high temp oxidation
high temp oxidation
(OP)
First I'd like to just say that this is my favorite forum on the webpage. You can learn a lot by just reading the posts in here.
I have question though, currently we are using an astm 297 HH for a high temperature application. I have investigating possible alternatives given relatively the same budget. What are some possible alternatives should i consider in hoping to find a longer resistance to high temperature oxidation.
Applicatin has low loads, little abrasion. Combustion chamber environment.
Currently I am planning on using other astm 297 grades, but I don't know which ones would be better off hand, but i can change from 297, i'm just not sure what i should look at.
Cheers
I have question though, currently we are using an astm 297 HH for a high temperature application. I have investigating possible alternatives given relatively the same budget. What are some possible alternatives should i consider in hoping to find a longer resistance to high temperature oxidation.
Applicatin has low loads, little abrasion. Combustion chamber environment.
Currently I am planning on using other astm 297 grades, but I don't know which ones would be better off hand, but i can change from 297, i'm just not sure what i should look at.
Cheers





RE: high temp oxidation
RE: high temp oxidation
The chamber is wood fueled. Fuel is sorted to minimize contaminates added.
RE: high temp oxidation
http://www.specialmetals.com/products/
There are other high temperature, nickel-chromium alloys like Hastelloy X or Haynes 230 , offered by Haynes.
http://www.haynesintl.com/guestbooknew.asp
Either way, these will be expensive because of the alloy content.
RE: high temp oxidation
For some improvement you could move to HL. The higher Cr will give better overall corrosion resistance.
With all of these alloys, and HH most, the exact chemistry balance is very critical. The Ni and Cr contents must be right or you will have poor performance.
Another option, but more expensive would be cast Alloy X (45%Ni, 22%Cr, 9%Mo). This is the best greneral service high temp alloy.
= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: high temp oxidation
This Alloy X, is it easy to find? Our current supplier has a limited selection, but I am looking to find a new supplier. Do you know where it is available in USA/Canada?
RE: high temp oxidation
There are many high alloy cast sources in the US. Give me some info and maybe I can point you.
= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: high temp oxidation
As far as I know we have never used sand casts.
Do surface coatings help in environments like this? Is it possible that a cheaper base material with a proper coating might help?
RE: high temp oxidation
If you are looking for these parts to be investment cast you might try http://www.oicc-co.com/
I have worked with them in the past and they always did a good job.
= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: high temp oxidation
RE: high temp oxidation
I just got the chemical analysis back of the ASTM A-297 HH alloy we had been using. The proper portions of Cr and Ni are 25% and 12% respectively, and our material contained 24% and 13.5%. Are these errors great enough to make a noticable difference?
RE: high temp oxidation
As has been noted, %Cr is the key to high temperature oxidation resistance of the iron base chrome-nickel cast alloys listed under A-297. More similar in cost to HH are grades HI and HE both having more chromium. Somewhat more expensive are HK and HL. Note that the high chrome -low nickel alloys will have considerable delta ferrite, which may prove detrimental to your service conditions (greater potential for formation of the brittle constituent-sigma.
RE: high temp oxidation
The other thing to do is age some samples at 2000F and 1400F. They should both be non-magnetic and have reasonable tensile ductilities.
I suggested HL becuase it will offer the best oxidation resistance while still staying with a reasonable Ni content (read cost). It is also a fully austenitic alloy.
= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: high temp oxidation