JPS62238347A - Aluminum alloy excellent in wear resistance - Google Patents

Abstract

PURPOSE:To develop an Al alloy stock lightened in weight and excellent in wear resistance and mechanical strength, by adding specific amounts of Si or further Mg, Cu, Mn, and Fe to Al. CONSTITUTION:As an Al alloy as a sliding material for automobile parts such as piston, cylinder, rotor, etc., compressor parts, etc., an Al alloy containing, by weight, 10.5-14% Si is used. In this way, an Al alloy stock excellent in wear resistance in which Si with 10-50mum inside grain side existing as the second-phase grains in the structure comprises >=1% by area ratio can be obtained. In order to improve the strength of this alloy, 0.3-1.0 Mg and 1.5-7% Cu are further incorporated. Moreover, for improving the heat-resisting strength of this Al alloy, incorporation of Mn and Fe in the range of 0.2-1.0% suffices.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an aluminum alloy with excellent wear resistance.

(Prior Art) Automotive parts such as pistons, cylinders, and rotors, as well as sliding parts such as compressor parts, require materials that are lightweight, have excellent wear resistance, and have high mechanical strength. Materials that satisfy this condition include humanities-3T materials. Among A1-3t-based materials, materials with an Si content of 10.5 to 14 wL%, which have the highest mechanical strength, are mainly used. Al-3 with an amount of Si of 10.5 to 14 wt%
In addition to AC8B and 4032, T-type materials include AC8B and 4032.
-39387, Japanese Unexamined Patent Publication No. 59-16661, Patent Application No. 58-
There is an alloy disclosed in No. 039956.

(Problems to be Solved by the Invention) In addition to AC8B and 4032, there are alloys disclosed in Japanese Patent Publication No. 56-39387, Japanese Patent Application Laid-open No. 59-16661, and Japanese Patent Application No. 58-039956 as humanities-3i materials. but,
These examples have a problem in that they do not have sufficient wear resistance. That is, depending on the alloy composition, casting method, and conditions, Al-St alloy materials may have a composition consisting only of fine eutectic crystals, and therefore may not have sufficient wear resistance. In addition, with the aim of improving the strength of Al-St alloy materials, attempts are being made to make the second phase particles finer by reducing the size of the ingot or by rapid solidification, but the excessive fineness of the second phase particles However, there is a problem in that wear resistance decreases.

(Means for Solving the Problems) The present invention provides the following features: (1) Si present as second phase particles of an aluminum alloy containing 10.5 to 4 wt% of St, with the remainder consisting of Al and inevitable impurities. Among them, the particle size is 10-50j
An aluminum alloy with excellent wear resistance, characterized in that Lm is 1% or more of a''J.

(2) The aluminum alloy with excellent wear resistance according to claim (1), containing Mg: 0, 3-1, 0 wt% and/or Cu: 1.5-7 wt%.

(3) An aluminum alloy with excellent wear resistance as set forth in claim (1) or (2) containing 0.2-1.0 wt% of Mn and/or Fe.

Here, the unreleased target alloy is 10.5 to 14 wt% Si.
The reason for limiting the selection to aluminum alloys containing IJI
do. If the Si content is less than 10.5 wt%, the Si present as second phase particles will inevitably become so-called eutectic St, which will be fine particles with a particle size of less than 10 pm. And so. Furthermore, if the Si content exceeds 14%, the particle size will inevitably increase to 104 m in the normal manufacturing method.
Since the above St has an area ratio of 1% or more, the Si content is set to 14 wt% or less.

In addition, the Al-3N wear-resistant alloy contains Mg and C to increase its strength.
Contains u. The amount is usually Mg: 0.3 to 1. Owt
%, C:u: 1, 5 to 7 wt%. In addition, M n and Fe may be contained in order to supplement wear resistance and heat resistance strength. The amount is usually 0.2-1.0wt%
It is.

Next, the influence of the size of Si and the area ratio on wear resistance, which is a component of the present invention, will be explained based on examples.

(Example) Six types of alloys were manufactured using the method shown in Table 1 using test specimens with different St sizes and surface precisions, and the wear resistance was compared. Alloys 0 had a common composition of 11 to 12. 5Si-0,7Mg
-4,2Cu-0,4Mn-0,4Fe.

Wear test pieces were taken from the 3zφ extruded rod and continuous cast body obtained by the method shown in Table 1, and the wear resistance was compared using an Okoshi type abrasion tester. Wear test conditions are weight 2
．． 1kg, a! The rubbing speed was 1.1 m/s, and cast iron was used as the mating material.

Table 2 shows the structures of various materials and the results of wear tests.

In addition, Figure 2 shows the relationship between the area ratio of Si with a grain size of less than 10 m and the specific wear amount.
Since the specific wear amount increases as the area ratio increases, l
It is considered that St of less than 0.0 m does not strongly affect wear resistance. Therefore, the grain size of Si is set to 104 m or more. In addition, if the particle size is larger than 50 gm, the mechanical strength of the aluminum alloy will decrease, so the L limit of the particle size of St is 5.
0 lm.

Figure 1 shows the relationship between the Si area ratio and the specific wear amount for grain sizes of 10 to 50 mm.
As the Si area ratio of 0gm increases, it decreases, and when the one-surface precision becomes 1% or more, the specific wear amount is 4.5X 10-7mm.
z/kg or less, which poses no practical problem, so the Si area ratio with a particle size of 10 to 50 gm was set to 1% or more.

In an aluminum alloy containing 10.5 to 14 wt% of Si, Si with a particle size of lO to 505 m is used as second phase particles.
If 1% or more of St is present, it is impossible to have a structure in which there is no Si of less than 10 pm, and there is always a certain amount of Si of less than 10 gm.
Invention of a typical example of a 0 structure in which the area ratio of Si with a normal grain size of less than 10 lm is 7% or more. Alloy (1) and comparative alloy (6) are shown in FIG. In the invention alloy (1), the second phase particles and 12 have a particle size of 110-50p.
There are so-called primary Si and eutectic Si of iogmt.

In comparative alloy (6), the second phase particles have a particle size of 10. Only less than m eutectic Si is present.

(Effects of the Invention) According to the present invention, since the SK area ratio of grain sizes of 1O to 50jLm is set to 1% or more, the wear resistance of an aluminum alloy containing 5ilO, 5 to 14 wt% is improved. I can do it.

This is a graph showing. FIG. 3 is a micrograph showing the microstructure of an aluminum alloy.

Figure 1 □Area ratio QO (b) (X100) Comparative alloy

Claims (3)

[Claims] (1) Si: Contains 10.5 to 14 wt% and the remainder is Al and inevitable impurities. Among the Si present as second phase particles of the aluminum alloy, the particle size is 10 to 50 μm.
An aluminum alloy with excellent wear resistance, characterized by an area ratio of 1% or more. (2) Mg: 0.3 to 1.0 wt% and/or Cu:
The aluminum alloy with excellent wear resistance according to claim (1), containing 1.5 to 7 wt%. (3) An aluminum alloy with excellent wear resistance according to claim (1) or (2), containing 0.2 to 1.0 wt% of Mn and/or Fe.