The bolts need a hollow hole drilled lengthwise in the center. The bolt heater is slipped in and electricty applied. After a calulated time, the bolt will reach full temperature and elongate. You then snug the bolts, basically "hand tight", then turn off the juice and pull the heaters.
Flieger may be right, Inconel may not stretch as much as you need for this application. Someone from a bolt heating company will need to look at your application.
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Talk to these guys. I think they will be able to run the calculations.