Numerical Simulation For Stainless Steel Powder During The Process Of Hot Isostatic Pressing And Studies On The Can Manufacturing

Hot isostatic pressing (HIP) near net shape forming of powder could form metal parts with relative density of 100% no matter what shapes they are. It's fit to form metal alloys with high melting point, which are hard for machining, casting, forging and many other methods, such as Ti and Ni alloys. However, hot isostatic pressing includes complicated thermal-mechanical deformation, and its deformation mechanism is very complex. Therefore, in order to near net form final parts, finite element simulation should be used to forecast deformation and optimize the shapes of cans.This work describes powder constitutive properties using Shima yielding criterion, simulates powder deformation in the process of hot isostatic pressing using the software of Marc and modifies can shapes and dimensions repeatedly according to the simulated deformation results. The simulated results show that under the conditions of 120Mpa and 1300℃, the final relative density of tension-compression testing sample reaches to more than 95% from 70%, which satisfies the utility requirements for functional parts. Its radial shrinkage reaches to 12% or so, and axial shrinkage is little. By designing conformal cans and decreasing can thickness step by step, the final shape and dimension of the optimized tension-compression testing sample are gained. On the basis of simple parts simulation, turbine disk with complex shape is simulated. Deformation trend of turbine disk in the process of hot isostatic pressing is gained, and the inserted cores guarantee the partial shapes of internal powder, but they block powder densification. The inserted cores'and cans'shapes of turbine disk are expected to be optimized to increase the powder density. The optimized cans are formed to gain the final parts with accurate shapes and dimensions after hot isostatic pressing.The cans of hot isostatic pressing demand highly of air tightness, so they have to be detected strictly before forming under high temperature and pressure. This work takes the optimized tension-compression sample for case, firstly the partial parts of the can are manufactured by machining, and then they are joined to a whole part by TIG welding, and detected in respect of air tightness by helium mass spectrometer leak detector. At last, powder-filling, vibration, vacuum-pumping and crimpling are conducted to assemble the can.This work takes the simple parts for case, and studies the numerical simulation of hot isostatic pressing near net shape forming of powder as well as can manufacturing, which establish the foundation for complex parts manufacturing.