Erosion by molten aluminum, abrasion damage and heat checks in aluminum die casting dies are common problems.
The damage can be reduced dramatically by applying tungsten and/or titanium carbide in the problem prone areas of new or repaired dies using the electro-spark process. The coating protects the die surface due to its extremely high anti-wetting property against molten aluminum and maintains high hardness at operating temperatures. The coating minimizes erosion, scoring and heat checks and extends the die life. As an added benefit the coating increases product quality by providing excellent release properties, liquid flow and gas release.
Molten Al flows rapidly into die. Then, fraction is occurred and wearing is in progress on surface of die.
Against hardness 350-400HMV die, Coating layer by cermets electrode that is hardness more than 2000HMV extremely protects die surface.
Die surface is occurred erosion contacting with high temperature molten Al.
Preventing erosion amount within 1/10 from die surface by worse wettability coating material.
* Referring to Erosion Test Results
Molten Al and die surface are easy to react each other, seizing and scuffing are occurred at contact area.
Preventing seizing and scuffing by uneasy-react ( worse wettability ) coating material against molten Al.
Stress is accumulated in die surface with repetition of Heat by teeming molten Al ( Expanding ) and Cooling by die lubricant ( Shrinkage ) occurring Heat Cracks.
Insulation effects of intercalated minute air in sight roughness die surface ( tongued and grooved face ) by coating controls expanding and shrinking to prevent Heat Cracks occurred.
Underfill is occurred in product when molten Al contacts cooled die surface and cooling down to reduce liquid flow
Insulation effects of intercalated minute air in sight roughness die surface ( tongued and grooved face ) by coating keeps liquid temperature and flow to prevent Underfill occurred.
Liquid flows along die design and is occurred Flow Line at cold shut.
Coating with certain degree of surface roughness at cold shut controls flow directions uniformly to prevent Flow Line by its turbulence.