CN109207817B

CN109207817B - Preparation process of high-conductivity and high-strength aluminum alloy and aluminum alloy prepared by preparation process

Info

Publication number: CN109207817B
Application number: CN201811222612.XA
Authority: CN
Inventors: 张源硕; 王岗; 颜鹏
Original assignee: Guangya Aluminium Co ltd
Current assignee: Guangya Aluminium Co ltd
Priority date: 2018-10-19
Filing date: 2018-10-19
Publication date: 2020-09-15
Anticipated expiration: 2038-10-19
Also published as: CN109207817A

Abstract

A preparation process of an aluminum alloy with high conductivity and high strength and the aluminum alloy thereof comprise the following steps: (1) melting solid pure aluminum in a melting furnace to obtain liquid pure aluminum; (2) adding silicon, magnesium, iron, copper, manganese and zinc into the smelting furnace in the step (1); according to the mass fraction, the proportion of each component is controlled as follows: 0.15 to 0.3 percent of silicon, less than or equal to 0.2 percent of iron, less than or equal to 0.1 percent of copper, 0.04 to 0.06 percent of manganese, 0.3 to 0.5 percent of magnesium, 0.08 to 0.12 percent of zinc and the balance of aluminum; fully mixing to obtain aluminum alloy liquid; pouring and cooling the aluminum alloy liquid to obtain primary aluminum alloy; (3) extruding and forming the primary aluminum alloy obtained in the step (2) to obtain a secondary aluminum alloy; (4) sending the secondary aluminum alloy obtained in the step (3) to an aging furnace, enabling the internal temperature of the aging furnace to be uniform, and starting a heating power supply; cooling after aging to obtain the processed aluminum alloy with high conductivity and high strength; the aluminum alloy is provided with an aluminum alloy having an electrical conductivity of 34.2Ms/m and a tensile strength of 176 MPa.

Description

Preparation process of high-conductivity and high-strength aluminum alloy and aluminum alloy prepared by preparation process

Technical Field

The invention relates to the technical field of aluminum alloy, in particular to a preparation process of an aluminum alloy with high conductivity and high strength and an aluminum alloy thereof.

Background

Among the currently known conductive materials, copper and copper alloys have been regarded as the first choice for producing conductive materials because of their excellent conductive properties, but the trade price of copper has begun to rise rapidly as the global reserve of copper resources has been drastically reduced and depleted. According to recent data, the current trade price of copper per ton is about $ 7000, and such high investment cost leads to the price of copper wire and other products rising, so that the world electricians consciously recognize the importance and urgency of improving or searching for a new power transmission line. And the rapid rise of copper price also causes numerous large and medium manufacturing and processing enterprises at home and abroad to begin to find substitutes for copper and copper alloy. In contrast, the current market price of commercial aluminum per ton is only about $ 2800, and thus, the search for an aluminum alloy material to replace copper alloy is the focus of attention in the world.

At present, the aluminum alloy conductive material is mainly applied to two directions, namely an urban rail transit conductive rail and an aluminum alloy bus, according to the technical requirements of CJ/T414-2012 urban rail transit steel-aluminum composite conductive rail, the aluminum alloy conductivity is 30.92-31.57Ms/m, the tensile strength is more than or equal to 215MPa, the yield strength is more than or equal to 160MPa, and the tensile rate is more than or equal to 8 percent, so that the requirements can be met; in part 2 of the GB5585.2-2005-T electrical copper, aluminum and alloy bus: in aluminum and aluminum alloy buses (the aluminum content is more than or equal to 99.5%), the conductivity of LMR and LHMR is required to be more than or equal to 35.38Ms/m, the tensile strength is more than or equal to 68.6MPa, and the tensile rate is more than or equal to 20%; the conductivity requirements of LMY and LHMY are more than or equal to 34.51Ms/m, the tensile strength is more than or equal to 118MPa, and the tensile rate is more than or equal to 3 percent (LMR is a soft aluminum bus, LHMR is a soft aluminum alloy bus, LMY is a hard aluminum bus, LHMY is a hard aluminum alloy bus). It follows that aluminum alloys tend to be lower in strength when they have higher electrical conductivity, and not higher in strength.

