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

The invention relates to an electroslag casting device additionally provided with electromagnetic stirring and a method thereof. The electroslag casting device belongs to the technical field of special steel electroslag metallurgy and comprises a crystallizer, a crystallizer water jacket and an electromagnetic stirrer; an annular magnet is sleeved on the outer wall of the crystallizer and positioned at the middle-upper part of the crystallizer, a loop is wound on an iron core of the annular magnet, an electromagnetic stirrer water jacket is arranged at the periphery of the annular electromagnet, and the electromagnetic stirrer water jacket is communicated with the crystallizer water jacket; a melting consumable electrode forms molten steel drops which then enter a slag layer; the molten steel drops fall down in a spiral line way in the slag layer under the action of the rotary electromagnetic field and then enter a steel ingot liquid tank; the steel ingot liquid tank raises continuously and also enters into an effective magnetic field action region of the electromagnetic stirrer; and meanwhile, electric current in the molten steel is acted with the rotary magnetic field to produce the electromagnetic force which then drives the molten steel to rotate. The invention has simple equipment, and has the obvious functions of improving the surface quality, the subsurface quality and the solidifying tissue of a casting blank and the isometric crystal ratio, and lightening the internal defects, such as the center segregation, the center looseness, and the like.

The invention discloses a method for manufacturing a super-thick super-huge single steel ingot. In the invention, two original blanks are placed on a chassis in parallel, the upper parts of the two original blanks are respectively provided with a dead head, two side baffles are respectively arranged at two sides of the original blanks and the dead heads to form a solidification area to be melted; a consumable electrode is inserted in the solidification area to be melted, steel on the consumable electrode is slowly melted in the solidification area to be melted by using the traditional electroslag remelting technology, the steel is solidified at the same time of being melted till the solidification area to be melted is completely filled with the steel melted from the consumable electrode, and the two original blanks are welded together. Compared with electroslag remelting, the method has low production cost and high production efficiency; the internal quality of the super-thick super-huge single steel ingot manufactured with the method disclosed in the invention is higher than that of a super-huge single steel ingot manufactured with a die casting technology and continuous casting, and especially, the trends of center dispersion and center segregation can be reduced greatly. The method can be used for producing the super-thick super-huge single steel ingots, and the super-thick super-huge single steel ingots which are of a structure having different chemical components along thickness direction and can be used for manufacturing composite steel plates.

The invention provides a method for producing low-alloy and large-size square steel by continuously casting and continuously rolling. The process flow is as follows: molten iron pretreatment, converter smelting, refining, continuously casting, heating, continuously rolling and slow-cooling; the converter tapping temperature is 1640-1670 DEG C; after the LF refining is performed to the molten steel, the refining is performed in a VD or RH refining device for 20-40 minutes, the small flow soft argon blowing is performed to the molten steel during the late period of refining for 5 or more minutes, and the molten steel temperature is controlled between 1540 DEG C and 1570 DEG C after the refining is finished; the superheat degree of the tundish molten steel is controlled within 25 DEG C, the casting speed is 0.5-0.9 m/min, the width and the length of the cross section of the casting billet are respectively 280-320 mm and 380-420 mm; and the charging temperature of the casting billet is 700-800 DEG C, the tapping temperature is 1050-1180 DEG C and the total time of heating is 3 hours or more; the initial rolling temperature is 1050-1160 DEG C, the finishing temperature is 850 DEG C or higher, and the length and the width of the square steel are both 130-160 mm; and the stacking for slow-cooling is performed by using the waste heat of the square steel. The invention reduces the central porosity and the central cracks inside the steel casting billet and eases the influence of the residual stress in the steel billet to the internal structure of the square steel in the temperature reduction process, thereby reducing the central cracks in the process of continuously rolling the square steel and improving the qualification rate of flaw detection.

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 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 technical field of continuous casting of the iron and steel industry, and particularly relates to a submerged nozzle device with a stirring effect for square billet and round billet continuous casting molds. The submerged nozzle device comprises a vertically through tubular body, an inner cavity is defined by the body, a slag line is sleeved outside the side wall of the body, and connected spiral grooves are arranged on the inner surface of the side wall of the body. Cleanliness and the mechanical property of molten steel are improved, and the submerged nozzle device has the advantages of simple structure, remarkable effect, low cost and suitability for popularization.

The invention discloses a swirl generator with a submersed nozzle, a tundish and application. The swirl generator with the submersed nozzle comprises a swirl generator body and a step hole formed in the center of the top end of the swirl generator body, wherein a plurality of blades are arranged on the top of the swirl generator body; the curvature of one end of each blade is consistent to the curvature of the excircle of the swirl generator body; the curvature of the end, which is away from the excircle of the swirl generator body, of each blade is consistent with the curvature of the hole wall of the step hole; and a swirl cavity is formed between every two blades. The swirl generator with the submersed nozzle has the beneficial effects that the swirl generator is simple in structure andreasonable in design, homogeneity of distribution of inner flow fields of the submersed nozzle is improved, thus, stability of flowing of liquid steel in a crystallizer is improved remarkably, and the quality of a steel product is improved favorably.

