17-4PH Conditioned H900 Low Rockwell Hardness
17-4PH Conditioned H900 Low Rockwell Hardness
(OP)
We were testing 17-4PH condition H900, .0831 in diameter, for Rockwell testing. We found from our labs that it had a low Rockwell, around 35-36. We decided to get them tested via tensile strength and use the results to get the rockwell hardness number. Again these ranged from 34-36 where as it should have ranged from 40-48. These parts have undergone heat treatment twice. What could be the cause of the low hardness testing?





RE: 17-4PH Conditioned H900 Low Rockwell Hardness
If you can use AISI 420 you can get the hardness within 4RC accuracy, for example 44-48RC.
RE: 17-4PH Conditioned H900 Low Rockwell Hardness
What was the wire purchasing specifications?
What exactly were the two heat treatments, time and temperature?
The reason for these questions is that you can get 17/4 in several conditions. The one you will see most is the coldheading wire, H1150 x 2 heat treatments.
There are some other considerations when heat treating a small part such as yours, especially time at temperature.
RE: 17-4PH Conditioned H900 Low Rockwell Hardness
RE: 17-4PH Conditioned H900 Low Rockwell Hardness
Your material is so small, you may be "mushing" the material out thus the lower hardness numbers.
RE: 17-4PH Conditioned H900 Low Rockwell Hardness
We use 17-7 in C condition, then heat treat to CH900. We often see 46-48HRc (converted) in as recieved and after H900 we'll get 49-51. We also see good consistancy as Metalguy does.
israelkk is right hardness is not a great indicator of this steel. Also if you dont start with C material then all bets are off as to how your particular heat of material will accept any of the transformation processes (IE: T or R)
Nick
I love materials science!
RE: 17-4PH Conditioned H900 Low Rockwell Hardness
RE: 17-4PH Conditioned H900 Low Rockwell Hardness
RE: 17-4PH Conditioned H900 Low Rockwell Hardness
Most of the 17-7 that make is thin walled tubing. Hardnesses are all over the place, but strengths are consistant.
= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: 17-4PH Conditioned H900 Low Rockwell Hardness
Monkeydog called it right. I have had trouble forever with our guys doing faux hardness tests on undersized parts. Put a quarter sized pellet from the same heat # in with the small part heat treat batch and Rockwell test it on the broad side. You will find the right numbers and consistency you are looking for.