High-strength 6061 alloy automobile part valve body production process

Abstract

The invention relates to a preparation method of an aluminum alloy, in particular to a production process of a high-strength 6061 alloy part valve body, which comprises the following components in percentage by weight: 0.75 to 0.8 percent of silicon element Si, 0.4 to 0.65 percent of iron element Fe, 0.30 to 0.40 percent of copper element Cu, 0.15 percent of magnesium element Mn, 0.8 to 1.2 percent of magnesium element Mg, 0.25 to 0.35 percent of chromium element Cr, 0.1 percent of titanium element Ti, 0.05 percent of single impurity (not more than 0.15 percent in total) and the balance of aluminum. The strength of the prepared product is high through the processes of smelting, casting, annealing, extruding, quenching and the like.

Description

Technical Field

[0001] The invention relates to a production process of an aluminum alloy, in particular to a production process of a high-strength 6061 alloy automobile component valve body. Background Art

[0002] With the rapid development of the new energy vehicle industry, consumers have higher and higher requirements for the safety of automobiles. Anti-lock braking system (ABS) is widely used in automobile manufacturing as a safety braking system. ABS has the functions of anti-lock and anti-skid. It adjusts the braking conditions of the car through electronic sensors and oil pressure control, effectively improving the safety of the car. Due to the particularity of its working environment (oil pressure control) and the importance of its function (safety system), strict requirements are placed on the organization and performance of the materials of the main structural components of the ABS system.

[0003] 6061 aluminum alloy is a common material for preparing ABS main structure. 6061 aluminum is a heat-treatment-strengthened alloy with good formability, weldability and machinability. The types and contents (mass percentage) of various elements in the existing 6061 aluminum alloy are: copper Cu: 0.15-0.4, manganese Mn: 0.15, magnesium Mg: 0.8-1.2, zinc Zn: 0.25, chromium Cr: 0.04-0.35, titanium Ti: 0.15, silicon Si: 0.4-0.8, iron Fe: ≤0.7, and the rest is Al; its mechanical properties are: tensile strength T4 state is not less than 205MPa, T6 state is not less than 290MPa; compressive yield strength is 55.2MPa. In order to adapt to product performance, the types and contents of each element in 6061 will be adjusted accordingly. For example, the Chinese invention patent with publication number CN115976377B improves the mechanical properties of 6061 by adjusting the types and contents of each element in 6061. According to the records in the patent, the yield strength of each embodiment is generally greater than 270MPa, and the tensile strength is generally greater than 290MPa. Compared with the common 6061 aluminum alloy, the mechanical properties are improved to a certain extent.

[0004] In the above patent, 6061 aluminum alloy is mainly used for the preparation of electronic cigarette shells, and the performance requirements of electronic cigarette shells are much lower than those of ABS main parts. Therefore, in order to meet the use requirements of ABS main structures, it is necessary to further improve the 6061 aluminum alloy material. Summary of the invention

[0005] In order to overcome the deficiencies in the prior art, the present invention provides a high-strength 6061 alloy automobile component valve body production process to meet the performance requirements of the valve body.

[0006] To achieve the above object, the present invention discloses a high-strength 6061 alloy automobile component valve body production process, comprising the following steps:

[0007] (S1) Raw material ratio, element Si: 0.75-0.8%, element Fe: 0.4-0.65%, element Cu: 0.30-0.40%, element Mn: 0.15%, element Mg: 0.8-1.2%, element Cr: 0.25-0.35%, element Ti: 0.1%, single impurity 0.05%, all elements total not more than 0.15%, aluminum is the balance;

[0008] (S2) smelting, using a secondary smelting process, the first smelting temperature is 740-760°C; the secondary smelting temperature is;

[0009] (S3) casting, using hot top mold casting, a casting speed of 40-43 mm / min, a casting water volume of 3000-33000 l / min, and the casting is an aluminum rod;

[0010] (S4) homogenization annealing: the cast aluminum rod is subjected to a two-stage homogenization annealing process, firstly at 540°C for 2 hours, then the temperature is raised to 575°C and kept for 8 hours;

[0011] (S5) extrusion molding, setting the following extrusion conditions: setting the extrusion barrel temperature to 420-460° C., controlling the mold heating temperature to 460-500° C., the aluminum rod heating temperature to 490-530° C., the aluminum rod extrusion speed to 4-8 m / min, and the product outlet temperature to 535-550° C.;

[0012] (S6) quenching the extruded product;

[0013] (S7) stretching and straightening the quenched product by 0.8 to 1.2%;

[0014] (S8) The quenched product is subjected to a peak aging process, the aging temperature is 170-180°C, the aging temperature is not more than 3h, and the product is kept at this temperature for 9h before cooling to room temperature.

