http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Joint Strength in High Speed Friction Stir Spot Welded DP 980 Steel
Nathan Saunders,Michael Miles,Trent Hartman,Yuri Hovanski,Sung-Tae Hong,Russell Steel 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.
High speed friction stir spot welding was applied to 1.2 mm thick DP 980 steel sheets under different welding conditions, using PCBNtools. The range of vertical feed rates used during welding was 2.5~102 mm per minute, while the range of spindle speeds was 2500~6000 rpm. Extended testing was carried out for five different sets of welding conditions, until tool failure. These welding conditionsresulted in vertical welding loads of 3.6~8.2 kN and lap shear tension failure loads of 8.9~11.1 kN. PCBN tools were shown, in thebest case, to provide lap shear tension failure loads at or above 9 kN for 900 spot welds, after which tool failure caused a rapid dropin joint strength. Joint strength was shown to be strongly correlated to bond area, which was measured from weld cross sections. Failure modes of the tested joints were a function of bond area and softening that occurred in the heat-affected zone.
Hossain, Md. Abu Mowazzem,Hasan, Md. Tariqul,Hong, Sung-Tae,Miles, Michael,Cho, Hoon-Hwe,Han, Heung Nam Hindawi Limited 2014 Advances In Materials Science And Engineering Vol.2014 No.-
<P>Mechanical properties and failure behaviors of friction stir spot welded (FSSW) joints of two dissimilar ferrous alloys, cold-rolled carbon steel (SPCC) and 409L stainless steel (SUS 409L), are investigated under opening-dominant combined loads. The texture of dissimilar FSSW joints depends on the upper sheet material. The failure contours for the FSSW joints under combined loads are constructed in terms of the axial load and shear load by modifying existing failure criteria for resistance spot welds. The shape of the failure contour also depends on the upper sheet material. The failure contours are nearly elliptic in shape when the upper sheet is SPCC and are relatively straight lines when the upper sheet is SUS 409L.</P>
Friction Stir Spot Welded Joints of 409L Stainless Steels Fabricated by a Convex Shoulder Tool
Md. Abu Mowazzem Hossain,Md. Tariqul Hasan,Sung-Tae Hong,Michael Miles,Hoon-Hwe Cho,한흥남 대한금속·재료학회 2013 METALS AND MATERIALS International Vol.19 No.6
Spot joints of ferritic 409L stainless steel are successfully fabricated by friction stir spot welding (FSSW) using a convex shoulder tool. The welding process, microstructure and failure of the FSSW joint are investigated experimentally. During the FSSW process, the Z-force history shows significant variations depending on the contact phenomena between the tool and the joined sheets, while the Z-torque history shows a rather steady increase without pronounced changes in the trend until the initiation of dwelling. Electron back-scatter diffraction suggests that both continuous dynamic recrystallization and recovery occurred in the stir zone during the FSSW process. Observation of the FSSW joint that failed under the given lap shear load shows that the cracks, which are the result of the interfaces between the upper and lower sheets, propagated into the weld along the interfacial surfaces, after which a necking/shear failure occurred. Finally, the rupture of the joint, which was initiated by the necking/shear failure, propagated along the circumference of the weld.