Fatigue properties of friction welded joints with flash by austenitic stainless steel and various machine part carbon steels

Abstract

The purpose of this study was to achieve high performance and high function of an industrial product under low cost. The fatigue test of SUS304/S35C and SUS304/S55C friction welded joints with flash was investigated by the rotating bending fatigue test. The experimental results were as follows. (1) The broken part of friction welded joints of SUS304/S35C and SUS304/S55C was changed by amplitude stress, its part was toe of flash of S35C and S55C when amplitude stress was low. And, in the case of the high amplitude, it was specimen parallel part of SUS304. (2) The stress concentration factor of toe of flash of S35C and S55C was the increased with an increase in upset pressure. This tendency was slightly in the case of SUS304, and in the case of carbon steel, it was increased remarkably with increase of carbon. (3) When amplitude stress was low, the broken part of S35C and S55C joints was toe of flash, this fatigue strength was decreased remarkably with an increase in upset pressure. This main reason was the increased stress concentration factor. (4) When amplitude stress was high, the broken part of the SUS304 was the parallel part and the reason was that it was red hot. Heat occurred because of internal friction and low thermal conductivity. But this red-hot temperature was prevented completely by dropping water at 50 ml/min. (5) When the parallel part the length of SUS304 was < 25 mm, the amplitude stress broken by red-hot temperature was increased with a decrease in the parallel part length.

Keywords::

• friction welding
• dissimilar metal
• SUS304
• carbon steel
• fatigue property

Notes

Presented at the Autumn National Conference 2009.