Disclosure of Invention

The invention aims to provide a preparation process of an aluminum alloy with high conductivity and high strength, which can be used for preparing the aluminum alloy with high conductivity and high strength by controlling the proportion of silicon, magnesium, iron, copper, manganese and zinc.

The invention also provides an aluminum alloy with high conductivity and high strength, wherein the conductivity of the aluminum alloy is 33.0-34.5 Ms/m, and the tensile strength of the aluminum alloy is 170-200 MPa.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation process of an aluminum alloy with high conductivity and high strength comprises the following steps:

(1) melting solid pure aluminum in a melting furnace to obtain liquid pure aluminum;

(2) adding silicon, magnesium, iron, copper, manganese and zinc to the smelting furnace in the step (1); according to the mass fraction, the proportion of each component is controlled as follows: 0.15 to 0.3 percent of silicon, less than or equal to 0.2 percent of iron, less than or equal to 0.1 percent of copper, 0.04 to 0.06 percent of manganese, 0.3 to 0.5 percent of magnesium, 0.08 to 0.12 percent of zinc and the balance of aluminum;

fully mixing to obtain aluminum alloy liquid; pouring and cooling the aluminum alloy liquid to obtain primary aluminum alloy;

(3) extruding and forming the primary aluminum alloy obtained in the step (2) to obtain a secondary aluminum alloy;

(4) sending the secondary aluminum alloy obtained in the step (3) to an aging furnace, enabling the internal temperature of the aging furnace to be uniform, and starting a heating power supply; and cooling after aging to obtain the processed aluminum alloy with high conductivity and high strength.

Further, in the step (4), the aging temperature is 180-190 ℃.

Further, in the step (4), the aging heat preservation time is 15-22 h.

Further, in the step (4), the furnace used for aging is a secondary furnace, the temperature uniformity is +/-6 ℃, the heating rate is 2-3 ℃/min, and the standing time before entering the furnace cannot be more than 20 hours.

In the step (3), the primary aluminum alloy is pre-heated before being extruded in the step (2).

Further, in the step (4), the secondary aluminum alloy is placed on an aging furnace skip with wheels, and the aging furnace skip is pushed into the aging furnace.

Further, in the step (4), a circulating fan is used for ensuring the uniform temperature inside the aging furnace.

Furthermore, in the step (2), the smelting furnace is also provided with filling materials, and the content of the filling materials is not more than 0.1%;

the filling material comprises: simple substances and impurities.

A high conductivity and high strength aluminum alloy comprising, in mass fractions: 0.15-0.3% of silicon, less than or equal to 0.2% of iron, less than or equal to 0.1% of copper, 0.04-0.06% of manganese, 0.3-0.5% of magnesium, 0.08-0.12% of zinc, less than or equal to 0.1% of filling material and the balance of aluminum.

Further, the aluminum alloy has an electrical conductivity of 33.0 to 34.5 Ms/m.

Further, the tensile strength of the aluminum alloy is 170 to 200 MPa.

The invention has the beneficial effects that:

1. the design comprises fusion casting, extrusion and agingThe alloy composition of the product mainly controls the content of Mg and Si so as to fully combine the Mg and the Si into Mg₂Si, and can be Mg after aging treatment₂Si is completely separated out, so that the performance and the conductivity can be ensured; and simultaneously, the additional magnesium, iron, copper and zinc are blended to ensure that the additional substances have synergistic action.

2. The design can prepare the aluminum alloy with the conductivity of 34.2Ms/m and the tensile strength of 176MPa by matching with the aging temperature of 185 ℃ and the aging heat preservation time of 20 h.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments.

