An investigation of adhering layer formation during tool wear progression in turning of free-cutting stainless steel

Abstract Experimental results have shown that an adhering layer is formed on the tool face when machining CaS free-cutting stainless steel. It has also been shown that tool life increases greatly with the stable layer formed on the tool face because the layer protects the tool from abrasive wear and diffusive wear. The composition of the adhering layer is mainly compound ternary oxides of (CaO, MgO, MnO)Al 2 O 3 SiO 2 and the distribution of the composition varies in different areas of the rake face. The optimum range of composition proportions of inclusions in steel, for the favourable formation of the adhering layer, is established according to experimental results. The deformation behaviour, extruding condition and extruding process of the non-metallic inclusions in CaS free-cutting stainless steel are discussed in detail.