What are the Ahadith regarding recitation of Surah Kahf? Is there any special significance for reading it on Friday?

Regarding the recitation of Surah Kahf, both narrations of reciting it from memory and also from the Quraan itself exist in the hadith.
a) ibn Mardawaih reports from ibn Umar marfooan: He who recites Surah Kahf on the day of Jumuah, nur (light) will be spread out for him from below his feet till the sky, it will shine for him till the Day of Judgement and hsi sins between the two Jumuahs will be forgiven for him.

In Tafseere Roohul Ma'ani vol.8 pg. 288, under the tafseer of Surah Kahf, there are three Ahaadith which support the recitation of Surh Kahf from the Quraan and there also appear a few narrations on reciting from memory.

3) Surah Kahf can be recited on the night of Jumuah (Thursday night) or on the Day of Jumuah. Narrations regarding its recitaiton at both times are found in the treasure of Ahaadith.

a) ibn Mardawaih reports from Abdullah ibn Mughaffal marfooan: The home in which Surah Kahf is recited, shaitaan does not enter that house on that specific night. (Roohul Ma'ani, vol. 8, pg. 289).

Many Ulama are of the opinion that it is sunnat to recite Surah Kahf on the Day of Jumuah and on the same token, many are of the view that is sunnat to recite it on the Night of Jumuah and they also state that it will be commendable to read it at both times. (Roohul Ma'ani, vol.8 pg. 289).

and Allah Ta'ala Knows Best

Mufti Ebrahim Desai