32results about How to "High flex ratio" patented technology

The invention relates to a method for producing the fine grained dual phase steel, especially by low carbon(manganese) steel. The method comprises making the common low carbon(manganese) steel austenization, obtaining small austenitic organism after multi-pass deformation of recrystallized zone, over-cooling to a certain temperature in the temperature range of A3-Ar3 by proper cooling speed to apply multi-pass deformation with a strain rate between 0.1s-1 to 30s-1, getting 80-90% ferrite transforming mass by controlling each pass dependent variable, then quickly cooling or quenching to the room temperature. The average dimension of isometric ferrite grain in fine grained dual phase organism is less than 5 mum. The Martensite island integration number is 10-15% and the average dimension is less than 3 mum. The method is more controllable and is easy to apply on the conventional hot mill.

The invention discloses a HRB600E reinforcement steel bar and a production method thereof. The reinforcement steel bar consists of the following elements in percentage by weight: 0.20-0.28 percent of C, 1.30-1.60 percent of Mn, 0.30-0.80 percent of Si, 0.80-0.12 percent of V, less than or equal to 0.020 percent of S, less than or equal to 0.030 percent of P, 0.05-0.40 percent of Cr and the balance of Fe and inevitable impurities. The production method comprises a smelting procedure, a continuous casing procedure and a steel rolling procedure. In the smelting procedure, molten steel in a ladle is alloyed, so that the molten steel contains 0.08-0.12 percent by weight of V and 0.05-0.40 percent by weight of Cr. The vanadium content of the reinforcement steel bar is reduced by about 30-40 percent than the vanadium content of a reinforcement steel bar with the same level of yield strength, and the reinforcement steel bar has the advantages of high yield strength, high tensile strength, high yielding-to-tensile ratio, high specific elongation and the like.

The invention relates to the technical field of hot-rolled ribbed steel bars, and discloses steel for a 635 MPa level high-strength hot-rolled steel bar. The steel is prepared from, by weight, 0.22-0.30% of C, 0.50-0.80% of Si, 1.40-1.60% of Mn, not larger than 0.025% of P, not larger than 0.025% of S, 0.015-0.035% of Nb, 0.105-0.145% of V, 0.15-0.35% of Cr, 0.018-0.025% of N and the balance Fe. According to the steel for the 635 MPa level high-strength hot-rolled steel bar and a machining method thereof, by adopting C, C is a cheap element, the strength of the steel can be remarkably improved, the extension performance of the steel can be lowered, meanwhile, the cold brittleness and aging sensitivity of the steel are improved, the integrated ingredients are reasonable, the comprehensive performance of the whole steel is improved, the stability of the steel performance is enhanced, the overall performance of the steel on the aspects of yield strength, tensile strength, the high yield ratio, the percentage elongation after fracture, the total elongation percentage under the maximum force and the like is good, meanwhile, the steel metallographic structure is ferrite+pearlite, the granularity is 11.5, the good fatigue resistance is achieved, the steel is suitable for large-scale industrial production, and benefits are remarkable.

The invention relates to a reinforcement bar and a production technology thereof, in particular to a high-strength hot-rolled reinforcement bar of the 830 MPa level, and a production technology of the reinforcement bar. The reinforcement bar comprises the following chemical components by weight: 0.38 to 0.43% of C, 0.7 to 0.9% of Cr, 0.6 to 0.8% of Mn, 0.15 to 0.25% of Mo, 0.2 to 0.3% of Si, 1.6 to 2% of Ni, 0.035% of S, 0.035% of P, 0.035% of N and the balance of Fe. The shear strength of the reinforcement bar can reach 830 MPa; the reinforcement bar has the advantages of high strength, good ductility, high lagging and fracture resistance, economy of steel material, underrelaxation, easiness in welding, high upset performance and the like, can enable carbide to dissolve fully and diffuse uniformly, and avoids that intercrystalline corrosion and pitting exceeding are caused due to intercrystalline separation of carbide.

The invention provides an HRB500E ordinary-speed hot-rolled ribbed steel bar with a tensile-to-yield ratio greater than 1.28 and a production method thereof. The production method of the HRB500E ordinary-speed hot-rolled ribbed steel bar with the tensile-to-yield ratio greater than 1.28 comprises the following process stages which are sequentially conducted: blast furnace molten iron smelting, molten iron desulfurization pretreatment, converter molten steel smelting, LF refining, square billet continuous casting and hot continuous rolling. The HRB500E ordinary-speed hot-rolled ribbed steel bar is prepared from the following components in percentage by weight: 0.19 to 0.25 percent of C, 0.60 to 0.80 percent of Si, 1.45 to 1.60 percent of Mn, less than or equal to 0.040 percent of P, less than or equal to 0.035 percent of S, 0.065 to 0.10 percent of V, 0.010 to 0.022 percent of Nb, 0.008 to 0.020 percent of N, and 0.0020 to 0.0050 percent of B. The specification of the ordinary-speed hot-rolled ribbed steel bar is 10 mm to 40 mm. The cooling bed cooling mode is natural cooling. The HRB500E ordinary-speed hot-rolled ribbed steel bar with the tensile-to-yield ratio greater than 1.28 and the production method of the HRB500E ordinary-speed hot-rolled ribbed steel bar with the tensile-to-yield ratio greater than 1.28 are adopted.

