A high-strength steel bar above 630mpa and its application method for reinforced concrete

Abstract

The invention discloses a more than 630MPa level high strength steel bar comprising the following components: by weight, 0.28%-0.38% of carbon, 0-0.35% of silicon, 0-0.90% of manganese, 0.80%-1.50% of Cr, 3.00%-4.00% of nickel, 0.40%-0.60% of molybdenum, 0-0.015% of P, 0-0.015% of sulfur, 0-2.0ppm of hydrogen, 0.10%-0.20% of vanadium, 0-0.025% of titanium, 0-0.20% of copper, 0-0.05% of aluminum, 0-0.50% of residual elements and the balance of Fe; the invention also designs an application method of the more than 630MPa level high strength steel bar in reinforced concrete; and the more than 630MPa level high strength steel bar has the advantages of high strength, steel saving, no pollution, good hardenability, low tendency to crack and low relaxation degree.

Description

technical field [0001] The invention relates to a high-strength steel bar above 630MPa level and an application method of the reinforced concrete. Background technique [0002] At present, steel bars for construction are used as steel for concrete structures. Most of the ordinary steel bars are HRB335 and HRB400 steel, and a small amount of HRB500 steel is used. Although the above-mentioned ordinary steel bars are widely used in house construction in my country, especially buildings (houses) Due to the low yield strength of the steel bars, the steel bars of the face plate are subjected to artificial active loads during the construction process, and the upper steel bars of the double-layer two-way steel bars are often bent and deformed, which cannot meet the structural restrictions on the protective thickness of the reinforced concrete, resulting in cracks, resulting in engineering Hidden danger to quality. [0003] In the prior art, the atomic activity of carbon and nitrogen ...

AI Technical Summary

Problems solved by technology

[0002] At present, steel bars for construction are used as steel for concrete structures. Most of the ordinary steel bars are HRB335 and HRB400 steel, and a small amount of HRB500 steel is used. Although the above-mentioned ordinary steel bars are widely used in house construction in my country, especially buildings (houses) Due to the low yield strength of the steel bars, the steel bars of the face plate are subjected to artificial active loads during the construction process, and the upper steel bars of the double-layer two-way steel bars are often bent and deformed, which cannot meet the structural restrictions on the protective thickness of the reinforced concrete, resulting in cracks, resulting in engineering Quality hidden danger

[0003] In the prior art, the atomic activity of carbon and nitrogen elements in the steel raw material composition is low, and the air mass formed by each atom cannot form a strong interaction with the dislocation, and the dislocation can be activated without providing a large external stress, so that the performance Very unstable, and at the same time, the hydrogen content in the forging steel bar is above 2.0ppm, and the forging steel bar is prone to cracks, which induces hydrogen-induced cracks and hydrogen-induced delayed hysteresis cracks

[0004]In the prior art, only a single quenching method is generally used, which cannot prevent the quenching cracking and internal cracking of the forgings, and at the same time, the carbides cannot be further fully dissolved and cannot be uniformly quenched. Diffusion, so that the precipitation of carbides between grains cannot be avoided, resulting in excessive intergranular corrosion and pitting corrosion, which affects the technical effect of the heat treatment process after smelting.