阅读说明：本技术 一种汽车门槛梁用铝合金及汽车门槛梁加工方法 (Aluminum alloy for automobile doorsill beam and automobile doorsill beam machining method ) 是由 罗世兵 张兴状 于 2021-06-07 设计创作，主要内容包括：本发明公开了一种汽车门槛梁用铝合金及汽车门槛梁加工方法,本发明汽车门槛梁用铝合金各组分的重量百分比为：Si：0.77-0.80％,Fe：≤0.25％,Cu：0.05-0.08％,Mn：0.52-0.55％,Mg：0.62-0.65％,Cr：0.06-0.09％,Zn：≤0.10％,Ti：≤0.10％,余量Al。本发明门槛梁加工方法采用前述铝合金。本发明铝合金抗拉强度Rm≥300MPa,屈服强度RP0.2≥270MPa,延伸率A≥12％,符合生产门槛梁的铝合金材料要求,且本发明挤压门槛梁可持续挤压＞14H无颗粒析出拉伤等硬质合金挤压缺陷,可降低同挤压设备同模具的挤压抗力即突破压力20Mpa,可提高单幅挤压模具寿命至有效产出型材＞40T。(The invention discloses an aluminum alloy for an automobile threshold beam and a processing method of the automobile threshold beam, wherein the aluminum alloy for the automobile threshold beam comprises the following components in percentage by weight: si: 0.77-0.80%, Fe: less than or equal to 0.25 percent, Cu: 0.05 to 0.08%, Mn: 0.52-0.55%, Mg: 0.62-0.65%, Cr: 0.06-0.09%, Zn: less than or equal to 0.10 percent, Ti: less than or equal to 0.10 percent and the balance of Al. The threshold beam processing method adopts the aluminum alloy. The tensile strength Rm of the aluminum alloy is more than or equal to 300MPa, the yield strength RP0.2 is more than or equal to 270MPa, the elongation A is more than or equal to 12 percent, the requirements of the aluminum alloy material for producing the threshold beam are met, the threshold beam can be extruded continuously for more than 14H, the defects of hard alloy extrusion such as granule separation and strain are avoided, the extrusion resistance of the same extrusion equipment and the same die, namely the breakthrough pressure is 20MPa, and the service life of a single-width extrusion die can be prolonged until the section bar is effectively produced for more than 40T.)

1. The utility model provides an aluminum alloy for car threshold roof beam which characterized in that: the weight percentage of each component is as follows: si: 0.77-0.80%, Fe: less than or equal to 0.25 percent, Cu: 0.05 to 0.08%, Mn: 0.52-0.55%, Mg: 0.62-0.65%, Cr: 0.06-0.09%, Zn: less than or equal to 0.10 percent, Ti: less than or equal to 0.10 percent and the balance of Al.

2. The aluminum alloy for an automobile rocker beam according to claim 1, wherein: the weight percentage of each component is as follows: si: 0.77-0.80%, Fe: 0.15 or less, Cu: 0.05 to 0.07%, Mn: 0.52-0.53%, Mg: 0.62-0.64%, Cr: 0.07-0.08%, Zn: less than or equal to 0.03 percent, Ti: less than or equal to 0.04 percent and the balance of Al.

3. The aluminum alloy for an automobile rocker beam according to claim 1, wherein: the weight percentage of each component is Si: 0.774%, Fe: 0.146%, Cu: 0.053%, Mn: 0.529%, Mg: 0.637%, Cr: 0.072%, Zn: 0.022%, Ti: 0.031%, and the balance Al.

4. The aluminum alloy for an automobile rocker beam according to claim 1, wherein: the weight percentage of each component is Si: 0.793%, Fe: 0.121%, Cu: 0.061%, Mn: 0.528%, Mg: 0.632%, Cr: 0.072%, Zn: 0.013%, Ti: 0.030% and the balance Al.

5. The aluminum alloy for an automobile rocker beam according to claim 1, wherein: the weight percentage of each component is Si: 0.790%, Fe: 0.127%, Cu: 0.065%, Mn: 0.523%, Mg: 0.626%, Cr: 0.074%, Zn: 0.011%, Ti: 0.029% and the balance of Al.

6. A method for processing an automobile threshold beam is characterized in that: an aluminum bar cast from an aluminum alloy using the rocker beam for automobiles according to any one of claims 1 to 5; use 3600T extruder extrusion aluminium bar shaping car threshold beam section bar and make car threshold beam goods, aluminium bar diameter phi 268mm, mould temperature: 470 ± 10 ℃, extrusion barrel temperature: 440 +/-10 ℃, the internal diameter of the extrusion cylinder is phi 276mm, and the discharge speed is as follows: 2.5m/min, aluminum bar temperature: 490 +/-10 ℃, extrusion cylinder length 1450mm, on-line quenching: the extruded aluminum alloy section is cooled in a quenching device by strong wind, the front area of a cooling fan is cooled by using the auxiliary cooling of a rear area of 75Kw of 110Kw, the frequency of the fan is switched to be more than 45Hz, the temperature of the aluminum alloy section before quenching is 535 and 560 ℃, and the temperature of the aluminum alloy section after quenching is less than 90 ℃.

7. The method of machining an automobile rocker beam of claim 6, wherein: the method comprises the following steps: A. in the smelting of 6082 aluminum alloy, adding proper magnesium-silicon alloy to control the element proportion in the aluminum alloy, wherein the temperature of the aluminum liquid is 750 ℃ during the adding; B. when the aluminum bar is cast, two stages of filter plates are adopted for filtering, wherein the first stage of filtering is 40 meshes, and the second stage of filtering is 60 meshes; C. an oil pressure casting machine and a casting disc are used for casting, wherein a water curtain type cooling mode is used for cooling a crystallizer, and the casting process needs to be continuously carried out; D. carrying out homogenization annealing on the cast aluminum bar, and continuously keeping the temperature at 570 ℃ for 10H; E. extruding and forming the aluminum bar to prepare a threshold beam product; F. and (3) continuously preserving the temperature of the automobile doorsill beam product for 7 hours at the atmosphere temperature of 180 ℃ for artificial aging.

8. The method of machining an automobile rocker beam according to claim 7, wherein: and D, performing homogenizing annealing by adopting water cooling.

Technical Field

The invention relates to an aluminum alloy for an automobile threshold beam and a processing method of the automobile threshold beam.

Background

In an automobile body structure, a rocker beam is important for transmitting the force of a front and side collision in addition to improving the strength of a door frame against stepping. The energy absorption characteristic of the threshold beam in the side collision process of the automobile has an important relation with the safety of the automobile body, and meanwhile, the threshold beam has important influence on the structural strength and the rigidity of the whole automobile. In addition, in order to reduce the intrusion amount in the process of automobile side collision to ensure the safety of passengers, the doorsill beam is generally designed into an integral structure from the lower section of an A column to the lower section of a C column of an automobile, and meanwhile, cold-punching high-strength steel materials with larger thickness are adopted, so that the doorsill beam has larger weight and deviates from the current trend of light weight of the automobile, and therefore, the adoption of high-strength aluminum alloy is a main trend.

The existing aluminum alloy material for producing the threshold beam needs to meet the conditions that Rm is more than or equal to 300MPa, RP0.2 is more than or equal to 270MPa, and A50 is more than or equal to 12 percent, and under the conditions, the hard alloy has the defects of particle precipitation, roughness, strain fracture and the like easily occurring in the extrusion process, has large damage on an extrusion die and poor sustainable extrusion performance, and causes the need of frequent die replacement, thereby affecting the production efficiency.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the aluminum alloy for the automobile doorsill beam with good sustainable extrusion performance and the processing method of the automobile doorsill beam adopting the aluminum alloy are provided.

In order to solve the technical problem, the aluminum alloy for the automobile doorsill beam comprises the following components in percentage by weight: si: 0.77-0.80%, Fe: less than or equal to 0.25 percent, Cu: 0.05 to 0.08%, Mn: 0.52-0.55%, Mg: 0.62-0.65%, Cr: 0.06-0.09%, Zn: less than or equal to 0.10 percent, Ti: less than or equal to 0.10 percent and the balance of Al.

