What is the quality difference between round bar and screw steel?
Physical and mechanical properties are different. Because of the different chemical composition and strength of reinforcing steel, they are different in physical and mechanical properties. The cold bending property of steel is good, can make the hook 180, screw steel can only make straight hook 90 degrees; steel weldability is good, with ordinary carbon steel electrode can be used to low alloy electrode; anti fatigue performance and toughness in steel bar is good.
Different grades of steel (different chemical composition). Round steel (HPB235) is carbon steel, steel is Q235; thread steel is low alloy steel; HRB335 grade steel is 20MnSi (20 manganese silicon); HRB400 grade steel bars are 20MnSiV or 20MnSiNb or 20MnTi etc.;
Different shape. The outer surface of the round steel is smooth; the outer surface of the spiral steel has a spiral rib. 2. different production standards. In the current standard, round bar that HPB235 grade steel, and its production standards are "hot-rolled smooth steel reinforced concrete" (GB13013); rebar generally refers to HRB335 and HRB400 grade steel, its production standard is "the reinforcement of concrete hot rolled ribbed bar" (GB1499). 3. different strength. The design strength of round steel (HPB235) is 210MPa; the strength of thread steel is higher than that of round bar; the design strength of HRB335 is 300MPa; the design strength of HRB400 is 360MPa.
