Cu-Cr合金的热型连铸
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摘要
本课题采用热型连铸控制的方法，使第二相Cr在凝固时以纤维析出，用Cr纤维承担强度，铜基体承担导电。这样就避免了人工复合带来的不润湿、化学反应和不互溶等问题，两相界面处于低能状态，具有良好的热稳定性能和高温性能。强度和导电率都比较高。
本课题采用感应加热电源代替传统的碳化硅棒改进了热型连铸实验设备，从而大大增加了加热功率，提高了铸型的温度梯度，减小了Cu-Cr合金固+液两相区的范围，为拉铸良好表面质量的Cu-Cr合金提供了保障。利用该设备成功地拉铸出含Cr量1.29wt％的Cu-Cr合金棒材。在未经冷加工强化情况下观察其显微组织，发现具有规则柱状晶的定向凝固组织，测试其材料性能，抗拉强度达390Mpa，延伸率29％，导电率53％IACS，综合性能显著高于用普通工艺制备的铜合金棒材。
拉铸高含Cr量的Cu-Cr合金最大困难在于Cr的熔点高，Cu-Cr合金结晶范围比较宽，溶质分配系数低，高温下Cr容易氧化。因此提高温度梯度，缩小Cu-Cr合金固+液两相区的范围，增加Cr的流动性，减轻Cr的成分过冷，在大加热功率的环境下控制好固液界面以及避免Cr氧化是本课题的重点。
铸件的力学性能和导电性能与铸件的表面质量有关，而表面质量与拉铸工艺参数有关。控制好拉铸速度，冷却水量，冷却距离，铸型温度等工艺参数以控制固+液两相区在尽可能小的范围和最理想的位置可以消除表面热裂纹、豆状突起，防止拉断和拉漏。拉铸实验表明，在熔炼温度1300℃，铸型温度1198℃，拉铸速度35mm／min，冷却距离8mm可以拉铸出表面光滑，致密的(?)5mm的Cu-1.29wt％Cr合金棒材。
成分为过共晶的Cu-Cr合金通过控制好铸造工艺参数同样可以得到亚共晶组织。本课题得到了纤维链状的亚共晶组织，经过力学性能、导电性能测试与分析发现：铸态的Cu-Cr合金抗拉强度与含Cr量成正比，与拉铸速度成反比。
The specimen were made with heated mould continuous casting process, in which Cr phase is solidified separately as fiber from Cu matrix. Cr fiber acts as strength and Cu matrix acts as electrical conductivity. In this way, difficulties of soakage dissolve in artificial composite, and chemistry reaction can be avoid. Two phase interphases get along well under low energy state. The specimen have excellent hot stability and high temperature performance. Both strength and electrical conductivity are high.
Induction heat is adopted instead of traditional carborundum heating to improve heated mould continuous casting equipment. Thereby, it greatly increases heating power, increases casting mould temperature gradient, minishes S+L two phase range of Cu-Cr alloy , ensure excellent surface quality of Cu-Cr alloy. Cu-1.29wt%Cr alloy wires were casted successful by this equipment and directional solidification microstructure in as-cast specimen is found. The result showed a tensile strength of 390Mpa, elongation 29%, and electrical conductivity 53% IACS. Their synthetic property is higher than those made by common process.
It is very difficult to cast Cu-Cr alloy which contain high Cr content, because Cr has high melting point, Cu-Cr alloy have large range of solidification temperature, the solution distribution coefficient is low and in high temperature Cr is easy to oxida. So it is more important to improve temperature gradient to shorten S+L two phase range of Cu-Cr alloy to make Cr flow easier, lighten Cr constitutuinal super-cooling, under high heating power condition to control S+L interface well and to avoid Cr to oxide.
