ã€China Aluminum Network】 Yang Huanjun, Zheng Meiyu, Liu Yang, Qu Yingchun, Jiang Caihui (Shandong Nanshan Aluminum Co., Ltd., Longkou, Shandong, 265706) Abstract : This paper mainly studies the effect of aging environmental temperature change on the sealing weight loss of middle temperature sealing products. Through the same experimental summer and winter season aging time, the difference of sealing weight loss is very different, and the key to determine the quality of sealing hole is the aging. The ambient temperature, in order to save energy and reduce consumption, timely start hot water washing process and stabilize the sealing quality. Remarks: The serial numbers in Tables 1-1 and 1-2 correspond to the samples that are simultaneously subjected to oxidation and sealing treatment. After the sealing of 1-1 is completed, the samples are taken after washing, after the sealing of 1-2 is completed. After washing for 10 min, take a sample. Electrical Actuator,Pinion Actuator,Motor Actuator,Heavy Electric Rotary Actuator ZHEJIANG KINKO FLUID EQUIPMENT CO.,LTD , https://www.kinkoflow.com
Key words: aging ambient temperature; middle temperature sealing; weightlessness; hot water washing process 1 Introduction:
Due to the porosity of the anodic oxide film, it has extremely high chemical activity and physical adsorption properties. To improve its corrosion resistance, the anodic oxide film needs to be closed. Compared with room temperature sealing, the medium temperature sealing time is short. Non-fluorine, no blue after sealing, clean surface and bright light, inner cavity is also a metal color, which meets the high standard requirements of customers, and the other medium temperature sealing hole formula does not contain fluorine, which meets the needs of national environmental protection and EU ROHS directives. Has the advantage of faster sealing (> 2μm/min).
Sealing weight loss is an arbitration method for inspecting the quality of the sealing hole. According to the provisions of GB5237.2-2008, the anodic oxide film should be tested with nitric acid pre-soaked phosphoric chromic acid, and the mass loss value should not exceed 30 mg/dm2. At the same time, the national standard also stipulates the time for sampling the medium-temperature sealing material, that is, the weight loss test is performed after the sealing is completed for 120 hours.
However, in actual production, due to the long sampling period (≥120h), it will inevitably increase the pressure of workshop inventory and the delivery time of orders, which will cause some impact on the normal delivery of the company. At the same time, the profiles are not fully aged and delivered to the customer. Inevitably, there are disputes, so most aluminum plants in China are discussing the possibility of shortening the aging time of profiles to a great extent under the premise of guaranteeing the quality of sealing holes.
Our company is located in the coastal area of ​​Shandong Peninsula, with large temperature difference between winter and summer. It was found in actual production for many years that using the same sealing process parameters, the quality of sealing in summer and winter is obviously different. In summer, the weight loss after aging is completely 20 hours after sealing. Qualified, but winter (less than zero degrees) after sealing the aging weight loss 120 hours are often at the standard edge, easily unqualified, leading to the workshop had to take 120 hours after the weight loss test to determine whether the end of the pass, great It caused a waste of manpower and material resources.
Therefore, in order to explore the essential differences between the sealing quality in summer and winter, the company used different aging methods to compare the sealing weight loss test, and established different testing conditions and testing under the same environment (temperature) to ensure different Under the precondition that the test conditions are basically the same as the data of the environment detection seal weight loss during the same period, a reasonable sealing process is developed to ensure the quality of the sealing product of the oxidation product at different temperatures, improve the production efficiency, and at the same time reduce the energy consumption to some extent.
2 Experimental methods 2.1 The materials used for the experimental materials were randomly selected from 6063/T5 oxidation sealing profiles produced by our company's oxidation workshop. The thickness of the oxide films was performed according to AA10 and AA15 standards.
2.2 Sealing process parameters control range Ni2+: 0.9-1.1g/L
PH: 5.8-6.2
Temperature: 50-52°C
Time: 12min
Hot water washing process: water temperature: 75-80°C, time: 5min
2.3 Experimental steps 1. During the time period from June to July in summer and from December to January in winter, the temperature difference is relatively large. In order to ensure the validity of the test results, the sampling time is maintained at a fixed daily time.
