合金成分及熔炼工艺对高熔点Cu-Ni合金组织及热物性的影响

发布时间：2018-03-04 04:07

  本文选题：铜-镍合金　切入点：熔炼工艺　出处：《南昌航空大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着冶炼强度的不断加大,高炉炉衬的保护技术变得越来越重要,目前通用的解决方法是在砌砖之间埋设具有高热导率的纯铜水套,实行强制冷却,延长高炉使用寿命。然而纯铜水套存在3个不可避免的缺点,一是水套铸造过程中易熔穿,二是在实际使用过程中由于高炉内温度较高,只要水量、水压或水温稍有波动,水套即可能迅速熔穿,三是纯铜热导率过高易产生“气锤”的负面影响。究其原因是由于纯铜的熔点较低,开发高熔点高热导铜合金对研制高性能冷却水套等热交换器件意义重大。本文依据铜合金相图,在Cu-Ni合金基础之上,添加Mo、Nb、Y等元素,分别制备了Cu-Ni-Mo、Cu-Ni-Nb-Y和Cu-Ni-Nb-Mo合金,系统研究了合金成分及熔炼工艺对合金组织、熔点、热导率和硬度的影响规律,获得如下结论:(1)同一成分下,电弧熔炼水冷铜坩埚制备工艺比感应熔炼石英玻璃坩埚制备工艺所获得的Cu-Ni-Mo合金组织粗大、热导率稳定,电弧熔炼制备的Cu-Ni-Mo合金的熔点和硬度更高。(2)Cu-Ni-Mo合金,Mo元素的增加对两种熔炼方式下制备的合金熔点影响不大,但当合金组织中出现Mo相时,合金熔点明显提高。(3)在Cu-Ni-Nb合金中添加微量稀土元素Y,能够细化合金组织,能使合金组织中的第二相愈发粗长,Y元素能改善合金热导率,对于合金熔点来说,Y元素却对Cu-Ni-Nb合金有负面的影响,Y元素对于合金硬度的影响很小,单从细化组织方面影响合金硬度。(4)Cu-Ni-Nb-Mo合金,当Ni元素含量一定时,随着Nb、Mo的增加,合金组织中第二相增加,改善了合金热导率,但会使合金熔点降低。(5)本文条件下,各元素对Cu-Ni-Nb-Mo合金热导率和熔点影响的主次因素顺序都为Ni-Nb-Mo,Ni元素对铜合金导热率和熔点的影响是显著的,合金中元素Ni含量越高,合金热导率下降越大,合金熔点越高,其次要因素是Nb,末要因素是Mo;(6)本文条件下,采用正交实验综合平衡法得出高导热率高熔点铜合金的最优成分为Cu-15Ni-3Nb-2Mo,其热导率为54.70 W/m·k,熔点为1131.59℃。
[Abstract]:With the increasing of smelting strength, the protection technology of blast furnace lining becomes more and more important. At present, the common solution is to install pure copper water jacket with high thermal conductivity between masonry, and to carry out forced cooling. The service life of blast furnace is prolonged. However, there are three unavoidable disadvantages of pure copper water jacket. One is that the water jacket is fusible in casting process, the other is that the temperature in blast furnace is higher in actual use, so long as the water quantity, water pressure or water temperature fluctuate slightly, The water jacket is likely to melt through quickly, and the third is that the high thermal conductivity of pure copper is liable to produce the negative effect of "air hammer". The reason is that the melting point of pure copper is low. The development of high melting point and high thermal conductivity copper alloy is of great significance to the development of high performance cooling water jacket and other heat exchangers. Based on the phase diagram of copper alloy and on the basis of Cu-Ni alloy, the Cu-Ni-Mo-Mo Cu-Ni-Nb-Y and Cu-Ni-Nb-Mo alloys were prepared, respectively. The effects of alloy composition and melting process on the microstructure, melting point, thermal conductivity and hardness of the alloy were systematically studied. The Cu-Ni-Mo alloy prepared by arc melting water-cooled copper crucible is thicker than that obtained by induction melting quartz glass crucible, and its thermal conductivity is stable. The melting point and hardness of the Cu-Ni-Mo alloy prepared by arc melting have a little effect on the melting point of the alloy prepared under the two melting modes, but when Mo phase appears in the microstructure of the alloy, the increase of Mo element in Cu-Ni-Mo alloy has little effect on the melting point of the alloy. The melting point of the alloy is obviously increased. 3) adding trace rare earth element Y to the Cu-Ni-Nb alloy can refine the microstructure of the alloy and improve the thermal conductivity of the alloy by increasing the second phase of the second phase and increasing the length of Y element. For the melting point of the alloy, Y element has a negative effect on the hardness of the Cu-Ni-Nb alloy. The effect of Y element on the hardness of the alloy is very small. The hardness of the alloy, Cu-Ni-Nb-Mo alloy, is affected only by refining the microstructure. When the content of Ni element is constant, with the increase of the content of Ni element, the effect of Y element on the hardness of the alloy is very small. The increase of the second phase in the microstructure of the alloy improves the thermal conductivity of the alloy, but reduces the melting point of the alloy. The order of the primary and secondary factors influencing the thermal conductivity and melting point of Cu-Ni-Nb-Mo alloy is that the effect of Ni-Nb-Mo-Ni element on the thermal conductivity and melting point of copper alloy is significant. The higher the Ni content in the alloy, the greater the thermal conductivity of the alloy and the higher the melting point of the alloy. In this paper, the optimum composition of Cu alloy with high thermal conductivity and high melting point is Cu-15Ni-3Nb-2Mo.The thermal conductivity of Cu-15Ni-3Nb-2Moand the melting point of Cu-15Ni-3Nb-2Mois 54.70W / m 路k, and the melting point is 1131.59 鈩，

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