Consulting Services to the Metals Industry Cavitation: A Brief Review of the Literature Stephen P. Midson The Midson Group, Inc.

Consulting Services to the Metals Industry NADCA Technical Paper From 1981

Consulting Services to the Metals Industry Cavitation means literal generation of cavities in a fluid »Occurs when the local pressure falls below the vapor pressure of the fluid »Whenever bubble nuclei are available In zinc die casting, cavitation bubbles can be formed in the cavity, the gooseneck or the nozzle Definition of Cavitation: Davis & Murray

Consulting Services to the Metals Industry Mechanism of Cavitation Erosion

Consulting Services to the Metals Industry Bubbles in the liquid can impact surfaces at speeds of 130 m/sec (300 miles/hr) Peak surface stresses of 900 MPa (130 ksi) have been measured Damage from Cavitation

Consulting Services to the Metals Industry Cavitation bubbles are produced in places where low pressures occur »Bends »Changes in cross-section »Junctions between runners »Protrusions, such as ejector pins Bubbles carried downstream & can collapse on die surfaces Effect of Flow System Geometry on Erosion

Consulting Services to the Metals Industry Examples of Cavitation

Consulting Services to the Metals Industry Examples of Cavitation

Consulting Services to the Metals Industry I talk often about cavitation because it is one of the most common failures of dies During my course on runner design, I discuss cavitation due to ejector pins standing into the flow (or back from the die) & bad runner design (i.e. square bends) Morris Murray

Consulting Services to the Metals Industry SAE paper from 2000 Reported cavitation erosion data for selected aluminum alloys used with squeeze & semi-solid casting Results show that type of casting process, surface finish & alloy chemistry influence erosion wear DasGupta & Killingsworth SPX Corp.

Consulting Services to the Metals Industry Flow 3-D Most recent version of Flow 3-D has potential to simulate cavitation and identify areas vulnerable to cavitation damage The cavitation model can be turned on or off by the user for a filling analysis.

Consulting Services to the Metals Industry End of Filling Cavitation Potential Found Mostly on One Side of the Cavity Metal colored by cavitation potential (red is bad)

Consulting Services to the Metals Industry Kado, Hasuno & Asada »Ryobi Limited Simulation test of die erosion in die casting with acoustic cavitation 2008 Japanese Die Casting Association Congress