Hot‑rolled deformed steel bars, commonly known as rebar, have longitudinal and transverse ribs on the surface and a solid round cross‑section. They are supplied in straight lengths or coils and are abbreviated as HRB. Common grades include HRB400 and HRB500, where the numbers indicate the yield strength, and the suffix “E” denotes seismic (earthquake‑resistant) grade. They are mainly used in the construction industry, combined with concrete to withstand compressive, tensile, and bending stresses.