大单重纯钼板坯高温塑性变形行为及热轧开坯工艺研究
|
摘要
附加值高的钼板材在钼产品结构中所占比例较低,国内生产的钼板材单重多在二十公斤以下,不能满足国内外市场对超大、超宽、超长钼板材的需求。基于此,为了优化钼产品结构,本文对大单重钼板坯的高温塑性变形行为及热轧工艺进行了探索。利用Gleeble-1500热-力学模拟机,对单重为100Kg的钼板坯进行了轧制热模拟实验,通过建立应力应变本构方程,结合扫描电镜分析设备,研究了不同变形参数对变形抗力以及显微组织的影响,拟定了合理的轧制工艺。利用1500T四辊可逆热轧机对轧制工艺进行了生产验证,对热轧板材进行了室温和高温力学性能分析,并利用X射线衍射仪、扫描电子显微镜对其织构和断口形貌进行了分析。主要研究结论如下:
1.纯钼板坯高温压缩变形时,流变应力随变形温度的升高而减小,随应变速率的增大而增大;随着应变速率的增加,不同变形温度下的流变应力之间的差值逐渐减小;同一应变速率下,峰值应力随变形温度的升高向应变小的方向推移。当应变速率?=0.01s~(-1)～1s~(-1),板坯在加工过程中出现了动态回复和再结晶现象,并随着温度的升高更趋明显;当应变速率?=1s~(-1)～5s-1时,则只出现动态回复现象。
2.纯钼高温塑性变形过程中,流变应力σ与变形温度T,应变速率?之间的本构方程为:ε= 6. 19182×10~8[s inh( 0.0038σ)]~(7.7175)exp[-282478.9/(RT)],平均热激活能Q=282.4789 KJ/mol;利用推导出的流变应力本构方程得到的峰值应力预测值与实验值较吻合,最大相对误差为12.53%,平均相对误差仅为3.68%。此本构方程可为纯钼热加工工艺的制定提供理论依据。
3.在热-力学模拟试验所拟定的合理的变形范围内进行开坯轧制实验,结果表明,合理的开坯轧制工艺为:最佳开坯温度1450℃～1500℃,平均道次变形率20～22%,轧制速度48～53 m/min。在此工艺参数条件下可获得理想的热轧板材。
4.交叉轧制可削弱热轧钼板材在单向轧制过程中产生的110｝〈uvw〉织构,有利于降低钼板材的各向异性;同时,随着轧制变形量的增加,有利于｛100｝〈uvw〉和｛111｝〈uvw〉织构的形成和强化,当变形量达90%以上时,｛100｝〈uvw〉织构最强。
5.总变形量为94%的热轧钼板材,在室温下的最大抗拉强度为586.2MPa,而延伸率仅为0.54%;在1000℃～1200℃的高温拉伸下,最大抗拉强度为336.02～175.5MPa,延伸率为26.7%～67%。这与相同变形量下的标准试样基本一致;热轧钼板材在室温下的拉伸断口表现为脆性断裂,从断口形貌中可以观察到内部有分层迹象,但层间厚度比相同变形量下的标准试样大;高温拉伸断口表现为韧性断裂,温度对韧性影响不明显。
As high added value product, molybdenum plate is in low proportion of molybdenum product structure. For the domestic molybdenum plate, the weight of single heavy is below 20 kg. In order to optimize molybdenum product structure and meet domestic and international market demand for larger, wider, and longer molybdenum plate, the large single heavy molybdenum slab rolling technology is explored in this paper. Using Gleeble-1500 simulate machine, the thermal simulation test is performed on molybdenum slab which single heavy is 100 kg. The influence of different deformation parameters on the deformation resistance and microstructure is studied by establishing constitutive equation and using material analysis equipment so as to develop reasonable rolling technology. The cogging technology is especialy studied by four-roll reversing mill with 1500t. The mechanical properties at room and high temperature were performed on hot-rolled plates. Fracture morphology and texture were analysed with SEM and XRD. The main conclutions were followed as:
1. The flow stress of pure molybdenum slab is decreased with the increasing of deformation temperaure in the higt temperature compressive experiment, but increased with the increasing of deformation rate. The different in flow stress at different temperature was decreased gradually with the increasing of strain rate. Peak stress goes on the direction to smaller strain with the increasing of deformation temperature. When strain rate ? = 0.01 s-1～1s~(-1), molybdenum slab in the machining process appeared the phenomenon of dynamic response and recrystallization but appeared the phenomenon of dynamic response when strain rate ? = 1 s-1～5s-1.
