Heat treating 15-5 after HIP
Heat treating 15-5 after HIP
(OP)
Thanks for reading. I have a product I manufacture that is made of 15-5 stainless. Up until just recently the process was; casting, heat treat H1950, heat treat H900, then machine.
Due to casting issues we have deceided to have our product HIP'ed (hot isostatic pressure). I am wondering what process to put the product through after HIP. They will go to the HIP facility after the H900 treatment. The HIP process is 2075 degrees, 15k psi, 3 hour min. After HIP I will do the machine work.
My question is will I be able to just do the H900 process after machining or will I have to also do the H1950 solution treatment? I have not been able to get an answer on this and thought I would throw it out here as there seems to be a lot of knowledge here.
Thanks
Due to casting issues we have deceided to have our product HIP'ed (hot isostatic pressure). I am wondering what process to put the product through after HIP. They will go to the HIP facility after the H900 treatment. The HIP process is 2075 degrees, 15k psi, 3 hour min. After HIP I will do the machine work.
My question is will I be able to just do the H900 process after machining or will I have to also do the H1950 solution treatment? I have not been able to get an answer on this and thought I would throw it out here as there seems to be a lot of knowledge here.
Thanks





RE: Heat treating 15-5 after HIP
Do the HIP process at 2075 degrees (oF I presume) right after casting. It will do most of the homogenization-solutionizing. Probably imposssible to do accelerated cooling from HIP or else it could entirely save you the solutionizing step.
Then solutionize at 1900 oF for 1/2 hour, quench, rough machine, H900, machine or grind to fit.
RE: Heat treating 15-5 after HIP
The parts that are going through HIP now have already been through the solution treatment. I assume the HIP, since it is not a rapid cool down, will undo that?
Then do the 1900 for 1/2 hour, rough machine and then H900?
I was hoping to avoid the h1950 treatment but it looks like I will have to redo that, right?
Matt
RE: Heat treating 15-5 after HIP
However, I lack experience with this particular operation.
Suggest that you find out the maximum cooling rate within the HIP machine (they always have T-t profiles). Also, is this alloy UNS 92110 (cast version of 15-5)? http://
and is this to meet some spec. such as ASTM A747?
Probably, less costly in the long run to solve the casting feed/solidification problem to eliminate forming porosity.
RE: Heat treating 15-5 after HIP
I entirely agree with kenvlach's suggestions.
RE: Heat treating 15-5 after HIP
The other advantage of HIP is the strength increase. We need all the strength we can get so the props stay together. Otherwise blades have a tendency to fly off.
There is no spec to which we need to HT these to. Just whatever we find that works the best. There has to be a balance between ductility and hardness. Too hard and the blades fly off, too soft and they bend. It's a balance act.
The minor cast voids are also a cosmetic issue. If HIP removes the voids, like I hope, it will eliminate a great deal of finish time.
So from what I gather here I should treat these parts after HIP as if they just came out of the mold?
Thanks for all the input.
Matt
RE: Heat treating 15-5 after HIP
As an aside can you not consider a 2 piece construction,i.e the barrell can be solid/pipe which can be inserted during casting or can be welded separately. This might reduce your problems and eliminate the need to Hip.
RE: Heat treating 15-5 after HIP
When I was looking for billet I given wait times of about a year. I can have a casting made in 10 days.
I have considered billet and I would offer it to my customers but the cost would be about much more than that of cast.
You are correct in that a two piece or weld on blades are not an option. The blades fly off!
RE: Heat treating 15-5 after HIP
RE: Heat treating 15-5 after HIP
There are ways to make these as welded structures that would be stronger than castings. Think of splitting the hub, so that each blade and its transition to the hub would be a single machined piece. Then weld the hub sections together. This way the welds are in lower stress locations.
Remember with HIP that it will only help with closed (internal) defects. Any that are open to the surface will be unaffected.
I doubt that the cooling rate from HIP will be fast enough. You will probably have to follow it with the 1905H step.
= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: Heat treating 15-5 after HIP
Thanks for the input, well thought out! I make several hundred a year of these.
The holes are deep in the casting and yes the HIP facility said the cooling rate is quite slow.
With the exception of the holes this program is going very well. I like your idea about welding the hub but I have soooooo much time and money in the current project I need to get it rolling before I get into another idea.
Thanks for your input!
RE: Heat treating 15-5 after HIP
Do you take samples from each heat of castings and heat treat them to come up with an optimum aging temp?
I have seen this done with forged blade/hub segments. The process was; forge, rough machine hub, welded together, rough machined, annealed, bulk machined, heat treated and aged, then finish machined and polished.
This could be done with castings, forgings, or machined from plate sections. If I was going to weld thick sections I would look to an alloy like 17-7PH.
The real reason that I asked about volume was that I was thinking about powder metallurgy. You could even do individual segments, sinter, assemble and then HIP.
= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: Heat treating 15-5 after HIP
The HIP and HT (after HIP) are 2 expenses we didn't expect to have. Of course they will reduce the profit margin. Down the road after we establish the improved durability of our product we can get away with charging more for our product.
From input here and other sources I think the process is going to be;
cast
HIP
H1950
machine
age to H1025 or H1075
final hand finish
Unless anyone finds any problems with this process.
Matt
RE: Heat treating 15-5 after HIP
My only other question, and I hope that some one knows, Does 15-5 care how long it sits between the 1950 and aging? It does matter with some grades, but not others.
Looks good.
= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: Heat treating 15-5 after HIP
Tolerance is not that critical. As long as we are within .005" we will have a superior product.
Thanks for the input.