... : screw,gear, shaft ,connection rod ,camshaft,etc. parts 2.Tractor and construction machinerey : tanks, guide wheels,etc.3.Machine ... tool manufacture:bed of lathe , milling machine, grinding machine ;gear, shafts,spline shaft ,etc ... machinery: steel rebar, srew,etc.8.Railway transportation: steel guide railway heat treatment ,artical play9.University : do experience , ...