SELF-TAPPING SCREW PERFORMANCE IN ALUMINUM-STEEL JOINTS

摘要

Over the last few decades, lightweight material joints including plastics, aluminum, magnesium and various composites have been widely used in many mechanical and structural applications such as automotive, aircraft and so on, for their high strength-to-weight ratio and the significant improvement for the fuel economy and energy efficiency. Self-tapping screws are one of major technologies to connect the various joints and provide system integrity in ease of system assembly, low cost, etc. In this study, tightening performance of thread cutting screw in aluminum joints is evaluated. Effect of repeated tightening and loosening on the screw performance is investigated for the screw residual torque after environmental thermal cycling. Cyclic temperature fluctuates between 130°C and -20°C in a computer-controlled environmental chamber. Joint coupon materials are steel and aluminum material. Analysis of experimental data provides a useful insight into the self-tapping process into aluminum joints.