Friedman, from the Bronx, New York, started the pioneering punk band The Dictators in 1972. Eight years later, he started the heavy metal band Manowar with Joey DeMaio.
He left Manowar in the late 1980s and has since toured under his own name and in reunions of The Dictators.
In February, Friedman announced he was suffering from the neurological disease ALS.
"Ross was a pioneer in both punk and heavy metal," reads a statement from the Metal Hall of Fame.
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