thorangle
Mechanical
- Mar 13, 2002
- 40
I have a 3/4-10 UNC threaded rod, conforming to IEEE standard C135.1-1999, IEEE standard for zinc-coated steel bolts and nuts for overhead line construction.
The failed section of the bolt has striation marks indicative of fatigue failure, and a small zone with typical brittile failure charateristics.
The anomaly:
parallel to the fatigue striations is a zone of discoloration. The zone is approximatly .08" wide, with "clean" normal fatigue striations on either side. The discoloration is blueish rain-bow, similare in apearance to when heat-treated steel is overheated by grinding. The depth of the discoloration appears to be very shallow, i.e. less than .005" into the fatigue fracture face.
Anyone have some thoughts as to what might have caused this anomaly?
Thanks
The failed section of the bolt has striation marks indicative of fatigue failure, and a small zone with typical brittile failure charateristics.
The anomaly:
parallel to the fatigue striations is a zone of discoloration. The zone is approximatly .08" wide, with "clean" normal fatigue striations on either side. The discoloration is blueish rain-bow, similare in apearance to when heat-treated steel is overheated by grinding. The depth of the discoloration appears to be very shallow, i.e. less than .005" into the fatigue fracture face.
Anyone have some thoughts as to what might have caused this anomaly?
Thanks