RU2230131C1 - Alloy of the system of aluminum-magnesium-manganese and items made out of the alloy - Google Patents

Abstract

FIELD: non-ferrous metallurgy. SUBSTANCE: the invention is dealt with metallurgy, in particular, with a makeup of thermally non-hardenable wrought aluminum alloys of the system of aluminum- magnesium -manganese with a magnesium share of more than 3 % in mass. The alloy may be used in industrial production basically of the thin sheets used for the following blanking and bending for manufacture of items like the members of containers, jars lids, jars lids openers and also for welded and non-welded elements of designs in shipbuilding, construction, motor-car industry. The invention offers the alloy based on aluminum and the item made out of it, that contain the following components (in mass %): magnesium - 3.0-5.8, manganese - 0.1-1.0, titanium -0.005-0.15, iron - up to 0.5, silicon - up to 0.4, chromium - up to 0.3, zinc - up to 0.4, copper - up to 0.25, at least one component taken from a group, containing nickel and a cobalt - 0.0005-0.25, at least one component taken from a group, containing boron and carbon - 0.00001-0.05, aluminum and permissible impurities- the rest. At that the total contents of manganese, chromium, titanium and nickel and-or a cobalt does not exceed 1.1. Technical result of the invention is that the stated alloy and items made out of it have improved mechanical properties, good stamping ability and rust resistance, that allows to increase service life of the items, to expand the list of produced items, to reduce labor input at their production. EFFECT: the stated alloy and items made out of it have improved mechanical properties, good stamping ability, rust resistance, increase service life of the items and reduced labor input at their production. 8 cl, 3 tbl, 3 ex

Description

The invention relates to the field of metallurgy, in particular to compositions of thermally unstrengthened wrought aluminum alloys of the aluminum-magnesium-manganese system with a magnesium content of more than 3% by weight. The alloy can be used in the production of mainly thin sheets used for subsequent stamping and bending into products, such as container elements, can covers, keys for cans, as well as for welded and non-welded structural elements in shipbuilding, construction, and automotive industry.

Alloys of the aluminum-magnesium-manganese system have relatively low strength values, but high ductility and corrosion resistance in the annealed state, they are well welded, all types of semi-finished products are made from them (sheets, plates, profiles, stampings) and due to this combination of properties they are widely used in various branches of technology. The only way to harden these alloys is cold deformation (hardening), which increases strength, but reduces ductility, stampability and corrosion resistance. Cold deformation also leads to the fact that with prolonged curing of products or their low-temperature heating (for example, solar heating), the strength properties of these products decrease.

Despite this, in both Russian and foreign practice, there are conditions for the supply of material with varying degrees of hardening. In Russia, these are: N - chartered, H1 - quarter chartered, H2 - semi-chartered, H3 - three quarters chartered. Abroad - this is: H1 - strain hardened, Н2 - strain hardened and partially annealed, Н4 - strain hardened and exposed to thermal effects during varnishing, paint or drying.

Thin sheets from an alloy of the aluminum-magnesium-manganese system in cured (H1) and cured and partially annealed state (Н2 and Н4) are widely used for the manufacture of various products and structures.

Such alloys, first of all, include domestic alloys AMg3, AMg4, AMg4.5, AMg5.

GOST 4784-97 discloses an aluminum-magnesium-manganese (AMg4) alloy system containing the following components, wt.%:

Magnesium 3.5-4.5

Manganese 0.2-0.7

Chrome 0.05-0.25

Iron Up to 0.5

Silicon Up to 0.4

Copper Up to 0.1

Zinc Up to 0.25

Titanium To 0.15

Aluminum Else

Thin cold-rolled sheets in the H1, H2, H4 state of this alloy have, on the one hand, insufficiently high strength values, and, on the other hand, low formability, which does not allow stamping of complex shapes in this state.

Patent RU 2156319 (C 22 C 21/08) discloses an aluminum-magnesium-manganese system alloy for the production of rolled or drawn materials, containing the following components, wt.%:

Magnesium 3.0-5.0

Manganese 0.5-1.0

Iron Up to 0.25

Silicon Up to 0.25

Zinc Up to 0.4

One or more elements from the group:

Chrome Up to 0.25

Copper Up to 0.2

Titanium Up to 0.2

Zirconium Up to 0.2

Aluminum Else

in this case, Mn + 2Zn> 0.75, and the volume fraction of material dispersoids is more than 1.2%.

