si particles I
60% or more of the area of the stack was occupied by particles with a diameter of 10 μm or less.

On the other hand, the comparison material NO45 is an AC88 alloy known as an aluminum alloy with excellent wear resistance, and a commercially available product thereof was used as a test piece.

The wear resistance and machinability of the various aluminum alloy materials mentioned above were investigated by comparing them with Billet 1, which had been cast with the same composition as the present invention material, and the results are shown in Table 2 below. It was +3.

[Left below] Table 2 N-11): The wear resistance test was carried out using an ultra-thread type wear tester with a rotating disk, friction distance: 600 m, IIJ I? Y speed: 2m/n1i
n, counterpart material: The test was conducted under the test conditions of FC-30 (JIS).

(N12):1. IJJ tool life is: front rake angle 20 degrees, side rake angle: 10 degrees, front relief angle near 1, side relief angle = 7 degrees, front cutting edge angle: 8 degrees, side edge angle: 0 degrees , Nose radius: Ofg1, using carbide bi1- with the following specifications, cutting depth: 0.1111II+, feed rate: 0.0511#l, rotation speed: 500 rpm, D'l lubricant: petroleum cutting. After performing cutting with a cutting distance of 111:200 TrL under the following conditions, the wear width of the flank surface of the cutting tool was measured.

As can be seen from the wear resistance test results in the table above, the connecting rod materials according to the present invention are cast metals having the same alloy composition but with different particle sizes and distributions of 3i crystals in aluminum 71~Rix. Compared to the original material, it clearly had superior wear resistance, and the effect of reducing the variation was observed, and it also had significantly superior wear resistance compared to the comparison material. .

On the other hand, in a comparison of cutting tool performance, the material of the present invention has a remarkable effect on cutting tools compared to the as-cast material.
Although it was slightly inferior to the comparative materials, it showed excellent machinability equivalent to or better than 118.

In addition, all of the materials of the present invention exhibited a tensile strength of U/10 匈/- or more, and the tensile strength of the comparative material was 1-33Ay/a.
dJ: Excellent stiffness and elongation of 3% or more, far superior to the comparative material's elongation of 0.5%.

According to the C1 wood invention material, as shown in Figures 1 and 2, the large end (1) and the small end (2 and arm part 3) are integrated. In addition to manufacturing a one-piece two-piece neck 1" bolt (Δ), the large end (1) is divided into two tightening bolts (4) as shown in Figures 3 and 4.
It can also be made into a split connecting rod (13) that is connected with b, and either large end (1
) While eliminating the need to separately install a bearing metal on the inner surface, it is possible to manufacture a small and lightweight cylinder that is thin and has small reinforcing ribs, which in turn reduces YJ construction locos 1 and provides even higher performance than conventional products. A connecting rod with excellent performance was obtained.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; Fig. 1 is a plan view of an integrated connecting rod, Fig. 2 is a longitudinal cross-sectional view of the center thereof, and Fig. 3 is a partially fragmented view of a split-type connecting rod. The plan view and FIG. 4 are its center vertical cross-sectional views. (A) (B)...Connecting rod, (1)...
・Large end, (2)...small end, (3) arm, (4)...
・Tightening bolt. Patent applicant: Showa Aluminum Co., Ltd. Representative: Hisashi Shimizu, patent attorney ff1′”1.・

Claims (2)

[Claims] (1) Si 16-30wt%, CO 0.3-7,
Qwt% and fl# is substantially aluminum
A full miniram alloy, in which primary Si particles with a particle size of 40 to 80 μy+t occupy an area of 60% or more of the total primary 3i particle area and are uniformly distributed in the aluminum matrix of the alloy, and a particle size of 10 μm or less An aluminum alloy-J neck ingot, characterized in that the eutectic Si particles are formed of a material in which the eutectic Si particles occupy 60% or more of the area of the eutectic Si particles and are uniformly distributed. (2) 16 to 30 wt% of Si, 0.3 to 7 of Cu,
Qw1%, and Mg 0.3-2. □wt%, the remainder being substantially aluminum, the aluminum matrix of the alloy having a grain size of 40
~80 μ milk primary 3i particles account for 60 μ of the total primary 3i particle area
% or more, uniformly distributed, and particle size 10μT
Eutectic 3i particles of n or less account for 60% of the total area of eutectic 3i particles
An aluminum alloy connecting rod characterized in that it is formed of a material that occupies a larger area and is uniformly distributed.