No. There is a possible way for you to keep the armor but not the enchant. Enchanting was designed to have a 1/3 SUCCESS rate above +3 Enchants. Good luck with your enchanting =)
Blessed scrolls: enchants = Keeps the armor if failed but not the +.
Scrolls: enchants = Destroys the armor if failed and gets u crystals.
For more info look at:
http://www.lineage2.com/Knowledge/enhancements.html