Abstract: The low temperature superheater pipe of 130/3.81-MX boiler exploded after being put into use for about one year. The failed pipe was analysed by means of chemical analysis,metallographic examination,mechanical test and heat treatment experiment. It was found that pipe graphitized and pearlite of the pipe spheroidized beause of running for a long time in super temperature. Thus the mechanical property of the pipe was reduced greatly in working pressure,precausions for pipe explosed is put out.