Author/Authors :
Chen، نويسنده , , Y.C. and Fujii، نويسنده , , H. and Tsumura، نويسنده , , T. and Kitagawa، نويسنده , , Y. and Nakata، نويسنده , , K. and Ikeuchi، نويسنده , , K. and Matsubayashi، نويسنده , , K. and Michishita، نويسنده , , Y. and Fujiya، نويسنده , , Y. and Katoh، نويسنده , , J.، نويسنده ,
Abstract :
Banded structures, which vary with welding parameters, were observed in friction stir processing of 316L austenite stainless steel. Sigma phase precipitation was detected in banded structures by transmission electron microscopy. The amount of banded structure had direct ratio relations with heat input. The higher the heat input, the larger the area of banded structures. This is attributable to slower cooling rate at high heat input, which results in longer exposure to the temperature range for precipitation. The formation of sigma phase produced Cr depletion, which resulted in largely degraded corrosion resistance. The present study suggests that low heat input (i.e. low rotation speeds, low working loads and high welding speed) contributes to restrain sigma phase precipitation.
