The effect of heat treatment on the machinability of AISI 304 austenitic stainless steel

ABSTRACTMaster ThesisTHE EFFECT OF HEAT TREATMENT ON THEMACH NAB L TY OF AISI 304 AUSTEN T C STA NLESS STEELVedat TAŞDEM RFırat UniversityGraduate School of ScienceDepartment of Mechanical Education2006, Page:73The AISI 300 series of stainless steels represent the largest group (65-70%) of total inuse. Especially, the austenitic stainless steels have excellent corrosion resistance due to the highchromium content. Today, these steels have generally found application areas such as petro-chemistry, chemistry, food and other good industries.However, the machinability and tool life are greatly restricted due mainly to the built upedge properties of these steels during machining. One of the most efficient parameter whichsignificantly effects the tool life is the Ni and Si elements in microstructure. To improve themachinability characteristics of these steels, different heat treatment conditions may providesome advantage.In this study, the AISI 304 austenitic stainless steels was firstly annealed at 1050 oC for1 hour and quenched. After quenching the same specimens were heat-treated again at 700 for 30min, 90 min and 240 min, respectively. In this way, the effect of the heat treatment conditionson machinability of material was investigated.In the experiments, different setting of cutting speed, feed rate and depth of cut wereused in the allowance standard of ISO. Different combinations of these machining parameterswere tested using factorial experimental design method.As a result, it was observed that the heat treatment conditions were effected themachinability of material depending on the different machining parameters.Key Words: Austenitic stainless steel, heat treatment, machinability, wear, built up edgeI