What could be an explanation for UNS S17400 (17-4PH) to have areas of low hardness (measuring about 94 HRB)?

I have found small areas of low hardness on a sample of UNS S17400 machined from rod supplied in condition A and then heat treated to H1100. Bulk of the sample is in the appropiate range. Nothing...

04 January 2016 4,715 2 View