heat treating
heat treating
(OP)
We have an application with bent stainless steel tubes that we need heat treated. but the tubes will be used in an operational temperature of about 1000F. Is it necessary to heat treat them or will the application of 1000F take care of them?





RE: heat treating
RE: heat treating
RE: heat treating
PRC-0001 (REV.F), "PROCESS SPECIFICATION FOR THE HEAT TREATMENT OF STEEL ALLOYS"
which you can get here for free
http://www
RE: heat treating
RE: heat treating
if the 304 SS is in the annealed condition when bending
then it is normally recommended to re-anneal them after bending. stress relieving in my opinion is not enough.
because the parent material will work harden during bending.
MfgEngGear
RE: heat treating
So now you're wondering about how the cold working is going to affect the useage of the tubing. Remember that all of your ductility occurs between the yield strength and the ultimate strength. When you bend it -- once -- you will modify the yield strength, but you will not be changing the ultimate strength. Burst is calculated based on ultimate strength and not yield strength. So when you bend it, your ultimate is unchanged so your burst SF remains unchanged somewhere between 20:1 and 200:1.
But what about cyclic loading? Even after you have made the bend, you would have to determine if your stress is above the material's endurance limit at service temperature. If it is close, then you would probably be good to anneal it, but at 1,000F, I can't imagine there being a problem.
Now, it's time to talk about creep. If you're going to have a problem, I doubt it will be because you didn't anneal it. It will be because of the creep properties of metals at elevated temperatures. Even then, at the (I assume) very low stresses you're dealing with, I don't think it's going to be a problem. If you want to know more about high temperature creep, do some research on the internet. I would imagine that you're going to find that you're still just fine.
Here's some good reading on the subject of 304 from a steel supplier:
http://www.sandmeyersteel.com/304.html
I vote to bend it and be done with it. If you're still worried, talk to your vendor.
Engineering is not the science behind building. It is the science behind not building.
RE: heat treating
Cheers
MfgEnggear