Experimental Research Of Abrasive Water Jet Milling Titanium Alloy

Titanium alloy material is widely used in the industry of equipment manufacturing, because it has excellent physical properties. There are many negative influences in manufacturing difficult materials such as titanium alloy with traditional processing technology, because titanium alloy has low heat conductivity, small elastic modulus, and strong chemical activities. Abrasive water jet is a new non-traditional machining technology, which adopts high pressure water as energy transfer medium to accelerate the particle of finest abrasive. Abrasive water jet technology has obvious advantages in cutting difficult-to-machine materials as titanium alloy, because damage of abrasive with a high-velocity affects object materials and the technique does not produce much heat on the material surface.Research adopted post-mixed abrasive water jet to mill titanium alloy in this paper. Through the analysis of four influence parameters of jet pressure, standoff distance, transverse feeding and nozzle movement speed with the single factor experiment, it shows:the material removal rate is higher when jet pressure is greater, the material removal rate is lower when nozzle movement speed and transverse feeding are greater. The choice of appropriate distance between the target of nozzles should be according to the processing conditions. Analyzing the weight of four influence parameters for optimizing the processing parameters combination by orthogonal test method in this paper. Using residual stress detector to measure the residual stress in titanium alloy surface after milling and making comparative analysis of four parameters influence on the residual stress. Establishing mathematical model of the residual stress when post-mixed abrasive water jet milling titanium alloy and comparing the model values with the test results, establishing the mathematical model of residual stress with multiple impact parameter with the method of dimensional analysis. It is concluded that post-mixed abrasive water jet damage of titanium alloy is compressivc stress and shearing stress, and the crystal damage of material has the destruction of form of the inter granular and trans granular fracture from the perspective of macro and micro milling workpiece surface morphology observation analysis. Having umerical calculation of abrasive impact to titanium alloy material with SPH-FEM coupled algorithm, and combined with finite element analysis software ANSYS AUTODYN dynamics visualization analysis module of impact damage evolution process. The stress peak value is1.389×106KPa when abrasive particles affect titanium alloy at692m/s speed, the material model of stress tensor is respectively-2.128×105kPa、-5.294×105kPa in the X, Y direction, and through the dynamics software to simulate material model equivalent strain in the particle impact of the titanium alloy under the velocity of632m/s，692m/s,747m/s.Through the experimental analysis and numerical calculation, this paper provides reference of the post-mixed abrasive water jet milling titanium alloy material in practical production, and puts forward deficiency and the focus of the follow-up work.