Application: AISI1045 hot rolled round bars could get good comprehensive mechanical properties after the heat treatment of quenching and tempering, and AISI 1045 hot rolled round bars are widely used in all kinds of important structural parts, especially those parts which are worked under under alternating loads such as linkages, bolts, gears, shafts and so on. Its disadvantages of low hardness, low wear resistance can be improved by Q+T and surface quenching.