A-286 Test for Over/Under Aged 1

[TEV]

I have a large number of small parts machined from A-286. After machining, a few of the parts were found to be harder or softer than recommended specification, believed to be due to improper age hardening treatment. We need a quick way to sort the defective from the acceptable parts. Unfortunately, hardness testing is considered destructive on this part. Any suggestions?

 

[GRoberts]

Some of the portable hardness testers make very tiny indentations, similar to an HV5 or HV10. Is this still too big? Check out some of the instuments at the web page below.

http://www.radiatronics.com/equipment/eqpt_hardness.htm#Proceq

 

[yates]

TEV, Are you sure hardness variation comes from improper age heat treat ? Hardness variation would be difficult to see if all the parts were aged together, since A-286 is fairly forgiving during age (small temp. variations within load will not produce different hardness). After machining however (since A-286 has a very sensitive response to cold work) change of cutting tool during the machining operation can make superficial hardness change considerably. To monitor this, we generally use microhardness (Vickers or Knoop scale) as suggested by GRoberts with 100 gm or 200gm application force.