(2) adding silicon, magnesium, iron, copper, manganese and zinc to the smelting furnace in the step (1); according to the mass fraction, the proportion of each component is controlled as follows: 0.15-0.3% of silicon, less than or equal to 0.2% of iron, less than or equal to 0.1% of copper, 0.04-0.06% of manganese, 0.3-0.5% of magnesium, 0.08-0.12% of zinc, less than or equal to 0.1% of filling materials and the balance of aluminum;

wherein the filling material comprises a simple substance and an unavoidable compound or mixture.

Further, in the step (4), the aging temperature is 180-190 ℃.

Further, in the step (4), the aging heat preservation time is 15-22 h.

Further, in the step (4), the furnace used for aging is a secondary furnace, the temperature uniformity is +/-6 ℃, the heating rate is 2-3 ℃/min, and the standing time before entering the furnace cannot be more than 20 hours. The time from the extrusion to the product before the product enters an aging furnace cannot exceed 20 hours, if the standing time is too long, natural aging occurs, the final result of artificial aging is affected, and the mechanical property and the conductivity are lower by about 10%.

More specifically, in the step (3), the primary aluminum alloy is pre-heated before the extrusion of the primary aluminum alloy in the step (2); firstly, the preheating energy reduces the deformation resistance of the aluminum bar in the extrusion process, and on the other hand, the temperature of the extruded section bar is ensured to be high enough to reach the quenching temperature. .

the filling material comprises: simple substances and impurities. The simple substance can help the tensile strength and the conductivity, and trace simple substances such as Ag, Au or C can help the conductivity; the other part is impurities, the limited content reduces the influence on the performance, and the small amount of impurities can provide the filling effect, thereby saving the cost.

Further, the tensile strength of the aluminum alloy is 170 to 200 MPa.

And (3) performance testing:

and (3) conductivity test: preheating the instrument by using a conductivity meter according to the requirement and strictly according to GB/T12966-2008, and calibrating the conductivity meter; at least selecting more than 3 test points to measure according to the size, shape and state of the test surface, measuring for 2-3 times near each test point, reading the conductivity test value of each part, and taking an average value.

And (3) testing tensile strength: the test piece was clamped at both ends by tensile clamps and placed in a testing machine exactly as in GB/T16865-.

Example A (185 ℃ C.. times.16 h):

TABLE 1 compounding ratio of examples A1-A6

Examples A1-A6 were tested for conductivity and tensile strength and are given in Table 2.

TABLE 2 conductivity and tensile Strength of examples A1-A6

And (4) conclusion:

the electrical conductivity of the examples increased sequentially as the Si content increased, and when the Si content reached 0.25kg, the aluminum alloy had the maximum electrical conductivity of 33.9Ms/m and the tensile strength thereof was 173 MPa; when the maximum value of the conductivity is reached, the conductivity is reduced to 31.2Ms/m in sequence along with the increase of the content of Si; therefore, the design can reach the optimal range of conductivity and tensile strength when the silicon content is 0.15-0.3%.

Example B (185 ℃ C.. times.16 h):

TABLE 3 compounding ratio of examples B1-B6

TABLE 4 conductivity and tensile Strength of examples B1-B6

	Conductivity (Ms/m)	Tensile Strength (MPa)
			Example B1	30.6	183
Example B2	32.3	177
			Example B3	33.3	174
Example B4	33.4	173
			Example B5	34.2	169
Example B6	34.1	164

And (4) conclusion:

the electrical conductivity of the examples increased sequentially with increasing Mg content, and when the Mg content reached 0.45kg, the aluminum alloy had the maximum electrical conductivity of 33.4Ms/m and its tensile strength of 173 MPa; when the maximum value of the conductivity is reached, the conductivity is not obviously improved along with the increase of the Mg content; therefore, when the Mg content is 0.3-0.5%, the optimal range of conductivity and tensile strength can be achieved.

