阅读说明：本技术 一种高成形性5754铝合金板的制备工艺 (Preparation process of high-formability 5754 aluminum alloy plate ) 是由 付凯 王飞 祖立成 崔立治 冉凡青 尹竹松 刘昊 于 2020-11-23 设计创作，主要内容包括：本发明属于铝合金加工制造领域,涉及一种高成形性5754铝合金板的制备工艺,铝合金原料按照重量百分比进行配料,即Si≤0.15％、Fe：0.20～0.35％、Cu≤0.10％、Mn：0.20～0.30％、Mg：2.80～3.10％、Cr：0.08～0.12％、Zn≤0.08％、Ti：0.01～0.03％,单个杂质≤0.05％,合计≤0.15％,余量为Al,通过合适的均匀化温度,铸锭保温后消除晶内偏析,枝晶偏析,减少粗大的非平衡相和共晶相,使得铸锭组织和成分更均匀,控制热轧速度,促进析出相充分破碎,冷轧阶段通过控制压下量以及增加一道中间退火,最终成品获得良好的成形性能和综合力学性能。(The invention belongs to the field of aluminum alloy processing and manufacturing, and relates to a preparation process of a high-formability 5754 aluminum alloy plate, wherein aluminum alloy raw materials are mixed according to the weight percentage, namely Si is less than or equal to 0.15%, Fe: 0.20-0.35%, Cu is less than or equal to 0.10%, Mn: 0.20-0.30%, Mg: 2.80-3.10%, Cr: 0.08-0.12%, Zn is less than or equal to 0.08%, Ti: 0.01-0.03%, less than or equal to 0.05% of single impurities, less than or equal to 0.15% in total and the balance of Al, by proper homogenization temperature, after ingot heat preservation, intragranular segregation and dendrite segregation are eliminated, coarse nonequilibrium phase and eutectic phase are reduced, so that the structure and components of the ingot are more uniform, the hot rolling speed is controlled, the precipitated phase is promoted to be fully crushed, and in the cold rolling stage, good forming performance and comprehensive mechanical property of the final product are obtained by controlling the reduction and adding one intermediate annealing.)

1. A preparation process of an aluminum alloy plate 5754 with high formability is characterized by comprising the following steps:

A. preparing materials: proportioning 5754 aluminum alloy raw materials according to weight percentage, namely, Si is less than or equal to 0.15%, Fe: 0.20-0.35%, Cu is less than or equal to 0.10%, Mn: 0.20-0.30%, Mg: 2.80-3.10%, Cr: 0.08-0.12%, Zn is less than or equal to 0.08%, Ti: 0.01-0.03%, less than or equal to 0.05% of single impurity, less than or equal to 0.15% in total, and the balance of Al;

B. casting: adding the prepared aluminum alloy raw material into a smelting furnace, uniformly mixing, smelting into liquid aluminum alloy, and performing standing, refining, slagging off, online degassing and filtering to obtain aluminum alloy cast ingot;

C. homogenizing: carrying out homogenization heat treatment on the aluminum alloy cast ingot in a heating furnace, namely heating the aluminum alloy cast ingot to 540-560 ℃, preserving heat for 4-8 h, and then cooling to 500 ℃ and preserving heat for 2 h;

D. hot rolling: transferring the homogenized aluminum alloy ingot to a hot rolling mill for hot rolling, wherein the hot rolling is carried out by adopting a 1+5 frame, the ingot is roughly rolled by R1, the thickness of an intermediate blank is set to be 50mm, the temperature of the intermediate blank is 400-440 ℃, the rolling speed is increased after the ingot enters a five-frame finish rolling, the hot rolling speed is 2.0-2.2 m/s, the full crushing of a compound is ensured by high-speed rolling, the dynamic recrystallization is fully carried out, the hot rolling finishing temperature is 320 +/-10 ℃, and the finishing thickness is selected to be 4.0 +/-0.1 mm, so that a completely recrystallized hot rolled blank is obtained;

