RU2313594C1 - Aluminum-based alloy - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: the present innovation deals with obtaining aluminum-based alloys necessary for manufacturing stampings, particularly those of automobile wheels disks. The alloy in question has got the following composition, weight%: copper 0.8-2.2; magnesium 1.2-2.6; manganese 0.2-0.6; iron ≤0.25; silicon ≤0.20; zinc 5.0-6.8; titanium ≤0.1; chromium 0.08-0.17; zirconium 0.01÷0.12; boron 0.0008-0.005; antimony 2.5-3.5; indium 2.5-3.5; boron 0.4-0.5; hydrogen (0.3-4.1)10^-5, aluminum - the rest. The alloy in question is of optimal combination of strength and plasticity that guarantee the required level of performance characteristics of automobile wheels disks, the decrease of their weight in combination with high technological effectiveness at volumetric stamping, especially complex-shaped articles.

EFFECT: higher strength and plasticity of the alloy.

2 cl, 1 ex, 3 tbl

Description

The invention relates to the field of metallurgy, and in particular to the production of aluminum-based alloys intended for the manufacture of stampings, in particular stampings of automobile wheel disks.

Alloys of the Al-Zn-Mg-Cu system are known, for example, B95, B96ts1, which are used for the production of structural stampings. However, the alloys have low manufacturability during volumetric stamping, which does not allow to obtain complex in the form of stamping.

For the prototype adopted well-known deformation alloy 7075, containing the following components, wt.%:

Copper 1.2 ÷ 2.0 Magnesium 2.1 ÷ 2.9 Manganese <0.3 Iron <0.50 Silicon <0.40 Zinc 5.1 ÷ 6.1 Titanium <0.20 Chromium 0.18 ÷ 0.28 Aluminum the rest (ASTM B221M).

The disadvantages of this alloy include the following:

- the alloy has insufficient ductility in the cast state and, naturally, a tendency to crack during casting;

- the alloy contains a large number of alloying elements and impurities (more than 10%), which leads to the formation of coarse primary insoluble intermetallic compounds and, accordingly, reduces the fatigue characteristics of the products.

The technical task of the present invention is to create an alloy with the optimal combination of strength and ductility, which guarantee the required level of operational characteristics of the wheels of automobile wheels, reducing their weight in combination with high adaptability for stamping, especially of complex shapes.

The specified technical result is achieved in that the aluminum-based alloy containing copper, magnesium, manganese, iron, silicon, zinc, titanium, chromium, according to the invention additionally contains zirconium, boron and hydrogen in the following ratio of components, wt%:

Copper 0.8 ÷ 2.2 Magnesium 1.2 ÷ 2.6 Manganese 0.2 ÷ 0.6 Iron ≤0.25 Silicon ≤0.20 Zinc 5.0 ÷ 6.8 Titanium ≤0.1 Chromium 0.08 ÷ 0.17 Zirconium 0.01 ÷ 0.12 Boron 0.0008 ÷ 0.005 Hydrogen (0.3-4.1) 10 ^-5 Aluminum rest,

wherein: Ti + Zr + Cr≤0.25%, Cu + Mg + Zn≤8.6%.

The addition of boron and zirconium provides an increase in the processability of the alloy during deformation, especially during upsetting and volume stamping due to the formation of a fine-grained homogeneous structure in ingots. The presence of less than 0.0008% boron in the alloy leads to the formation of a coarse, coarse-grained structure in ingots and, as a consequence, a decrease in manufacturability during deformation.

When the ingot contains more than 0.005% boron, clusters of TiB ₂ intermetallic compounds are formed, which reduce the fatigue and plastic characteristics of the semi-finished products.

The presence of hydrogen in the alloy promotes the formation of titanium hydrides, which, being modifiers, additionally grind the structure of the ingot.

When the content of zirconium ingots is less than 0.01% in the semi-finished products, an inhomogeneous coarse-grained crystallized structure is formed, which increases the anisotropy of the properties over the cross section of the semi-finished products.

