Abnormal Wear Failure of Tungsten Carbide Parts
a)Plastic deformation collapse of tungsten carbide geometric shape.
(When the binder deforms from heat and force the surface bulges exposing weakened structure and rapid erosion occurs)
b)Chipping on edge
(When the tungsten carbide is too hard,density is not homogenous,braze joint is not complete,macro porosity is present or foreign material is present in the carbide.Chipping can occur when the carbide edge is allowed to vibrate while engaged.)
c)Thermo Cracking
(When the tungsten carbide is improperly cooled,stress builds in the tungsten carbide,as steel expands and contracts 8 times faster than carbide,trapping stress in the carbide.The stress becomes relieved and becomes paralles fracture to the steel body.Thermo cracking can occur when the carbide is rapidly heated from friction and then quenched in cold liquid)
d)Fracture by impact
(When solid objects are struck by tungsten carbide,because the carbide has no ductility,the impact stress follows the least line of resistance and fracture occurs when stress locates non homogenous structure,macro porosity or foreign material in the carbide substrate.If the carbide is to hard impact fracture will be increased)
e)Crater or packets of erosion
(Sections of carbide can pullout from uneven stress,non homogenous structure,or press cracks,which are incomplete fusion of material while being pressed,resulting in pre cracked materials)
f)Built up edge where cut material sticks
(When the cut material adheres to the binder in tungsten carbide and is knocked off by impact,the built up edge can break loose,pulling chunks of tungsten carbide from the continuous surface.
g)Notching at the depth of cut
(Notching is a wear property caused by localized impact of abrasive material such as sand or other loose foreign material.Notching weakens the continuous surface and can lead to premature failure from fracture or other abnormal wear characterisitcs)
