(1. 天津職業(yè)技術(shù)師范大學(xué) 汽車模具智能制造技術(shù)國家地方聯(lián)合工程實(shí)驗(yàn)室，天津 300222；
2. 天津市天鍛壓力機(jī)有限公司，天津 300222)
摘 要: 以7075鋁合金擋風(fēng)梁在熱成形過程中的減薄率為研究對象，通過熱拉伸試驗(yàn)，研究了7075鋁合金在變形溫度為440~480 ℃、應(yīng)變速率為0.001~0.1 s-1條件下的真實(shí)應(yīng)力-應(yīng)變曲線，并將其引入數(shù)值模擬模型，分析了板料初始溫度(440~500 ℃)、壓邊力(20~50 kN)、摩擦因數(shù)(0.1~0.7)對7075鋁合金擋風(fēng)梁熱沖壓成形危險(xiǎn)區(qū)域標(biāo)記點(diǎn)減薄率的影響規(guī)律及其預(yù)測模型，并進(jìn)行了實(shí)驗(yàn)驗(yàn)證。結(jié)果表明：擋風(fēng)梁成形件危險(xiǎn)區(qū)域標(biāo)記點(diǎn)的減薄率隨著板料溫度的上升先減小后增大，隨著壓邊力的增大而增加，隨著摩擦系數(shù)的增大呈上升趨勢，且變形過程中標(biāo)記點(diǎn)減薄率由高到低依次為A＞D＞C＞B。經(jīng)修正后的預(yù)測模型與實(shí)驗(yàn)值進(jìn)行比較，所得最大誤差為6.7%，最小誤差為1.5%。
關(guān)鍵字: 7075鋁合金；熱沖壓；成形性能；減薄預(yù)測
（1. National-Local Joint Engineering Laboratory of Intelligent Manufacturing Oriented Automobile Die and Mould, Tianjin University of Technology and Education, Tianjin 300222, China;
2. Tianjin Tianduan Press Co., Ltd., Tianjin 300222, China）
Abstract:Aiming at the thinning rate of 7075 aluminum alloy windshield in the hot forming process，the true stress-true strain curves of 7075 aluminum alloy were studied by hot tensile tests under the deformation temperature of 440-480 ℃ and strain rate of 0.001-0.1 s-1, and they were introduced into the numerical simulation model. The influence of the initial temperature of sheet metal (440-500 ℃), blank holder force (20-50 kN), and friction coefficient (0.1-0.7) on the thinning rate of hot stamping dangerous zone marked points of 7075 aluminum alloy windshield was analyzed, and the prediction model was verified by experiments. The results show that the thinning rate of marked points in the dangerous area of windshield forming part decreases first and then increases with the increase of sheet metal temperature, increases with the increase of blank holder force, and increases with the increase of friction coefficient. The thinning rates of the marked points are A＞D＞C＞B in the order from high to low during the deformation process. The modified prediction model is compared with the experimental value, and the maximum error obtained is 6.7%, and the minimum error is 1.5%.
Key words: 7075 aluminum alloy; hot stamping; formability; thinning prediction
