Copyright © 2008 Badger Metal Tech, Inc DMC – Feb Die Casting Die Failure Cavitation Effect & Correction Castings with breakout areas shown as risers Die with breakout areas shown as pitting

Copyright © 2008 Badger Metal Tech, Inc Could this lead to a New Chapter in the study of High Pressure Die failure?

Copyright © 2008 Badger Metal Tech, Inc  Construction Equipment – Excavators, Crawler Tractors, Loaders  High Impact Machines – Hammers, Crushers, Etc.  Construction Equipment – Excavators, Crawler Tractors, Loaders  High Impact Machines – Hammers, Crushers, Etc. Correlation to Die Casting Dies? Steel Failure – Hydraulic Machinery

Copyright © 2008 Badger Metal Tech, Inc  Steel Failure – Fast Fill Nitrogen Charge Areas Piston Cylinders  Cause and Correction Contamination of steel - Unsuccessful Design changes- Unsuccessful Failure of other related components  Steel Failure – Fast Fill Nitrogen Charge Areas Piston Cylinders  Cause and Correction Contamination of steel - Unsuccessful Design changes- Unsuccessful Failure of other related components Correlation to Die Casting Dies? Steel Failure – Hydraulic Machinery

Copyright © 2008 Badger Metal Tech, Inc  High Speed Photography  Special pressure transducers  High Speed Photography  Special pressure transducers Joint Research Program with Caterpillar

Copyright © 2008 Badger Metal Tech, Inc  Previously mistaken for: Bad steel Erosion Heat Treatment  None of the Above  Previously mistaken for: Bad steel Erosion Heat Treatment  None of the Above Failure Mode - Cavitation Does this look familiar?

Copyright © 2008 Badger Metal Tech, Inc  Fatigue by Fluid entrained gases  Tiny bubbles imploding on surface of the member on which or over which the fluid is flowing  Resulting in high cycle fatigue failure  Fatigue by Fluid entrained gases  Tiny bubbles imploding on surface of the member on which or over which the fluid is flowing  Resulting in high cycle fatigue failure What is Cavitation – Really? Image source: Dr. Joe Evans Ph.D

Copyright © 2008 Badger Metal Tech, Inc Breaking down the Bubble A tiny Jack Hammer Vapor bubble in various stages of collapse. Solid lines predicted by model. Dotted lines obtained through experiment. Stages 1-3 spherical Stage 4 small depression Depression more toroidal in its 3D shape. Upon implosion, the re-entrant micro jet would form at the bottom of the bubble with its energy directed towards the solid surface. Image source: Dr. Joe Evans Ph.D

Copyright © 2008 Badger Metal Tech, Inc Bubble Stage Collapse BELOW a Solid Boundary 1-18 shows a bubble collapsing At stage 7, small dot at bottom of bubble Grows in size in following stages then appears to penetrate the upper boundary in Stage 14. Stage 18 is just prior to total collapse and shock wave generation. Image source: Dr. Joe Evans Ph.D

Copyright © 2008 Badger Metal Tech, Inc Cavitation Effect Cavitation pattern during flow Bubbles formed at left result in damage at right Source: Dr. Joe Evans Ph.D

Copyright © 2008 Badger Metal Tech, Inc  Gear Pump: suction side of pump negative pressures at entry positive pressures at first gear tooth  How to accelerate? Increase air entrainment cavitation failure was accelerated cavitation failure more pronounced  Gear Pump: suction side of pump negative pressures at entry positive pressures at first gear tooth  How to accelerate? Increase air entrainment cavitation failure was accelerated cavitation failure more pronounced Where does Cavitation Show Up? Photo at right shows damage at low pressure side of leading edge of impeller

Copyright © 2008 Badger Metal Tech, Inc  Propellers, Pumps, Cylinders,  High Pressure Die Casting  Propellers, Pumps, Cylinders,  High Pressure Die Casting Collapsing Bubble Damage

Copyright © 2008 Badger Metal Tech, Inc  Each operational cycle: millions of low pressure cycles cycles go from void to positive pressures thousands – translates to billions  Billions of cycles cause extremely high cycle fatigue initially microscopic particles removed as more removed – visible to naked eye  Each operational cycle: millions of low pressure cycles cycles go from void to positive pressures thousands – translates to billions  Billions of cycles cause extremely high cycle fatigue initially microscopic particles removed as more removed – visible to naked eye How do little bubbles do so much damage?

Copyright © 2008 Badger Metal Tech, Inc  Fact - Trapped gases in molten metal: collapse - billions of void to positive pressures cause loss of fatigue strength of metal initially microscopic  Jack hammer effect small microscopic particles grow in size visible chucks of metal from die previously attributed to thermal fatigue  Fact - Trapped gases in molten metal: collapse - billions of void to positive pressures cause loss of fatigue strength of metal initially microscopic  Jack hammer effect small microscopic particles grow in size visible chucks of metal from die previously attributed to thermal fatigue How about Die Casting Dies?