Sheets from this alloy have high weld strength and good weldability. The disadvantages of this alloy include the fact that thin cold-rolled sheets of this alloy in the H2 and H4 state have insufficient strength, low formability and corrosion resistance, and sheets from this alloy in the H1, H2, H4 states, i.e. after hardening or after hardening and partial annealing, they lose strength properties during aging or low-temperature heating, which leads to tearing during sheet stamping, as well as premature destruction during storage of products from this alloy due to corrosion damage and strength reduction, which, in turn, it reduces the life of the products, limits the range of manufactured products, increases the complexity of their manufacture.

The objective of the invention is to increase the strength, stampability and corrosion resistance of thin sheets and products from them, as well as reducing the effect of loss of strength during prolonged aging (storage) of products.

The problem is solved in that the proposed aluminum alloy containing magnesium, manganese, titanium, iron, silicon, chromium, zinc, copper, aluminum and acceptable impurities, additionally containing at least one element selected from the group comprising nickel and cobalt , and at least one element selected from the group comprising boron and carbon, in the following ratio of components, wt.%:

Magnesium 3.0-5.8

Manganese 0.1-1.0

Titanium 0.005-0.15

Iron Up to 0.5

Silicon Up to 0.4

Chrome Up to 0.3

Zinc Up to 0.4

Copper Up to 0.25

At least one element

selected from the group including

Nickel and cobalt 0.0005-0.25

At least one element

selected from the group including

Boron and carbon 0.00001-0.05

Aluminum and acceptable impurities

the total content of manganese, chromium, titanium and nickel and / or cobalt does not exceed 1.1.

In private embodiments of the invention, the problem is also solved by the fact that the alloy additionally contains at least one element selected from the group comprising cerium, zirconium, vanadium, beryllium, hafnium, scandium and molybdenum to 0.15 wt.% Each and not more than 0 , 5 wt.% In total.

The most favorable ratios for some elements in the alloy are the following, wt.%:

Magnesium 4.2-5.4

Manganese 0.2-0.6

Iron 0.1-0.3

Silicon 0.05-0.18

The content of permissible impurities in the alloy does not exceed, wt.%: Lead, cadmium, bismuth, tin, indium, gallium, sodium, potassium, calcium, barium, fluorine, nitrogen, oxygen, lithium - 0.05%, hydrogen - 2.5 × 10 ^-5 , sulfur - 0.005, niobium, tungsten, tantalum - 0.03, silver, yttrium - 0.15.

The problem is also solved by the product of a thin sheet of thermally unstrengthened aluminum-based alloy made of the above alloy.

The product may be an element of a container, in particular a can, for example a lid, key, housing.

The product can be made welded, for example, part of the welded structure in shipbuilding, an element of the building structure in the form of cladding, etc.

The product may be coated on one or both sides with a protective coating, for example, varnish, or the product may be laminated with plastic or painted.

The invention consists in the following.

In well-known alloys, severe cold deformation (hardening) during subsequent low-temperature heating (Н2 and Н4 states) leads to intensive release of β-phase particles (Al ₃ Mg ₂ ) along the grain boundaries in the form of a continuous continuous network, which leads to a decrease in strength properties, stampability, technological plasticity, corrosion resistance, in addition, the instability of the solid solution leads to the process of its further decay during long aging in storage conditions or during technological heating of finished products and how quently - to reduce their property, destruction and reduced engine life.

The composition of the proposed alloy is selected so that Co and / or Ni increase the solubility of Mg in Al. In this case, the stability of the Mg solid solution in Al increases, and the stresses in the crystal lattice decrease. Therefore, the volume fraction of the β phase (Al ₃ Mg ₂ ) released during annealing, technological heating or aging (long-term storage) decreases, which leads to an increase in strength, corrosion resistance, and increases the stability of properties during long aging. In addition, Co and / or Ni bind iron into more compact precipitates and more dispersed than Al ₃ Fe particles of the AlFeCo and AlFeNi phases, which leads to an increase in processability (stampability) during cold deformation of sheets. Additives B and / or C form carbides and / or borides with elements such as Ti, Ni, Co, Fe. These particles serve as the nucleation sites for the β (Al ₃ Mg ₂ ) phase released during heating of the caked sheet. Isolation of the β phase on these particles or on the particle / matrix interface reduces their amount released at the grain boundaries, which leads to an increase in technological plasticity, stampability of sheets, and their corrosion resistance.