Example C (185 ℃ C.. times.16 h):

TABLE 5 compounding ratio of examples C1-C6

TABLE 6 conductivity and tensile strength of examples C1-C6

	Conductivity (Ms/m)	Tensile Strength (MPa)
			Example C1	32.4	165
Example C2	32.7	171
			Example C3	33.3	174
Example C4	33.5	176
			Example C5	33.0	174
Example C6	31.9	166

And (4) conclusion:

comparing example C1 with example C2, it can be seen that example C2 has 0.05kg of Fe, which increases the conductivity by 0.3Ms/m and the tensile strength by 6MPa, thus Fe provides conductivity and tensile strength in the system.

The electrical conductivity of the examples increased sequentially as the Fe content increased, and when the Fe content reached 0.15kg, the aluminum alloy had the maximum electrical conductivity of 33.5Ms/m and its tensile strength of 176 MPa; when the maximum value of the conductivity is reached, the conductivity is reduced along with the increase of the Fe content; therefore, when the design needs to control Fe to be less than or equal to 0.2 percent, the aluminum alloy can have a lifting effect.

Example D (185 ℃ C.. times.16 h):

TABLE 7 compounding ratios of examples D1 to D7

TABLE 8 conductivity and tensile Strength of examples D1-D6

	Conductivity (Ms/m)	Tensile Strength (MPa)
			Example D1	32.3	170
Example D2	32.6	173
			Example D3	33.0	176
Example D4	33.2	176
			Example D5	33.6	176
Example D6	33.3	174
			Example D7	33.3	174

And (4) conclusion:

comparing example D1 with example D2, it can be seen that example D2 has 0.05kg of Cu which increases the conductivity by 0.3Ms/m and the tensile strength by 3MPa, so that Cu provides conductivity and tensile strength in the system.

The electrical conductivity and tensile strength of the examples increased sequentially as the Cu content increased, and when the Cu content reached 0.10kg, the aluminum alloy had the maximum electrical conductivity of 33.6Ms/m and the tensile strength of 176 MPa; when the maximum value of the conductivity is reached, the conductivity is not obviously improved along with the increase of the Cu content; and when the content of Cu exceeds 0.10kg, the tensile strength starts to decrease; therefore, when the copper content is less than or equal to 0.1 percent, the optimal conductivity can be achieved.

Example E (185 ℃ C.. times.16 h):

TABLE 9 compounding ratios of examples E1 to E6

TABLE 10 conductivity and tensile Strength of examples E1-E6

	Conductivity (Ms/m)	Tensile Strength (MPa)
			Example E1	31.3	168
Example E2	31.7	169
			Example E3	32.9	175
Example E4	33.3	174
			Example E5	33.0	170
Example E6	33.0	170

And (4) conclusion:

in comparative examples E1 to E3, when the Mn content is 0.04kg, the improvement range of the conductivity and the tensile strength is large, namely, in example E2, the improvement of 0.01kg is only 0.4Ms/m and 1MPa compared with that of example E1; in example E3, the yield of 0.01kg was increased by 1.2Ms/m and 6MPa compared with example E2.

The conductivity of the examples is increased sequentially with the increase of the Mn content, and when the Mn content reaches 0.06kg, the Mn content does not affect the performance of the aluminum alloy any more; therefore, when the Mn content is 0.04-0.06% of the designed Mn, the optimal conductivity and tensile strength can be achieved.

Example F (185 ℃ C.. times.16 h):

TABLE 11 compounding ratios of examples F1 to F8

TABLE 12 conductivity and tensile strength of examples F1-F6

Comparing example F2 with example F1, example F2 has 0.02kg more Zn than example F1, and example F2 has 1.3Ms/m more conductivity and 3MPa more tensile strength than example F1, so the addition of Zn to the aluminum alloy system in the design can improve the conductivity and tensile strength; when the content of Zn reaches 0.12, the content of Zn is continuously increased, so that the conductivity and the tensile strength are not changed any more; therefore, the Zn of the designed aluminum alloy has the optimal performance when the Zn is 0.08-0.12%.