The performance of mechanics and electrical conductivity relates to casting surface quality, surface quality is determined by casting parameters. Hot tearing, scab can be eliminated. Breakdown and leakage can be avoided, when casting velocity, cooling water capacity, cooling distance, casting mould temperature and S+L two phase range are available, experiments showed that when melting
temperature is 1300℃, casting mould temperature is 1198℃, casting velocity is 35mm/min and cooling distance is 8mm , Good 5mm wire of Cu-1.29 wt %Cr can be casted.
Even if Cr content is above 1.28wt%, hypo-eutectic can still be achieved when casting parameter are control well. The result show that their tensile strength increases with increase of the Cr content, their electric conductivity become higher with increase of the casting speed for as-cast specimen.
本课题采用感应加热电源代替传统的碳化硅棒改进了热型连铸实验设备，从而大大增加了加热功率，提高了铸型的温度梯度，减小了Cu-Cr合金固+液两相区的范围，为拉铸良好表面质量的Cu-Cr合金提供了保障。利用该设备成功地拉铸出含Cr量1.29wt％的Cu-Cr合金棒材。在未经冷加工强化情况下观察其显微组织，发现具有规则柱状晶的定向凝固组织，测试其材料性能，抗拉强度达390Mpa，延伸率29％，导电率53％IACS，综合性能显著高于用普通工艺制备的铜合金棒材。
拉铸高含Cr量的Cu-Cr合金最大困难在于Cr的熔点高，Cu-Cr合金结晶范围比较宽，溶质分配系数低，高温下Cr容易氧化。因此提高温度梯度，缩小Cu-Cr合金固+液两相区的范围，增加Cr的流动性，减轻Cr的成分过冷，在大加热功率的环境下控制好固液界面以及避免Cr氧化是本课题的重点。
铸件的力学性能和导电性能与铸件的表面质量有关，而表面质量与拉铸工艺参数有关。控制好拉铸速度，冷却水量，冷却距离，铸型温度等工艺参数以控制固+液两相区在尽可能小的范围和最理想的位置可以消除表面热裂纹、豆状突起，防止拉断和拉漏。拉铸实验表明，在熔炼温度1300℃，铸型温度1198℃，拉铸速度35mm／min，冷却距离8mm可以拉铸出表面光滑，致密的(?)5mm的Cu-1.29wt％Cr合金棒材。
成分为过共晶的Cu-Cr合金通过控制好铸造工艺参数同样可以得到亚共晶组织。本课题得到了纤维链状的亚共晶组织，经过力学性能、导电性能测试与分析发现：铸态的Cu-Cr合金抗拉强度与含Cr量成正比，与拉铸速度成反比。
The specimen were made with heated mould continuous casting process, in which Cr phase is solidified separately as fiber from Cu matrix. Cr fiber acts as strength and Cu matrix acts as electrical conductivity. In this way, difficulties of soakage dissolve in artificial composite, and chemistry reaction can be avoid. Two phase interphases get along well under low energy state. The specimen have excellent hot stability and high temperature performance. Both strength and electrical conductivity are high.
Induction heat is adopted instead of traditional carborundum heating to improve heated mould continuous casting equipment. Thereby, it greatly increases heating power, increases casting mould temperature gradient, minishes S+L two phase range of Cu-Cr alloy , ensure excellent surface quality of Cu-Cr alloy. Cu-1.29wt%Cr alloy wires were casted successful by this equipment and directional solidification microstructure in as-cast specimen is found. The result showed a tensile strength of 390Mpa, elongation 29%, and electrical conductivity 53% IACS. Their synthetic property is higher than those made by common process.
It is very difficult to cast Cu-Cr alloy which contain high Cr content, because Cr has high melting point, Cu-Cr alloy have large range of solidification temperature, the solution distribution coefficient is low and in high temperature Cr is easy to oxida. So it is more important to improve temperature gradient to shorten S+L two phase range of Cu-Cr alloy to make Cr flow easier, lighten Cr constitutuinal super-cooling, under high heating power condition to control S+L interface well and to avoid Cr to oxide.
