大规格纯钛细晶棒材的锻造工艺
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摘要
研究了加热温度对Gr.2纯钛晶粒度的影响,并据此制定了4种锻造工艺,利用3150吨水压机锻造生产出直径为ϕ250 mm的Gr.2大规格棒材。棒材经650℃退火1 h空冷后,按照ASTM E112标准要求进行晶粒度和组织均匀性分析,并对其力学性能进行测试。结果表明:随着加热温度的升高,Gr.2纯钛晶粒逐渐长大;当加热温度超过800℃时,晶粒尺寸显著增大,棒材成品锻造优选在700～800℃区间加热为佳;随着变形量的增加,棒材晶粒尺寸逐渐减小,变形量对晶粒细化的贡献作用较显著;当变形量增加到一定值时,其对晶粒尺寸的影响趋势变缓,此时适当降低锻造温度,可进一步细化晶粒,使大规格纯钛棒材的平均晶粒尺寸小于63.5μm,满足ASTM E112中晶粒度5级的要求;随着晶粒尺寸的减小,棒材的强度略有增加,而塑性差别不大。
The effect of heating temperature on the grain size of Gr.2 pure titanium was studied. Four forging processes were put forward, and the large size Gr.2 bar with a diameter of 250 mm was produced by forging with 3150 ton hydraulic press. After annealing at 650 ℃ for 1 h followed by air cooling, the grain size and microstructure uniformity of the bar were analyzed according to ASTM E112 standard, and its mechanical properties were investigated. The results show that with the increase of heating temperature, the grain size of the Gr.2 pure titanium bar increases gradually, and the grain size increases significantly when the heating temperature exceeds 800 ℃, and thus the forging of the finished bar is preferably heated in the range of 700-800 ℃. With the increase of deformation amount, the grain size of the bar decreases gradually, and the contribution of deformation amount to grain refinement is obvious. When the amount of deformation increases to a certain value, the effect of deformation on the grain size becomes slower, and when the forging temperature is reduced properly, the grain size can be further refined, and the average grain size of the large size pure titanium bar is less than 63.5 μm, which meets the requirements of ASTM E112 grade 5. With the decrease of grain size, the strength of the bar increases slightly, but the plasticity basically keeps unchanged.
The effect of heating temperature on the grain size of Gr.2 pure titanium was studied. Four forging processes were put forward, and the large size Gr.2 bar with a diameter of 250 mm was produced by forging with 3150 ton hydraulic press. After annealing at 650 ℃ for 1 h followed by air cooling, the grain size and microstructure uniformity of the bar were analyzed according to ASTM E112 standard, and its mechanical properties were investigated. The results show that with the increase of heating temperature, the grain size of the Gr.2 pure titanium bar increases gradually, and the grain size increases significantly when the heating temperature exceeds 800 ℃, and thus the forging of the finished bar is preferably heated in the range of 700-800 ℃. With the increase of deformation amount, the grain size of the bar decreases gradually, and the contribution of deformation amount to grain refinement is obvious. When the amount of deformation increases to a certain value, the effect of deformation on the grain size becomes slower, and when the forging temperature is reduced properly, the grain size can be further refined, and the average grain size of the large size pure titanium bar is less than 63.5 μm, which meets the requirements of ASTM E112 grade 5. With the decrease of grain size, the strength of the bar increases slightly, but the plasticity basically keeps unchanged.
引文
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[10] 路君,曾小勤,丁文江.晶粒度与合金强度关系[J].轻金属,2008(8):59-64.LU Jun,ZENG Xiao-qin,DING Wen-jiang.Relationship between grain degree and strength of alloy[J].Light Metals,2008(8):59-64.
[11] Wan H L,Xu B Q,Dai Y N.Preparation of titanium powders by calciothermic reduction of titanium dioxide[J].Journal of Central South University,2012,19(9):2434-2439.
[12] Xu C,Zhu W F.Comparison of microstructures and mechanical properties between forging and rolling processes for commercially pure titanium[J].The Chinese Journal of Nonferrous Metals,2012,22(8):1939-1946.
