The present invention relates to a HRB500 and HRB500E coiled reinforcing steel bar production process, which comprises the following process: A, heating a steel billet, wherein three-stage type heating is adopted, the steel billet adopts V or VN microalloying, a size is 150 mm*150 mm, a temperature of a first-stage heating segment of the steel billet heating process is 800-950 DEG C, a temperature of a second-stage heating segment is 950-1100 DEG C, and a soaking segment temperature is 1050-1150 DEG C; B, carrying out temperature control rolling, wherein a rolling starting temperature is 950-1050 DEG C, a finish rolling starting temperature is controlled to 850-930 DEG C, and a final rolling speed is controlled to 27-100 m/s; C, carrying out temperature control cooling, wherein a laying temperature is controlled to 820-870 DEG C, a cooling fan is opened to carry out rapid cooling, a cooling rate is controlled to 8-25 DEG C/sec, a final cooling temperature is controlled to 650-680 DEG C, and natural cooling or slow cooling is performed; D, collecting the coiled material; E, inspecting; and F, packaging. The process has characteristics of controllable process, low production cost, and high production efficiency, wherein yield strengths of the produced HRB500 and HRB500E coiled reinforcing steel bars are more than or equal to 500 MPa, tensile strengths are more than or equal to 630 MPa, yield strength ratios are more than or equal to 1.25, elongation rates are more than or equal to 15%, the total elongation rates under the maximum force are more than or equal to 9.0%, performance indexes are excellent, and the produced HRB500 and HRB500E coiled reinforcing steel bars are uniform and stable.

HRB500 and HRB500E coiled reinforcing steel bar production process

The invention relates to a smelting technology of III grade hot-rolled ribbed bars. The invention belongs to the technical field of steel smelting. The technical scheme of the invention is that: vanadium-containing molten iron is adopted as a raw material; a vanadium increasing process in a bar production procedure is divided into two steps that: first, during a steel producing procedure, vanadium slag extracted from the vanadium-containing molten iron is added, and vanadium elements are reduced and added into molten steel, such that first-step vanadium increasing is carried out; second, when steel is discharged from a converter, vanadium-containing molten iron is directly poured into the ladle, such that second-step vanadium increasing is carried out. During the process, the vanadium elements in the vanadium-containing molten iron are directly converted into the vanadium elements in the vanadium-containing molten steel. The vanadium alloyed raw materials (the vanadium slag and the vanadium-containing molten iron) are internal materials sourced from a steel refinery. With the composite vanadium increasing method, a problem of high cost in the production process of the III grade hot-rolled ribbed bars is solved. The produced ribbed bars satisfy both the performance requirement and the shock resistance requirement. With the method, direct and highly efficient utilization of rare resources is realized, the technology process is reduced, the production efficiency is improved, and the production cost is reduced.

Smelting technology of III grade hot-rolled ribbed bars

HRB600E aseismic reinforcement steel bar and production method thereof

Corrosion-resistant hot-rolled ribbed steel bar with yield strength not less than 600Mpa and production method thereof

The invention belongs to the field of iron and steel metallurgy and steel rolling, particularly relates to a 500MPa-grade aseismic microalloy steel bar containing V and having a high strength-yield ratio and a production method thereof, and aims to solve the technical problem of low strength-yield ratio of the existing 500MPa-grade aseismic alloy steel bar containing vanadium and nitrogen. The 500MPa-grade aseismic microalloy steel bar containing V and having the high strength-yield ratio is prepared from the following components: 0.20-0.25% of C, 0.35-0.65% of Si, 1.20-1.60% of Mn, 0.070-0.170% of V and 0.0100-0.0120% of N. The production method of the microalloy steel bar is mainly characterized by adding vanadium-nitrogen alloy and FeV in a steel tapping process for controlling the contents of N and V in molten steel to be in a certain range; meanwhile, a subsequent rolling process is matchoed. The produced steel bar is high in lower yield strength surplus and excellent in aseismicperformance; the strength-yield ratio of the steel bar reaches 1.40 or above.