The performance of mechanics and electrical conductivity relates to casting surface quality, surface quality is determined by casting parameters. Hot tearing, scab can be eliminated. Breakdown and leakage can be avoided, when casting velocity, cooling water capacity, cooling distance, casting mould temperature and S+L two phase range are available, experiments showed that when melting
temperature is 1300℃, casting mould temperature is 1198℃, casting velocity is 35mm/min and cooling distance is 8mm , Good 5mm wire of Cu-1.29 wt %Cr can be casted.
Even if Cr content is above 1.28wt%, hypo-eutectic can still be achieved when casting parameter are control well. The result show that their tensile strength increases with increase of the Cr content, their electric conductivity become higher with increase of the casting speed for as-cast specimen.
引文
[1] 马如璋、蒋民华、徐祖盛．功能材料学概论．第2版．北京：冶金工业出版社，1999．34-37
[2] 陈国君、王序军．金属功能材料“十五”市场需求．金属功能材料，2001，8(6)：10～16
[3] 颜景和、王恩久，电线电缆，1992．2：15～17
[4] 谢建新、王自东、吴春京．单向纤维晶强化超高强度钢丝制备工艺．中国．发明专利，公开号：CN1259409A
[5] 谢建新，王自东、吴春京．单向纤维晶强化超高强度钢丝制备．北京科技大学学报，1998，20(6)：556
[6] 谢建新、张鸿、王自东．高性能金属材料组织精确控制成型加工技术．首届留日学者21世纪材料科学技术研讨会论文集(卷2)．北京：冶金工业出版社，2000，10
[7] 刘平、康布熙、曹兴国等．快速凝固Cu-Cr合金导电性分析．洛阳工学院报，1998，19(4)：1～4
[8] Wright RN. Age.hardening behavior of dynamically consolidated vapidly solidified Cu-2% Zr powder. Material Science and Engineering, 1998, (114):167
[9] Rishi P Sigh, Alan lauley. Microstructure and properties of spmy cast Cu-Zr alloys. Material Science and Engineering,1991,A145:253
[10] Correia JB, Daries HA, sellarm CM. The microstructure and properties of water atomized and extruded Cu-Cr alloy powders. Material Science and Enginneering, 1991, (133):265
[11] 刘平、曹兴国、康布熙等．快速凝固高强度高导电性Cu-Cr合金的组织和性能．兵器材料科学与工程，1997，(1)：12～16
[12] 刘平、曹兴国、康布熙等．快速凝固Cu-Cr-zr-Mg的组织和性能．中国有色金属学报，1999，(2)：241～246
[13] 刘平、曹兴国、康布熙等．多级雾化Cu-Cr合金粉末成型后的组织和性能．中国有色金属学报，1999，9(4)：677～681
[14] 王强、梁淑华、范志康．Cu-Cr系合金材料制造工艺的新进展．材料导报，2000，(8)：22
[15] 马凤仓、倪锋、杨涤心．铜铬合金制备方法研究现状．材料开发与应用，2002，17(3)：35～38
[16] Dew-Haughes D. mater Sci&Eng(A), 1993,(168):35～40
[17] 周镇华等．材料学报，1996，(6)：1～6
[18] Versnyder F L, Shank M E, Mater Sci&eng, 1970,(6):213
[19] 李建国、毛协民、傅恒志等．材料研究进展，1991，(6)：461
[20] LiJG, Mao XM, Fu HZ, Acta metal sinica, 1991,(4):71
