RU is a pink aluminum oxide obtained by fusion of calcined alumina and chrome ore in electric arc 

furnaces. Its high purity and self-edged reposition characteristic makes RU a special product for 

vitrified grinding wheels. 

TYPICAL CHEMICAL ANALYSIS 

Al2O3 99.10%

Fe2O3 0.04

Na2O 0.34

Cr2O3 0.41

TYPICAL PHYSICAL PROPERTIES 

Specific Gravity: 3.94 g/cc

Knoop 100 Hardness: 1900 kg/cm2

Toughness: 43% (ANSI-B74.8 R2007)

BULK DENSITY (g/cc)

Grit Size R HD Grit Size R HD

10 1.72 - 1.82 1.82 - 1.92 50 1.65 - 1.75 1.75 - 1.85

12 1.72 - 1.82 1.82 - 1.92 60 1.64 - 1.74 1.74 - 1.84

14 1.74 - 1.84 1.82 - 1.92 70 1.58 - 1.68 1.68 - 1.78

16 1.73 - 1.83 1.82 - 1.92 80 1.57 - 1.67 1.68 - 1.78

20 1.72 - 1.82 1.83 - 1.93 90 1.52 - 1.62 1.63 - 1.73

24 1.72 - 1.82 1.81 - 1.91 100 1.51 - 1.61 1.63 - 1.73

30 1.72 - 1.82 1.81 - 1.91 120 1.51 - 1.61 1.63 - 1.73

36 1.71 - 1.81 1.79 - 1.89 150 1.46 - 1.56 1.55 - 1.65

40 1.71 - 1.81 1.79 - 1.89 180 1.45 - 1.55 1.53 - 1.63

46 1.71 - 1.81 1.79 - 1.89 220 1.42 - 1.52 1.50 - 1.60