Research On Electric Vacuum Metallurgy And Forming Technology Of Nuclear Power Slot Wedge Copper Alloy

In this paper, according to the working conditions of the material performancerequirements of nuclear power generator slot wedge, the CuCo2BeZr alloy have been takenin a series of strengthening process test by using electric vacuum metallurgy, heat treatmentprinciple and process, and it is obtained the nuclear power slot wedge materials with goodperformances finally.The alloy were prepared in vacuum melt furnaces with electrolytic copper, cobalt,Cu-4%Be master alloy, Cu-7.5%Zr master alloy. Before closing the furnace, it could be gotfrom the cobalt, electrolytic copper, Cu-4%Be master alloy, Cu-7.5%Zr master alloy in itin order, then vacuum up to1000Pa and set the parameters of melting temperature, castingtemperature. In order to have a better quality of the bubble, it is ensured that pressure is0.01Mpa above that filling with argon, which could control the pressure and theatmosphere of the furnace. The results show that it can get high purity CuCo2BeZr alloy bythe vacuum melting process with controlling the right vacuum degree, the refiningtemperature and the refining of time.In the experiment of pressing processing and drawing processing, thepressing-drawing tools were working under a condition of long time of high temperatureand high pressure with strong friction change; in addition, the shape, the size, and thematerial of the tools are all responsible to the quality of the product. So to have areasonable design of pressing-drawing tools is to ensure the quality of the product, and alsoto consideration of the service life of the mould, also the convenient for use, etc. Areasonably design in mould, is good for optimization process, is good for improving theefficiency and reducing the cost of the products.It can be got a excellent performance of products CuCo2BeZr copper alloy throughthe electric vacuum metallurgy, the thermal deformation G=5.42,(940±10)℃multiply1hsolid solution processing,30%cold deformation processing,540℃for4h aging treatment.The conclusion show that, after pressing but not solid solution, the products are not fullysolid solution, the cross sections have some obvious grain boundaries, some are notapparent, these caused grain size display in uniform, detection attenuation reflects bad; theother condition, after pressing with solid solution, shows good grain boundaries, long withthin cross section size are in uniform, detection waveform display is well. By using ultrasonic inspection, it has not found internal defects that can reach the requirements ofslot wedge copper alloy technical index.The obtained CuCo2BeZr alloy was analysis in the organization structure and thetensile fracture morphology characteristics. The results show that the products have a goodroom temperature and high temperature (427℃) performance; in room temperatureconditions, the elongation of δ is17%, the tensile strength σbis845MPa, tensile strengthσ0.2is755MPa, while in high temperature condition, the elongation δ is7.5%, the tensilestrength σbis574MPa, the tensile strength σ0.2still can be up to555MPa, and in hightemperature condition it can still meet the use of nuclear power slot wedge in needs. And itneither in high or low temperature shows well in plastic. The CuCo2BeZr alloy’scomprehensive mechanics performance can meet with the mechanical performance indexof the nuclear power slot wedge which are working in high temperature continuously, alsoit have provide a scientific basis for the failure of nuclear power slot wedge in innermechanism and may have predicted the service life of the product.