No, it does not get flipped automatically. When face-down monsters are Tributed, they are sent to the Graveyard without being flipped face-up first.

If you want to activate the Flip Effect of your monster before Tributing it, you have to manually Flip Summon the monster during your Main Phase, then Tribute it. You cannot Flip Summon a monster if it was placed on the field this turn by the turn player (a card can be flipped during the same turn if control changes), OR if that card already declared an attack or manually changed its Battle Position (Book of Moon does not count as "manually" changing its Battle Position). You cannot use the card Ultimate Offering to flip your monster (you can never use Ultimate Offering in this way), then Tribute Summon. A Flip Summon is not counted as a "Normal Summon or Set per turn."

Effects of monsters that activate when they are "sent to the Graveyard" (such as Sangan) still will activate even though the monster was face-down. However, if the card says something like "when this face-up card is sent to the Graveyard", then it will not activate if it was face-down. In addition, if the card says something like "when this card is destroyed and sent to the Graveyard", then it will not activate if it was Tributed. Tributing does not count as "destroying", but it does count as "sending to the Graveyard" and "removing from the field".