[21] 李金富．西北工业大学博士论文，1998
[22] LuxB,HaourG, MollandF.Metall, 1981;35:1235
[23] 李金山．西北工业大学博士论文，1998
[24] 潘清跃．西北工业大学博士论文，1997
[25] GillSC,Kurz W.ActaMetallTrans, 1993,41:3503
[26] GremaudM,CarrardM,KurzW.ActaMetallTrans, 1991,39:1431
[27] ClineHE.MetallTrans, 1984,15A: 1013
[28] Tiller WA, Jackson K A, Rutter JW, Chalmers B, Acta metal, 1953,(1):428
[29] Mullins w w, sekerka R F, Japplphys, 1964, (35):444
[30] 陈国良．高温合金学．北京：冶金工业出版社，1988
[31] Ohno A, Continuous Casting of single crysted Ingots by the O.C.C process, Journals of Metals, 1986,(38):14～16
[32] Ohno A, Casting of Near Net Shape products, The metallurgical Society, 1988,177～184
[33] 许振明、李建国、傅恒志．OCC技术研究现状及其进展．特种铸造及有色合金，1999，(1)：32～35
[34] H.Soda,G.Motoyasu,etal. Alloy Casting by the Horizontal Ohno continuous casting system,CastMetals, 1993,6(2):76～86
[35] 许广济等．热型连铸工艺参数对铸锭表面质量的影响．甘肃工业大学学报，1999，9，25(3)：27～31
[36] 田莳．材料物理性能．北京：北京航空航天大学出版社，2001，76
[37] 黎沃光等．铅锡合金的热型连铸．铸造技术，1997，(5)：42～44
[38] 丁浩．定向凝固中热裂纹的形成过程．稀有金属材料与工程，1997，2，26(1)：19～21
[39] 胡汉起．金属凝固原理．第2版．北京：机械工业出版社，2000．188-190
[40] Jackson K A. Hunt J D.Lamellar and rod eutectic growth. TMS of AIME., 1966(236):1129-1142
[41] Mullins W W. Sekerka R F. Stability of a planar interface during solidification of a
dilute binary alloy., J.Appl. phys, 1996(35):444-451
[42] 胡汉起．金属凝固原理．第2版．机械工业出版社，2000，128-130
[43] 彭立明、毛协民、温宏权．凝固工艺对自生复合Cu-Cr合金电车线综合性能的影响．功能材料，2001，32(2)：158～160
[44] 温宏权、毛协民．高强度导电性Cu-Cr合金定向凝固微观组织研究．铸造设备研究，1997，(4)：39～41
[45] 马凤仓、倪锋、杨涤心．铜铬合金制备方法研究现状．材料开发与应用，2002，6，17(3)：35～38
[46] 付大军．铬对铜-铬合金电车线性能的影响．有色金属，2003，5，55(2)：6～8
[2] 陈国君、王序军．金属功能材料“十五”市场需求．金属功能材料，2001，8(6)：10～16
[3] 颜景和、王恩久，电线电缆，1992．2：15～17
[4] 谢建新、王自东、吴春京．单向纤维晶强化超高强度钢丝制备工艺．中国．发明专利，公开号：CN1259409A
[5] 谢建新，王自东、吴春京．单向纤维晶强化超高强度钢丝制备．北京科技大学学报，1998，20(6)：556
[6] 谢建新、张鸿、王自东．高性能金属材料组织精确控制成型加工技术．首届留日学者21世纪材料科学技术研讨会论文集(卷2)．北京：冶金工业出版社，2000，10
[7] 刘平、康布熙、曹兴国等．快速凝固Cu-Cr合金导电性分析．洛阳工学院报，1998，19(4)：1～4
[8] Wright RN. Age.hardening behavior of dynamically consolidated vapidly solidified Cu-2% Zr powder. Material Science and Engineering, 1998, (114):167
[9] Rishi P Sigh, Alan lauley. Microstructure and properties of spmy cast Cu-Zr alloys. Material Science and Engineering,1991,A145:253
