Is there biblical evidence of seraphims being angels?

I have heard angels and seraphim being used interchangeably. is there any biblical evidence that they are different or the same? The only verse I know off the top of my head is Isaiah 6:2 > Isaiah 6:2 Above it stood the seraphim: each one had six wings; with twain he covered his face, and with twain he covered his feet, and with twain he did fly. (KJV) My question is whether angels and seraphim are the same thing or not, and why.