Friction stir processing on carbon steel

Abstract

Friction stir processing of medium carbon steel samples has been carried out using a milling machine and toolsmade of cemented tungsten carbide. Samples have been machined from 40 and 40X steels. The tools have been made inthe shape of 5u5u1.5 mm and 3u3u1.5 mm tetrahedrons. The microstructure of stirred zone has been obtained using thesmaller tool and consists of fine recrystallized 2–3 Pm grains, whereas the larger tool has produced the “onion-like”structures comprising hard quenched “white” 500–600 MPa layers with 300–350 MPa interlayers of bainite needles. Themean values of wear intensity obtained after measuring the wear scar width were 0.02 mm/m and 0.001 mm/m for nonprocessedand processed samples, respectively.