Designing a competitive free-machining steel composition enabling less expensive steelmaking,manufacturing and recycling has long been a desirable objective.Foremost amongst a new approach has been simply to promote graphite formation to act as an internal lubricant,thus reducing or eliminating the need for special alloying additions(e.g.Pb,S,P,Bi,Se,Te)which can make the steels difficult to process or re-cycle,and,as more stringent health and safety legislation is introduced might eventually lead to restrictions or total prohibition from certain manufactured products.However,the sluggish kinetics of graphite formation in steel does not lend itself to the normal requirement of rapid manufacturing in the high tonnage steel industry.In consequence,this paper reports the machining characteristics of experimental carbon steel with a composition which accelerates graphite formation during a high temperature anneal.Three starting microstructures prior to annealing have been considered; martensite,bainite and ferrite/pearlite.These influence the eventual graphite dispersion and hence the machinability characteristics.The machining characteristics have been measured and also compared with commercial free-cutting steel grades.