[0015] Preferably, when adding raw materials, silicon element Si is added as AlSi master alloy, iron element Fe is added as AlFe master alloy, copper element Cu is added as AlCu master alloy, magnesium element Mg is added as pure Mg ingot, and chromium element Cr is added as AlCr master alloy.

[0016] Preferably, refining and slag removal are carried out at any time during the first smelting and the second smelting.

[0017] Preferably, during the casting process, online degassing is used, wherein the degasser rotor rotates at least 500 times, and 30ppi and 40ppi double-click filter plates are used for filtration.

[0018] Preferably, during the homogenization annealing process, it is necessary to ensure that the Mg2Si strengthening phase is dispersed and precipitated.

[0019] Preferably, during the extrusion process, an online water tank quenching is used with a water volume of 15 to 25 m 3 / h, room temperature after quenching.

[0020] The present invention has the following technical effects:

[0021] 1. After testing, the product prepared by this process has a tensile strength greater than 380Mpa, a yield strength greater than 320Mpa, an elongation greater than 14%, a Brinell hardness greater than 110HBW, and a grain size greater than level 4. Compared with the common 6061 aluminum alloy, the tensile strength and yield strength are greatly improved.

[0022] 2. Within the composition range of 6061 alloy valve body profile, control the content of Mn element to avoid the risk of recrystallization at high temperature during extrusion; control the content of Ti element to avoid the formation of excess intermediate compounds; add appropriate amount of Fe and Cr elements, which has a significant effect on improving mechanical properties, and can refine grains and improve organizational morphology.

[0023] 3. Aiming at the performance requirements of 6061 alloy valve body profile, the present invention adopts 6061 alloy design with high alloy composition, extrusion process with high extrusion temperature and peak aging process to achieve mass production. The present invention meets the technical indicators of customers and subsequent processing requirements through four aspects: alloy composition, homogenization process, extrusion process and heat treatment aging, and has been widely promoted and applied.

[0024] Instruction Manual

[0025] Figure 1 The metallographic diagram of the product obtained in Example 2;

[0026] Figure 2 The deformation strain curve of the product obtained in Example 2. DETAILED DESCRIPTION

[0027] The principles and features of the present invention are described below in conjunction with embodiments; the examples given are only used to explain the present invention; they are not used to limit the scope of the present invention.

[0028] A high-strength 6061 alloy automobile component valve body production process comprises the following steps:

[0029] (S1) The raw materials are prepared in proportion: element Si: 0.75-0.8%, element Fe: 0.4-0.65%, element Cu: 0.30-0.40%, element Mn: 0.15%, element Mg: 0.8-1.2%, element Cr: 0.25-0.35%, element Ti: 0.1%, a single impurity of 0.05%, the total of all single substances is not more than 0.15%, and aluminum is the balance.

[0030] Table 1 Content of each element in each embodiment (mass percentage %)

[0031] Si Fe Cu Mn Mg Cr Ti Al Impurities Example 1 0.75 0.4 0.3 0.15 0.8 0.25 0.1 0.9713 0.12 Example 2 0.76 0.5 0.32 0.15 0.95 0.28 0.1 0.9681 0.13 Example 3 0.8 0.65 0.4 0.15 1.2 0.25 0.1 0.963 0.15

[0032] When adding raw materials, silicon element Si is added according to AlSi master alloy, iron element Fe is added according to AlFe master alloy, copper element Cu is added according to AlCu master alloy, magnesium element Mg is added according to pure Mg ingot, and chromium element Cr is added according to AlCr master alloy. Within the composition range of 6061 alloy valve body profile, the content of Mn element is controlled to avoid the risk of recrystallization at high temperature during extrusion; the content of Ti element is controlled to avoid the formation of excess intermediate compounds; adding appropriate amounts of Fe and Cr elements has a significant effect on improving mechanical properties, and can refine grains and improve organizational morphology.

[0033] (S2) Melting: the first melting temperature is 740-760°C, and refining and slag removal are carried out during the melting process to ensure the purity of the solution; secondary refining and slag removal are carried out in a holding furnace to improve the purity of the solution before casting.

[0034] (S3) Casting: hot top mold casting, casting speed 40 ~ 43mm / min, casting water volume 3000 ~ 33000l / min, after casting, it is aluminum rod, online degassing, degasser rotor not less than 500 revolutions, 30ppi, 40ppi double filter plate filtering.

[0035] (S4) Homogenization annealing: A two-stage homogenization annealing process is used for the cast aluminum rod. First, the temperature is kept at 540°C for 2 hours, and then the temperature is increased to 575°C and kept for 8 hours. During the homogenization annealing process, it is necessary to ensure that the Mg2Si strengthening phase is dispersed and precipitated.

