threads seizing... ideas why?
threads seizing... ideas why?
(OP)
we have a 1 1/4-12 unf 1B and a 1 1/4-12 unf class not specified on drawing but with a pitch limit of 1.194/1.193
the material is 1144 steel and the temp is about 1000F
customer is complaining about parts not being able to be taken apart after in service for some time
Any ideas why these threads would be seizing? Thanks
My initial ideas are to explore different materials and to go to a course thread.
the material is 1144 steel and the temp is about 1000F
customer is complaining about parts not being able to be taken apart after in service for some time
Any ideas why these threads would be seizing? Thanks
My initial ideas are to explore different materials and to go to a course thread.





RE: threads seizing... ideas why?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: threads seizing... ideas why?
on another there are 3 parts with 2 being 1144 and then a tip that is threaded that may also be having a problem seizing that is 316 ss. I wish I knew more exactly what was seizing... the customer has just complained and all I have to go by is the salesman coming back and saying that he is upset that parts cannot be taken apart...
RE: threads seizing... ideas why?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: threads seizing... ideas why?
RE: threads seizing... ideas why?
RE: threads seizing... ideas why?
RE: threads seizing... ideas why?
If so, that may somehow explain the problem
RE: threads seizing... ideas why?
Is there combustion product build up on threads (soot/coke)?
Diffusion bonding might be occurring.
RE: threads seizing... ideas why?
desertfox
RE: threads seizing... ideas why?
RE: threads seizing... ideas why?
RE: threads seizing... ideas why?
RE: threads seizing... ideas why?
I was thinking of maybe using some steel with some Mo and Cr in it too...
I think that antiseize is used during assembly at our shop... but I doubt the customer reapplies when servicing at the boiler front
RE: threads seizing... ideas why?
Ted
RE: threads seizing... ideas why?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: threads seizing... ideas why?
desertfox
RE: threads seizing... ideas why?
Actually a little higher temper might be beneficial.
We have multiple B 16 fasteners that operate at 600F and are subject to periodic heating to 1000F for 4-6 hrs at a time. Our standard thread lubricant is a water based DAG, Colloidal Graphite, applied by dipping prior to use and reuse. There are very few problems with breaking a joint. All bolts and studs 1" and above are 8 threads.
Here is a another high temperature thread lubricant, Thermo-O-Plate 220, we use especially on finer pitch threads and the higher alloy threads with elevated temperatures.
http:/
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RE: threads seizing... ideas why?
RE: threads seizing... ideas why?
Thats probably still to high a temperature for 2.25Cr steel, have a look on this link:-
http:
Is it possible that you could provide a sketch or drawing of your threaded joint along with some technical information like bolt preload, how the joint gets heated up, material properties etc.
desertfox
RE: threads seizing... ideas why?
RE: threads seizing... ideas why?
RE: threads seizing... ideas why?
rmw
RE: threads seizing... ideas why?
All our tips are 316 SS with a few exceptions where a higher alloy is used along with a 304 nozzle. Th threads are 6 TPI.
One thing I did many years ago was to use a metal O-ring gasket between the tip and nozzle for sealing. This helped to prevent distortion due different CTE and differential heating. I would definately try to get away from mating two lapped surfaces under your operating conditions. By using the gasket we were able to tap the threads oversize and undercut the male threads
Just before I left I made 2 nozzles from Nitronic 60 because they are used in a make and break application for cleaning. I don't have any results as they only have about 500 hrs in operation due to rocess changes.
RE: threads seizing... ideas why?
RE: threads seizing... ideas why?
RE: threads seizing... ideas why?
RE: threads seizing... ideas why?
RE: threads seizing... ideas why?
Looks like thread galling to me.
desertfox