The invention discloses an earthquake-resistant steel bar. The earthquake-resistant steel bar is characterized by being prepared from, by weight percent, 0.21%-0.24% of C, 0.45%-0.55% of Si, 1.45%-1.55% of Mn, 0.018%-0.032% of Nb, not larger than 0.045% of P, not larger than 0.045% of S and the balance Fe and impurity elements. According to the earthquake-resistant steel bar, under the condition of guaranteeing that the need of the mechanical property is met, different element composition proportions are adopted according to different diameter specifications, the niobium content is reduced, and therefore the use level of niobium and iron is reduced, the production cost is reduced, and economic benefits are improved.

The invention provides a high-N composite reinforced 500MPa-grade and 600MPa-grade steel bar, a smelting method and a production method. Smelting is conducted by adopting a smelting process, in the converter smelting tapping process, according to the amount of 2.5-4.0 kg per ton of steel, high-nitrogen ferrovanadium alloy FeV30N14 with N being 14%-16% in content, V being 29%-31% in content and thebalance Fe and inevitable impurities is added, according to the amount of 0.2-0.25 kg per ton of steel, ferroniobium with Nb being 63.0%-65% in content by weight percentage is added, so that the V/Nratio of molten steel is controlled to be 3.49-3.83. According to the high-N composite reinforced 500MPa-grade and 600MPa-grade steel bar, the smelting method and the production method, vanadium nitrogen and ferroniobium in the prior art are replaced with the high-nitrogen ferrovanadium alloy (FeV30N14) and the ferroniobium, so that the nitrogen content in the steel just reaches a theoretical value, the V (N, C) precipitation strengthening effect is fully exerted, and the purposes of saving vanadium and reducing the cost are achieved.

The present invention provides a high-strength hot-rolled profile. The high-strength hot-rolled profile comprises the following chemical compositions of: 0.14-0.25% of C, 1.40-1.80% of Mn, 0. 40-0.60%of Si, 0.075-0.095% of V, less than or equal to 0.045% of P/S, 0.0215-0.025% of N, 0.015-0.020% of Nb, and the balance Fe and inevitable impurities. The V/N ratio of the chemical composition of the hot-rolled profile is 3.49-3.83. The hot-rolled profile also comprises chemical components B and Cr, the chemical composition of B being 0.0015-0.005%, and the chemical composition of Cr is 0.6-0.7%. According to the invention, the chemical compositions and rolling processes are adjusted on the basis of a common profile, and the comprehensive performance of the profile is improved.

The invention discloses an economical 500MPa-grade steel bar and a preparation method thereof. The economical 500MPa-grade steel bar comprises 0.20-0.25 wt% of C, less than or equal to 1.60 wt% of Mn,less than or equal to 0.80% of Si, less than or equal to 0.045% of P, less than or equal to 0.045% of S, more than or equal to 0.05% of Ti and the balance iron and inevitable impurity elements. The key Si content of the preparation method is achieved by silicomanganese and ferrosilicon alloy, and ferrotitanium is added in the tapping process; and compared with an existing 500 MPa-grade traditional vanadium and niobium hot rolling process, the alloy consumption is low, no precious metal element is contained, economical efficiency is achieved, and the cost can be reduced.

The invention discloses hot-rolled H-shaped steel for a buckling restrained brace and a production process. The hot-rolled H-shaped steel for the buckling restrained brace comprises, by mass, 0.09-0.12% of C, 0.19-0.22% of Si, 0.57-0.60% of Mn, less than or equal to 0.015% of P, less than or equal to 0.015% of S, 0.020-0.035% of V, less than or equal to 0.0080% of N, and the balance Fe and inevitable impurity elements. The production process of the H-shaped steel comprises the steps of blast furnace molten iron treatment, molten iron pretreatment, converter smelting, argon blowing station treatment, LF refining, special-shaped blank full-protection casting and H-shaped steel rolling. The hot-rolled H-shaped steel is narrow in yield strength range, large in yield ratio, good in extensibility and low in production cost.

The invention discloses a HRB500E anti-seismic rebar rolling method. The method includes a heating process, a rolling process and a cooling process. In the heating process, the temperature of a raw material before being fed into a heating furnace is lower than 500 DEG C, a raw material heating temperature ranges from 1200 DEG C to 1250 DEG C, the time of the material in the furnace is 70-100 minutes, and the heating furnace adopts a reducing atmosphere. The cooling process adopts a natural cooling manner. By the HRB500E anti-seismic rebar rolling method, weakening of intercrystalline binding force and excessive thinning of crystalline grains can be effectively avoided, dislocation density is reduced, and increase of yield-tensile ratio and avoidance of surface cracks are realized. The HRB500E anti-seismic rebar rolling method has the advantages of technical simplicity, excellent mechanical property, high product yield and the like, product production cost can be effectively reduced, and product quality is improved.

The invention discloses a 500Mpa large-scale straight threaded steel and a preparation method thereof. The chemical composition of the threaded steel contains: C: 0.22-0.25%, Si: 0.40-0.60%, Mn: 1.35-1.60% in mass percentage , P≤0.045%, S≤0.045%, V: 0.100~0.120%, N: 0.010%~0.020%, the rest is Fe and unavoidable impurities; the preparation methods include converter smelting, argon blowing and stirring, continuous casting, heating, Phosphorus removal and rolling; in the heating process, the furnace temperature in the preheating section is controlled to be 500~900°C, the furnace temperature in the heating section is 1100~1180°C, the furnace temperature in the soaking section is 1130~1180°C, and the heating time is 80~150min; In the rolling process, the rolling start temperature is 1000~1100°C, and the rolling speed decreases with the increase of the diameter of the straight rebar. The present invention eliminates or compresses the reticular ferrite in the finished straight rebar through proper heating temperature and rolling process to a very small range in the core, significantly improves the microstructure of 500MPa large-scale straight rebar, and ensures Its strength and bending properties meet the requirements.