(哈爾濱工業(yè)大學(xué)材料科學(xué)與工程學(xué)院，哈爾濱150001)
摘 要: 上機匣為直升機傳動系統(tǒng)中的關(guān)鍵零件，幾何形狀復(fù)雜，性能指標(biāo)要求高， 成形難度大。 采用純鉛為模擬材料，對上機匣成形方案進(jìn)行了試驗研究，確定了上機匣等溫精鍛成形分制坯、 終鍛、精整三個工步。通過對MB15鎂合金塑性圖的分析，確定其變形溫度范圍為350～380℃。 制坯、 終鍛時的變形溫度取380 ℃，以便金屬充填模膛； 精整時的變形溫度取350℃，以提高 鍛件力學(xué)性能。為保證鍛件幾何精度， 采用鍛后直接人工時效的熱處理方案(164℃時效24 h). 利用等溫精鍛工藝成功地鍛制出上機匣鍛件，鍛件的力學(xué)性能、顯微組織和尺寸精度均符合要求.
關(guān)鍵字: MB15鎂合金 等溫精鍛 上機匣
（School of Materials Science & Engineering,Harbin Institu te of Technology, Harbin 150001, P. R. China）
Abstract:Upper casing, as a key part in the driving system of helicopter, is difficult to be formed owing to its complex geometry and high demand for property. In order to design the forming process properly, the forming process of upper casing was investigated by the aid of physical modelling using pure lead. As a result, is othermal precision forging was adopted to form the upper casing and the forming process consists of three steps, pre-forming, final forging and ironing. Through the analysis of plasticity diagram of MB15 magnesium alloy, the forming temperature range was decided to be 350～380 ℃. The temperature for pre-forming and final forging was 380 ℃, which was helpfulf or the metal to fulfill the die cavity. The ironing temperature was 350℃, which raised the mechanical property of forging. For keeping the geometry precision of the forging, artificial aging was conducted directly after forming and the temperature and time were 164℃ and 24 h respectively. The upper casing was forged successfully with isothermal forging technique. Both the mechanical properties, microstructure and accuracy of forging can satisfy the requirements of the user.
Key words: MB15 magnesium alloy isothermal forging upperc asing