Example H:

table 13 was prepared by proportioning the best properties of examples A-F for example H1, and using the 6063 aluminum alloy of the prior art as example H2; and example H is compared to example H2 for performance to give Table 14;

TABLE 13 formulation of example H1 and example H2

Component (A)	Example H1(kg)	Example H2(kg)
			Si	0.25	0.30
Mg	0.45	0.70
			Fe	0.15	0.35
Cu	0.08	0.10
			Mn	0.05	0.10
Zn	0.10	0.10
			Cr	-	0.10
Ti	-	0.10
			Filling material	0.1	0.15
Al	99.20	98.00

TABLE 12 Effect of different aging Processes on example H

Description of the drawings:

by comparing Table 12, the highest conductivity achieved by the alloy of example H2 was 32Ms/m, the highest conductivity achieved by the alloy studied in this patent, example H1, was 34.2Ms/m, the tensile strength decreased with time, and the elongation increased with time. Meanwhile, the comparison also shows that the conductivity of the H2 of the examples H1 and H2 has a peak value with the prolonging of the aging time, and the conductivity can not change with the prolonging of the aging time after the peak value, so the optimal unconventional aging process researched by the patent is 185 ℃ multiplied by 20H.

The technical principle of the present invention is described above in connection with specific embodiments. The description is made for the purpose of illustrating the principles of the invention and should not be construed in any way as limiting the scope of the invention. Based on the explanations herein, those skilled in the art will be able to conceive of other embodiments of the present invention without inventive effort, which would fall within the scope of the present invention.

Claims

1. A preparation process of an aluminum alloy with high conductivity and high strength is characterized by comprising the following steps:

(4) sending the secondary aluminum alloy obtained in the step (3) to an aging furnace, starting heating to enable the internal temperature of the aging furnace to be uniform, and starting a heating power supply; cooling after aging to obtain the processed aluminum alloy with high conductivity and high strength;

in the step (4), the aging temperature is 180-190 ℃; the aging heat preservation time is 15-22 h.

2. The preparation process of the aluminum alloy with high conductivity and high strength as claimed in claim 1, wherein in the step (4), the furnace used for aging is a secondary furnace, the temperature uniformity is +/-6 ℃, the heating rate is 2-3 ℃/min, and the standing time before entering the furnace is not more than 20 hours.

3. The process for preparing an aluminum alloy with high conductivity and high strength as claimed in claim 1, wherein in the step (3), the primary aluminum alloy is pre-heated before the primary aluminum alloy in the step (2) is extruded.

4. The process of claim 1, wherein in step (4), the secondary aluminum alloy is placed on a wheeled aging trolley and the aging trolley is pushed into the aging furnace.

5. The process for preparing the aluminum alloy with high conductivity and high strength as claimed in claim 1, wherein in the step (4), a circulating fan is used to ensure uniform temperature inside the aging furnace.

6. The process for preparing the aluminum alloy with high conductivity and high strength according to claim 1, wherein in the step (2), the smelting furnace is also provided with a filling material, and the content of the filling material is not more than 0.1%; the filling material comprises: simple substances and impurities.

7. An aluminum alloy of high conductivity and high strength, characterized by comprising, in mass percent: 0.15-0.3% of silicon, less than or equal to 0.2% of iron, less than or equal to 0.1% of copper, 0.04-0.06% of manganese, 0.3-0.5% of magnesium, 0.08-0.12% of zinc, less than or equal to 0.1% of filling materials and the balance of aluminum; the aluminum alloy is prepared by the aluminum alloy preparation process of any one of claims 1-6.

8. The aluminum alloy of claim 7, wherein the aluminum alloy has an electrical conductivity of 33.0-34.5 Ms/m and a tensile strength of 170-200 MPa.