Fasterner's tighening torque measurement in real time at high temperature
Fasterner's tighening torque measurement in real time at high temperature
(OP)
Dear all,
Does anyone know how to measure the fastener’s torque at 1200 degree Celsius or even higher?
Are there any torque transducers about this? Or are there any companies can provide this kinds of service?
Thank you.
Does anyone know how to measure the fastener’s torque at 1200 degree Celsius or even higher?
Are there any torque transducers about this? Or are there any companies can provide this kinds of service?
Thank you.





RE: Fasterner's tighening torque measurement in real time at high temperature
RE: Fasterner's tighening torque measurement in real time at high temperature
Why would a torque wrench not work? How big is the thing that is at 1200°C? Can you work near to it?
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JHG
RE: Fasterner's tighening torque measurement in real time at high temperature
I consulted companies such as HBM and they all said their torque transducer cannot used at such high temperature.
The contact pressure transducers as far I know cannot used at such high temperature either.
There may be some indirect measuring method.
Thank you again for your response.
RE: Fasterner's tighening torque measurement in real time at high temperature
RE: Fasterner's tighening torque measurement in real time at high temperature
Thanks.
RE: Fasterner's tighening torque measurement in real time at high temperature
It might be easier to look at creep and elastic properties of the materials in a tensile test machine with a high temperature section.
RE: Fasterner's tighening torque measurement in real time at high temperature
I am in agreement with 3DDave on this matter, it might be worth doing a calculation of thermal expansion of the components after the joint as been initially made, the calculation in my book would assume uniform heating although I don't know whether that's true or not in your case
I guess if uniform heating isn't applicable then you could use some heat transfer software to calculate what occurs in the joint.
Folowing my initial assumption I would calculate all the stresses in the joint and fastener at room temperature and then perform expansion calculations at the final temperature and check out the stresses both in the fastener and joint materials, loosening can be caused by the fastener going over its yield stress or the clamped materials going beyond yield.
If the temperature is cycled then the loosening might well be progressive.
“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein
RE: Fasterner's tighening torque measurement in real time at high temperature
One design of tension indicating bolt has a pin inserted into a hole through the center of the bolt. Tightening the bolt stretches it but not the pin. The difference in length between the pin and bolt is easy to measure, and there should be no temperature limit to this technique.
RE: Fasterner's tighening torque measurement in real time at high temperature
RE: Fasterner's tighening torque measurement in real time at high temperature
RE: Fasterner's tighening torque measurement in real time at high temperature
Perhaps one of the high resolution laser position sensors could be used for this also.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
RE: Fasterner's tighening torque measurement in real time at high temperature
EdStainless, you method may be ok to measure the rotation between the nut and the shank but cannot used to measure other tightening torque loosen mechanism such as the deformation of the fastener and the plates.
moon161,btrueblood , seems your method with long extension is the only direct method can be used now. I am still looking for some force sensors made of ceramics or Silicon that can withstand 1000 oC, but I did not find them yet. Anyway, I will try your methods if I have to.
RE: Fasterner's tighening torque measurement in real time at high temperature
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Because silver is the best thermal conductor ever, silver teapots need thermal isolator, otherwise you can't pick up the teapot.
RE: Fasterner's tighening torque measurement in real time at high temperature
RE: Fasterner's tighening torque measurement in real time at high temperature
RE: Fasterner's tighening torque measurement in real time at high temperature
You want to know if the connection loosens, well try to measure its position.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
RE: Fasterner's tighening torque measurement in real time at high temperature
RE: Fasterner's tighening torque measurement in real time at high temperature
moon161,thank you for your help and kindness.
EdStainless and IFRs, the optical method may be a good one. We thought of it and will try it when the condition is ok.
EdStainless,there usually be preload on the fastener and when the temperature-induced deformation of the fastener is larger than that of the joint plates, the fastener will loose. In this condition, both the clamping force of the fastener and tightening torque of the nut will decrease, therefore, the fastener loose can also be measured through the tightening torque of the nut. Also in this condition, there almost no relative movement between the nut and the fastener shank.
We can measure out the deformation of the fastener, but can not measure out the local deformation of the joint pleats around the hole. The area is under-covered by the nut and fastener head. The fastener loose is related to the contact relationship between the fastener and hole.
I also agree that different joint have different loosen mechanism and I will test out the loosen mechanism first.
Tmoose, sorry for the wrong information. The material of the joint plates are both ceramics matrix composite and the that of the fastener is high-temperate alloy. Ceramics fastener is a another design and will not be tested currently.
RE: Fasterner's tighening torque measurement in real time at high temperature
http://www.hitecprod.com/pages/straingage_hfp.html
The bondable strain gage is rated less than 1200 C, but they may have some suggestions.
Walt
RE: Fasterner's tighening torque measurement in real time at high temperature
Strong,thank you. The high temperature strain gage can also be used to measure clamping force of the fastener. This is one of the solutions I am looking for.
Though the clamping force of the fastener or the strain of the fastener shank cannot be measured directly since the shank is hidden inside the fastener hole, I can add a block between the nut and the joint plate and measure out the block's strain. With the selection of the material of the block and some calculations, the influence of the block can be decreased to be ignorable.
RE: Fasterner's tighening torque measurement in real time at high temperature
another day in paradise, or is paradise one day closer ?
RE: Fasterner's tighening torque measurement in real time at high temperature
Thank you for your contribution.
I now have 3 methods to try:
1)Measure the torque of the nut using long bar with heat insulating section;
2)Measure the torque of the nut firstly as it is cold, and then heat the joint and after certain heating cycles, cool the joint down and measure the torque again. Repeat this process again and again. This method can judge whether the nut is loosen or not after some cycles of heating but can not tell the torque value when the temperature is very high(about 1000 oC or higher);
3)Add a block between the nut and one of the joint plate, and measure the compression strain in real time using the high-temperature strain gages, and then eliminate the block's influence by selection the block(both dimension and material) and calculation.
Thank you all.
RE: Fasterner's tighening torque measurement in real time at high temperature
another day in paradise, or is paradise one day closer ?
RE: Fasterner's tighening torque measurement in real time at high temperature
RE: Fasterner's tighening torque measurement in real time at high temperature
http://www.boltscience.com/pages/untightening.htm
http://mguler.etu.edu.tr/MAK205_Chapter4.pdf
Above are a couple of sites that might help with your problem
“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein
RE: Fasterner's tighening torque measurement in real time at high temperature
“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein
RE: Fasterner's tighening torque measurement in real time at high temperature
is the question about preload or torque ? as torque in the nut won't change with temperature.
why the need to measure in the oven ? why not remove from oven (and handle with care) ?
another day in paradise, or is paradise one day closer ?
RE: Fasterner's tighening torque measurement in real time at high temperature
What I was alluding to with those links that it's possible to calculate the increased stresses in both the clamped parts and the bolt after assembly due to increased temperature, not sure how accurate it would be but you can calculate it by hand using the assumption for the area of the clamped parts being based on 2.5 times the bolt diameter (Roy Mech site).
I've used calculations in the past based on this and had no problems albeit my materials were copper or aluminium being clamped with steel bolts.
“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein
RE: Fasterner's tighening torque measurement in real time at high temperature
another day in paradise, or is paradise one day closer ?
RE: Fasterner's tighening torque measurement in real time at high temperature
RE: Fasterner's tighening torque measurement in real time at high temperature
hi 3DDave
I agree about the material properties however I get the impression they are all the same grade of ceramic but we need that confirming.
At least if OP does a ball park calculation by hand it gives a starting point the hand calculation might show the joint is a non starter but who knows.
“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein