Alloy Steel 4142 is a medium carbon alloy steel with excellent toughness, ductility, wear resistance, and strength, 4142 is popular for a wide range of applications. It can be easily machined in the annealed state, but post treatment machining should be avoided. It is typically used in cams, drill collars, bolts, couplings, reamers axles, shafting, piston rods, rams, hydraulic shafts, gears, sprockets, valves, spindles, tools, boring tools, and other heavy duty machining components.