[10] Correia JB, Daries HA, sellarm CM. The microstructure and properties of water atomized and extruded Cu-Cr alloy powders. Material Science and Enginneering, 1991, (133):265
[11] 刘平、曹兴国、康布熙等．快速凝固高强度高导电性Cu-Cr合金的组织和性能．兵器材料科学与工程，1997，(1)：12～16
[12] 刘平、曹兴国、康布熙等．快速凝固Cu-Cr-zr-Mg的组织和性能．中国有色金属学报，1999，(2)：241～246
[13] 刘平、曹兴国、康布熙等．多级雾化Cu-Cr合金粉末成型后的组织和性能．中国有色金属学报，1999，9(4)：677～681
[14] 王强、梁淑华、范志康．Cu-Cr系合金材料制造工艺的新进展．材料导报，2000，(8)：22
[15] 马凤仓、倪锋、杨涤心．铜铬合金制备方法研究现状．材料开发与应用，2002，17(3)：35～38
[16] Dew-Haughes D. mater Sci&Eng(A), 1993,(168):35～40
[17] 周镇华等．材料学报，1996，(6)：1～6
[18] Versnyder F L, Shank M E, Mater Sci&eng, 1970,(6):213
[19] 李建国、毛协民、傅恒志等．材料研究进展，1991，(6)：461
[20] LiJG, Mao XM, Fu HZ, Acta metal sinica, 1991,(4):71
[21] 李金富．西北工业大学博士论文，1998
[22] LuxB,HaourG, MollandF.Metall, 1981;35:1235
[23] 李金山．西北工业大学博士论文，1998
[24] 潘清跃．西北工业大学博士论文，1997
[25] GillSC,Kurz W.ActaMetallTrans, 1993,41:3503
[26] GremaudM,CarrardM,KurzW.ActaMetallTrans, 1991,39:1431
[27] ClineHE.MetallTrans, 1984,15A: 1013
[28] Tiller WA, Jackson K A, Rutter JW, Chalmers B, Acta metal, 1953,(1):428
[29] Mullins w w, sekerka R F, Japplphys, 1964, (35):444
[30] 陈国良．高温合金学．北京：冶金工业出版社，1988
[31] Ohno A, Continuous Casting of single crysted Ingots by the O.C.C process, Journals of Metals, 1986,(38):14～16
[32] Ohno A, Casting of Near Net Shape products, The metallurgical Society, 1988,177～184
[33] 许振明、李建国、傅恒志．OCC技术研究现状及其进展．特种铸造及有色合金，1999，(1)：32～35
[34] H.Soda,G.Motoyasu,etal. Alloy Casting by the Horizontal Ohno continuous casting system,CastMetals, 1993,6(2):76～86
[35] 许广济等．热型连铸工艺参数对铸锭表面质量的影响．甘肃工业大学学报，1999，9，25(3)：27～31
[36] 田莳．材料物理性能．北京：北京航空航天大学出版社，2001，76
[37] 黎沃光等．铅锡合金的热型连铸．铸造技术，1997，(5)：42～44
[38] 丁浩．定向凝固中热裂纹的形成过程．稀有金属材料与工程，1997，2，26(1)：19～21
[39] 胡汉起．金属凝固原理．第2版．北京：机械工业出版社，2000．188-190
[40] Jackson K A. Hunt J D.Lamellar and rod eutectic growth. TMS of AIME., 1966(236):1129-1142
[41] Mullins W W. Sekerka R F. Stability of a planar interface during solidification of a
dilute binary alloy., J.Appl. phys, 1996(35):444-451
[42] 胡汉起．金属凝固原理．第2版．机械工业出版社，2000，128-130
[43] 彭立明、毛协民、温宏权．凝固工艺对自生复合Cu-Cr合金电车线综合性能的影响．功能材料，2001，32(2)：158～160
[44] 温宏权、毛协民．高强度导电性Cu-Cr合金定向凝固微观组织研究．铸造设备研究，1997，(4)：39～41
[45] 马凤仓、倪锋、杨涤心．铜铬合金制备方法研究现状．材料开发与应用，2002，6，17(3)：35～38
[46] 付大军．铬对铜-铬合金电车线性能的影响．有色金属，2003，5，55(2)：6～8