Results 1 to 8 of 8

Thread: need advise on dissimilar stainless welding

  1. #1
    Join Date
    Aug 2010
    Posts
    2
    Post Thanks / Like

    need advise on dissimilar stainless welding

    I need to know what alloy filler material to use on welding 440 stainless to 316. Any help would be greatly appreciated. Thanks!

  2. #2
    Join Date
    May 2006
    Location
    Eastern Washington
    Posts
    1,038
    Post Thanks / Like

    Re: need advise on dissimilar stainless welding

    This is from the lincoln site. My interpretation is that 308 should be used. Maybe someone with a little more brain power will turn up this morning.




    When should I use 308L, 309L or 316L filler metal?

    308L (including ER308LSi) is predominately used on austenitic stainless steels, such as types 301, 302, 304, 305 and cast alloys CF-8 and CF-3. For high temperature applications such as in the electrical power industry, the high carbon 308H electrode provides better creep resistance than does 308L.

    316L (including ER316LSi) filler metal should be used with 316L and 316 base metals. CF-8M and CF-3M are the cast equivalents of 316 and 316L, respectively.

    Use 309L (including ER309LSi) when joining mild steel or low alloy steel to stainless steels, for joining dissimilar stainless steels such as 409 to itself or to 304L stainless, as well as for joining 309 base metal. CG-12 is the cast equivalent of 309. Some 308L applications may be substituted with 309L filler metal, but 316L or 316 applications generally require molybdenum and 309L contains no molybdenum.

    Type 347 stainless steel filler metal is ideal for 347 and 321 base materials because it matches these stabilized grades. CF-8C is the cast equivalent of 347. Type 347 filler metal is also suitable most 308L filler metal applications.
    UA Local 598

  3. #3
    Join Date
    Sep 2006
    Posts
    73
    Post Thanks / Like

    Re: need advise on dissimilar stainless welding

    Whughes,

    The way I interpret that is 309L. It doesnt say only for 409 to 304L. I read it as "such as" disimilar materials.

    Use 309L (including ER309LSi) when joining mild steel or low alloy steel to stainless steels, for joining dissimilar stainless steels such as 409 to itself or to 304L stainless.

  4. #4
    Join Date
    May 2006
    Location
    Eastern Washington
    Posts
    1,038
    Post Thanks / Like

    Re: need advise on dissimilar stainless welding

    this is why I thought 308.....


    "but 316L or 316 applications generally require molybdenum and 309L contains no molybdenum."
    UA Local 598

  5. #5
    Join Date
    Aug 2010
    Posts
    2
    Post Thanks / Like

    Re: need advise on dissimilar stainless welding

    thanks guys i appreciate it

  6. #6
    Join Date
    Oct 2007
    Location
    Near Dayton, OH
    Posts
    2,499
    Post Thanks / Like

    Re: need advise on dissimilar stainless welding

    Sorry for the late posting.

    This will be a tough weld to make without it cracking. 440 Stainless has over 0.65% carbon in it. Max Carbon is 1%. It doesn't really make a big difference which stainless filler you chose, in light of the carbon content. 309L is probably the lesser of all evils, but anything with low carbon, molybdenum, chromium and Manganese will perform best. More nickel should help, but only like using a garden hose on a forest fire helps...

    The low moly content of the filler is a blessing in this situation, as the diluted moly content will actually help reduce the chances of cracking or embrittlement in the finished weld...

    Here's a link to a properties page for 440.

    http://www.azom.com/details.asp?Arti...4#_Composition

    If you get lucky and the weld doesn't crack in the heat affected zone next to the weld bead, the 440 base metal will be extremely hard and brittle in the HAZ, due to formation of martensite.

    You'll need to try and temper the weld and base metal to elminate the martensite. Unfortunately, the high alloy content may result in temper embrittlement. This is a different problem than the high carbon content, but the end result is the same; a joint with little or no impact toughness.

    http://www.keytometals.com/page.aspx...s&LN=EN&NM=102

    The next problem is all this slow cooling and tempering to brittleness will probably degrade the corrosion resistance of all the base metal and weld deposit. If corrosion resistance isn't a major factor, then this is not a serious problem.

