JPS6238420B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a wear-resistant aluminum alloy for extrusion forging, and more particularly to an aluminum alloy that is wear-resistant and has excellent extrudability, forgeability, and mechanical properties. BACKGROUND ART Automotive parts, such as sliding parts such as pistons and cylinders, have traditionally been required to be lightweight and wear resistant. Al--Si eutectic and hypereutectic alloys are now needed as materials that satisfy these characteristics, but these conventional alloys have the problems described below. A4032 (eutectic alloy): Excellent forgeability and extrudability, but poor wear resistance and tensile strength. A390 (Algyl, hypereutectic alloy): It has excellent wear resistance, but is difficult to extrude, and has poor forgeability, tensile strength, and fatigue strength. In addition to these, the aluminum alloys described in Japanese Patent Publication No. 48-41407 and Japanese Patent Publication No. 49-22284 have poor extrudability. The present invention overcomes the drawbacks and problems of various aluminum alloys explained above, namely, the wear resistance is superior to that of A4032 alloy, and the extrudability, forgeability and mechanical properties of Al- The present invention provides an aluminum alloy for extrusion forging that has better wear resistance than A390 alloy, which is a Si-based hypereutectic alloy. The wear-resistant extrusion forging aluminum alloy according to the present invention includes (1) Si7.5-13.5wt%, Cu3.0-6.0wt%, Mg0.3-1.0wt%, Fe0.25-1.0wt%, Mn0 The first invention is a wear-resistant aluminum alloy for extrusion forging characterized by containing .25 to 1.0 wt% and the balance consisting of Al and impurities, (2) Si7.5 to 13.5 wt%, Cu3.0 ~6.0wt%, Mg0.3~1.0wt%, Fe0.25~1.0wt%, Mn0.25~1.0wt%, Ni0.3~2wt%, with the balance consisting of Al and impurities. The second invention is a wear-resistant aluminum alloy for extrusion forging, (3) Si7.5-13.5wt%, Cu3.0-6.0wt%, Mg0.3-1.0wt%, Fe0.25-1.0wt%, A resistant material characterized by containing 0.25 to 1.0 wt% of Mn, and one or both of 0.05 to 0.4 wt% of Cr and 0.05 to 0.25 wt% of Zr, with the balance consisting of Al and impurities. A third invention is an aluminum alloy for abrasive extrusion forging, further comprising: (4) Si7.5-13.5wt%, Cu3.0-6.0wt%, Mg0.3-1.0wt%, Fe0.25-1.0wt% , Mn0.25~1.0wt%, Ni0.3~2wt%, and further contains one or two of Cr0.05~0.4wt%, Zr0.05~0.25wt%, and the balance is Al and This invention consists of four inventions, with the fourth invention being a wear-resistant aluminum alloy for extrusion forging characterized by comprising impurities. By refining the casting structure of these aluminum alloys, the primary Si size is 80μ or less, and Si-Mn
- Mechanical properties such as wear resistance, tensile strength, and fatigue strength are further improved by setting the Fe compound particle size to 120μ or less and the α-Al phase size to 100μ or less. The wear-resistant extrusion forging aluminum alloy according to the present invention will be explained in detail. First, the components and component ratios of the wear-resistant extrusion forging aluminum alloy according to the present invention will be explained. Si is an essential element for imparting wear resistance, and if the content is less than 7.5wt%, this effect will be small, and if the content exceeds 13.5wt%, primary Si
A large amount of is generated, making extrusion difficult, and at the same time, forgeability and mechanical properties, especially fatigue strength, deteriorate.
Therefore, the Si content is set to 7.5 to 13.5 wt%. Cu is an element that improves mechanical properties, prevents seizure, and improves wear resistance. If the content is less than 3.0wt%, this effect is small, and
If the content exceeds 6.0wt%, extrudability will be inhibited. Therefore, in order to maintain mechanical properties and wear resistance, the Cu content is set to 3.0 to 6.0 wt%. Mg is an element that not only improves mechanical properties but also forms Mg ₂ Si precipitates and imparts wear resistance.When the content is less than 0.3wt%, this effect is small, and when the content exceeds 1.0wt%, Extrusion when contained,
This will impede forgeability. Therefore, the Mg content is 0.3 to 1.0wt, which is within the range that does not inhibit extrudability and forgeability.
%. Fe and Mn have almost the same effect, that is, they promote the formation of fine eutectic Si and Si-based precipitates, and
It is an element that improves wear resistance by forming Si-Mn-Fe crystallized substances.If the content is less than 0.25wt%, this effect will be small, and if the content exceeds 1.0wt%, it will cause giant compounds. , resulting in deterioration of forgeability and mechanical properties. Therefore, the Fe content and Mn content are each 0.25 to 1.0 wt%. Ni is an element that imparts heat resistance (high-temperature strength) when the wear-resistant aluminum alloy for extrusion forging according to the present invention is used under high-temperature conditions of, for example, 200°C or higher, and the content is 0.3wt. If the content is less than 2 wt%, this effect will not be obtained, and if the content exceeds 2 wt%, the effect will be saturated, and further content will be uneconomical. Furthermore, the inclusion of Ni imparts wear resistance, that is, Al-Cu-Ni compounds of Hv1100 and
It forms an Al ₃ Ni compound with Hv770 to impart wear resistance, but in this case too, this effect is small if the content is less than 0.3wt%, and if it is contained in more than 2wt%, the compound becomes coarse. The effect of improving wear resistance disappears. Therefore, the Ni content is set to 0.3 to 2.0 wt%. Cr is an element that forms CrAl ₇ compounds with Hv510 and imparts wear resistance.If the content is less than 0.05wt%, this effect will be small, and if the content exceeds 0.4wt%, coarse compounds will be formed. , reducing extrudability and mechanical properties. Therefore, the Cr content is 0.05~
The content shall be 0.4wt%. Zr is an element that suppresses the coarsening of the structure that occurs during extrusion and heat treatment.When the content is less than 0.05wt%, this effect is small, and when the content exceeds 0.25wt%, coarse compounds are forming and reducing extrudability and mechanical properties. Therefore, the Zr content is
The content should be 0.05-0.25wt%. In addition to the above-mentioned components, B, Mo, Co, Sb, Nb, Pb,
One or more selected from Bi, V and 0.5 wt% or less, and Zn and 1 wt% or less may be contained. Furthermore, in the present invention, the aluminum alloy casting structure is limited to a primary Si size of 80μ or less, a Si-Mn-Fe compound size of 120μ or less, and an α-Al phase size of 100μ or less, thereby improving wear resistance and Mechanical properties can be further improved. Next, examples of wear-resistant extrusion forging aluminum alloys according to the present invention will be described. Examples No. 1 to No. 10 shown in Table 1 are wear-resistant extrusion forging aluminum alloys according to the present invention.
The size of the Si-Mn-Fe compound and α-Al phase was refined by casting at a cooling rate of 1.0°C/sec or higher. FIG. 1 shows a micrograph of a representative example of the metal structure of the No. 2 wear-resistant extrusion forging aluminum alloy ingot manufactured in this way according to the present invention. In Figure 1, the sunspots are primary Si, and the bright colors are Si-Mn.
- Fe compound, microcrystalline matter is eutectic Si, white background is α -
It is an Al phase. No. 10 in Table 1 corresponds to wear-resistant extrusion forging aluminum alloy No. 2 according to the present invention, and its structure is as shown in Table 1, primary Si size, Si-Mn-
Both the Fe compound size and the α-Al phase size are particularly large. In other words, this No. 10 does not refine the primary Si crystals by adding phosphorus during melting, and is cooled at a cooling rate of 0.5°C/sec or less. Figure 2 shows a micrograph of the metal structure of a representative example of the cast structure for comparison with No. 2 above. Comparative alloys Nos. 11 to 13 shown in Table 1 are made by adding phosphorus during melting to refine the primary Si crystals, and the temperature is 1.0℃/
It is cast at a cooling rate of sec or more. Wear-resistant extrusion forging aluminum alloys No. 1 to No. 10 according to the present invention manufactured in this way, as well as Nos. 11, 12, and 13 as comparative examples, were tested for various properties by the method shown below. compared. This result is the first
Shown in the table. Extrudability: From a 155φ billet to a 27φ round bar, those that can be extruded at an extrusion speed of 4 m/min or more are ○, those that can be extruded at less than 4 m/min to 2.5 m/min are △, those that can be extruded at a lower extrusion speed × Forgeability: Forged a 10φ x 20h specimen, processing rate 60
Items that do not crack up to 50% are rated ◎, items that do not crack up to 50% but break at 60% are ○, and items that break at 50% are marked ×. Wear resistance: wear rate determined by Okoshi type abrasion tester
Tests were conducted at 1.0 m/sec and a load of 3.2 kg, and the specific wear amount was compared. Tensile strength: Comparison was made using samples that were heat treated at 230°C for 30 minutes after solution treatment. Fatigue strength: Comparison was made using samples that were heat treated at 230°C for 30 minutes after solution treatment.