[0036] (S5) Extrusion molding: equipment debugging should be carried out before extrusion to ensure that the main machine and auxiliary equipment are operating normally. Then the following extrusion conditions are set: the extrusion barrel temperature is set to 420-460°C, the mold heating temperature is controlled at 460-500°C, and the total heating time does not exceed 24 hours. After reaching the temperature, it is hoisted out and put on the machine. The machine time is controlled not to exceed 5 minutes to avoid the mold temperature from decreasing. The aluminum rod adopts a low-frequency induction heating furnace, the aluminum rod heating temperature is 490-530°C, the aluminum rod extrusion speed is 4-8m / min, and the product outlet temperature is 535-550°C.

[0037] (S6) For quenching of extruded products, online water tank quenching is used with a water volume of 15 to 25 m 3 / h, room temperature after quenching.

[0038] (S7) The quenched product is stretched and straightened to a deformation of 0.8-1.2%. After the profile size is measured and qualified, it is cut to size and packed into baskets as required. When packing, the profiles are spaced 10-20 mm apart, and the layers are separated by padding blocks to avoid collision and ensure uniform subsequent aging.

[0039] (S8) The quenched product is subjected to a peak aging process, the aging temperature is 170-180°C, the aging temperature is not more than 3h, and the product is kept at this temperature for 9h before cooling to room temperature.

[0040] After the preparation is completed, in order to test the products prepared in each embodiment, taking Example 2 as an example, the performance of the product is tested according to the national standard GB / T228.1-2010 metal material tensile test room temperature test method. The relevant test parameters and results are shown in Table 2 below. The structural organization is as follows Figure 1 shown.

[0041] Table 2 Sample test results

[0042] name area Break gauge length Tensile Strength Yield Strength parameter Full area computing 0.2％ unit mm mm <![CDATA[N / mm 2 ]]> <![CDATA[N / mm 2 ]]> NBL002-24U-1178 28.09 35.13 391 324 name Elongation after break Maximum force Yield parameter Full area computing 0.2％ unit ％ kN kN NBL002-24U-1178 17.1 10.97 9.1

[0043] The stress-strain diagram is shown in the attached Figure 2 As shown, the performance of the final product is as follows: tensile strength is greater than 380Mpa, and yield strength is greater than 320Mpa, which are greatly improved compared to the existing aluminum alloy mechanical properties.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-strength 6061 alloy automobile parts valve body production process, characterized in that: The following steps are involved: (S1) Raw material ratio, element Si: 0.75-0.8%, element Fe: 0.4-0.65%, element Cu: 0.30-0.40%, element Mn: 0.15%, element Mg: 0.8-1.2%, element Cr: 0.25-0.35%, element Ti: 0.1%, single impurity 0.05%, all elements total not more than 0.15%, aluminum is the balance; (S2) smelting, using a secondary smelting process, the first smelting temperature is 740-760°C; the secondary smelting temperature is; (S3) casting, using hot top mold casting, a casting speed of 40-43 mm / min, a casting water volume of 3000-33000 l / min, and the casting is an aluminum rod; (S4) homogenization annealing: the cast aluminum rod is subjected to a two-stage homogenization annealing process, firstly at 540°C for 2 hours, then the temperature is raised to 575°C and kept for 8 hours; (S5) extrusion molding, setting the following extrusion conditions: setting the extrusion barrel temperature to 420-460° C., controlling the mold heating temperature to 460-500° C., the aluminum rod heating temperature to 490-530° C., the aluminum rod extrusion speed to 4-8 m / min, and the product outlet temperature to 535-550° C.; (S6) quenching the extruded product; (S7) stretching and straightening the quenched product by 0.8 to 1.2%; (S8) The quenched product is subjected to a peak aging process, the aging temperature is 170-180°C, the aging temperature is not more than 3h, and the product is kept at this temperature for 9h before cooling to room temperature.

2. The high-strength 6061 alloy automobile parts valve body production process according to claim 1 is characterized in that: When adding raw materials, silicon element Si is added as AlSi master alloy, iron element Fe is added as AlFe master alloy, copper element Cu is added as AlCu master alloy, magnesium element Mg is added as pure Mg ingot, and chromium element Cr is added as AlCr master alloy.

3. The high-strength 6061 alloy automobile component valve body production process according to claim 1 is characterized in that: During the first and second smelting processes, refining and slag removal should be carried out at any time.

4. The high-strength 6061 alloy automobile component valve body production process according to claim 1 is characterized in that: During the casting process, online degassing is adopted, wherein the degasser rotor rotates at least 500 times, and 30ppi and 40ppi filter plates are double-clicked for filtration.

5. The high-strength 6061 alloy automobile component valve body production process according to claim 1 is characterized in that: During the homogenization annealing process, it is necessary to ensure that the Mg2Si strengthening phase is dispersed and precipitated.

6. The high-strength 6061 alloy automobile component valve body production process according to claim 1 is characterized in that: During the extrusion process, online water tank quenching is used with a water volume of 15 to 25 m 3 / h, room temperature after quenching.

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