Effect of contact detecting method on pre-heating time and tensile strength in A6061, A2017 aluminium alloy to SUS304 stainless steel friction welding

摘要

The disparity of the pre-heating time due to differences in the contact detection methods was investigated for friction welding A6061 or A2017 aluminium alloy to SUS304 stainless steel, In addition, the effects of pre-heating time upon the joint strength were studied, The results may be summarised as follows:The pre-heating time is short and its dispersion is little for the pressure detection method, the limit switch detection method and the torque detection method compared with the manual operation method,For the torque detection method the pre-heating time is longer and its dispersion is greater in the case of A2017/SUS304 compared with A6061/SUS304; the friction welding behaviour of A2017/SUS304 is shown to be unstable.The effects of pre-heating time on joint efficiency are not seen in A6061/SUS304; however, for A2017/SUS304 joint efficiency reaches maximum with approximately 0.1 seconds preheating time and the joint efficiency declines with prolonged preheating times under the friction welding conditions employed in this study.In the case of A6061/SUS304 with the application of machine oil to the weld surface, the pre-heating time increases and its dispersion also becomes greater for torque detection method. Furthermore, although there is no correlation between the pre-heating time and joint efficiency, the joint efficiency decreases substantially compared with A6061/SUS304 with no machine oil applied to the weld surface; it re-affirmed that the state of cleanliness at the weld surface plays a big in the joint strength.