36results about How to "Reduce central porosity" patented technology

The invention discloses a method for improving center density of continuous cast slabs of high-level building steel. In the continuous casting process, the drawing speed of a casting machine is controlled to be 0.75 m / min-0.90 m / min; solidification tail end heavy reduction is adopted; dynamic secondary cooling control is adopted, and meanwhile, soft reduction and heavy reduction are adopted for carrying out reduction according to the distribution solid phase rate; and the superheat degree of tundish molten steel is controlled to range from 20 DEG C to 30 DEG C. According to the method, technical measures of stabilizing the drawing speed of the casting machine, reducing the superheat degree of tundish, carrying out secondary cooling dynamic control, carrying out solidification tail end heavy reduction control and the like are mainly applied comprehensively to reduce center porosity of the cast slabs of the high-building steel, then the center density of the cast slabs is improved, and internal quality of rolled materials is improved. For the cast slabs produced through the method, after implementation is carried out, the effect is better than that of an existing soft reduction technology, the center density is higher, the overall quality is better, and the use requirement of the high-building steel can be met better.

The invention discloses a production method capable of reducing dendritic segregation of a hot rolled coiled plate Q345B. The production method is characterized in that the hot rolled coiled plate Q345B comprises the following chemical components of, by weight, 0.06-0.12% of C, 0.4-0.59% of Mn, 0.06-0.15% of Si, less than or equal to 0.030% of P, less than or equal to 0.030% of S, 0.005-0.030% ofAls, 0.6-1.0% of Cr and the balance iron and unavoidable impurities. With respect to the matching ratios of the components, the contents of Mn and C are reduced, Cr is added and is used to exert solution strengthening and grain refining functions in steel, and a part of Mn and C is replaced, so that dendritic crystals and center segregation behaviors of manganese and carbon are weakened obviouslyunder the condition that the mechanical properties of strip steel are not affected, ferrite grains are refined, the spacing between pearlite pieces is reduced, the toughness and cold-working propertyof the steel are improved, the banded structure level of the rolled strip steel is lowered, the structure is refined, and the strength and mechanical property which meet the requirements are obtained.

The invention discloses a nickel brass strip. The nickel brass strip comprises, by weight percentage, 67%-73% of Cu, 2%-4.5% of Ni, 0.003%-0.015% of P, not larger than 0.01% of Pb, not larger than 0.012% of Fe and the balance Zn and inevitable impurities. According to the nickel brass strip, by optimizing the components and the content of the nickel brass strip, the corrosion resistance and wear resistance of the nickel brass strip are improved remarkably. The invention further provides a manufacturing of the nickel brass strip.

The invention belongs to the field of wide and thick plate continuous casting machine soft-reduction process in steel production, and particularly relates to an on-line calibration method for the opening of a wide and thick plate continuous casting machine soft-reduction segment. The on-line calibration method is mainly characterized by including the steps: pressing both an inlet and an outlet of the segment to the mechanical lowest position; measuring the actual opening of the segment; comparing the opening; determining a calibration value; calibrating the opening in an on-line manner; and calibrating the opening again. The on-line calibration method has the advantages that by the aid of the on-line calibration method for the opening of the segment, the opening of the segment can be accurately calibrated, a preset soft-reduction scheme can be accurately implemented to obviously improve the low power quality of a casting blank, the rate of blank samples with deviation within 0.5mm from a set roll gap can reach 100%, the rate of blank samples without deviation from the set roll gap can reach 87.60%, center line shrinkage and middle cracks are eliminated, and center segregation and center porosity are decreased.

A heating-insulating agent for the mould casting to prevent the shrinkage cavities on the end of steel ingot and carbon segregation is prepared from heat-generating metal material (12-18 Wt%), oxidant (15-55), slag-forming agent (15-35) and bulking agent (15-25) through proportional mixing.

The invention provides an electromagnetic stirring control method and system for continuous casting. The method comprises the steps that a temperature field calculation model is built; the casting blank shell solidification rate is tracked through the temperature field calculation model; a stirring position is determined according to the casting blank shell solidification rate, wherein the position where the casting blank shell solidification rate is 45%-70% is determined as the stirring position; an electromagnetic stirring device is moved to the stirring position to apply an electromagnetic field to a casting blank. The system comprises an inputting unit, a model building unit, a tracing unit, a determining unit and a moving device; the inputting unit is used for inputting a technological parameter of continuous casting production, the model building unit is used for building the temperature field calculation model, the tracing unit is used for tracing the casting blank shell solidification rate according to the input technological parameter and the temperature field calculation model, the determining unit is used for determining the position where the casting blank shell solidification rate is 45%-70% as the stirring position, and the moving device is used for moving the electromagnetic stirring device to the stirring position. According to the electromagnetic stirring control method and system for continuous casting, a temperature field, the stirring device and the moving device are combined, electromagnetic stirring on the casting block at the best stirring position is achieved, and the internal quality of the casting blank is improved.

