How can I figure out what kind of material this is?

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So I have to modify a GM HFv6 fuel rail for a custom application.  The material looks like polished chrome on the outside, and SS on the inside. I assumed it was a coated SS. So I cleaned off the coating and went at it with an internal purge and 309SS.  But I've run in to a problem.With or without filler, it appears to sugar right under the shielding gas (on the top of the weld), even with a spot or pulse.  Internally, the weld appears clean.  I welded a plug, then after the piece cooled, the weld ingot cracked around the perimeter and fell right out.  Here is a video of the spark test.  Please don't berate me for grinding over the trash can.  I know. The weird part is sugaring without filler with a purge.  I know both bottles are good, as I test each bottle as they come in.This has me thrown completely off.  I'm thinking of giving it a shot with some inconel and seeing what it does.  I just have to find some as I forgot to grab a box from the lot of no-longer certified scrap wire the last time I was at the office.I'll get some pictures of the actual piece whenever the battery on my phone charges back up.
Reply:hard to tell looking at the picture, but the flange looks like aluminum, maybe a zinc alloy.tackleexperts.comwww.necessityjigs.comhttps://www.facebook.com/groups/mach...dingequipment/
Reply:Originally Posted by brucerhard to tell looking at the picture, but the flange looks like aluminum, maybe a zinc alloy.
Reply:The flange is aluminum and not the part I'm interested in.  I only placed the ingot on it to get a better shot of it.
Reply:Here's the rail:And here's an autogenous weld on it.  It looks and welds just like haynes 200 series, but I don't know why a fuel rail would be made out of it. Perhaps it's a cobalt alloy?
Reply:If a magnet wont stick and it makes orange sparks I would say stainless......The weld pictured is way too hot  and undercut.......also looks like a different filler material than the parent metal?Last edited by B_C; 06-20-2013 at 03:25 PM.  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:The weld shown was without filler to see if I could get a different result, done with about 25-30 amps.  Any lower amperage and it wouldn't melt.I tried again with a lap joint on what I have to modify at the other end of the rail.  without filler, with a purge, same (as little amperage as possible), and it cracked down the center of the weld.
Reply:Hello pat8703, Have you considered silver soldering as an alternative in this case? One other possibility is to find a sacrificial part of the same type and cut some strips out of it to use for filler for your welding. A couple of thoughts for consideration. Good luck and best regards, Allanaevald
Reply:what are you using for filler?  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:Production fuel rail would be real surprised if it was Inconel  or any high dollar material .........the other fittings look silver soldered or oven brazed.....  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock