I Want my phone to be replaced using my warranty. My battery has a problem and phone signals/ antenna has a problem too. But my iPhone 5 has huge dents in the corners and buffs and scratches to its sides. But its not hugely damaged. Will Apple refuse service to my iPhone ?
You need to take it to the Apple Store. They will then make the decision whether to replace it under warranty or replace it as an out of warranty service due to the physical damage for a fee. Nobody can give you a definite answer you will just need to see what they say when you go to the store.
An out of warranty service is the process of replacing a faulty device not covered by warranty and involves a fee. Just like in your case with physical damage as this is something that is not covered by the 1 year limited warranty of the iPhone.