بررسي تاثير پارامترهاي شكل دهي به روش فشار گاز بر روي پر شدگي قالب و توزيع ضخامت ورق

Investigation of the Effect of Gas Pressure Forming Parameters on Mold Filling and Sheet Thickness Distribution

در اﻳﻦ ﺗﺤﻘﻴﻖ، ﺷﻜﻞدﻫﻲ ورق آﻟﻴﺎژ Al-A356 در ﻗﺎﻟﺐ ﻣﺨﺮوط ﻧﺎﻗﺺ ﺑﺎ ﻓﺮآﻳﻨﺪ ﻓﺸﺎر ﮔﺎز ﺑﻪ ﺻﻮرت ﺷﺒﻴﻪﺳﺎزي ﻋﺪدي و آزﻣﺎﻳﺸﮕﺎﻫﻲ ﻣﻮرد ﺑﺮرﺳﻲ ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ. ﻫﺪف از اﻳﻦ ﭘﮋوﻫﺶ، ﺑﺮرﺳﻲ ﺗﺎﺛﻴﺮ ﭘﺎراﻣﺘﺮﻫﺎﻳﻲ از ﻗﺒﻴﻞ ﻧﺴﺒﺖ ﻗﻄﺮ دﻫﺎﻧﻪ ﺑﻪ ارﺗﻔﺎع ﻗﺎﻟﺐ، زاوﻳﻪ، درﺟﻪ ﺣﺮارت و ﻓﺸﺎر ﺑﺮ ﭘﺮﺷﺪﮔﻲ ﮔﻮﺷﻪ ﻗﺎﻟﺐ و ﺗﻮزﻳﻊ ﺿﺨﺎﻣﺖ ﻗﻄﻌﺎت ﻣﻲﺑﺎﺷﺪ. ﻧﺘﺎﻳﺞ ﻧﺸﺎن ﻣﻲدﻫﺪ ﻛﻪ ﺑﺎ اﻓﺰاﻳﺶ ﻓﺸﺎر از 1 ﺑﺎر ﺑﻪ 8 ﺑﺎر، ﭘﺮﺷﺪﮔﻲ ﻗﺎﻟﺐ ﺣﺪود %15 ﺑﻬﺘﺮ ﺧﻮاﻫﺪ ﺷﺪ. اﻟﺒﺘﻪ اﻳﻦ در ﺣﺎﻟﻲ اﺳﺖ ﻛﻪ ﺿﺨﺎﻣﺖ ﺑﺤﺮاﻧﻲ ورق ﻛﺎﺳﺘﻪ ﺷﺪه و ﺑﻪ ﻛﻤﺘﺮ از 0/5 ﻣﻴﻠﻴﻤﺘﺮ ﺧﻮاﻫﺪ رﺳﻴﺪ. ﺑﺎ ﻛﺎﻫﺶ ﻧﺴﺒﺖ ﻗﻄﺮ ﺑﻪ ارﺗﻔﺎع، اﻓﺰاﻳﺶ ﭘﺮﺷﺪﮔﻲ ﻗﺎﻟﺐ ﻣﺸﺎﻫﺪه ﺷﺪ اﻣﺎ اﻳﻦ اﻣﺮ ﻛﺎﻫﺸﻲ ﺑﻪ اﻧﺪازه %14 در ﻣﻴﺰان ﻧﺎزك ﺷﺪن ﻗﺴﻤﺖ ﺑﺤﺮاﻧﻲ ورق داﺷﺖ. ﺑﺎ ﻛﺎﻫﺶ زاوﻳﻪ ﻣﺨﺮوط از 30 ﺑﻪ ﺻﻔﺮ درﺟﻪ ﻧﻴﺰ ﻣﺸﺨﺺ ﺷﺪ ﻛﻪ ﻻزم اﺳﺖ ﻣﻘﺪار ﻓﺸﺎر ﺣﺪود %25 اﻓﺰاﻳﺶ ﻳﺎﺑﺪ ﺗﺎ ﻗﺎﻟﺐ ﺑﻪ ﻃﻮر ﻣﻨﺎﺳﺒﻲ ﺗﻮﺳﻂ ورق ﭘﺮ ﺷﻮد. ﻫﻤﭽﻨﻴﻦ ﻧﺘﺎﻳﺞ ﻧﺸﺎن داد ﻛﻪ ﺑﺎ اﻓﺰاﻳﺶ دﻣﺎ از 350ºC ﺑﻪ 550ºC، ﻓﺸﺎر ﻻزم ﺑﺮاي ﭘﺮﺷﺪﮔﻲ ﻗﺎﻟﺐ از 8 ﺑﺎر ﺑﻪ 2 ﺑﺎر ﻛﺎﻫﺶ ﻣﻲﻳﺎﺑﺪ.

New forming processes should be capable of manufacturing complex and high quality components in addition to low production costs and high production speeds. The gas pressure forming process is one of the methods used in forming these parts. In this research, the formation of Al-A356 alloy sheet in incomplete cone with gas pressure process has been studied numerically and experimentally. In general, it can be said that the purpose of this study is to investigate the effect of parameters such as the ratio of diameter to height of the die, angle, temperature and pressure. In order to determine the effect of parameters, filling the corners of the die and distributing the thickness of the parts under different pressures has been investigated. Also, for simulating validation, the simulation results were first compared with experimental tests. The results show that the mold filling will improve around 15% by increasing the pressure from 1 bar to 8 bar. However, is reduced to less than 0.5 mm. Although, the mold filling increased by decreasing of the ratio of diameter to height but the critical thickness of the sheet is decreased around 14%. It was also found that for having a proper mold filling, it is necessary to increase the pressure value around 25% when the cone angle decrease from 30º to 0º. The results also showed that by increasing the temperature from 350°C to 550°C, the required pressure for filling the mold decreased from 8 to 2 bar.