2. The constitutive equation among temperature, strain rate and flow stress isε= 6. 19182×10~8[s inh( 0.0038σ)]~(7.7175)exp[-282478.9/(RT)]. The average thermal activation energy Q=282.4789 KJ/mol. Predicted value deduced from constitutive equation is consistent with the experimental value. The maximum relative error is 12.53%, and average relative error is only 3.68%. The constitutive equation can provides the theoretical basis for hot forming process of pure molybdenum slab.
3. Cross rolling can weaken｛110｝ texture caused by unidirectional cross in hot- rolled plate. Also can helps reducing anisotropy of molybdenum plate. Meanwhile, along with the increase of rolling deformation, it is helpful for formating and strengthening the texture of {100} and {111} . When deformation amount is more than 90%, the strongest texture is {100} .
4. The primary rolling experiment followed by reasonable rolling technical range in thermal simulate test indicated that the optimum cogging temperature, average deformation degree and rolling speed is 1450℃～1500℃, 20～22% and 48～53 m/min respectively. In this process parameters range can obtain ideal rolled sheet.
5. The maximum resistance strength of pure molybdenum plate with total deformation of 94% is 586.2 MPa and elongation is only 0.54% at room temperature. At high temperature, 1000℃～1200℃, the related value are 336.02～175.5 MPa and the elongation are 26.7%～67%. This is almost consistent with standard samples that have same deformation. Fracture morphology indicated that brittle fracture occurs at room temperature but ductile fracture at high temperature. Also, the delamination indication was found in plate interior, and the thickness of experimental samples is thicker than standard sample.
1.纯钼板坯高温压缩变形时,流变应力随变形温度的升高而减小,随应变速率的增大而增大;随着应变速率的增加,不同变形温度下的流变应力之间的差值逐渐减小;同一应变速率下,峰值应力随变形温度的升高向应变小的方向推移。当应变速率?=0.01s~(-1)～1s~(-1),板坯在加工过程中出现了动态回复和再结晶现象,并随着温度的升高更趋明显;当应变速率?=1s~(-1)～5s-1时,则只出现动态回复现象。
2.纯钼高温塑性变形过程中,流变应力σ与变形温度T,应变速率?之间的本构方程为:ε= 6. 19182×10~8[s inh( 0.0038σ)]~(7.7175)exp[-282478.9/(RT)],平均热激活能Q=282.4789 KJ/mol;利用推导出的流变应力本构方程得到的峰值应力预测值与实验值较吻合,最大相对误差为12.53%,平均相对误差仅为3.68%。此本构方程可为纯钼热加工工艺的制定提供理论依据。
3.在热-力学模拟试验所拟定的合理的变形范围内进行开坯轧制实验,结果表明,合理的开坯轧制工艺为:最佳开坯温度1450℃～1500℃,平均道次变形率20～22%,轧制速度48～53 m/min。在此工艺参数条件下可获得理想的热轧板材。
4.交叉轧制可削弱热轧钼板材在单向轧制过程中产生的110｝〈uvw〉织构,有利于降低钼板材的各向异性;同时,随着轧制变形量的增加,有利于｛100｝〈uvw〉和｛111｝〈uvw〉织构的形成和强化,当变形量达90%以上时,｛100｝〈uvw〉织构最强。
5.总变形量为94%的热轧钼板材,在室温下的最大抗拉强度为586.2MPa,而延伸率仅为0.54%;在1000℃～1200℃的高温拉伸下,最大抗拉强度为336.02～175.5MPa,延伸率为26.7%～67%。这与相同变形量下的标准试样基本一致;热轧钼板材在室温下的拉伸断口表现为脆性断裂,从断口形貌中可以观察到内部有分层迹象,但层间厚度比相同变形量下的标准试样大;高温拉伸断口表现为韧性断裂,温度对韧性影响不明显。
As high added value product, molybdenum plate is in low proportion of molybdenum product structure. For the domestic molybdenum plate, the weight of single heavy is below 20 kg. In order to optimize molybdenum product structure and meet domestic and international market demand for larger, wider, and longer molybdenum plate, the large single heavy molybdenum slab rolling technology is explored in this paper. Using Gleeble-1500 simulate machine, the thermal simulation test is performed on molybdenum slab which single heavy is 100 kg. The influence of different deformation parameters on the deformation resistance and microstructure is studied by establishing constitutive equation and using material analysis equipment so as to develop reasonable rolling technology. The cogging technology is especialy studied by four-roll reversing mill with 1500t. The mechanical properties at room and high temperature were performed on hot-rolled plates. Fracture morphology and texture were analysed with SEM and XRD. The main conclutions were followed as:
1. The flow stress of pure molybdenum slab is decreased with the increasing of deformation temperaure in the higt temperature compressive experiment, but increased with the increasing of deformation rate. The different in flow stress at different temperature was decreased gradually with the increasing of strain rate. Peak stress goes on the direction to smaller strain with the increasing of deformation temperature. When strain rate ? = 0.01 s-1～1s~(-1), molybdenum slab in the machining process appeared the phenomenon of dynamic response and recrystallization but appeared the phenomenon of dynamic response when strain rate ? = 1 s-1～5s-1.