Preferably, the weight percentage of each component is as follows: si: 0.77-0.80%, Fe: 0.15 or less, Cu: 0.05 to 0.07%, Mn: 0.52-0.53%, Mg: 0.62-0.64%, Cr: 0.07-0.08%, Zn: less than or equal to 0.03 percent, Ti: less than or equal to 0.04 percent and the balance of Al.

Preferably, the weight percentage of each component is Si: 0.774%, Fe: 0.146%, Cu: 0.053%, Mn: 0.529%, Mg: 0.637%, Cr: 0.072%, Zn: 0.022%, Ti: 0.031%, and the balance Al.

Preferably, the weight percentage of each component is Si: 0.793%, Fe: 0.121%, Cu: 0.061%, Mn: 0.528%, Mg: 0.632%, Cr: 0.072%, Zn: 0.013%, Ti: 0.030% and the balance Al.

Preferably, the weight percentage of each component is Si: 0.790%, Fe: 0.127%, Cu: 0.065%, Mn: 0.523%, Mg: 0.626%, Cr: 0.074%, Zn: 0.011%, Ti: 0.029% and the balance of Al.

The processing method of the automobile doorsill beam adopts the aluminum bar cast by the aluminum alloy of any one of the automobile doorsill beams; use 3600T extruder extrusion aluminium bar shaping car threshold beam section bar and make car threshold beam goods, aluminium bar diameter phi 268mm, mould temperature: 470 ± 10 ℃, extrusion barrel temperature: 440 +/-10 ℃, the internal diameter of the extrusion cylinder is phi 276mm, and the discharge speed is as follows: 2.5m/min, aluminum bar temperature: 490 +/-10 ℃, extrusion cylinder length 1450mm, on-line quenching: the extruded aluminum alloy section is cooled in a quenching device by strong wind, the front area of a cooling fan is cooled by using the auxiliary cooling of a rear area of 75Kw of 110Kw, the frequency of the fan is switched to be more than 45Hz, the temperature of the aluminum alloy section before quenching is 535 and 560 ℃, and the temperature of the aluminum alloy section after quenching is less than 90 ℃.

Preferably, the method comprises the following steps: A. in the smelting of 6082 aluminum alloy, adding proper magnesium-silicon alloy to control the element proportion in the aluminum alloy, wherein the temperature of the aluminum liquid is 750 ℃ during the adding; B. when the aluminum bar is cast, two stages of filter plates are adopted for filtering, wherein the first stage of filtering is 40 meshes, and the second stage of filtering is 60 meshes; C. an oil pressure casting machine and a casting disc are used for casting, wherein a water curtain type cooling mode is used for cooling a crystallizer, and the casting process needs to be continuously carried out; D. carrying out homogenization annealing on the cast aluminum bar, and continuously keeping the temperature at 570 ℃ for 10H; E. extruding and forming the aluminum bar to prepare a threshold beam product; F. and (3) continuously preserving the temperature of the automobile doorsill beam product for 7 hours at the atmosphere temperature of 180 ℃ for artificial aging.

Preferably, in the step D, water cooling is adopted for performing homogenization annealing.

The invention has the beneficial effects that: the tensile strength Rm of the aluminum alloy is more than or equal to 300MPa, the yield strength RP0.2 is more than or equal to 270MPa, the elongation A is more than or equal to 12 percent, the requirements of the aluminum alloy material for producing the threshold beam are met, the threshold beam can be extruded continuously for more than 14H, the defects of hard alloy extrusion such as granule separation and strain are avoided, the extrusion resistance of the same extrusion equipment and the same die, namely the breakthrough pressure is 20MPa, and the service life of a single-width extrusion die can be prolonged until the section bar is effectively produced for more than 40T.