    If this is a critical weld, where life or property are at risk, then invest some time and effort on researching the right pre- and post heat treatment. It will likely involve a staged(slow cooling down to 600C, then fast down to ~300C, then more, slower cooling to room temp) slow cooling post welding and maybe a 2 step tempering operation(1 to eliminate martensite, and another to eliminate temper embrittlement from the first tempering).

    You'll need some expert advice to come up with a weld procedure that avoids all the pitfalls in making this weld and preserving the mechanical and corrosion properties of the base metals involved.

    Last advice, make sure you don't use a "free machining" grade of 440 stainless. The free machining grades are alloyed with elements(usually Sulfur) that cause serious hot cracking problems. 440A or B will be easier to avoid cracking than 440C grade due to lower carbon contents.



    Quote Originally Posted by punkinbeck View Post
    thanks guys i appreciate it
    Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector

  7. #7
    Join Date
    Sep 2006
    Location
    NJ, USA
    Posts
    3,431
    Post Thanks / Like

    Re: need advise on dissimilar stainless welding

    Well, if you use 316 filler, at least that would match to your 316 base material section.

    But 440? And exactly -which- 440 alloy? 440A or 440B or 440C?

    And just what/why are you trying to weld some 440(A-B-C) to some 316?

    440 is a martensitic stainless steel and can get pretty hard (and brittle) with heat treatment.

    316 is an austentitic stainless steel and typically will not respond to heat treatment. Anealing and stress-relieving not withstanding.

    The witch's brew mixture between the two will depend a whole lot on how much inter-alloy mixing and what filler you use and how you pre- and post- heat everything.

    The 440 alloys typically are listed as NOT weldable btw. Right from Lincoln regarding martensitic stainless alloys: "They have a tendancy toward weld cracking on cooling when hard brittle martensite is formed."

    Also: "Steels with over 0.20% C often require a post weld heat treatment to soften and toughen the weld."

    Note that ALL the 440 alloy variants have greater than 0.20% carbon, ranging from 0.60-0.75% for 440A to 0.75-0.95% for 440B up to 0.95-1.20% for 440C.

    All the 440 variant also have 16.0-18.0% chromium and a max of 0.75% molybdenum.

    The 300-series austentitic stainless alloys have chromium and nickel and manganese, and 316 adds some molybdenum in as well. 316 (plain, not the variants) is 0.08% C, 2.00% Mn, 1.00% Si, 16.0-18.0% Cr, 10.0-14.0% Ni, and 2.0-3.0% Mo.

    Welding dissimilar steels is one thing. Sometimes you can find or use a filler that will be OK in that situation.

    But welding a 'weldable' stainless steel (316) to a generally non-weldable (440) stainless steel? Lincoln (and others) flat out list the 440 alloys as "welding not recommended". Exact quote right out of their literature.
    The best laid schemes ... Gang oft agley ...

  8. #8
    Join Date
    Apr 2010
    Location
    Galesburg, il USA
    Posts
    1,678
    Post Thanks / Like

    Re: need advise on dissimilar stainless welding

    Pretty good heads up in the post from A_Dab Re; 440SS,

    Every heat treater I've ever known hates this stuff, and if welded with 420SS for a complex section that is later heat treated they will turn it down or advise that you're on your own...

    If you're going to weld it to sit on a table top for show 309 may be the best choice. If you are welding something like a thin fillet knife blade to a 316 handle for looks it will likely break the first time you flex the blade.

    If you are making a tubular roll with solid ends for hardening 420SS is recommended and note the heat treater comment above.

    Good Luck

    Matt

    Edit; missed the good post from MoonRise above, spot on correct
    Last edited by Matt_Maguire; 08-09-2010 at 10:31 AM.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Page generated in 1,664,486,882.58572 seconds with 11 queries