Design And Finite Element Analysis Of Fixture For Machining Of End Face Seal Ring With Circumferential Waviness

Nuclear main pump is one of the heart equipment of the nuclear power plant. So far, the nuclear main pump is completely dependent on imports, which became a huge obstacle to the development of Chinese nuclear power industry. Seal ring manufacturing process has been the greatest bottleneck in the manufacturing technology of nuclear main pump. The end face seal ring with circumferential waviness is a non-contacting mechanical seal, which has many advantages, such as low wear, low leakage, and long service life, is used in the nuclear main pump seal.As a nuclear main pump seal, nuclear main pump seal ring works in extremely bad working conditions. And the materials that possess excellent physical and chemical properties were used to meet the rigorous requirement. With excellent mechanical, thermal, chemical properties, ceramics are commonly materials used in manufacturing rings. But the great brittleness and ultrahigh hardness makes ceramics difficult machined materials for traditional processing techniques.To solve the difficult, in this paper, a novel fixture was designed for machining of end face seal ring. The seal ring produces pre-deformation by pre-loading, which can achieve the desired corrugated surface. Then removing the high points of the deformation by plane lapping. After lapping, we release the pre-loading, the face of seal ring restores elastic deformation, and forms corrugated surface. The main contents and conclusions are as follows:(1)A novel fixture was designed for machining of end face seal ring. The seal ring produces pre-deformation by applying torque wrench pre-loading to the fixture, which can achieve the desired corrugated surface.(2)Through the finite element analysis of the seal ring fixture, the relationship of pre-loading and pre-deformation was found, which provides certain theoretical guidance for the following polishing test.(3)Analyses the effect of geometric parameters of sealing ring machining fixture on the fixture radial deformation and equivalent stress. And optimization of geometric parameters of the sealing ring machining fixture. With the loss of the rotary speed, the removal rate reduced, but the surface quality improved, the surface roughness and surface damage both reduced. (4)Lapping and polishing experiments of SiC specimen was conducted. The effect of different process parameters, including abrasive size and rotory speed, on processing qulity was researched.(5)When rotory speed was40rpm, SiC specimen was polished using10μm,5μm,1μm diamond abrasive. The smaller the abrasive size, the lower the surface roughness, and the smaller the surface damage. And0.2μm surface roughness was gained using1μm diamond abrasive.(6)When abrasive size was1μm. we selected the rotory speed at40rpm,20rpm,10rpm, to polish the SiC specimen. With the increase of rotory speed, the surface quality improved, the surface roughness and the surface damage reduced.