American Welding Society Forum
Welding to MIL-278, M-1, class A. Base material is 304L. Can I use 316L in place of 308L. Also does the same apply to P-1 class A? If so where can I find the documentation to back up the question. Thanks again-Ted.
If you want to weld 304L by 316L filler, instead of 308L, it is possible.
But I couldn't undrestand what "MIL-278, M-1, class A" means.
MIL- 278 is the Navy fabrication document for welding, machinery, piping and pressure vessels. Class M-1, category A is an inspection requirement, P-1 is for piping.
Thank you- Ted
I can't say for MIL-278 but if you were working with ASME IX you could because both fillers are the same SFA/A-number (5.9) ER308 has slightly less chrome but slightly more nickel. Molybdenum is also higher in the 316. Generally, ER316 will be more expensive than ER308. The welding characteristics of either is similar if not identical. One of the best books I've found for stainless steels in the "Design Guidelines for the Selection and Use of Stainless Steel" - it is simple to follow in fairly easy to follow terms. The book (part of a series of similar books) is available through the Specialty Steel Industry of the United States - (202) 342-8630. It used to be free of charge, I think it still is but you'd have to call. Good luck.
Thank you very much for your response. I keep getting conflicting opinions on 316L on 304 base material. I'm new to this Navy work (MIL-278) and haven't had enough time to learn all the ins and outs of this code. I do know that they have some requirements that don't parallel ASME codes. Also I have a call into my inspector asking for some help. The problem is I'm having a hard time getting electrode in 308L tested to MIL-19933.I have plenty 316L that's why I want to use 316L instead of 308L.
I'm looking at the more current tech. pub. S9074-AR-GIB-010/278, so please verify that the version of MIL-STD-278 is the same, but table III is the welding filler meterial chart, which only breaks down the material you are working on into the austenitic high alloy steel S-No., which is S-8. For S-8, it specifies A-8A filler metal for SMAW, A-8B filler metal for SAW, GMAW and GTAW, and consumable inserts. If you look at table II, it will tell you which filler metals fall under these groups. As far as I know, the class of the weld does not affect qualification at all, it only affects the inspection type required and acceptance criteria. The type of weld (ie pipe/machinery/structure) also affects the joints allowed.
Thank you Mr. Roberts. I'm working from that same code revision I just left off all of the numbers in front of 278. I agree that chart identifies the electrode as A-8B. Where I'm confused is just because they are lumped into that category doesn't make them interchangable- correct?
i.e. My past experience tells me that when using 316L base material because of it's superior corrision resistance over 304L one wouldn't weld the 316L with 308L because it's in the same A-8B category- correct?
I'm trying to find the supporting documentation that hopefully explains this. I also feel that I need to find this in a "MIL" document so that if and when I ever have to verify my information , I can. Again thank all of you for helping me- Ted.
I don't remember ever seeing anything beyond the table mentined earlier as far as filler metal requirements. But yes, as far as I know, technically qualification for an A-8B electrode would qualify you for any of them. However, it definately would not be advised to interchange them all willy-nilly. As far as 308 vs 316, I agree with Niekie. In the majority of circumstances, 316 weld metal may outperform 308 weld metal due to its higher Mo content, but it is not always the case. If ever deviating off of the industry standard, (which for welding 304 base would be 308 filler) you should always know what kind of environment the weldment is going to be exposed to, and/or get specific customer approval.
Check out the "For Sale" section of the BBS. Someone has 900# of 3/32" dia.308L 60# rolls for sale.
I think that there is a statment in MIl STd 278 that indicates welders and procedurs qualified in accordance with ASME Sec IX may perform welding in accordance with ....
IF you are just wanting to qualifiy welders and procedures it may help. I worked with Mil Standards for about 6 years as a navy welder. I remember this statement from either 278 or 248.
If it is any help, the welding procedures we used for A-8 material on P-1 piping stated the individual filler metals for the specific classes/.types/grades of base metal. More than likely, you only have to perform one PQR for all of the 300 series classes.
I am awaiting for some information on how to get a current 278 and 248 and maybe I can be more help.
Have a nice day.
I have never worked with the Mil spec's, so I cannot give a direct answer. I know that some companies state in their specifications that the filler metal must be of the same nominal composition as that of the base metal. This means that you would not be allowed to use a 316 filler to weld 304.
From a fundamental point of view, it would make very little difference in most applications. In some applications however, the Mo contained in the 316 is an undesirable element. (e.g. Nitric acid service) If you therefore want to make the substitution, I would suggest the following:
1) Check the final service of the weldment to ensure that you do not have a problem with the Mo in the weld.
2) Apply to your client to use the 316 by way of a concession.
If they have a significant problem with this, they will let you know.
Hope this helps.
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