I have a project consisting of 321 ss. The problem is I have never dealt with 312 ss before. I've used 304, 308 and 316L. I am hoping there is somone available to steer me in the right direction for filler material and possibly welding proceedures.
SS321 is a stabilised steel and the composition is usually
C =0.06 , Cr = 18.0 , Ni = 10 , Ti = 0.5
Titanium is added to prevent intergranular corrosion ( IGC which happens when Chromium reacts with carbon to form Chromium carbides removing chromium from the system and exposing the metal to corrosion ) Titanium has a closer affinity to carbon than chromium.
Noibium additions also provide the same function as Titanium . Titanium can be lost from the electrode and the weld pool due to its ease of oxidation . For this reason Niobium containing consumables should be used when welding this material . I feel it is better you contact your electrode manufacturers for providing you the right filler.
Have you thought about using 347 stainless steel to weld the 321?
Chuck is right about 347 being the most common filler choice for the 321.
I think you will find that when the rubber meets the road 321 will behave very much like 304, 308 and 316. Distortion control in sheet, purge, surface prep and heat inputs will demonstrate negligable difference to a manual GTA welder.
Tell us more about your project (specifics) and you will get good advice I'm sure.
Yes SS347 is the right choice
Chuck is right. 347 is the way to go. Does any body even manufacture 321 for arc processes any more? Although it will hold up better with GTAW.
And Lawrence is right too. You can't even see the difference when welding.
Well, I never could anyway. Some I suppose could. Those who knew they were welding 321. Ha!!
We have decided to use heliarc. The material is .125 thick and our WPS call out for 308L-T-1. Does that spark anyones interest. I am very appreciative of all the imput I can get.
I am assuming 321 was chosen for a reason. Usually sensitization. If your working Section IX you can 'Job Specific Addenda' your WPS for 347 without requal.
IF I am not mistaken E308 T-X is Flux cored electrodes with no Ti or Cb+ Ta content ? Also the carbon content when the suffix "-X" is "-1" shall be 0.04 % max and when the suffix "-X " is "-2" shall be 0.03%
SS347 will be the better bet
Ok I just read what ASM has to say
By providing low (0.04 % max ) carbon in these electrodes it is possible to obtain resistance to intergranular corrosion resulting from carbide precipitation without the use of stabilisers such as columbium or titanium . A carbon content of 0.04 % max has been shown to be adequate in weld metal even though it is recognized that similar base metal specifications require a 0.03 % limitation. This low carbon alloy however is not so strong at elevated temperatures as the colombium stabilized alloys.
They do specify that it is a FCAW electrode.
I hope this helps
prasad,
That really is the point too. Even though ASME allows a substitution for WPS quals from 308 to 321 or vice-versa, this does not mean that from an engineering standpoint this is acceptable. 321 could very well have been chosen for its high temp strength as well as its stabilization properties in which case 308 may not be acceptable. Especially considering that reducing C will reduce tensile strength.
Once again, the code does not replace SEJ, and it explicity says so.
By ADP
Date 07-18-2007 23:57
I thank all of you for your technical input and I hope to be speaking with you again in the near future.
ADP
We weld 321ss all the time.. 347 filler wire is the best choice, they made a 321 filler which also works ok.. If you have to leak check things down to 10-6 then you could get into issues with welds leaking because there are stringers (ti) in 321 that can cause the problem..
