Significant enhancement of hardness characteristics was achieved through the Frictional Stir Burnishing (FSB) process. The enhanced region was generated by the FSB process where the thickness and hardness were approximately 200 µm and 900 HV, respectively, under the conditions of spindle speed of 10000 min -1 , a feed rate of 200 mm/min and a processing load of 750 N. The processing temperature was approximately 600~750 ˚C under compressive stress condition. Although this temperature is lower than A 3 transform point (normally 780 ˚C), it is known that A 3 transform point decreases under the compressive stress condition. And after the tool passed, the temperature dropped rapidly. This process can be assumed to be the same as a quenching process. However, the obtained hardness value is harder than that of the regular quenched material. When the processing load was 500 N, extremely hard regions over 1000 HV were obtained. In this case, it is thought that the material was not transformed into martensite. It can be concluded that the severe stirring process of FSB caused the grain refinement.
The frictional stir burnishing can give frictional heat and large stir, to the surface Gf work pieccs , Those facters madc enha 皿 ced layers on some of stcct materials ( S45C and SUS304 ) . The enhanced layers are obscrvcd clcarly in cross section of processing surface by eptical microscope in those cases . S45C carbon − steel was hardened and its hardness is over 900HV . It is thought that the main factor that the hardcned laycr was obtained is martensitic transformation. SUS304 stainless − steel which can be not given heat − treatment for transformatien was also hardened , It is thought that the factors that the hardened layers were obtained is grain refinement or deformation induced transformation .
Significant enhancementof hardness characteristics was achieved through the Frictional Stir Burnishing (FSB) process. The enhanced region was generated by the FSB process where the thickness and hardness were approximately 200 pm and 900 HV, respectively, under the conditions of a spindle speed of 10000 min'i, a feed rate of 200 mmfmin and a processing load of 750 N. The processing temperature was approximately 800 "C and dropped rapidly after the tool passed. This process can be assumed to be the same as a quenching process. However, the obtained hardness value is harder than that of the regular quenched material. When the processing load was 5eO N, extremely hard regions over 1OOO HV were obtained. It was confirmed that the processing temperature did not exceed the Ai transformation peint in this case. It can be concluded that the severe stirring process ofFSB caused the grain refinement.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.