2. The constitutive equation among temperature, strain rate and flow stress isε= 6. 19182×10~8[s inh( 0.0038σ)]~(7.7175)exp[-282478.9/(RT)]. The average thermal activation energy Q=282.4789 KJ/mol. Predicted value deduced from constitutive equation is consistent with the experimental value. The maximum relative error is 12.53%, and average relative error is only 3.68%. The constitutive equation can provides the theoretical basis for hot forming process of pure molybdenum slab.
3. Cross rolling can weaken｛110｝
4. The primary rolling experiment followed by reasonable rolling technical range in thermal simulate test indicated that the optimum cogging temperature, average deformation degree and rolling speed is 1450℃～1500℃, 20～22% and 48～53 m/min respectively. In this process parameters range can obtain ideal rolled sheet.
5. The maximum resistance strength of pure molybdenum plate with total deformation of 94% is 586.2 MPa and elongation is only 0.54% at room temperature. At high temperature, 1000℃～1200℃, the related value are 336.02～175.5 MPa and the elongation are 26.7%～67%. This is almost consistent with standard samples that have same deformation. Fracture morphology indicated that brittle fracture occurs at room temperature but ductile fracture at high temperature. Also, the delamination indication was found in plate interior, and the thickness of experimental samples is thicker than standard sample.
引文
[1]张启修,赵秦生.钨钼冶金[M].北京:冶金工业出版社,2007,26-45.
[2]王发展,等.钼材料及其加工[M].北京:冶金工业出版社,2008,1-21.
[3]罗振中.钼的应用及其发展[J].中国钼业,1998,22(4):18-20.
[4]罗振中.我国钼工业现状及发展对策浅议[J].中国钼业,2000,24(4):3-6.
[5]钟培全.钼与钼合金的应用及其加工方法[J].中国钼业,2000,24(5):15-16.
[6]王东辉,袁晓波,李中奎,等.钼及钼合金研究与应用进展[J].稀有金属快报,2006,25(12):1-5.
[7] Youngmoo Kim. Consolidation behavior and hardness of P/M molybdenum[J]. Powder Technology,2008,(186) :213–217.
[8]吴贤,张健,康新婷,等.钼粉的制备技术及研究现状[J].稀有金属材料与工程,2007,36(3):562-565.
[9]李晶,左羽飞.钼粉还原过程的形貌演变[J].稀有金属,2007,31(3):73-76.
[10]林小芹,贺跃辉,王政伟,等.钥粉的制备技术及其发展[J].粉末冶金材料科学与工程,2003,8(2):128-132.
[11]周志德.金属粉末轧制[J].粉末冶金工业,2001,11(1):36-39.
[12] Guigon P, Simon O. Roll Press Design2Influence of Force Feed Systems on CoMPaction [J]. Powder Technology. 2003,130 (1-3):41-48.
[13] Dube R K. Metal Strip via Roll CoMPaction and Related Powder Metallurgy Routes [J]. International Materials Reviews. 1990,35 (5):253-291.
[14]谭兆强,李笃信,李昆,等.纯钼注射成形工艺的研究[J].粉末冶金工业,2008,18(1):19-22.
[15] German R M, Cornwall R G. Worldwide market and technology for powder injection molding [J].The International Journal of Powder Metallurgy. 1997,33(4):23-28.
[16]崔忠圻.金属学与热处理[M].北京:冶金工业出版社,1989,214-218.
[17]李鹏.热轧工艺对钼板材成品性能的影响[J].稀有金属与硬质合金,2005,33(2):35-37.
[18]杨明杰,李麦海,魏忠梅.轧制温度对钼板组织与性能的影响[J].稀有金属与硬质合金,1999,137(2):30-31.
[19]杨文甲.粉末冶金TZM钼合金板坯热轧开坯工艺的研[J].有色矿冶,1995,11(3):30-33.
[20]韩强,张相一.纯钼板及钼合金板热轧工艺探讨[J].中国钼业,2001,25(1):39-42.
[21]朱爱辉,王快社,吕新矿.钼板轧制工艺的优化[J].机械工程材料,2007,31(2):26-28.
[22]熊自强.生产工艺对粉冶热轧钼板硬度和弯曲性能的影响[J].中国钼业,1995,19(3):22-24.
[23]王鹏.钼板轧制工艺与弯曲工艺性能[J].中国钼业,1995,19(5):23-25.
[24]朱恩科.退火温度对钼带组织及性能的影响[J].中国钼业,2001,25(4):71-73.
[25] Liu Sha.Annealing behavior of molybdenum alloys containing 3 wt% rhenium [J]. International Journal of Refractory Metals & Hard Materials.1999,17(5):381-384.
[26] T.Mrotzek,A.Hoffmann,U.Martin. Hardening mechanisms and recrystallization behaviour of several molybdenum alloys [J]. International Journal of Refractory Metals & Hard Materials.2006,24(4):298-305.
[27]邓自南,郭磊.轧制工艺对深加工用温轧钼板材组织和性能的影响[J].稀有金属与硬质合金,2008,36(3):24-26.
[28]邓自南,赵娟,杨明杰.轧制工艺对深冲钼带组织和性能的影响[J].稀有金属快报,2008,27(4):18-21.
[29] Tom Walde.Plastic anisotropy of thin molybdenum sheets[J].International Journal of Refractory Metals & Hard Materials. 2008,26(5):396-403.
[30]张军良,李中奎等.交叉轧制及退火对钼铼合金箔材深冲性能的影响[J].中国钼业,2009,33(3):32-36.
[31] C.-G. Oertel, I. Huensche. Plastic anisotropy of straight and cross rolled molybdenum sheets [J].Materials Science and Engineering A .2008,483-484:79–83.
[32] ChengfanGu, JunliangZhang. Microstructure and Mechanical Properties of Molybdenum Sheet after Cross Rolling Processing[J].Transactions of Materials and Heat Treatment.2004,25(5):61-65.
[33]肖松涛,杨明杰,那菲.加工工艺对交叉钼片性能的影响[J].中国钼业,2005,29(1):26-27.
[34]张文征.2009年钼业年评[J].中国钼业,2009,33(6):1-6.
[35]程景峰,余莉,许洁瑜.中国钼金属制品发展现状分析[J].中国钼业,2009,33(4):16-20.
[36]许洁瑜,程景峰.2008年上半年我国钼产品进出口分析[J].稀有金属快报,2008,27(9):20-23.
[37]石明柱,李林,王宝芝,等.高品质宽幅钼板的研制[J].中国钼业,2004,28(2):46-48.
[38]李大成,杨刘晓,孙院军,等.钼金属深加工产品现状及技术应用分析[J].中国钼业,2008,32(1):8-13.
[39]董允杰,张金全.国内外钼制品对比及评述[J].中国钼业,2001,25(5):6-9.
[40]洪成淼,董建新,张麦仓,等.热变形参数对GH846合金显微组织的影响[J].稀有金属材料与工程,2010,39(4):608-612.
[41]王宏伟,易丹清,王斌,等.Mg-6.3Zn-0.7Zr-0.9Y-0.3Nd镁合金的高温塑性变形行为的热压缩模拟[J].中国有色金属学报,2010,20(3):378-383.
[42]寇琳媛,金能萍,张辉,等.7150铝合金高温热压缩变形流变应力行为[J].中国有色金属学报,2010,20(1):43-48.