The invention belongs to the field of alloys, in particular to a high-quality alloy steel bar and a production process thereof. The high-quality alloy steel bar comprises the following components in percentage by weight: 0.10 to 0.50 percent of C, 0.10 to 1.50 percent of Cr, 0.50 to 1.50 percent of Mn, 0.010 to 0.015 percent of Ti, less than or equal to 0.40 percent of Si, less than or equal to 0.035 percent of P, less than or equal to 0.035 percent of S, 0.020 to 0.050 percent of Al, less than or equal to 0.020 percent of N, less than or equal to 0.03 percent of Mo, 0.05 to 0.50 percent of V, less than 0.030 percent of Ni, less than or equal to 0.090 percent of Cu, less than or equal to 0.0018 percent of B, less than or equal to 0.0014 percent of O and the balance of Fe and inevitable impurities. In the process, a crystallizer electromagnetic stirring mode is adopted, the current intensity of crystallizer electromagnetic stirring equipment is 0 to 550A, the frequency of the crystallizer electromagnetic stirring equipment is 2 to 4Hz, the solidified end section is slightly rolled and the rolling reduction is 3 to 9 millimeters. In the invention, the internal quality of casting blanks can be improved obviously, and the central looseness and composition segregation of the cast blanks can be reduced.

The invention discloses a C110 steel graded petroleum casing pipe containing rare earth. The petroleum casing pipe is prepared from the following components in percentage by weight: 0.27 to 0.30 percent of C, 0.15 to 0.30 percent of Si, 0.35 to 0.50 percent of Mn, 1.35 to 1.45 percent of Cr, 0.60 to 0.70 percent of Mo, 0.02 to 0.04 percent of V, 0.10 to 0.20 percent of Ni, 0.02 to 0.05 percent ofAl, 0.02 percent of Re, less than or equal to 0.020 percent of P and less than or equal to 0.005 percent of S. The invention further discloses a production method of the petroleum casing pipe. According to the petroleum casing pipe and the production method thereof, inner tissues of the petroleum casing pipe are uniform and chemical components are not segregated; the SSC resistance of the petroleum casing pipe is improved; the obtained petroleum casing pipe has good quality, the service life is prolonged, the transportation safety of a pipeline is increased and requirements on social development are easy to met.

The invention discloses a preparation method for high-quality continuously cast mother billets of a plastic mould steel extra-thick plate. The preparation method is characterized in that in a continuous casting process, billet pulling speed is controlled to be 0.80m / min-0.90m / min; solidification end is heavily pressed down; and press-down amount is distributed according to a solid phase rate under light pressing and heavy pressing. The preparation method disclosed by the invention improves internal quality of cast billets by a solidification end dynamic heavy-pressing technology, so that the center segregation defect and the center porosity defect of cast billets are improved; under the target of producing the extra-thick plate with specification of 120 mm (compression ratio only being 2.12 to 1), internal quality of a flaw detection thick plate with a low compression ratio is effectively improved, and a flaw detection qualification rate of the flaw detection thick plate with the low compression ratio in a production process is controlled to be 99% or higher. Cast billets industrially produced by the method are good in effect after being implemented, and can efficiently meet use requirements of mould steel.

The invention provides a large steel-ingot electro-slag hot-topping device evenly provided with heat sources and a large steel-ingot electro-slag hot-topping method. The device comprises a hydraulic fixing support, a hydraulic transmission rod, a lifting arm, a control cabinet, a trolley, an upper clamping device, a lower clamping device, an upper electrode cross arm, a lower electrode cross arm and a double-layer graphite electrode pair. An inner-layer graphite electrode of the double-layer graphite electrode pair is in a solid column shape, an outer-layer graphite electrode is in a hollow pipe shape, the two electrodes are coaxially arranged, flushed with each other and inserted into liquid premelting slag in a feeder head box; the upper electrode cross arm and the lower electrode cross arm are connected to the lifting arm and connected with the control cabinet. The inner-layer graphite electrode is clamped by the upper clamping device, and the upper clamping device is connected to the upper electrode cross arm. The outer-layer graphite electrode is clamped by the lower clamping device, and the lower clamping device is connected to the lower electrode cross arm. By means of the large steel-ingot electro-slag hot-topping device and the method, the metal yield is increased, the uniformity of steel-ingot chemical components and purity degree of steel are improved; the solidification condition of the centers of the steel ingots is improved; the heating efficiency is high, the heating effect is good, the utilization rate of feeder head molten steel is increased; the utilization rate of the steel ingots is increased.

The invention discloses a submerged nozzle swirl generator, a tundish and its application, comprising a swirl generator body with a stepped hole at the center of the top of the swirl generator body, and a top center of the swirl generator body Several blades are provided, one end of the blade is consistent with the curvature of the outer circle of the swirl generator body, and the end of the blade away from the outer circle of the swirl generator body is consistent with the curvature of the wall of the stepped hole, Moreover, a swirl cavity is formed between two pairs of the blades. Beneficial effects: the structure is simple, the design is reasonable, and the uniformity of the flow field distribution inside the submerged nozzle is improved, thereby significantly improving the stability of the molten steel flow in the crystallizer, thereby helping to improve the quality of steel products.