For samll loads, the friction and wear no special requirements for important casting, such as protective cover, cover, oil pan, hand wheels, frame, floor, hammer, small handle, etc.
Under moderate load of casting, such as the base, frame, box, knife, bed, bearing seat, tabl,e. wheels, cover, pump, value, pipe, flywheel, motor blocks and other.
Requirements withstand greater load and a certain degree of tightness or corrosion resistance of the more important castings such as cylinder, gear, base, flywheels, bed, cylinder block, cylinder liner, piston, gear box, brake wheel, coupling plate, medium pressure value, etc.
Under high load, wear and high air tightness important casting, such as heavy machine tools, shears, presses, automatic lathe bed, frame, high-pressure hydraulic parts, piston rings, force larger gear, cams, bushings, large engine crankshaft, cylinder block, cylinder liner, cylinder head, etc.