Influence Of The Triple Spheroidization On Surface Hardness From Drilling Resistance Behavior Of Powder Coated Gray Cast Iron

The objective of this study on the influence of the triple spheroidization on surface hardness from drilling resistance Dry drilling of powder coated gray cast iron using universal testing machine Compressive mode the surface hardness in powder coating areas normal hardness and Charpy impact resistance were considered. The spheroidizing temperatures were 3002661616C 4502661616C and 6002661616C the spheroidizing time spanned the range of 6 hours and cooled down in the furnace to room temperature for 24 hours. The drilling resistance test the high-speed twist drill diameter of 3 mm the rotating speed of 1000 revmin and the crosshead speed of 5-25 mmmin were investigated. It was found that the surface hardness from drilling resistance normal hardness and Charpy impact resistance increased as the spheroidizing temperatures increased. The maximum surface hardness was found at the third spheroidization.