E. cold rolling: carrying out heat treatment intermediate annealing after the hot-rolled aluminum alloy coiled material is cold-rolled to 1.6mm, keeping the temperature of an aluminum alloy coiled material core part for 2h after the temperature reaches 320 ℃, then discharging the aluminum alloy coiled material from a furnace and naturally cooling to room temperature to obtain a completely O-state intermediate annealing structure, continuously carrying out cold rolling after the coiled material is cooled to room temperature, wherein the cold rolling processing rate is 30-40%, the thickness of the cold-rolled aluminum alloy coiled material is 1.03mm, and the cold-rolled aluminum alloy coiled material is subjected to texturing rolling to 1.0 mm;

F. annealing of a finished product: and (3) finishing final annealing of the cold-rolled aluminum alloy coiled material in a continuous air cushion furnace, wherein the transmission speed of the aluminum alloy coiled material is 60-80 mm/s, the heat preservation of the metal at 480-490 ℃ is ensured for 20s, and the annealed aluminum alloy coiled material is oiled on line.

2. The process for preparing the high-formability 5754 aluminum alloy plate as claimed in claim 1, wherein the aluminum alloy ingot casting in the step B is cast by electromagnetic stirring, a furnace top temperature control mode is selected for smelting, the temperature of molten aluminum in the smelting process is controlled to be 720-760 ℃, a dummy ingot head is used for traction casting in the casting process, and the milling amount of the single surface of the ingot casting is more than or equal to 8 mm.

3. The process for preparing the high-formability 5754 aluminum alloy plate as claimed in claim 2, wherein in the step C, the temperature of the aluminum alloy ingot is raised by setting the temperature of furnace gas, the raising rate is 70-80 ℃/h, the temperature of the ingot is kept for 4-8 h after reaching the target temperature of 540-560 ℃, the temperature is cooled to 500 ℃ by air cooling after the temperature is kept for 2h, and the temperature reduction rate is 20 ℃/h.

4. The process for manufacturing an aluminum alloy sheet as set forth in claim 3, wherein in step E, the core part and the surface layer of the coil are welded with a thermocouple and then are integrally placed in a pusher furnace, the temperature of the furnace gas is set to 380 ℃ to raise the temperature of the coil, when the temperature of the surface of the coil reaches 320 ℃, the temperature of the furnace gas is lowered to 320 ℃, and after the temperature of the core part of the coil reaches 320 ℃, the temperature is maintained for 2 hours.

5. The process for producing aluminum alloy sheet of high formability 5754 as set forth in claim 4, wherein in the step E, the roll is roughened by plasma electric spark to a surface roughness of more than 1.0 μm to obtain a texture pattern by electric spark treatment.

6. The process for preparing an aluminum alloy sheet with high formability 5754 as set forth in claim 5, wherein the amount of dry oil after the aluminum alloy coil is oiled on line in the step F is 0.7-1.0 g/m²。

Technical Field

The invention belongs to the field of aluminum alloy processing and manufacturing, relates to a preparation process of a high-formability 5754 aluminum alloy plate, and particularly relates to a preparation process of a high-formability 5754-O-state aluminum alloy plate.

Background

With the continuous development of the industrial level, the automobile industry has higher and higher requirements on the lightweight of manufacturing materials. The aluminum alloy is used as a renewable energy source, and can realize the light weight of the material to the maximum extent under the condition of meeting the requirement of the performance of the industrial material, thereby achieving the purposes of energy conservation and emission reduction.

The 5754-O alloy manufactured by the prior art has high cracking tendency in the subsequent stamping forming process, and is easy to be necked or cracked at the position with large stamping depth. In the manufacturing process of the aluminum alloy, homogenization before hot rolling and an intermediate annealing added in the cold rolling stage play an important role in improving the plasticity and the stamping forming performance of finished materials. Because of the unbalanced solidification in the casting process and the composition supercooling phenomenon in the rapid cooling process, the ingot inevitably has the intracrystalline segregation and the coarse unbalanced phase and a certain amount of the low-melting-point coarse eutectic phase, which can not be eliminated in time in the finished product, the forming performance of the material is seriously influenced, the plasticity of the material is reduced, and the stamping cracking of parts is caused.

Disclosure of Invention

In view of the above, the invention provides a preparation process of a 5754-O state aluminum alloy plate with high formability, which aims to solve the problems that the forming performance of finished products of 5754-O state aluminum alloys prepared by the existing preparation process is not enough, and cracking risks exist in the stamping forming process of parts.