【table】

[Table] As is clear from this Table 1, the wear-resistant aluminum alloy for extrusion forging according to the present invention is as follows: Comparative Example 11
It has better wear resistance than A4032 alloy, and
It is superior to the Al-Si hypereutectic alloy of Comparative Example 12 in extrudability, forgeability, and mechanical properties, and furthermore,
Wear-resistant extrusion forging aluminum alloy No. 2 according to the present invention has a primary Si size of 50 μm or less, Si-Mn
-70μ and α-Al with Fe compound size 120μ or less
The phase size is 60μ, which is less than 100μ, and each size of No. 10 is significantly larger than the above size, resulting in poor mechanical properties and wear resistance, so it is advantageous to limit the size of the alloy structure. It can be seen that it is. Incidentally, FIG. 3 shows that the size of crystallized substances is influenced by the cooling rate during casting. That is, the Si-Mn-Fe compound size is 120
In order to keep the temperature below μ, a cooling rate of 0.5° C./sec or higher is required. As explained above, since the wear-resistant aluminum alloy for extrusion forging according to the present invention has the above-mentioned structure, it not only has excellent wear resistance but also has excellent extrudability, forgeability, and mechanical properties. It also has the effect of having excellent physical properties.

[Brief explanation of the drawing]

Fig. 1 is a micrograph showing the metal structure of an ingot of the wear-resistant aluminum alloy for extrusion forging according to the present invention, Fig. 2 is a photomicrograph showing the metal structure of a conventional ingot of aluminum alloy, and Fig. 3 is a photomicrograph showing the metal structure of an ingot of a conventional aluminum alloy ingot. FIG. 3 is a diagram showing the relationship between crystallized substance size and cooling rate.

Claims (1)

[Claims] 1 Contains 7.5 to 13.5 wt% Si, 3.0 to 6.0 wt% Cu, 0.3 to 1.0 wt% Mg, 0.25 to 1.0 wt% Fe, and 0.25 to 1.0 wt% Mn, A wear-resistant aluminum alloy for extrusion forging characterized by consisting of the remainder Al and impurities. 2. The wear-resistant aluminum alloy for extrusion forging according to claim 1, characterized in that the primary crystal size is 80μ or less, the Si-Mn-Fe compound particle size is 120μ or less, and the α-Al phase size is 100μ or less. 3 Contains 7.5 to 13.5 wt% of Si, 3.0 to 6.0 wt% of Cu, 0.3 to 1.0 wt% of Mg, 0.25 to 1.0 wt% of Fe, 0.25 to 1.0 wt% of Mn, and 0.3 to 2 wt% of Ni. , the balance being Al and impurities.A wear-resistant aluminum alloy for extrusion forging. 4. The wear-resistant aluminum alloy for extrusion forging according to claim 3, characterized in that the primary crystal size is 80μ or less, the Si-Mn-Fe compound particle size is 120μ or less, and the α-Al phase size is 100μ or less. . 5 Contains Si7.5-13.5wt%, Cu3.0-6.0wt%, Mg0.3-1.0wt%, Fe0.25-1.0wt%, Mn0.25-1.0wt%, and further contains Cr0.05-1.0wt%. A wear-resistant aluminum alloy for extrusion forging, characterized in that it contains one or two of 0.4wt% Zr and 0.05 to 0.25wt% Zr, with the balance consisting of Al and impurities. 6. The wear-resistant aluminum alloy for extrusion forging according to claim 5, characterized in that the primary crystal size is 80μ or less, the Si-Mn-Fe compound particle size is 120μ or less, and the α-Al phase size is 100μ or less. 7 Contains 7.5 to 13.5 wt% Si, 3.0 to 6.0 wt% Cu, 0.3 to 1.0 wt% Mg, 0.25 to 1.0 wt% Fe, 0.25 to 1.0 wt% Mn, and 0.3 to 2 wt% Ni. A wear-resistant aluminum alloy for extrusion forging, further comprising one or two of the following: 0.05 to 0.4 wt% of Cr and 0.05 to 0.25 wt% of Zr, with the remainder being Al and impurities. 8. The wear-resistant aluminum alloy for extrusion forging according to claim 7, characterized in that the primary crystal size is 80μ or less, the Si-Mn-Fe compound particle size is 120μ or less, and the α-Al phase size is 100μ or less. .