Analysis of traditional production process characteristics of HRB400 Ⅲ Ⅲ grade hot rolled ribbed bar

V, Nb, Ti and other alloys were added to the third grade rebar (20 MnS uli, 400Mpa) in the production process. Compared with ordinary grade II threaded steel bars, it has the advantages of high strength, good toughness, good weldability and good seismic performance. In the construction market of developed countries such as Europe, grade ⅲ rebar accounts for 80% of the total rebar. 1995, the former Ministry of Metallurgy and the Ministry of Construction jointly issued a document to promote its application, and the Ministry of Construction incorporated the technical conditions of new grade III threaded steel bars into the national standard GBJ 10-89 Code for Design of Concrete Structures.

Advantages of V-bearing Grade Ⅲ rebar

A. Economy: Compared with the second grade rebar, the new third grade rebar can save steel 10- 15% due to its high strength, thus reducing the construction cost of building projects.

B, high strength and good toughness: after microalloying treatment, the yield point is above 400Mpa, and the tensile strength is above 570Mpa, which is 20% higher than that of secondary rebar.

C. Earthquake resistance: Vanadium-containing steel bars have high bending resistance, aging resistance and low cycle fatigue performance, and the earthquake resistance is obviously superior to grade II rebar.

D, easy welding: because the carbon content is less than or equal to 0.54%, it has good welding performance, is suitable for various welding methods, and the process is simple and convenient.

E. Convenient construction: new three-level threaded steel bars are adopted to increase the construction gap and ensure the convenience and quality of construction.