In order to achieve the aim, the invention provides a preparation process of an aluminum alloy plate 5754 with high formability, which comprises the following steps:

A. preparing materials: proportioning 5754 aluminum alloy raw materials according to weight percentage, namely, Si is less than or equal to 0.15%, Fe: 0.20-0.35%, Cu is less than or equal to 0.10%, Mn: 0.20-0.30%, Mg: 2.80-3.10%, Cr: 0.08-0.12%, Zn is less than or equal to 0.08%, Ti: 0.01-0.03%, less than or equal to 0.05% of single impurity, less than or equal to 0.15% in total, and the balance of Al;

B. casting: adding the prepared aluminum alloy raw material into a smelting furnace, uniformly mixing, smelting into liquid aluminum alloy, and performing standing, refining, slagging off, online degassing and filtering to obtain aluminum alloy cast ingot;

C. homogenizing: carrying out homogenization heat treatment on the aluminum alloy cast ingot in a heating furnace, namely heating the aluminum alloy cast ingot to 540-560 ℃, preserving heat for 4-8 h, and then cooling to 500 ℃ and preserving heat for 2 h; on the premise of maximally saving energy, ingot casting homogenization is realized, the comprehensive mechanical property of a final product can be effectively improved, and the product has better stamping forming performance and higher fracture elongation than a common product without homogenization; the homogenized heat preservation process of the aluminum alloy cast ingot can reduce the segregation of intragranular components, eliminate non-equilibrium phases, balance the structure, reduce excess phases, eliminate metastable phases and promote the transformation of intermetallic compounds from needle-shaped beta phases to alpha phases.

D. Hot rolling: transferring the homogenized aluminum alloy ingot to a hot rolling mill for hot rolling, wherein the hot rolling is carried out by adopting a 1+5 frame, the ingot is roughly rolled by R1, the thickness of an intermediate blank is set to be 50mm, the temperature of the intermediate blank is 400-440 ℃, the rolling speed is increased after the ingot enters a five-frame finish rolling, the hot rolling speed is 2.0-2.2 m/s, the full crushing of a compound is ensured by high-speed rolling, the dynamic recrystallization is fully carried out, the hot rolling finishing temperature is 320 +/-10 ℃, and the finishing thickness is selected to be 4.0 +/-0.1 mm, so that a completely recrystallized hot rolled blank is obtained; the method ensures that the hot rolling adopts a high-speed rolling mode, is a key control process of the invention, and can promote the alloy to be fully and dynamically recrystallized in the hot rolling process to obtain the hot rolled blank with more uniform tissue.

E. Cold rolling: carrying out heat treatment intermediate annealing after the hot-rolled aluminum alloy coiled material is cold-rolled to 1.6mm, keeping the temperature of an aluminum alloy coiled material core part for 2h after the temperature reaches 320 ℃, then discharging the aluminum alloy coiled material from a furnace and naturally cooling to room temperature to obtain a completely O-state intermediate annealing structure, continuously carrying out cold rolling after the coiled material is cooled to room temperature, wherein the cold rolling processing rate is 30-40%, the thickness of the cold-rolled aluminum alloy coiled material is 1.03mm, and the cold-rolled aluminum alloy coiled material is subjected to texturing rolling to 1.0 mm;

F. annealing of a finished product: the cold-rolled aluminum alloy coiled material is subjected to final annealing in a continuous air cushion furnace, the transmission speed of the aluminum alloy coiled material is 60-80 mm/s, the heat preservation of metal is guaranteed for 20s in a range of 480-490 ℃, the material is guaranteed to be fully dissolved through differential temperature heat preservation, the annealed aluminum alloy coiled material is subjected to on-line oil coating, and the on-line oil coating can guarantee that the sufficient lubrication is realized in the subsequent client stamping process and the stamping quality of parts is guaranteed.

And further, in the step B, the aluminum alloy ingot casting is cast by electromagnetic stirring, a furnace top temperature control mode is selected for smelting, the temperature of molten aluminum in the smelting process is controlled to be 720-760 ℃, a dummy ingot head is used for traction casting in the casting process, and the milling surface amount of the single surface of the ingot casting is more than or equal to 8 mm.

