The general operating speeds shown on the chart are provided to give to the users an idea, in terms of occupational safety and prevention of accidents. High speeds shown with an asterisk (*) may only be attained on equipment specially designed for those speeds indicated on the label of the grinding wheel and only after taking necessary safety measures.
Cutter Grinding
(Large surfece / Manual Grinding)
20-25
Cutting (Grinding wheels with bakelite binding agent)
45-80*
Grinding with cylindirical wheels
15-25
Cylindrical grinding
25-30*
Disc grinding
20-30
Internal grinding
20-35
Cutter grinding (Machine blades)
20-25
Coarse grinding with bakalite)
35-45*
Ceramic, small bore
25-30
Surface grinding
20-30
Toll grinding
25-30
EKRR (88A) - Pink aluminious abrasive with 99 % AL2O3
Very hard, but a little more brittle than EKRW and therefore less impact-sensitive especially around the edges. Suitable for grinding high-alloyed steels of great tensile strength before hardening. It is commonly used for making mounted points for steel and cast iron processing.
It is hard and brittle and its hardness is around 9 on the Mohs' hardness scale. This sharp aluminous abrasive is the most commonly used one for tool grinding (tool and high-speed steels) and for precision grinding of hardened and stainless steels.
Dark Red Fused Alumina is a special high-purity aluminium oxide made of pure alumina with the addition of approx. 2.1 % chromium oxide in an electric arc furnace in a batch process. Due to the high percentage of chromium oxide interspersed in the crystal lattice of aluminium oxide in solid solution, the hardness of DARK RED Fused Alumina lies between that of WHITE fused Alumina and BROWN/REGULAR aluminium oxide. Dark Red Fused Alumina is mainly employed in ceramic-bonded grinding wheels for the precision grinding of annealed malleable cast iron, external cylindrical grinding of high-speed steel, internal grinding of heat-treated steel, tool grinding of high-speed tool steel and others. In special cases, Dark Red Fused Alumina can be used as a substitute for mono-crystalline aluminium oxide in creep-feed grinding.
SGC (C) - Green Silicon carbite.
A particularly hard, very brittle abrasive with a hardness of about 9.5 on the Mohs' hardness scale. This impact-and percussion-sensitive abrasive is used primarily for processing hard metals and ceramic cutting materials, glass and also acid-resistant steels with austenitic structure.
SC (CD)- Green Silicon carbite.
Very hard but less brittle than GSC. Its hardness is about 9.5 on the Mohs' hardness scale. It is used for grinding metallic and non-metallic blanks of low tensile strength, grey iron, spheroidal graphite iron, chilled cast iron, malleable iron before annealing, brass, bronze, aluminium, organic mineral, and ceramic materials.
