If the connection using a double-headed stud and a single nut cannot be disassembled and heating is required, where should the heating be applied? Screw stud or nut?
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The two devices are connected using double-headed studs and nuts; one end of the stud is screwed into a threaded hole in one of the devices, while the other end passes through a hole in the other device and is secured with a nut. The nut is too tight to remove at the moment; I plan to use gas welding to heat it before trying to take it off. Which part should be heated – the stud or the nut?
Have you tried a loosening agent? Burn the nut
Heating is not recommended. Heating the stud only exacerbates the seizure between the nut and the stud. If the nut is heated, although it will expand slightly due to heat, its strength will decrease while its plasticity will increase, which is likely to lead to more severe interlocking. It is best to use a coolant to cool the studs, with liquid carbon dioxide being an appropriate choice. We have encountered similar problems before, and we were able to remove the nuts successfully using this method.
It can be removed using a bolt breaker
Shouldn’t heating the screw stud cause it to elongate, thereby creating a gap between the nut and the mating surface, making it easier to loosen? For stud cooling, is it actually effective for the stud to shorten? !
So I still don’t quite understand how thermal expansion and contraction affect the tightness of studs and nuts. Why do bolts and nuts need to be tightened thermally? Isn’t it because the thermal expansion of the bolt itself is greater than that of the equipment, which creates gaps at the tightening contact surface and thus reduces the original tightening torque, requiring re-tightening? In that case, wouldn’t it be more logical to heat the stud part?
Nut: When heated, the nut expands outward, and so does its inner diameter. But first, it involves using a loosening method: spraying a loosening agent or soaking in kerosene, and then hitting it from the left and right.
It’s not that reason; it’s that the tightening torque is simply too high, 15,000 NM! When loosening, a greater torque is required – so great that it even cut through the drive shaft of an imported Empark electric hydraulic wrench! There’s really no other way.
Generally, we use a rust remover spray; after some time, we strike it with a impact wrench to remove it, as heating is rather troublesome.
This question is interesting. It doesn’t make much sense that an excessive torque prevents the nut from being loosened; the torque required to loosen it should be less than the torque required to tighten it.
If nothing else works, use oxy-acetylene welding to cut it off, or saw it off with a saw! ! ! ! ! ! Bolts generally aren’t very valuable