The invention provides a steel continuous casting method. By means of the method, segregation-free center-porosity-free casting blanks with high internal quality can be efficiently obtained by striking the casting blanks under proper conditions so as to make the casting blanks vibrate. According to the steel continuous casting method, at least one pair of striking and vibrating devices is arranged on the two sides of the short edge faces of a casting blank containing unset parts when the casting blank with a rectangular cross section is cast through the manufacturing method; while the casting blank is cast, vibration is applied to the casting blank by continuously striking the short edge faces of the casting blank; and by striking the short edge faces, a displacement delta (x) curve of the long edge faces of the casting blank in the thickness direction of the casting blank and intersection points of lines when the displacement delta (x) is equal to 0.10 mm, which are defined in the formula (1) and the formula (2) below, are generated, and the short edge faces are struck by adjusting the vibration energy, the distance between shafts of guide rollers and the unset thickness, so that the distance between the intersection point, away from the original point, of the intersection points and the struck positions of the short edge faces of the casting blank in the width direction of the casting blank is 200 mm or above.

The invention relates to a forging method of an H13 steel vertical continuous casting round billet. The method comprises the following steps: the continuous casting billet is subjected to heat preservation in a furnace of 450+/-10 DEG C, the temperature is raised to 850+/-10 DEG C at the speed of less than or equal to 60 DEG C/h and raised to 1270+/-10 DEG C at the speed of less than or equal to 120 DEG C/h, the continuous casting billet is air-cooled for 20+/-5 min, put into a furnace of 1200+/-10 DEG C furnace for insulation and pulled up on an oil press for four passes, the first-pass reduction rate is 35-45%, then the continuous casting billet is turned over by 90 degrees for second pass, the reduction rate of the second pass is 30-40%, the continuous casting billet is turned over by 180 degrees for third pass, the reduction rate of the third pass is 25-35%, the continuous casting billet is turned over by 90 degrees for fourth pass, the reduction rate of the fourth pass is 20-30%,the blank is chamfered after the fourth pass is finished, put into a furnace of 1000-1150 DEG C for heat preservation, discharged from the furnace and sent to a radial forging machine for reciprocating forging, the last pass is a finishing pass, the drawing and beating speed is 1.3-1.5 m/min, the other passes are the main deformation passes, the reduction rate is 15-30%, and the drawing and beating speed is greater than or equal to 6 m/min. The yield of the continuous casting round billet is improved, the cost is reduced, and the problems of flaw detection and center loosening are solved.

The gear steel comprises the following chemical components in percentage by mass: 0.12 to 0.23 percent of C, 0.17 to 0.42 percent of Si, 1.7 to 2.5 percent of Mn, 0.4 to 1.25 percent of Cr, 0.5 to 1.45 percent of Mo, 0.35 to 0.75 percent of Ni, 0.1 to 0.35 percent of V, 0.002 to 0.007 percent of B, less than or equal to 0.015 percent of P, less than or equal to 0.015 percent of S, less than or equal to 0.01 percent of Cu, less than or equal to 0.015 percent of Al, less than or equal to 0.008 percent of Ti, less than or equal to 0.02 percent of N, less than or equal to 0.002 percent of O and the balance of Fe and inevitable impurity elements. The preparation method comprises the procedures of molten steel smelting, refining and deoxidizing, continuous casting, rolling, quenching and tempering which are conducted in sequence, the soft argon blowing time in the refining and deoxidizing procedure is larger than or equal to 30 min, the final secondary cooling water amount in the continuous casting procedure is controlled to be 0.5-0.9 L/kg steel, and through steelmaking component control, temperature control, slag charge control, refining and deoxidizing control, argon blowing control, alloy optimization control and low residual element control, the production efficiency of the steel is improved. And through the controlled rolling and controlled cooling process, the transverse performance, ductility, toughness and compactness are guaranteed, the overall hardness, tensile strength, yield strength and impact toughness are improved, the strength and toughness of the wind power gear steel are both considered, and the tooth breaking risk is avoided.

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 provides a method for continuously casting steel. By means of the method, segregation-free center-porosity-free casting blanks with high internal quality can be efficiently obtained by striking the casting blanks under proper conditions so as to make the casting blanks vibrate. According to the method for continuously casting steel, at least one pair of striking and vibrating devices is arranged on the two sides of the short edge faces of a casting blank containing unset parts when the casting blank with a rectangular cross section is cast through the manufacturing method; while the casting blank is cast, vibration is applied to the casting blank by continuously striking the short edge faces of the casting blank; and by striking the short edge faces, a displacement delta (x) curve of the long edge faces of the casting blank in the thickness direction of the casting blank and intersection points of lines when the displacement delta (x) is equal to 0.10 mm, which are defined in the formula (1) and the formula (2) below, are generated, and the short edge faces are struck by adjusting the vibration energy, the distance between shafts of guide rollers and the unset thickness, so that the distance between the intersection point, away from the original point, of the intersection points and the struck positions of the short edge faces of the casting blank in the width direction of the casting blank is 200 mm or above.