[43] MCQUEEN H J, YUE S, RYAN N D, FRY E. Hot working characteristics of steels in austenitic state [J]. Journal of Materials Processing Technology.1995,53(1-2):293-310.
[44] MCQUEEN H J, RYAN N D. Constitutive analysis in hot working[J].Materials Science and Engineering A.2002,322 (1-2): 43–63.
[45] SOLHJOO SOHEIL. Analysis of ?ow stress up to the peak at hot deformation[J].Materials and Design.2009,30(8):3036–3040.
[46] H. Mirzadeh, A. Najafizadeh. Flow stress prediction at hot working conditions [J]. Materials Science and Engineering A.2010,527(4-5):1160–1164.
[47]吕新矿,朱爱辉,王快社.7150大尺寸Mo-1板轧制工艺研究[J].稀有金属快报,2006,25(4):28-32.
[48]赵德文,铁维麟.轧制应变速率参数Ε的精确计算方法[J].应用科学学报,1995,13(1):103-107.
[49]陈程,尹海清,曲选辉,等.钼变形抗力的研究[J].稀有金属材料与工程,2007,36(7):20—23.
[50]李树棠.晶体X射线衍射学基础[M].北京:冶金工业出版社,1990,199-202.
[2]王发展,等.钼材料及其加工[M].北京:冶金工业出版社,2008,1-21.
[3]罗振中.钼的应用及其发展[J].中国钼业,1998,22(4):18-20.
[4]罗振中.我国钼工业现状及发展对策浅议[J].中国钼业,2000,24(4):3-6.
[5]钟培全.钼与钼合金的应用及其加工方法[J].中国钼业,2000,24(5):15-16.
[6]王东辉,袁晓波,李中奎,等.钼及钼合金研究与应用进展[J].稀有金属快报,2006,25(12):1-5.
[7] Youngmoo Kim. Consolidation behavior and hardness of P/M molybdenum[J]. Powder Technology,2008,(186) :213–217.
[8]吴贤,张健,康新婷,等.钼粉的制备技术及研究现状[J].稀有金属材料与工程,2007,36(3):562-565.
[9]李晶,左羽飞.钼粉还原过程的形貌演变[J].稀有金属,2007,31(3):73-76.
[10]林小芹,贺跃辉,王政伟,等.钥粉的制备技术及其发展[J].粉末冶金材料科学与工程,2003,8(2):128-132.
[11]周志德.金属粉末轧制[J].粉末冶金工业,2001,11(1):36-39.
[12] Guigon P, Simon O. Roll Press Design2Influence of Force Feed Systems on CoMPaction [J]. Powder Technology. 2003,130 (1-3):41-48.
[13] Dube R K. Metal Strip via Roll CoMPaction and Related Powder Metallurgy Routes [J]. International Materials Reviews. 1990,35 (5):253-291.
[14]谭兆强,李笃信,李昆,等.纯钼注射成形工艺的研究[J].粉末冶金工业,2008,18(1):19-22.
[15] German R M, Cornwall R G. Worldwide market and technology for powder injection molding [J].The International Journal of Powder Metallurgy. 1997,33(4):23-28.
[16]崔忠圻.金属学与热处理[M].北京:冶金工业出版社,1989,214-218.
[17]李鹏.热轧工艺对钼板材成品性能的影响[J].稀有金属与硬质合金,2005,33(2):35-37.
[18]杨明杰,李麦海,魏忠梅.轧制温度对钼板组织与性能的影响[J].稀有金属与硬质合金,1999,137(2):30-31.
[19]杨文甲.粉末冶金TZM钼合金板坯热轧开坯工艺的研[J].有色矿冶,1995,11(3):30-33.
[20]韩强,张相一.纯钼板及钼合金板热轧工艺探讨[J].中国钼业,2001,25(1):39-42.
[21]朱爱辉,王快社,吕新矿.钼板轧制工艺的优化[J].机械工程材料,2007,31(2):26-28.
[22]熊自强.生产工艺对粉冶热轧钼板硬度和弯曲性能的影响[J].中国钼业,1995,19(3):22-24.
[23]王鹏.钼板轧制工艺与弯曲工艺性能[J].中国钼业,1995,19(5):23-25.
