EFFECTS OF WELDS SCALE ON PITTING RESISTANCE OF AUSTENITIC STAINLESS STEELS
焊接氧化皮对奥氏体不锈钢孔蚀性能的影响

The pitting resistance for three kinds of austenitic stainless steels with weld scales were investigated by electrochemical technology in NaCl solution. The result showed that the pitting in the area covered with weld scale occurred more easily than in the base metals. After the weld scale being removed by pickling, the same material showed better pitting resistance for all the three stainless steels tested. For the three kinds of steels covered with weld scale, the pitting resistance order was NK1>316>304. The secondary ion mass spectroscopy (SIMS) analysis indicated that the depletion of chromium made the pitting resistance of the steel covered with scales worse. However, the NK1 covered with weld scale had better pitting resistance than that of the 304 stainless steels because copper element was rich in surface film and took part in the process of film forming, which improved the electrochemical behavior and strengthened it's resistance.