JPS62127447A - Aluminum alloy for casting - Google Patents

Abstract

PURPOSE:To obtain an Al alloy for casting excellent in wear resistance and fatigue resistance by specifying a composition consisting of Si, Cu, Mg, Ti, Sb, and Al. CONSTITUTION:The Al alloy for casting has a composition consisting of 8-10% Si, 1.5-3% Cu, 0.3-0.5% Mg, 0.05-0.15% Ti, 0.1-0.2% Sb, and the balance Al with impurities. In this alloy, wear resistance is secured by Si with proper composition, tensile strength is improved by Cu and Mg, primary-crystal silicon is refined by Ti, eutectic silicon is refined, and further dendritic structure is refined and casting defects are reduced by means of a high-pressure solidification casting method, so that strength can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cast aluminum alloy that is applied to scroll members of scroll-type fluid machines and various cast products.

[Problems to be solved by conventional technology and invention] Conventionally,
AC8A, which is used as a heat-resistant and wear-resistant aluminum alloy for cast products such as engine pistons, has an Al-5t-based eutectic composition as shown in Table 1, so primary silicon should not crystallize. However, in actual sand casting, it is 50
Coarse primary crystals with a length of ~100 μm are precipitated. In addition, the eutectic silicon that occupies most of the material is coarse and has a length of 50 to 150 μm. Therefore, although the wear resistance is good, the toughness is low (approximately 1% in terms of tensile elongation), and the fatigue strength, especially notch fatigue strength having stress concentration areas, is weak.

The present invention has been made to solve the above-mentioned drawbacks.
The purpose is to provide a cast aluminum alloy with excellent wear and fatigue resistance.

c.Means and effects for solving the problems] The cast aluminum alloy according to the present invention contains 8 to 10 wt% Si (hereinafter %
(abbreviated as ), Cu is added from 1.5 to 1.5 to improve the tensile strength.
396 and Mg by 0.3 to 0.5%, Ti by 0.05 to 0.15% to refine the primary silicon, and sb by 0.1 to 0.1 to refine the eutectic silicon. 296, and the rest are At and mechanical impurities (Fe.

Zn, etc.), and in order to achieve a strength of 1 m by 1 m by refining the primary crystal, eutectic silicon, refining the dendrite structure, and reducing casting defects.
+, ', l casting method was adopted.

〔Example〕

Examples of the present invention will be described below.

In this example, samples were cast using four types of aluminum alloys having the components shown in Table 2 using a high-pressure solidification method with a molten metal temperature of 750°C, a mold temperature of 250°C, and a molten metal pressing force of 1000 kg/cIi2. Solution treatment was performed at 510°C for 4 hours, followed by artificial aging treatment at 170°C for 4 hours. Then, T-shaped test pieces were cut out from each sample obtained by the above casting method and subjected to a shank bending fatigue test. The results are shown in FIG. As is clear from the figure, the fatigue strength of the samples made of aluminum alloys A, B, and C is approximately 1.5 times higher than that of the samples made of conventional AC8A.

In addition, a flat test piece was cut out from each sample, and a surface pressure of 10 and 'j/mrn2. Fig. 2 shows the results of a sliding wear test of 30 mIn at a sliding speed of 1 m/see under oil lubrication conditions, and Fig. 3 shows the results of a comparison of static strength. Aluminum alloy A
Trial created with , B, and C! As shown in FIG. 2, IIf: wear amount is almost the same between the 11-1 and the conventional AC8A, and it can be seen that the 11-abrasion properties of the two are the same. Furthermore, as shown in FIG. 3, it can be seen that the static strength is higher than that of the conventional AC8A in terms of tensile strength and elongation.

〔Effect of the invention〕

As described above, according to the present invention, the fatigue strength can be improved by about 1.5 times compared to the conventional AC8A, and wear resistance equivalent to or higher than that of the conventional AC8A can be obtained. , we can provide cast aluminum alloys with excellent wear and fatigue resistance.

[Brief explanation of drawings]

Figure 1 is a diagram comparing the fatigue strength of the aluminum alloy according to the present invention and a conventional example, Figure 2 is a diagram comparing the wear resistance of both, and Figure 3 is a diagram comparing the static strength of both. be.

Claims (1)

[Claims] Si: 8-10%, Cu: 1.5-3%, Mg in weight%
:0.3~0.5%, Ti:0.05~0.15%, S
b: Cast aluminum alloy with excellent wear and fatigue resistance, consisting of 0.1 to 0.2%, balance Al and impurities.