[24]朱恩科.退火温度对钼带组织及性能的影响[J].中国钼业,2001,25(4):71-73.
[25] Liu Sha.Annealing behavior of molybdenum alloys containing 3 wt% rhenium [J]. International Journal of Refractory Metals & Hard Materials.1999,17(5):381-384.
[26] T.Mrotzek,A.Hoffmann,U.Martin. Hardening mechanisms and recrystallization behaviour of several molybdenum alloys [J]. International Journal of Refractory Metals & Hard Materials.2006,24(4):298-305.
[27]邓自南,郭磊.轧制工艺对深加工用温轧钼板材组织和性能的影响[J].稀有金属与硬质合金,2008,36(3):24-26.
[28]邓自南,赵娟,杨明杰.轧制工艺对深冲钼带组织和性能的影响[J].稀有金属快报,2008,27(4):18-21.
[29] Tom Walde.Plastic anisotropy of thin molybdenum sheets[J].International Journal of Refractory Metals & Hard Materials. 2008,26(5):396-403.
[30]张军良,李中奎等.交叉轧制及退火对钼铼合金箔材深冲性能的影响[J].中国钼业,2009,33(3):32-36.
[31] C.-G. Oertel, I. Huensche. Plastic anisotropy of straight and cross rolled molybdenum sheets [J].Materials Science and Engineering A .2008,483-484:79–83.
[32] ChengfanGu, JunliangZhang. Microstructure and Mechanical Properties of Molybdenum Sheet after Cross Rolling Processing[J].Transactions of Materials and Heat Treatment.2004,25(5):61-65.
[33]肖松涛,杨明杰,那菲.加工工艺对交叉钼片性能的影响[J].中国钼业,2005,29(1):26-27.
[34]张文征.2009年钼业年评[J].中国钼业,2009,33(6):1-6.
[35]程景峰,余莉,许洁瑜.中国钼金属制品发展现状分析[J].中国钼业,2009,33(4):16-20.
[36]许洁瑜,程景峰.2008年上半年我国钼产品进出口分析[J].稀有金属快报,2008,27(9):20-23.
[37]石明柱,李林,王宝芝,等.高品质宽幅钼板的研制[J].中国钼业,2004,28(2):46-48.
[38]李大成,杨刘晓,孙院军,等.钼金属深加工产品现状及技术应用分析[J].中国钼业,2008,32(1):8-13.
[39]董允杰,张金全.国内外钼制品对比及评述[J].中国钼业,2001,25(5):6-9.
[40]洪成淼,董建新,张麦仓,等.热变形参数对GH846合金显微组织的影响[J].稀有金属材料与工程,2010,39(4):608-612.
[41]王宏伟,易丹清,王斌,等.Mg-6.3Zn-0.7Zr-0.9Y-0.3Nd镁合金的高温塑性变形行为的热压缩模拟[J].中国有色金属学报,2010,20(3):378-383.
[42]寇琳媛,金能萍,张辉,等.7150铝合金高温热压缩变形流变应力行为[J].中国有色金属学报,2010,20(1):43-48.
[43] MCQUEEN H J, YUE S, RYAN N D, FRY E. Hot working characteristics of steels in austenitic state [J]. Journal of Materials Processing Technology.1995,53(1-2):293-310.
[44] MCQUEEN H J, RYAN N D. Constitutive analysis in hot working[J].Materials Science and Engineering A.2002,322 (1-2): 43–63.
[45] SOLHJOO SOHEIL. Analysis of ?ow stress up to the peak at hot deformation[J].Materials and Design.2009,30(8):3036–3040.
[46] H. Mirzadeh, A. Najafizadeh. Flow stress prediction at hot working conditions [J]. Materials Science and Engineering A.2010,527(4-5):1160–1164.
[47]吕新矿,朱爱辉,王快社.7150大尺寸Mo-1板轧制工艺研究[J].稀有金属快报,2006,25(4):28-32.
[48]赵德文,铁维麟.轧制应变速率参数Ε的精确计算方法[J].应用科学学报,1995,13(1):103-107.
[49]陈程,尹海清,曲选辉,等.钼变形抗力的研究[J].稀有金属材料与工程,2007,36(7):20—23.
[50]李树棠.晶体X射线衍射学基础[M].北京:冶金工业出版社,1990,199-202.