For metal crowns on teeth.
Model
Crown remover 3×1 type; straight tip;curved tip
Material
The head of the crown remover shall be made of 40Cr13, 32Cr13Mo and 30Cr13 materials as specified in GB/T1220.
Main technical indicators
When the head of the crown remover is matched with the connecting rod, the disassembly should be easy and flexible, without obvious loosening phenomenon, and the sliding hammer should be able to slide easily on the connecting rod.
The blade of the crown remover should be sharp, and there should be no rolling or breaking of the blade.
The head of the crown removable device should be heat treated, and its hardness: 40Cr13 and 32Cr13Mo are 510 ~ 660HV0.2 and 30Cr13 are 460 ~ 560HV0.2.
The surface of the crown remover can be made bright or unbright, and the surface roughness (except edge and knurling)Ra value should not be greater than: 0.4μm with bright and 0.8μm without bright.
The corrosion resistance of the surface of the crown removing device should not be lower than the requirements of class B in YY/T 0149 boiling water test method.
The crown removing device should be straight, and there should be no edge, burr or crack except the edge. Knurling should be clear and complete.
