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

Examination of contact detecting methods such as pressure, torque, limit switch and manual operation which detects the contact point of welding materials for friction process was carried out, so as to clear the pre-heating time of each method and the effect of pre-heating time on the joint strength in A6061 aluminum alloy/SUS304 stainless steel and A2017 aluminum alloy/SUS304 stainless steel. Moreover, the joint strength was judged by statistical investigation. The results are as follows. (1) The pre-heating time was smaller in contact detecting methods such as pressure, torque and limit switch than manual operation. (2) Pre-heating time didn't affect on the joint strength and its dispersion in A6061/SUS304, but affected on these in A2017/SUS304. (3) Mechanical oil painting on the weld material surface increased pre-heating time in torque detecting method. (4) Mechanical oil painting on the weld material surface also decreased the joint strength and increased its dispersion in all contact detecting methods. Therefore, cleanliness of the weld material surface was found to be one of the important factor for joint performance.