Drawings

FIG. 1 is a cross-sectional view of an automotive rocker beam;

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The automobile aluminum alloy doorsill beam is processed according to the following steps:

1. in the process of smelting 6082 alloy, adding proper magnesium-silicon alloy to control the element proportion of the aluminum alloy, wherein the temperature of the aluminum liquid is 750 ℃ during the adding process, and the table 1 shows the proportion of each component of a control group and each adjusted component;

TABLE 1

2. The aluminum bar is cast by adopting two-stage filtration, wherein the first-stage filtration is 40 meshes, and the second-stage filtration is 60 meshes;

3. the used oil pressure casting machine and the casting disc are used for casting, wherein the crystallizer is cooled by a water curtain type cooling mode, the casting process needs to be continuously carried out, and a bar with the length of 6 meters is cast;

4. carrying out homogenization annealing on the cast aluminum bar, and continuously keeping the temperature at 570 ℃ for 10H;

5. detecting the aluminum bar, and meeting the control requirements of table 1;

6. cutting off the process waste materials at the head and the tail of the 6-meter long aluminum bar to obtain a plurality of sections of short bars with the length of 1400mm for extrusion; 7. the aluminum bar was formed into a rocker beam article (shown in FIG. 1) using a 3600T extruder; diameter phi 268mm of the aluminum bar, mold temperature: 470 ± 10 ℃, extrusion barrel temperature: 440 +/-10 ℃, the internal diameter of the extrusion cylinder is phi 276mm, and the discharge speed is as follows: 2.5m/min, aluminum bar temperature: 490 +/-10 ℃, extrusion cylinder length 1450mm, on-line quenching: and (3) carrying out forced air cooling on the extruded aluminum alloy section in a quenching device, wherein the temperature of the aluminum alloy section before quenching is 535-560 ℃, and the temperature of the aluminum alloy section after quenching is less than 90 ℃. The temperature before the extrusion of the aluminum bar is improved to improve the fluidity of the metal material and improve the extrudability, the temperature range of an outlet is controlled to be 535 and 560 ℃, the front area of the cooling fan adopts a 110Kw rear area of 75Kw for auxiliary cooling, and the frequency of the fan is switched to be more than 45Hz to improve the cooling rate.

8. Cutting 2500mm (as a quenching area) at the head and tail of the process, reserving performance sample sections with two ends and the middle part of 300mm, artificially aging at 180 ℃/7h, and verifying and testing the mechanical properties of the material by using a universal tensile testing machine. The standard requirements of the aluminum alloy doorsill beam are met by the detection control group and 6 embodiments: the tensile strength Rm is more than or equal to 300MPa, the yield strength RP0.2 is more than or equal to 270MPa, and the elongation A is more than or equal to 12 percent. The press breakthrough pressure and the longest continuous extrusion time are greatly different.

Table 3 shows the comparison of the resistance and the longest continuous extrusion time of the same mold used for the production of the aluminum alloy profile produced by the extrusion of the comparison group and the extrusion of the 6 compositions;

TABLE 2

Table 3 shows the comparison of the life of the extrusion dies of the control group with the life of the extrusion dies produced by the above 6 compositions, wherein the die design is uniform;

TABLE 3

As can be seen from Table 2, the extrusion resistance of the rocker beam extruded by the present invention is low, and the extrusion breakthrough pressure is only 243-248MPa, while the extrusion resistance of the rocker beam product produced by the control group is high, and the breakthrough pressure is 265MPa, which is reduced by about 20MPa compared with the control group. According to the table 2, the single-width die continuously extrudes the mixture without particle separation or particle strain, the mixture is continuously extruded by the single-width die of the control group for 8H, and the mixture is promoted to the single-width die for continuously extruding for 14-16H. As can be seen from the data in Table 4, the damage to the extrusion die is obviously reduced due to the reduction of the extrusion resistance of the raw materials, the service life of the control group, namely the service life before the adjustment of the intermediate alloy component of the aluminum bar is 25-26T, and the service life of the single die after the adjustment of the component of the aluminum bar is 39-41T, so that the service life of the extrusion die is obviously prolonged.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.