Copyright © 2008 Badger Metal Tech, Inc Die Steel Ejector Insert Die Steel Cover Insert Die Cast Trapped Gas – Phase 1 More Info on our web

Copyright © 2008 Badger Metal Tech, Inc Die surface begins to fatigue Die particles begin to be removed Die Cast Trapped Gas – Phase 2 More Info on our web

Copyright © 2008 Badger Metal Tech, Inc Die break out and/or heat check starts More die particles removed Visible Break Out & Heat Checking More Info on our web

Copyright © 2008 Badger Metal Tech, Inc Over past 25 Years 100,000+ die casting dies In the USA, Canada & Mexico In the USA, Canada & Mexico

Copyright © 2008 Badger Metal Tech, Inc Historical Evidence  100,000+ Dies in 25 years No Die Caster, Tool Shop –sees more  Castings tell the bubble story breakout prevalent at gate area of casting breakout prevalent at flow direction change  Everyday we see damage caused by cavitation damage attributed to bad steel, heat treat, erosion  100,000+ Dies in 25 years No Die Caster, Tool Shop –sees more  Castings tell the bubble story breakout prevalent at gate area of casting breakout prevalent at flow direction change  Everyday we see damage caused by cavitation damage attributed to bad steel, heat treat, erosion

Copyright © 2008 Badger Metal Tech, Inc Mistaken Identity  Asked to repair heat checks in die majority of time these are breakout conditions NOT HEAT CHECKING  Usually close to gate area can feel with eyes closed the pitting also evident in flow change areas  Asked to repair heat checks in die majority of time these are breakout conditions NOT HEAT CHECKING  Usually close to gate area can feel with eyes closed the pitting also evident in flow change areas

Copyright © 2008 Badger Metal Tech, Inc How to Counter Die Cast Die Cavitation Effect?  Remove all trapped gases - Impossible  Get rid of bubbles – Break them up  Increase fatigue resistance of steel  Place surface in compression  Increase surface hardness  Remove all trapped gases - Impossible  Get rid of bubbles – Break them up  Increase fatigue resistance of steel  Place surface in compression  Increase surface hardness

Copyright © 2008 Badger Metal Tech, Inc How does help reduce cavitation effect?  Breaks up trapped gas bubbles  High compression to counter fatigue  Micro-texture improves flow  Breaks up trapped gas bubbles  High compression to counter fatigue  Micro-texture improves flow

Copyright © 2008 Badger Metal Tech, Inc Flow Effect v/s Cavitation Flat Surface 1.Fast Flow 2.Poor Fill 3.Erosion prone 4.Cavitation Effect Flat Surface 1.Fast Flow 2.Poor Fill 3.Erosion prone 4.Cavitation Effect Textured Surface 1.Turbulent Flow 2.Better Fill 3.Less Porosity 4.Less Cavitation Textured Surface 1.Turbulent Flow 2.Better Fill 3.Less Porosity 4.Less Cavitation While metal rushes over a flat surface, the cavitation from trapped gases due to local pressure fluctuations develop high pressures on the surface of the die – result erosion and breakout.

Copyright © 2008 Badger Metal Tech, Inc Compressive Texturing Effect

Copyright © 2008 Badger Metal Tech, Inc Residual Stress Curves Residual Stress Curves High Compressive Values help counter metal fatigue failure X-Ray Diffraction Curves T-41H High Surface Compression Shallow Knee Maximized Depth

Copyright © 2008 Badger Metal Tech, Inc TOOLING CIRCLE OF LIFE TOOLING CYCLE OF LIFE anti-soldering permanent flow effect “resistance to thermal fatigue cracking & breakout from cavitation effect Badger Metal Tech, Inc. Badger Metal Tech, Inc. FAX Toll Free

Copyright © 2008 Badger Metal Tech, Inc Additional Benefits © Reduced cavitation breakout and pitting © Eliminate lamination porosity © Better heat dissipation © Increased lubricity and improved metal flow © Compressive stress after weld repair © Better paint adherence – especially powder © Reduced cavitation breakout and pitting © Eliminate lamination porosity © Better heat dissipation © Increased lubricity and improved metal flow © Compressive stress after weld repair © Better paint adherence – especially powder Why apparent less porosity?

Copyright © 2008 Badger Metal Tech, Inc Casting Surface Lamination with trapped gas Die Steel Cover Insert Die Steel Ejector Insert Lamination of Casting Skin

Copyright © 2008 Badger Metal Tech, Inc Casting Surface Die Steel Cover Insert Die Steel Ejector Insert Problem Solved

Copyright © 2008 Badger Metal Tech, Inc © To make effect permanent © Where a need exists for an anti-soldering, anti-galling or washout © To make effect permanent © Where a need exists for an anti-soldering, anti-galling or washout Return to first slide Continue

Copyright © 2008 Badger Metal Tech, Inc + Combining the curves Back to coupons

Copyright © 2008 Badger Metal Tech, Inc Doesn’t this warrant further study by the DMC?