Steelwallet are not affected by X-ray machines in the airport ,it is an electronic device , it's like
a small PC,  the security personnel can not start dismantling your PC or laptop during inspection which is not done or normal.

Steelwallet is more of a backup tool offline , which is used to store your recovery words, steelwallet preserve your seed from fire,water, electric shock e.t.c. Aside from the steelwallet you have to get another means of backup for your seed