When the zirconium content is more than 0.12%, primary Al ₃ (Zr, Ti) intermetallic compounds appear, which reduce the processability of the ingots during deformation and contribute to the formation of internal defects.

The presence along with the strongest anti-recrystallizer zirconium in the proposed alloy in small amounts of titanium and chromium, with their total content (Zr + Ti + Cr) not exceeding 0.25%, contributes to the formation of non-recrystallized structure in stampings with a minimum number of eutectic components and the absence of primary intermetallic transition elements with aluminum.

A decrease in the alloying degree of the alloy with the main components of Cu, Mg, and Ti (less than 8.6%) reduces the likelihood of the formation of coarse excess phases and their negative effect on the workability during deformation and the plastic properties of stampings.

An example embodiment of the invention.

Under the industrial conditions of the foundry of the applicant's enterprise, experimental ingots of aluminum alloy with the chemical composition shown in Table 1 were cast.

Table 1 Alloy number Cu Mg Mn Fe Si Zn Ti Cr Zr AT N
10 ^-5 one 2.2 2.6 0.6 0.25 0.2 5.0 0.1 0.08 0.01 0.0008 4.1 2 1.6 1.2 0.4 0.15 0.1 5.6 0.06 0.12 0.08 0.001 2.7 3 0.8 1.9 0.2 0.20 0.15 6.8 - 0.17 0.12 0.005 0.3 four 1.6 2.4 0.25 0.4 0.3 5.6 0.15 0.25 - -

1-3 proposed alloy, 4 - known alloy.

After homogenization at ingots at temperatures of 455-470 ° C for 20 hours and subsequent turning, stamping of automobile wheel disks was made of ingots. Stampings were subjected to heat treatment according to the regime:

- quenching from temperatures of 465-475 ° C after holding 90 min in water with a temperature of 20-25 ° C,

- aging according to T2 mode (I stage 110-120 ° С, exposure 5 hours, II stage 165-175 ° С, exposure 15 hours).

Technological plasticity, shown in table 2, was determined on samples taken from homogenized ingots.

Table 2. Alloy number Sprain Draft,
% δ,% Ψ,% one 82.3 90,4 78 2 85.8 96.4 84 3 81.4 91.3 76 four 72,4 83,2 62

The complex of mechanical properties of the claimed and known alloy is presented in table 3.

Table 3 Alloy number σ _in σ _0.2 δ MCU, number
cycles to failure RSK,
point MPa % one 518 442 11,4 1090 3 2 510 432 12.6 1100 four 3 525 456 10.8 1050 3 four 476 392 8 1000 four

As can be seen from the obtained and presented results, the composition of the proposed alloy allows to increase technological ductility by 1.2-1.35 times, ductility by 1.35-1.6 times with an increase in strength indicators by more than 1.1 times, preservation of corrosion properties and improving fatigue resistance.

Using the proposed alloy for the production of stampings, including rims of automobile wheels, will improve the manufacturability of their production, as well as the reliability and availability of products in operation.

Compared with the known alloy, the proposed alloy has an optimal combination of strength and ductility, which guarantee the required level of performance characteristics of automobile wheel disks, reduction of their mass in combination with high adaptability for die forging, especially for complex products.

Claims (3)

1. An aluminum-based alloy containing copper, magnesium, manganese, iron, silicon, zinc, titanium, chromium, characterized in that it additionally contains zirconium, boron and hydrogen in the following ratio, wt.%: Copper 0.8 ÷ 2.2 Magnesium 1.2 ÷ 2.6 Manganese 0.2 ÷ 0.6 Iron ≤0.25 Silicon ≤0.20 Zinc 5.0 ÷ 6.8 Titanium ≤0.1 Chrome 0.08 ÷ 0.17 Zirconium 0.01 ÷ 0.12 Boron 0.0008 ÷ 0.005 Hydrogen (0.3-4.1) · 10 ^-5 Aluminum rest 2. The aluminum-based alloy according to claim 1, characterized in that the sum Ti + Zr + Cr≤0.25%. 3. The aluminum-based alloy according to claim 1, characterized in that the sum of Cu + Mg + Zn≤8.6%.