[13] Ouyang D L,Wang K L,Cui X.Dynamic recrystallization of Ti-6Al-2Zr-1Mo-1V in β forging process[J].The Chinese Journal of Nonferrous Metals,2012,22(4):761-767.
[14] Zhang X H,Tang B,Zhang X L.Microstructure and texture of commercially pure titanium in cold deep drawing[J].The Chinese Journal of Nonferrous Metals,2012,22(3):496-502.
[15] Xu C,Zhu W F.Transformation mechanism and mechanical properties of commercially pure titanium[J].The Chinese Journal of Nonferrous Metals,2010,20(11):2162-2167.
[2] 张喜燕,赵永庆,白晨光.钛合金及应用[M].北京:化工出版社,2005.
[3] 叶勇,王金彦.钛合金的应用现状及加工技术发展概况[J].材料导报,2012,26(s1):360-363.YE Yong,WANG Jin-yan.Current situation of titanium alloy application and development of processing technology[J].Materials Review,2012,26(s1):360-363.
[4] 李东,赵永庆.钛合金晶粒细化进展[J].材料导报,2005,19(11):421-423.LI Dong,ZHAO Yong-qing.Titanium alloy grain refinement[J].Materials Review,2005,19(11):421-423.
[5] 鲍利索娃E A.钛合金金相学[M].陈石卿译.北京:国防工业出版社,1986.
[6] 王海,樊亚军,崔文俊.轧制工艺对纯钛小规格棒材微观组织和力学性能的影响[J].中国有色金属学报,2013,23(1):624-628.WANG Hai,FAN Ya-jun,CUI Wen-jun.Effect of rolling technology on microstructure and mechanical properties of pure titanium small gauge rods[J].The Chinese Journal of Nonferrous Metals,2013,23(1):624-628.
[7] 邬桑,欧阳德来,鲁世强.TB6钛合金β热处理晶粒生长及片层转变行为[J].材料热处理学报,2015,36(4):20-24.WU Sang,OUYANG De-lai,LU Shi-qiang.Grain growth and laminar transformation behavior of TB6 titanium alloy beta heat treatment[J].Transactions of Materials and Heat Treatment,2015,36(4):20-24.
[8] 唐建成,黄伯云,贺耀辉.Ti-Al基合金中的Hall-Petch关系及影响因素分析[J].金属学报,2002,38(4):365-368.TANG Jian-cheng,HUANG Bo-yun,HE Yao-hui.Relation between Hall-Petch and its influencing factors in Ti-Al-based alloy[J].Acta Metallurgical Sinica,2002,38(4):365-368.
[9] 孙前江,王高潮,李淼泉.细化晶粒对钛合金超塑性的影响[J].材料导报,2010,23(9):126-143.SUN Qian-jiang,WANG Gao-chao,LI Miao-quan.Effect of grain refinement on superplasticity of titanium alloy[J].Introduction of Materials Review,2010,23(9):126-143.
[10] 路君,曾小勤,丁文江.晶粒度与合金强度关系[J].轻金属,2008(8):59-64.LU Jun,ZENG Xiao-qin,DING Wen-jiang.Relationship between grain degree and strength of alloy[J].Light Metals,2008(8):59-64.
[11] Wan H L,Xu B Q,Dai Y N.Preparation of titanium powders by calciothermic reduction of titanium dioxide[J].Journal of Central South University,2012,19(9):2434-2439.
[12] Xu C,Zhu W F.Comparison of microstructures and mechanical properties between forging and rolling processes for commercially pure titanium[J].The Chinese Journal of Nonferrous Metals,2012,22(8):1939-1946.
[13] Ouyang D L,Wang K L,Cui X.Dynamic recrystallization of Ti-6Al-2Zr-1Mo-1V in β forging process[J].The Chinese Journal of Nonferrous Metals,2012,22(4):761-767.
[14] Zhang X H,Tang B,Zhang X L.Microstructure and texture of commercially pure titanium in cold deep drawing[J].The Chinese Journal of Nonferrous Metals,2012,22(3):496-502.
[15] Xu C,Zhu W F.Transformation mechanism and mechanical properties of commercially pure titanium[J].The Chinese Journal of Nonferrous Metals,2010,20(11):2162-2167.