And further, in the step C, heating the aluminum alloy cast ingot by setting the temperature of furnace gas, wherein the heating rate is 70-80 ℃/h, keeping the temperature for 4-8 h after the temperature of the cast ingot reaches the target temperature of 540-560 ℃, cooling to 500 ℃ by air cooling after the heat preservation is finished, and keeping the temperature for 2h, and the cooling rate is 20 ℃/h.

And E, welding a thermocouple into the core part and the surface layer of the coiled material in the step E, then integrally loading the coiled material into a push type heating furnace, setting the temperature of furnace gas to be 380 ℃ for heating the coiled material, reducing the temperature of the furnace gas to 320 ℃ when the surface of the coiled material reaches 320 ℃, and preserving the temperature for 2 hours after the core part of the coiled material reaches 320 ℃.

And furthermore, in the step E, the roller is roughened by plasma electric spark, the surface roughness of the roller is more than 1.0 mu m, and the texture pattern processed by the electric spark is obtained.

Further, in the step F, the amount of dry oil after the aluminum alloy coiled material is oiled on line is 0.7-1.0 g/m²。

The invention has the beneficial effects that:

1. according to the preparation process of the high-formability 5754 aluminum alloy plate disclosed by the invention, by virtue of a proper homogenization temperature, after ingot casting is carried out heat preservation, the intragranular segregation and the dendrite segregation are eliminated, the coarse nonequilibrium phase and the eutectic phase are reduced, the structure and the components of the ingot casting are more uniform, the hot rolling speed is controlled, the fully crushing of the precipitated phase is promoted, and in the cold rolling stage, the good forming performance and the comprehensive mechanical property of a final product are obtained by controlling the reduction and adding one intermediate annealing.

2. Compared with the prior art, the preparation process of the high-formability 5754 aluminum alloy plate has the greatest advantages of improving the fracture elongation of the material on the basis of energy conservation, enabling the mechanical properties of the material to be more uniform in three directions, improving the forming performance of the material, realizing the application of the 5754 aluminum alloy material in the field of automobile part stamping, improving the rejection rate in the stamping process and reducing the stamping cost of the parts.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter.

Drawings

For the purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made to the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a microstructure diagram of a precipitated phase of a hot rolled blank according to an embodiment of the present invention;

FIG. 2 is a microstructure diagram of a precipitated phase of a hot rolled billet according to a comparative example of the present invention;

FIG. 3 is a metallographic structure diagram of a hot rolled billet according to an example of the present invention;

FIG. 4 is a texture pattern morphology diagram after the cold rolled blank is subjected to texturing rolling in the embodiment of the invention;

FIG. 5 is a drawing curve of an aluminum alloy sheet product manufactured in accordance with an example of the present invention in three directions.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

Examples

A preparation process of an aluminum alloy plate with high formability 5754 comprises the following steps:

A. preparing materials: proportioning 5754 aluminum alloy raw materials according to weight percentage, namely Si: 0.15%, Fe: 0.35%, Cu: 0.10%, Mn: 0.30%, Mg: 3.10%, Cr: 0.12%, Zn: 0.08%, Ti: 0.03 percent, less than or equal to 0.05 percent of impurities and the balance of Al;

B. casting: adding the prepared aluminum alloy raw material into a smelting furnace, uniformly mixing, smelting into liquid aluminum alloy, performing standing, refining, slagging off, online degassing and filtering, casting the liquid aluminum alloy into an aluminum alloy ingot, wherein the aluminum alloy ingot is cast by adopting electromagnetic stirring, the smelting selects a furnace top temperature control mode, the temperature of molten aluminum in the smelting process is controlled to be 720-760 ℃, a dummy ingot head is used for traction casting in the casting process, and the single-sided milling amount of the ingot is more than or equal to 8 mm; the size of the aluminum alloy cast ingot is 630mm 1380mm 7400mm, the cast ingot is milled to cut the head and the tail, and the size after the milling is 610mm 1350mm 7000 mm;

C. homogenizing: carrying out homogenization heat treatment on the aluminum alloy cast ingot in a heating furnace, namely heating the aluminum alloy cast ingot by setting furnace gas temperature, wherein the heating rate is 70-80 ℃/h, keeping the temperature for 6h after the temperature of the cast ingot reaches a target temperature of 540 ℃, cooling to 500 ℃ after the heat preservation, keeping the temperature for 2h, and the cooling rate is 20 ℃/h; on the premise of maximally saving energy, ingot casting homogenization is realized, the comprehensive mechanical property of a final product can be effectively improved, and the product has better stamping forming performance and higher fracture elongation than a common product without homogenization; the homogenized heat preservation process of the aluminum alloy cast ingot can reduce the segregation of intragranular components, eliminate non-equilibrium phases, balance the structure, reduce excess phases, eliminate metastable phases and promote the transformation of intermetallic compounds from needle-shaped beta phases to alpha phases.

