A ring of the present invention comprises: an outer ring divided into first and second outer rings formed in mutually corresponding shapes, the outer ring being formed of a mixture prepared by mixing a tungsten carbide, a second carbide consisting of a combination of an iron-based carbide and a carbon nitride, and a metal binder phase at a specified ratio; an inner ring removably assembled between the first and second outer rings, the inner ring comprising an outside inner ring that forms the outer circumferential surface of the ring and an inside inner ring that forms the inner circumferential surface of the ring; ring insertion parts formed in the first and second outer rings, respectively, such that opposite portions of the outside inner ring and opposite portions of the inside inner ring are inserted into, and coupled to, the ring insertion parts; and assembly protrusions formed in the first and second outer rings, respectively, and inserted into the outer circumferential surface of the inside inner ring
