The two hit thing would basically be for the same general "power level" between what's getting hit and what's doing the hitting, right? In that context alone it is good (although I haven't heard of a weapon breaking after two strikes outside of display swords, but maybe I'm wrong). 
Other then this scenario there would be no point with a steel weapon that would break in two hits, the same as an iron weapon, or a weapon made out of dragon scales. Then you have to consider if the Hulk is punching you, you can't have his punch deflected twice by an iron sword. Basically, there's an insane number of variables to consider. So your two hit could be used as a base and then determine how many more or less hits from that amount would be needed depending on what you know of the situation. The number can vary so wildly that I can see some things taking hundreds of hits while others shattering instantly, such as the Hulk against an iron sword.