what kind of steel did you compare it to? different steel compositions and different hardening techniques can change the malleability and strength of steel.
so basically that attack delivered 42 Megatons of force to push Saitama through the spaceship. That's nearly as much as what the Tsar Bomba delivered when it was detonated, 50 megatons, and that was history's biggest man made explosion.
Now I wanna figure out the math behind Saitama's serious series punch that happens just after that. He ************* cleared the clouds in the sky because of how powerful that punch was.