The questioner asks:

“What is Salafiyyah? Is it a Hizb? What is the ruling on ascribing to it?”

Al-‘Allâmah Sâlih al-Fawzân:

“Salafiyyah is the original affair. The madhab of the Salaf as-Sâlih (pious predecessors) – the Muhâjirûn and the Ansâr and those who followed them exactly (in Faith). (At-Tawbah 9:100). It is the original affair and whoever opposes it and exits from it is misguided. This ummah will split into 73 sects, all of them in the hell fire except for one; they (i.e. the companions) asked, “Who is it?” He said, “The one upon what I and my companions are upon today.” This is Salafiyyah; what the prophet – صلى الله عليه وسلم – and his companions were upon, and the Imams who came after them. This is Salafiyyah and it is the original affair. It is not what they say – a sect from the sects. No! It is the original affair and the sects are the ones that have split from it. Yes.”

http://www.salaficentre.com
http://www.learnaboutislam.co.uk