Yes, there's a technical name for it. Coined by Mort Walker, the creator of Beetle Bailey, in a 1964 article "Let's Get Down to Grawlixes" in the newsletter of the National Cartoonists Society in the US. This was later reprinted (expanded?) in The Lexicon of Comicana. The coinage, along with several others such as jarns, quimps, and nittles, all of them making typographic distinctions among obscenities, was intended to be satirical, but has since adopted for real. Why grawlix, which originally meant a spiral symbol, was the one that came to mean any sort of such substitution is a @#$%&*ing mystery, though the title of the original essay may have had something to do with it.
I shouted @#$%&?! when I banged my elbow, and while Mom was all, Watch your bleeping mouth, Dad was just, Nice grawlix son.