D. Hot rolling: transferring the homogenized aluminum alloy cast ingot to a hot rolling mill for hot rolling, wherein the hot rolling is carried out by adopting 1+5 stands, the cast ingot is roughly rolled by R1, the thickness of an intermediate billet is set to be 50mm, the temperature of the intermediate billet is 420 ℃, the rolling speed is increased after the cast ingot enters a five-stand finish rolling, the hot rolling speed is 2.1m/s, the compound is ensured to be fully crushed by high-speed rolling, the dynamic recrystallization is fully carried out, the hot rolling finishing temperature is 320 ℃, and the finishing thickness is selected to be 4.0mm, so that a fully recrystallized hot rolled blank is obtained; the method ensures that the hot rolling adopts a high-speed rolling mode, is a key control process of the invention, and can promote the alloy to be fully and dynamically recrystallized in the hot rolling process to obtain the hot rolled blank with more uniform tissue. The microstructure of the precipitated phase of the hot rolled blank is shown in figure 1. compared with the hot rolled coil phase which is not homogenized in figure 2, the alloy has no coarse primary phase, because the supersaturated solid solution is decomposed after the long-term heat preservation at the temperature near the solidus, and the structure is more uniform. Metallographic structure analysis of the hot rolled stock structure as shown in fig. 3, the material had been completely recrystallized to obtain an O-phase metallographic structure with uniform grains.

E. Cold rolling: the hot-rolled aluminum alloy coil is cold-rolled to 1.6mm and then is subjected to heat treatment intermediate annealing, a thermocouple is welded in the core part and the surface layer of the aluminum alloy coil and then is integrally placed in a push type heating furnace, the temperature of furnace gas is set to 380 ℃ for heating the coil, the temperature of the furnace gas is reduced to 320 ℃ when the surface of the coil reaches 320 ℃, and after the core part of the coil reaches 320 ℃, heat is preserved for 2 hours to ensure that the nucleation distortion energy stored after the material is cold-rolled is completely released to obtain uniform tissues, so that the material performance is more uniform in the rolling direction, the direction vertical to the rolling direction and the direction forming an angle of 45 degrees with the rolling direction. Then, the aluminum alloy coiled material is taken out of the furnace and naturally cooled to room temperature to obtain a completely O-state intermediate annealing structure, the coiled material is continuously subjected to cold rolling after being cooled to the room temperature, the cold rolling processing rate is 30-40%, the thickness of the aluminum alloy coiled material after the cold rolling is 1.03mm, and the aluminum alloy coiled material after the cold rolling is subjected to texturing rolling to 1.0 mm; the roller is roughened by plasma electric spark, the roughness of the surface of the roller is more than 1.0 mu m, and the texture pattern processed by the electric spark is obtained, and the appearance is shown in figure 4;

F. annealing of a finished product: finishing final annealing of the cold-rolled aluminum alloy coiled material in a continuous air cushion furnace to obtain the aluminum alloy coilThe material conveying speed is 60-80 mm/s, the heat preservation of metal is guaranteed for 20s at the temperature of 480-490 ℃, the sufficient solid solution of the material is guaranteed through differential temperature heat preservation, the aluminum alloy coiled material is oiled on line after annealing, and the dry oil amount of the aluminum alloy coiled material after the oil coating on line is 0.7-1.0 g/m². The online oiling can ensure that the sufficient lubrication is realized in the follow-up client stamping process, and the stamping quality of parts is ensured. And finally, performing mechanical property test on the finished product, wherein the tensile curve is shown as the attached figure 5, and the alloy shows relatively uniform mechanical properties in three directions.

Comparative example

The comparative example differs from the examples in that the comparative example lacks step C, i.e. the aluminium alloy sheet is hot rolled directly after casting.

Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.