claiming a draw

Sorry if this sounds naive but, I thought that you could claim an automatic draw after 50 half-moves with a solo king. In a recent match I tried to do this but it didn't work. Can anyone clarify this for me? Is a player who turns down a draw in these circumstances being unfair or impolite?

Its 100 half moves and not 50. Draw can be claimed after 100 half moves, but in those 100 half moves, there shouldn't be a capture nor a pawn move from any of the players...the no. of pieces are not a criteria..