2. Each month is randomly selected for 5 days. The temperature difference is relatively small. Samples in production are randomly sampled and the sawing samples are divided into 5 groups. Weight loss tests are performed according to the aging time of 0h, 24h, 48h, 72h, and 120h respectively. Statistical test data.
3, in order to ensure the accuracy of the experimental data, each group to take two samples at the same time for the weight loss test, specimens were cut to do the serial number identification, the test results to take the average.
4. Other process parameters involved in the experiment are normal process parameters.
Remarks: In the summer months of June and July, the average temperature is 25-30°C, and in December and January of winter, the average temperature is -10°C-5°C.
3 Experimental Results and Discussion It is well known that the aging time has a great influence on the quality of the sealing hole. If the weight loss test is performed immediately after the sealing of the oxide film is completed, the test result value will be very large. After the aging time is reached, the weight loss will occur. Test, then the results are qualified. This shows that after the sealing of the oxide film is completed, some reactions are also performed during the storage process to further complete the sealing process. This process is called aging. Studies have shown that the aging of the oxide film is the process of volume expansion after the water in the pores of the oxide film has absorbed water. The surface area of ​​the expanded material that is in contact with the air is further reduced by the stuffed film pores, and the tightness of the film is increased [1].
Research found that [2]: aging temperature and aging time are important factors that affect the quality of aging. The low temperature of aging will inhibit the aging process and slow the ageing. Regardless of the aging temperature, the aging speed is faster within 24 hours, and the aging speed is significantly reduced after 24 hours.
Therefore, the experimental statistics are as follows: 
As can be seen from Table 1-1 and 1-2:
1. Within 24 hours from the end of sealing the hole to aging time, the aging time has a great influence on weight loss. The aging time is 24 hours, and the changing trend is rapidly dropping. The trend is basically stable;
2. Within 24 hours from the end of sealing to aging, hot water washing can significantly reduce the value of weight loss, indicating that the hot water washing process has played a role in improving the aging effect; but the hot pure water washing time should be guaranteed to be better than 5 min to ensure hot water washing. Aging effect.
3. In the period from June to July, 24 hours after aging, the weight loss of the sealing hole can meet the requirements of GB5237.2-2008, and no hot water washing is required.
Remarks: The numbers in Tables 2-1 and 2-2 correspond to the samples that were simultaneously subjected to oxidation and sealing treatment. After the sealing of 2-1 is completed, the samples are taken after washing, after the sealing of 2-2 is completed. Hot water for 10 minutes before sampling.
As can be seen from Table 2-1 and 2-2:
1. The temperature in winter is too low, and the effect of plugging and aging is obviously reduced. After 120 hours of aging, weightlessness is still often unqualified;
2. After using the hot water washing process in winter, it can significantly accelerate the aging effect and shorten the aging time, which can basically guarantee that after 48 hours of aging, the weight loss of the product will become qualified;
In order to further verify the above results, it is convenient for the workshop to determine the time period for using the hot water washing process. We randomly sampled and tested each month and counted the number of scraps due to unsealed holes every month. We found that the basic period was 5-9 months. It is not necessary to start the hot water washing process, but from the end of October, the sealing hole starts to be unstable. In order to ensure the quality of the sealing hole, the workshop is informed to turn on the hot water washing process in time.
4. Conclusion 1. The reason for the large difference in sealing weight loss between summer and winter seasons is that the aging temperature plays a leading role in the aging process;
2. The hot water washing process after sealing the hole can play the role of accelerating aging and shortening the aging time;
3. Through comparative analysis of tests, hot water washing process is not used during summer and autumn from June to September, and hot water washing process is started in winter in October, so that the quality of sealed pores has been stabilized.
references:
[1]Pang Chengxian.Study on the Oxidation Film Aging Process of Building Profiles Sealed at Room Temperature[J].Aluminum Processing,2004.
[2] Fang Baojun, Liu Yimin. Effect of aging temperature on sealing quality of aluminum profiles after sealing at room temperature [J]. Aluminium Processing, 2004.