The presence in the alloy of one or more elements from the group: cerium, zirconium, vanadium, beryllium, hafnium, molybdenum, scandium in the indicated amounts leads to an improvement in the weldability of the alloy due to additional modification of the structure and a decrease in the degree of oxidizability of the molten metal during fusion welding.

All this leads to the production of thin caked and partially caged sheets with higher values of strength, stampability (technological plasticity), corrosion resistance and reduces the effect of loss of strength during long aging (storage), which leads to an increase in the service life of products, expands the range of manufactured products reduces labor costs for their manufacture.

Examples.

Flat ingots with a section of 100 × 500 mm were cast, the chemical composition of which is given in Table 1.

The ingots were homogenized at a temperature of 480-500 ° C for 6 hours.

Hot rolling of the ingots was carried out at a temperature of 430-450 ° C to a thickness of 6 mm, then the hot-rolled sheet was annealed at a temperature of 310-350 ° C for 3-5 hours and rolled into a cold sheet at a thickness of 1.8 mm, some of the sheets were rolled after additional annealing to a thickness of 0.3 mm, providing a cured state.

Partial annealing of all sheets with a thickness of 1.8 and 0.3 mm was carried out at a temperature of 100-150 ° C for 5-10 hours.

To simulate long-term storage of products and short process heatings, an additional annealing of 0.3 mm sheets at 70 ° C for 100 hours and curing at room temperature for 3000 hours were used.

In addition to the usual mechanical tensile properties, we evaluated the technological plasticity of sheets by bending tests (GOST 14019-80) and extruding (stamping) by the Eriksen method (GOST 10510-80) and resistance to stress corrosion cracking during bending according to GOST 9019-74.

The mechanical and corrosion properties of the sheets are given in tables 2 and 3.

As can be seen from the data in table 2, the proposed alloy in comparison with the known has strength properties higher by 20-60 MPa, while its technological ductility and stampability is 1.5-2 times higher than that of the known. Resistance to corrosion cracking is also 2-3 times higher for the proposed alloy.

From table 3 it is seen that after prolonged curing at room temperature for 3000 hours or simulating heating of 70 ° C for 100 hours, the drop in strength properties of the known alloy is 50-80 MPa, and that of the proposed alloy is 10-25 MPa, which is 2- 3 times less.

Thus, the use of the proposed alloy allows to increase the service life of products, expand the range of manufactured products, reduces labor costs for their manufacture.

Claims (8)

1. An aluminum-based alloy containing magnesium, manganese, titanium, iron, silicon, chromium, zinc, copper, aluminum and admissible impurities, characterized in that it further comprises at least one element selected from the group comprising nickel and cobalt and at least one element selected from the group comprising boron and carbon in the following ratio of components, wt.%: Magnesium 3.0-5.8 Manganese 0.1-1.0 Titanium 0.005-0.15 Iron Up to 0.5 Silicon Up to 0.4 Chrome Up to 0.3 Zinc Up to 0.4 Copper Up to 0.25 at least one element selected from the group including Nickel and cobalt 0.0005-0.25 at least one element selected from the group including Boron and carbon 0.00001-0.05 Aluminum and acceptable impurities the total content of manganese, chromium, titanium and nickel and / or cobalt does not exceed 1.1. 2. The alloy according to claim 1, characterized in that it further comprises at least one element selected from the group consisting of cerium, zirconium, vanadium, beryllium, hafnium, scandium and molybdenum to 0.15 wt.% Each and not more than 0.5 wt.% In total. 3. The alloy according to claim 1 or 2, characterized in that it contains magnesium, manganese, iron and silicon in the following ratio, wt.%: Magnesium 4.2-5.4 Manganese 0.2-0.6 Iron 0.1-0.3 Silicon 0.05-0.18 4. The alloy according to any one of claims 1 to 3, characterized in that the content of permissible impurities does not exceed, wt.%: Lead, cadmium, bismuth, tin, indium, gallium, sodium, potassium, calcium, barium, fluorine, nitrogen, oxygen, lithium 0.05%, hydrogen 2.5 · 10 ^-5 , sulfur 0.005, niobium, tungsten, tantalum 0.03, silver, yttrium 0.15. 5. A product of a thin sheet of thermally unstrengthened aluminum-based alloy, characterized in that it is made of an alloy according to any one of claims 1 to 4. 6. The product according to claim 5, characterized in that it is an element of the container. 7. The product according to claim 6, characterized in that the capacity is a can. 8. The product according to claim 5, characterized in that it is made welded.

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