Problems in ageing heat treatment

[will123123]

I work for a company, often producing parts out of maraging steel and 13-8PH stainless steel. Unfortunately our heat treatment sub contractor are having a few power problems at the moment and there has been a couple of incidences of power loss during ageing of the above material part way through the process (after between 50% and 75% of the specified time).
Despite hardness tests suggesting they are within the post treatment specification I have directed the heat treaters to make up the aging time in a second step; the reason being while hardness looks fine, this do not give good information on mechanical properties.
Would any of you make a different decision?

 

[redpicker]

For me to decide what I would do, I would need to know what specifications were applicable, what the size of the parts were, what were the actual furnace times, and maybe a bunch of other information. My gut reaction would be to re-run the complete (full time) aging cycle, but I would need to know much more information to make a decision.

rp

 

[grayseal]

We heat treat 17-4 bar to the H1100 condition. There have been times when the chart recorder is not turned on. When this happens, I have them rerun the parts for the full four hours. I ran the mechanicals for one four hour cycle and compared them to parts ran for two four hour cycles. Tensile and yield were reduced by less than 4%, while elongation and reduction in area were unaffected.

grayseal