Mechanical Properties Of Pack Carburized AISI 4340 With Variation Energizer Composition of Barium Carbonate (BaCO3) And Sodium Carbonate (Na2CO3)

Abstract

The aim of this research was to determine the mechanical strength of AISI 4340 steel after pack carburizing with variation of barium carbonate (BaCO3) and sodium carbonate (Na2CO3) as energizer. The various ratios of energizer: 40/60, 50/50 and 60/40 w/w%. Mechanical test was conducted to determine tensile (ASTM E-8), impact charpy strength (ASTM E-23), rockwell hardness number (ASTM E-18) and microstructure characterization (ASTM E-3). Both type specimens were temperature pack carburized is 950ºC and holding time is 3 hours.  Results showed that specimen C has a lowest ultimate tensile strength mean values than the other specimens, which is 333.43±30.22 MPa. The results of the impact test showed that the lowest impact energy value is found in specimen C, which is 4.32 joules and the highest impact energy value is found in specimens without treatment, which is 15.80 joules. Based on microscope observation indicated that microstructure of specimen was martensite structure increase and the results of the hardness test was influenced by martensite phase, specimen C has the highest hardness compared to other specimens, which is 80.70 HRC while the untreated specimen is 56.90 HRC.