how to solve problem

there a problem happen make me learn a lot today.

there was a screw can't get out from the hole. And LN2 can't be loaded into tank.

we try to get it out through spanner but fail

lesson 1 xiaowei say use LN2 cold it

lesson 2 the cold location is important and i didn't insist on, we should cold the screw instead of the hole

lesson 3 cold also fail, the core problem is the nut can't get out rahter than the screw can't get out, so jason advise cut the nut and use something to replace the broken screw, it can still seal.

i didn't figure out solution and just follow other word.