(1. 大連理工大學 工業(yè)裝備結構分析國家重點實驗室，大連 116024； 2. 大連理工大學 汽車工程學院，大連 116024)
摘 要: 基于自主設計的圓臺模具淬火實驗平臺，研究高強度7075-T6鋁合金在HFQ溫成形過程中的瞬態(tài)傳熱規(guī)律。通過Beck非線性估算法(Beck反算法)獲得界面換熱系數(IHTC)在不同因素下(包括合模壓強與表面粗糙度)隨溫度變化的瞬態(tài)換熱規(guī)律，并分析各因素對IHTC的影響機理。結果表明：Beck反算法在計算瞬態(tài)換熱系數時具有較高的計算精度。7075-T6鋁合金與模具界面的瞬態(tài)換熱系數隨壓強增大而增大，當壓強增大到80 MPa時，瞬態(tài)平均換熱系數IHTC趨近于3375 W/(m2？K)。進一步，表面粗糙度也會影響7075-T6鋁合金溫成形過程的IHTC，當粗糙度大于0.57 μm并小于0.836 μm時，IHTC隨粗糙度的增大而明顯減小，當粗糙度小于0.57 μm或大于0.836 μm時，IHTC值均隨粗糙度的增大而緩慢減小。
關鍵字: 7075-T6鋁合金；HFQ溫成形；界面換熱系數；Beck反算法；工藝因素
（1. State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, China; 2. School of Automotive Engineering, Dalian University of Technology, Dalian 116024, China）
Abstract:Based on self-developed cylindrical-die experimental model, transient heat transfer law of high-strength 7075-T6 aluminum alloy in HFQ warm forming was investigated in this paper. Beck’s non-linear estimation method (Beck’s method) was used to calculate IHTC under different processing factors, including different closure pressure and surface roughness. The results showed that Beck’s method has a high accuracy in calculating IHTC; The transient IHTC of 7075-T6 aluminum increases with the increases of closure pressure, and when pressure is above 80 MPa, IHTC approaches to 3375 W/(m2？K). Furthermore, surface roughness can also affect IHTC, when surface roughness is between 0.57 μm and 0.836 μm, IHTC decreases obviously with the increase of surface roughness, and when surface roughness is larger than 0.836 μm or less than 0.57 μm, IHTC decreases slowly with the increase of roughness.
Key words: 7075-T6 alloy; HFQ warm forming; IHTC; Beck’s method; process factor
