Ever Work With 400 Series Stainless?

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I had to pick up a diaphragm for an old regulator today, so stopped at a steel supplier/ recycler  on the way.  As usual, I looked in the scrap steel dumpster and saw two bars that looked like stainless, perhaps 4" diameter and 10' long. Once in the building, I asked one of the workers who told me it was 400 series and they were told it couldn't be welded so wasn't worth keeping.I know some 400 series work-hardens and requires carbide tooling, but had never heard it couldn't be welded. I used some 416 cutouts for the bottoms of some crucibles once and had no trouble welding it, although I might have used some 4NiA,  IIRC.Any comments by anyone here about the 'worth keeping' part? What have you used 400 series for?
Reply:Exhaust systems can be made from 409 stainless.  It can be welded, but not all the other 400 grades can be.  Ferritic grades, those typically lower in alloying elements(chromium, nickel, molybdenum) are weldable.  The Martensitic grades tend to be more difficult to impossible to weld due to cracking issues.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Nobody else knows or has any opinion about this?
Reply:The textbook answer is that 416 stainless should not be welded due to high sulphur that causes hot cracking problems.  However, many people do weld 416.  We weld 416 here where I work and have done so for aircraft turbine parts for 30 years or so.  I am against it though.As for the other 400's, most of them are weldable.  There are differences between the different alloys.  Some may require heat treats.  We weld a lot of 410 and 430 autogenously with no heat treats and have no problems to speak of.
Reply:400 series stainless encompasses a WIDE range of products, from relatively inexpensive 'plain' ferritic iron-chromium 409 to a high-carbon high-chromium martensitic 'cutlery' grade like 420 or 440C.Asking about 400-series is almost like saying "steel" or "aluminum".    Well, a bit narrowed down but not really all that much because the 400-series is pretty wide in the chemical make-up and properties.The 300-series is a bit narrower in make-up and properties, but even there a spread in properties and suitable/correct fillers is encountered.  The best laid schemes ... Gang oft agley ...
Reply:obewan posted while I was composing and posting my above response.re: 416 and sulfur.  The spec for sulfur percentage allowed in 416 is pretty much the same for all the other 'general' stainless grades at 0.03% max allowable sulfur.  409 allows 0.045% max, some other grades might be 0.02% max.Although there is a 416Se which has a max of 0.06% sulfur and is listed as "generally considered unweldable".  But that may also be because of the added selenium (greater than 0.15% minimum) to make it a 'free-machining' grade.  Although Lincoln does suggest ER312 wire if trying to weld any of the 416 grades.Last edited by MoonRise; 03-20-2009 at 01:20 PM.  The best laid schemes ... Gang oft agley ...
Reply:Although Lincoln does suggest ER312 wire if trying to weld any of the 416 grades.----------------------------------------------------------------------------------------------------------Yes we use 312 any time we are worried about hot cracks and have better results.Yes I meant free machining 416 when I said sulphur.  I am trying to document cracking occurances here with 416 as they occur so I can push back on our chief engineer.  For all new work I push to substitute 410 for 416, but they push back on me due to cost and machining issues.
Reply:Free-maching grades of steel DO make machining easier.But they do so at a general drawback on decreases in ductility and impact resistance and fatigue properties.If you need a material with high strength (yield and/or fatigue) at a high temperature, why the H#@L would you go and muck up the alloy selection by using using a free-maching grade of material?!!?Not "you" obewan, the above 'you' is a general reference to some other person in general and not you specifically.    The best laid schemes ... Gang oft agley ...
Reply:The mechanical properties are somewhat unimportant since we are talking about aircraft igniters.  The 416 is on the connector part.  Sort of like a glorified spark plug where the wrench goes.  For the high temperature end where the igniter sparks in the turbine we usually use something like an Inconel or a Hastelloy - which gets welded autogenously to the stainless.  We don't use 416 on everything though.  It is somewhat rare.
Reply:400 series stainless encompasses a WIDE range of products, from relatively inexpensive 'plain' ferritic iron-chromium 409 to a high-carbon high-chromium martensitic 'cutlery' grade like 420 or 440C.Asking about 400-series is almost like saying "steel" or "aluminum". Well, a bit narrowed down but not really all that much because the 400-series is pretty wide in the chemical make-up and properties.
Reply:I was just thinking that if it was 4" solid then it would make a fine sheet metal roll........I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......