I'm trying to identify some type of nickel based alloy that is used as welded boiler tube attachments but due to the age of these parts, I can't seem to identify what they are made of. Each part is in the shape of a small I-Beam and the dimensions are 3/4"W X 1-1/2"H X 3"L. The material is cast and ever so slightly magnetic. Each part has a number stamped on it from the cast mold IT30577F with a logo that looks like a capital "H" with vertical line in the center encased in a circle. There is a double "HH" underneath this logo.
Any suggestions on what this material is, who made it and where I can find out what to use to weld it with would be appreciated.
Thanks
I'm sorry, I can't help you identify these parts, but I'm a little surprised that these parts are any part magnetic since nickel alloys are pure austenitic and are not magnetic due to the lack of ferrite.
Sounds like a cast tube-tie. These are usually a high carbon austenitic stainless steel, but are welded to the tube with a nickel alloy weld metal. The nickel alloy does a couple of things - 1. The thermal expansion coefficient is somewhat between the CrMo tube and the stainless steel to minimize thermal expansion stress, and 2. The nickel alloy weld is more resistant to carbon diffusion at elevated temperatures than a stainless weld (such as E309) would be. Carbon tends to migrate from the lower chromium base metal toward higher chromium weld metal and leave a "decarburized" zone next to the weld that is prone to cracking. The "IT30577F" is probably a manufacturer's part number. The "HH" could refer to the heat resistant grade HH, which is similar to wrought grade 309. Go to this website:
http://www.sfsa.org/sfsa/pubs/hbk/s9.pdf
I would agree with Chuck and Marty. I think your looking at a stainless steel, not a nickel alloy. Even the high temp high Fe 800's are fully austenitic. Though stranger things have happened.
WOW! Great link Marty. I think you may be onto something there.
Jeff,
You gotta watch out for Marty. He is quiet and doesn't show up a lot here in the Forum, but when he does, he is right on the money. (that's a compliment, Marty) I had the pleasure to meet Marty at the FabTech/AWS Show in Atlanta, and it was my pleasure. He is a great guy.
Now you've got me blushing. Truth is my job keeps me running on a lot of different welding and materials issues, and I just don't have much time to visit the forum. I kind of skim the topics and respond when I can. Lots of good folks here sharing good info, so I try to give back a little when I can. I remember when this all started as a dial-up bulletin board system with a 1-800 number. Some of the other original BBS members are still here. It has certainly come a long way since then!
Is there any high nickel alloys distributor in your city, like, for example, an INCO distributor? You can ask him, may be he'll be able to help you.
Giovanni S. Crisi
Sao Paulo - Brazil
Thanks for the help! They want us to weld this with 9018 but I protested and said to use Inconel. They insisted 9018 was the correct rod. They said they can't get Inconel due to the nickel shortage or more likely the price was too high. They ended up welding it with 9018. Was I right?
You were right. I would appreciate if you could drop me an email at welder4956@yahoo.com and let me know what shop is doing this. We have work in pretty much every major boiler shop in the U.S. right now and want to make sure they don't show up on one of our plant sites.
9018 what? With the 90 there's gotta be a suffix.
And perhaps this may sound harsh but whoever decided to weld either nickel or a SS with a 9018 is an idiot!!!!
Did they PWHT?
Were there H2 controls?
Were there preheats?
Have they tried to verify if delayed cold cracking exists?
I'm guessing that you have a weld metal of almost 100% martensite that is just waitin to crack. Load it on a truck and bang the bed and its done. Hit a chuckhole on the road and its done.
I hope I'm wrong and will be glad to eat my words on this one. ButI'm thinkin you got a problem.
LMFAO!!! You go Dude!!! You're right, of course... someone has set them up for a very hard fall....
Does the foundry mark look like this?
That's it! What is this metal?
This mark only identifies the foundry that cast the part. The mark was originally used by Ohio Foundry Co., but is now owned by another company. I think it may be WHEMCO Ohio Foundry, but have not found out for sure. If you took the word "OHIO" and stacked the letters all on top of each other, that what this mark looks like.
I would be curious, are these used as superheater tube alignment clips?
Charles
Yes. They are superheater tube alignment clips. Field construction bandages on an old coal fired plant .
We run into the use of these "alloy" clips all the time.
Over the years we have found that it is better to qualify the installation by fillet weld (or by a production scale mockup) using E7018-A1. The reason for that approach has been that when you qualify the installation with a butt weld procedure, the tensile strength requirements prohibit the use of 7018-A1 (which acts like a sacrificial filler metal if the clips become bound in service). Our clients would rather have the weld fail than to have the weld rip a chunk of boiler tube out as the expansion occurs.
I hope this ins't too confusing.
Charles
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