| 摘要 |
PURPOSE:To obtain a screw, which has higher corrosion resistance and higher wear resistance and consequently the scope of application of which is enlarged, by a method wherein powder build-up welding is performed while holding molten matter bythe side surface of a mold. CONSTITUTION:In an injection molding screw having a spiral thread onto the outer periphery of a shank, the surface of the flank of the thread is cladded with a build-up layer scatteringly holding hard particles in a base metal such as cobalt base alloy, iron base alloy, nickel base alloy or alloy of cobalt, iron and nickel by means of powder build-up welding, the progressing direction of which is along the longitudinal direction of said thread. Thus, the thread of the screw has a build-up layer cladded by means of powder build-up welding, the progressing direction of which is along the longitudinal direction of the thread. Because the build-up layer is made by welding and consequently tightly fixed to base material with strong bonding strength and at the same time through diffusion layer, thermal stress or the like is scattered through the diffusion layer and consequently no separation of the build-up layer develops. |
