金屬的鍛造拔長(zhǎng)工藝對(duì)金屬內(nèi)部空洞閉合的影響

【專家解說(shuō)】：大鍛件具有載荷大、工作條件差、安全可靠性要求高等特點(diǎn)，而鋼鐵冶金過(guò)程決定了鋼錠內(nèi)部不可避免地會(huì)存在空洞,內(nèi)部空洞的存在將嚴(yán)重影響大鍛件的性能。近來(lái)，隨著能源的日益緊張和大型工業(yè)的快速發(fā)展，特別是電力、冶金、造船、核能和航天等重大工程和裝備對(duì)相關(guān)核心零件的高質(zhì)量、高性能的要求，大鍛件內(nèi)部缺陷的相關(guān)研究開始得到高度重視。 CHAABAN和ALEXANDER[1]、任猛[2]和任廣升等[3]通過(guò)實(shí)驗(yàn)研究了空洞位置、砧寬比和壓下率對(duì)大鍛件內(nèi)部空洞閉合的影響，發(fā)現(xiàn)鍛件內(nèi)部不同位置空洞閉合情況并不相同，而砧寬比和壓下率是對(duì)空洞閉合有重要影響的兩個(gè)工藝參數(shù)。STÅHLBERG等[4-6]、WALLERÖ[7]和TANAKA等[8]的理論分析和實(shí)驗(yàn)研究表明，大鍛件材料屬性和空洞周圍的應(yīng)力應(yīng)變狀態(tài)對(duì)空洞閉合均有影響。崔振山等[9]運(yùn)用有限元法分析了不同形狀和大小的空洞閉合情況。這些研究雖然給出了一些定性結(jié)論[1-14]，但是都不能很好地揭示材料屬性和工藝參數(shù)對(duì)空洞閉合的影響機(jī)理，沒(méi)有建立空洞周圍應(yīng)力應(yīng)變狀態(tài) 與空洞閉合的定量關(guān)系，沒(méi)有提出有效的空洞閉合判定準(zhǔn)則。 參 考 文 獻(xiàn) [1] CHAABAN M A and ALEXANDER J M. A study of the closure of cavities in swing forging [C]// TOBIAS S A ed. International Machine Tool Design and Research Conference. Proceedings of the 17th International Machine Tool Design and Research Conference, September 20-24, 1976, Birmingham. Macmillan, London, 1977:633-645. [2] 任猛. 大型鋼錠內(nèi)部孔洞性缺陷鍛合過(guò)程的數(shù)值模擬和實(shí)驗(yàn)研究[D]. 北京:清華大學(xué). 1986. REN Meng. Numerical simulation and experimental investigation of the void closing in a large ingot during forging processes [D]. Beijing: Tsinghua University, 1986. [3] 任廣升，黃朝暉，白志斌. 大型鋼錠內(nèi)部孔洞性缺陷鍛合過(guò)程的數(shù)值模擬和實(shí)驗(yàn)研究[J]. 機(jī)械工程學(xué)報(bào), 1995, 31 (2):93 98. REN Guangsheng, HUANG Zhaohui, BAI Zhibin. Experimental investigation of strain distribution in cylinder model with void in the center during upset processes by photoplastic simulation [J]. Chinese Journal of Mechanical Engineering, 1995, 31(2):93-98. [4] STÅHLBERG U, KEIFE H, LUNDBERG M, et al. A study of void closure during plastic deformation [J]. J. Mech. Work. Technol. 1980, 4:51-63. [5] STÅHLBERG U. Influence of spread and stress on the closure of a central longitudinal hole in the hot rolling of steel [J]. J. Mech. Work. Technol. 1986, 13:65-81. [6] KEIFE H, STÅHLBERG U. Influence of pressure on the closure of voids during plastic deformation [J]. J. Mech. Work. Technol. 1980, 4: 133-143. [7] WALLERÖ A. Closing of a central longitudinal pore in hot rolling [J]. J. Mech. Work. Technol. 1985, 12:233-242. [8] TANAKA M, ONO S, TSUNENO M. Factors contributing to crushing of voids during forging [J]. J. Jpn. Soci. Technol. Plast. 1986, 27:927-934. [9] 崔振山, 任廣升, 徐秉業(yè), 等. 圓柱體內(nèi)部空洞的熱鍛閉合條件[J]. 清華大學(xué)學(xué)報(bào), 2003, 43(2):227-229, 233. CUI Zhenshan, REN Guangsheng, XU Bingye, et al. Void closing conditions for solid cylinders during hot forging [J]. J. Tsinghua Univ., 2003, 43(2):227-229, 233. [10] 孫捷先,郭會(huì)光. FM鍛造法的試驗(yàn)與有限元分析研究[J].機(jī)械工程學(xué)報(bào), 1986, 22(4):47-55. [11] HAMZAH S, STÅHLBERG U. A new pore closure concept for the manufacturing of heavy rings [J]. J. Mater. Process. Technol. 2001, 110:324-333. [12] 馬慶賢, 鐘約先, 曹起驤. 高溫塑性加工過(guò)程中缺陷修復(fù)規(guī)律[J]. 清華大學(xué)學(xué)報(bào), 1999, 39(11):94-96. MA Qingxian, ZHONG Yuexian, CAO Qixiang. Principle of internal defects recovery in processes of high temperature plastic deformation [J]. J. Tsinghua Univ., 1999, 39(11):94-96. [13] 金寧. 大鍛件孔隙性缺陷的壓合與焊合規(guī)律的研究及高溫柵的研究[D]. 北京:清華大學(xué). 1990. JIN Ning. Investigation of collapse and welding law of cavities and porous defects in large forgings, and development of high temperature Moire grids [D]. Beijing:Tsinghua University, 1990. [14] 任運(yùn)來(lái). 大型鍛件內(nèi)部缺陷修復(fù)條件和修復(fù)方法研究[D]. 秦皇島:燕山大學(xué). 2003. REN Yunlai. Study on healing condition and method of internal defect of large forgings [D]. Qinhuangdao:Yanshan University, 2003.