500MPa-grade aseismic microalloy steel bar containing V and Nb and having high strength-yield ratio and production method thereof

The invention relates to a 600-MPa grade vanadium-containing high-strength hot-rolled steel bar and a production method thereof, and belongs to the technical field of metallurgical steel-making and processing; the technical scheme is that the steel bar is prepared by the following components by mass: 0.21-0.25% of C, 0.35-0.60% of Si, 1.35-1.55% of Mn, 0.08-0.12% of V, 0.005-0.04% of N, not more than 0.040% of S, not more than 0.040% of P, and the balance of Fe and inevitable impurities; by adopting vanadium-increasing, nitrogen-increasing, and nitrogen-fixing processes during the smelting process, and by decreasing the initial rolling temperature and the finish rolling temperature during the rolling process, fine-grain, solid-solution and precipitation strengthening are realized at a lowtemperature and a high pressure, so the strength is increased; the hot-rolled steel bar contains a dual-phase structure of ferrite and pearlite, wherein the pearlite accounts for 25-50%; good cooperation of strength and toughness can be reached by controlling ratios, forms and sizes of the phases.

600-MPa grade vanadium-containing high-strength hot-rolled steel bar and production method thereof

The invention discloses a 400MPa-level vanadium-containing anti-seismic anti-corrosion rebar and a production method thereof The rebar is prepared from, by weight, 010-021% of C, 030-080% of Si, 10-160% of Mn, 06-10% of Cr, 005-040% of Cu, 0020-010% of V, and the balance Fe and unavoidable impurities, the amount of P is smaller than or equal to 0030%, and the amount of S is smaller than or equal to 0030% The production method includes converter or electric furnace smelting, steel ladle microalloying, external refining, continuous casting, casting blank heating, rolling and cooling bed air cooling The corrosion resistance of the rebar is improved by controlling the content of Cr and Cu in steel, technological parameters are controlled strictly, the V(C,N) precipitation strengthening effect is promoted under the condition of ensuring steel-plastic tenacity, and the 400MPa-level vanadium-containing anti-seismic anti-corrosion rebar excellent in performance is obtained

400MPa-level vanadium-containing anti-seismic anti-corrosion rebar and production method thereof

Control method for vanadium extraction by converter for removing vanadium and holding carbon

The invention discloses a method for increasing the nitrogen content in a vanadium-containing steel bar. The method comprises the following steps: performing ladle bottom nitrogen blowing stirring in the converter tapping process, adding a deoxidant in the steel ladle in the tapping process to control the oxygen activity of the molten steel to below 30 ppm, and adding the converter vanadium-containing slag to perform vanadium alloying so that the nitrogen content of the molten steel is 70-90 ppm before LF refining; in the LF converter refining process, adding ferrovanadium nitride to adjust the vanadium content in the molten steel, simultaneously stirring the molten steel by adopting the ladle bottom nitrogen blowing to substitute the bottom argon blowing to finally control the nitrogen content in the molten steel to 130-220 ppm. The nitrogen content is increased in the converter tapping-LF refining process so that the nitrogen content in the steel is controlled to 130-220 ppm; the vanadium alloying is performed by the converter vanadium-containing slag so that separation out of vanadium nitride from the steel is promoted. The steel performance is obviously increased, the alloy adding amount is reduced and simultaneously the production cost of the vanadium-containing steel bar is reduced.

Method for increasing nitrogen content in vanadium-containing steel bar

The invention relates to a method for producing microalloy steel by using rare elements in molten iron, in particular to a method for producing the microalloy steel by using trace elements such as V and Ti in the molten iron at high efficiency, and belongs to the technical field of metallurgy. The technical scheme is that: starting from the point of view of reducing steelmaking production cost, the resource advantages of the vanadium- and titanium-containing molten iron are exerted, the application flow of the microalloy elements such as V and Ti in the microalloy steel is changed, the rare elements such as [V] and [Ti] in the molten iron are directly added into molten steel in a mode of pouring the vanadium- and titanium-containing molten iron into a ladle, beneficial elements such as [C], [Si], [Mn] and [Cr] are added into the molten steel additionally, the molten iron is directly converted into the molten steel, the microalloy steel is produced at short flow and low cost, and the rare elements such as V and Ti in the molten iron are efficiency and fully utilized, so that the method for producing the microalloy steel is high-efficiency and low-cost. The method solves the problemthat the Ti element in the vanadium- and titanium-containing molten iron is difficult to extract and recycle, avoids the problem that partial vanadium element in the molten iron is partially lost in the extraction process, and has the advantages of vanadium and titanium increase, stable absorptivity, reduction of steelmaking cost and increase of steel yield.

Han Chunliang

Papers

600-MPa grade vanadium-containing high-strength hot-rolled steel bar and production method thereof

400MPa-level vanadium-containing anti-seismic anti-corrosion rebar and production method thereof

Control method for vanadium extraction by converter for removing vanadium and holding carbon

Method for increasing nitrogen content in vanadium-containing steel bar

Method for producing microalloy steel by using rare elements in molten iron