... for various brands Alfin ring, steel sheet, cooling channel,profile skirt.Graphite spray, graphite print Piston,engine piston for various ... of Pistons5.Machining process: Alfin ring, steel sheet, cooling channel,profile skirt.Graphite spray, graphite printin6.Surface Treatment: Graphite spray, ... steel plate inserting and casting in skirt,oil cooling channel casting in top,middle frum changing oval in ...