Caution: Always wear eye and ear protection at all times. If you aren't sure which power level to use then start with a lower level and work your way up. And remember that 1" of penetration into concrete is the rule of thumb. And yes, with the proper power level and correct length you can fasten to structural steel. But beware the noise and the recoil..
Increases bearing surface against material to be fastened for improved attachment to inconsistent base materials.