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Up Topic Welding Industry / Technical Discussions / 308 vs 309
- - By jer (**) Date 07-19-2005 18:26
I know that when welding stainless to steel to use 309 but what dis advatage is there when using 308

Thanks
Parent - - By - Date 07-19-2005 19:11
The 2 main advantages of using a 309 instead of a 308 when joining a stainless steel to another steel is 1) the higher chemistry,Cr=22.0-25.0 and Ni=12.0-14.0 for the 309, as opposed to Cr=18.0-21.0 and Ni=9.0-11.0 for the 308. And 2) the 309 has a higher ferrite percentage than the 308. A typical 309 can have a FN of approximately 12-18 FN, while the 308 is usually approximately 4-9 FN. Ferrite is beneficial in counteracting the possibility of hot cracking, or solifidication cracking. Both the 308 and the 309 have an All-Weld-Metal Tensile requirement of 80ksi minimum, but the 309 is usually recommended for welding stainless to dissimilar metals.

Chuck
Parent - - By swnorris (****) Date 07-19-2005 19:28
To add to what Chuck has said, the higher chromium content in 309 promotes the formation of ferrite and increases resistance to oxidation and corrosion. The higher nickel content in 309 promotes the formation of austenite, and increases high temperature strength, corrosion resistance, and ductility.
Parent - - By - Date 07-19-2005 19:36
Exactly. Sorry for not going into more detail. You are totaly correct. Thanks...

Chuck
Parent - - By jer (**) Date 07-19-2005 20:25
Thank you guys for the quick response. I now ordered some 309 mig wire for the job.
Parent - - By - Date 07-19-2005 20:57
May I suggest you order 309Si (or 309LSi) for your job. The higher silicon content gives better arc stability and better fluidity. The higher silicon also gives a more attractive weld bead appearance and reduces porosities as well as weld spatter.

Chuck
Parent - By Kix (****) Date 01-29-2008 21:19
Which is cheaper the 309L or the 309si or the 309Lsi?
Parent - - By RCraine Date 01-28-2008 21:56
Where can I find the tensile properties of 308, 309, and similar stainless weld metals?
Parent - - By Lawrence (*****) Date 01-28-2008 23:16
ASM Metals Handbook Vol 6
Parent - - By RCraine Date 01-29-2008 14:49
Thanks for the suggestion. Is there a free document that I can find it in? Our office doesn't have the publication, and are under a tight deadline. I'm trying to get my boss to buy AWS D1.6, but I don't think that is going to happen.
Parent - By bozaktwo1 (***) Date 01-29-2008 17:28
http://www.matweb.com/index.aspx

Try that site.  Register for free and you can find out all sorts of things about all sorts of materials.  Good luck.
Parent - - By GRoberts (***) Date 07-20-2005 02:15
With some dilution calculations, you can also end up with some martensite (hard and bittle without heat treatment) when using 308 for dissimilar welding. With 309, the weld is going to be austintic (with small amounts of ferrite), which is a lot more ductile and tougher.
Parent - - By smokey36 Date 01-30-2008 22:54
[deleted]
Parent - By GRoberts (***) Date 01-31-2008 20:02
FYI, on 309LSi, the L is still for low carbon (same as 309L), and the Si desginates that it has extra Silicon.  Your are correct that 309LSi is not sentitive to carbide precipitation, but it is from the low carbon.  The Si helps with flow of the weld metal, but doesn't really affect corrosion properties.
Up Topic Welding Industry / Technical Discussions / 308 vs 309

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