39results about How to "Reduce the incidence of cracks" patented technology

The present invention relates to one kind of round Cr-Mo alloy steel billet produced in a bow-type continuous casting machine and its production process. The molten steel for the round Cr-Mo alloy steel billet contains P not more than 0.012 wt% and S not more than 0.002 wt%, and has Mn/S weight ratio not smaller than 200. The present invention features that the continuous casting process has the second cooling with specific cooling water amount of 0.47-0.53, the first region cooling water amount accounting for 35-45 %, the second region cooling water amount accounting for 22-32 %, the third region cooling water amount accounting for 14-24 %, the fourth region cooling water amount accounting for 9-19 %, and Mn/S content ratio in steel not smaller than 200. The present invention can produce continuously cast round low carbon alloy steel billet without crack, shrinkage hole and other defects.

The invention relates to a production process of high-strength bent pipe steel, which is a production process of high-strength X80 steel plate used for bent pipes. Composition: C: 0.015-0.080%, Mn: 1.50-1.80%, Si: ≤0.30% , S: ≤0.0030%, P: ≤0.015%, Nb: 0.04~0.15%, Ti: 0.005~0.030%, V: ≤0.120%, Alt: ≤0.060%, N: ≤0.010%, Mo: 0.10~0.60 %, Cu: 0.10~0.50%, Ni: 0.10~0.50%, Cr: 0.10~0.30%, Ca: ≤0.01%, the rest is iron; in the slab reheating process, the slab heating temperature: 1100~1200℃; In the controlled rolling process, the termination temperature of controlled rolling in the recrystallization zone: 1000-1080°C, the start temperature of controlled rolling in the non-recrystallization zone: 900-980°C, the termination rolling temperature: 760-880°C; In the cooling process, the termination cooling temperature: 300-550°C, and the cooling rate: 3-40°C/s. The product of the invention has good comprehensive properties, especially excellent performance in low-temperature impact toughness, and can still maintain a Charpy impact energy of about 300J at about -30°C.

The invention discloses a method for in-situ reducing the residual stress of a titanium-based composite material prepared through selective laser melting. The method includes the steps that titanium-based composite material powder is prepared, wherein the titanium-based composite material powder comprises a combination of titanium or a titanium alloy and chemical substances generating reinforcingbodies, and the chemical substances comprise one or more of a B (boron) element, a C (carbon) element and rare earth elements; one or more layers of the titanium-based composite material powder is laid on a base plate of a selective laser melting device, and selective laser melting is performed; and one or more times of laser remelting is performed on the surface solidified after the selective laser melting; and operation is repeated till a titanium-based composite material component is prepared. According to the method, after laser remelting is performed on the surface solidified after selective laser melting, the local heat effect caused by scanning a powder layer by using high-energy laser beams as a heat source is lowered, the reaction of the reinforcing bodies can be more thorough, precipitation of the reinforcing bodies is thinner and smaller, the residual stress in the component preparing process is lowered, and the performance of the material is changed.

The invention relates to the technical field of steel and iron smelting, in particular to a continuous casting method of a high-carbon steel plate blank. The method comprises the following steps: the casting superheat degree of the high-carbon steel plate blank is controlled within 10-20 DEG C by low superheat degree; the low-pulling-speed continuous casting is performed for the high-carbon steel plate blank, and the pulling speed is controlled within 0.9-1.1 m/min; the aerial fog cooling is performed for the high-carbon steel plate blank; the taper of a crystallizer is controlled according to variable taper, wherein the alkalinity of covering slag in the crystallizer is controlled within 0.93-0.99; the melting point of the covering slag is not higher than 1050 DEG C; and the viscosity of the covering slag is not higher than 0.140 pa.s. The method reduces the large surface and angle stress, enhances the solidification uniformity of a blank shell, reduces the surface crack generation rate of the plate blank, and improves the center segregation level.

The invention discloses a chemically strengthened glass plate comprising a surface compressive stress layer and a base layer; the compressive stress layer consists of an outer layer and an inner layer, the inner layer is located between the outer layer and the base layer; the outer layer satisfies the requirements: the outer layer comprises, by the weight percentage based on oxides in the outer-layer, 58-62% of SiO2, 13-16.5% of Al2O3, 2.5-7% of Na2O, 7.8-16.1% of K2O, 5.5-7.1% of MgO, 0-0.9% of ZrO2, 0.005-0.015% of Fe2O3, and 0% of CaO. The inner layer satisfies the requirements: the inner layer comprises, by the weight percentage based on oxides in the inner layer, 58-62% of SiO2, 13-17.5% of Al2O3, 2.5-14.7% of Na2O, 3.8-16.1% of K2O, 4.5-7.1% of MgO, 0-0.9% of ZrO2, 0.005-0.015% of Fe2O3, and 0% of CaO. The base layer satisfies the requirements: the base layer comprises, by the weight percentage based on oxides in the base layer, 58-62% of SiO2, 13-17.5% of Al2O3, 12.5-14.7% of Na2O, 3.8-6.1% of K2O, 4.5-7.1% of MgO, 0-0.9% of ZrO2, 0.005-0.015% of Fe2O3, and 0% of CaO.

The invention discloses an ultrasonic combined adaptive anti-fatigue precision machining system and method of a multi-curvature curved surface, and belongs to the field of mechanical precision machining common technologies. The ultrasonic combined adaptive anti-fatigue precision machining system and method of the multi-curvature curved surface aim to solve the technical problem of how to machine acurved surface of a key part with the multi-curvature curved surface while guaranteeing that the part has the anti-fatigue performance of a part with the multi-curvature curved surface. According tothe adopted technical scheme, the ultrasonic combined adaptive anti-fatigue precision machining system structurally comprises a flexible grinding head device and a control unit. The control unit is electrically connected with and has control over the flexible grinding head device, an ultrasonic coupling agent circulation structure and an impact vibration structure. The flexible grinding head device is used for machining the multi-curvature curved surface of the part. The control unit is used for having control over the working state of the flexible grinding head device. The flexible grinding head device comprises a flexible adjustment box body, the ultrasonic coupling agent circulation structure and the impact vibration structure. The impact vibration structure is arranged in the flexibleadjustment box body. The interior of the flexible adjustment box body communicates with the ultrasonic coupling agent circulation structure. The invention further discloses the ultrasonic combined adaptive anti-fatigue precision machining method of the multi-curvature curved surface.

The invention relates to a withdrawal and straightening force fault diagnosis method of a sector segment of a continuous casting machine. The withdrawal and straightening force fault diagnosis method includes the steps that an equipment state parameter database of a withdrawal and straightening machine is set up; a withdrawal speed curve, a total withdrawing and straightening curve, a flow casting tracing curve and a hidden danger segment withdrawing and straightening curve are drawn respectively according to measured data. If first total withdrawal and straightening force and second total withdrawal and straightening force do not exceed the range of the corresponding total withdrawal and straightening force in the database, hidden danger does not exist, and diagnosis is over; and otherwise, existence of the hidden danger is confirmed and the next step is executed; stressed abnormal points are determined, and the stressed abnormal points are verified. With the adoption of the withdrawal and straightening force fault diagnosis method of the sector segment of the continuous casting machine, under the same working rate of the casting machine, due to the fact that the hidden danger existing in the sector segment can be found in advance, the stressed condition of a casting blank is greatly improved, the quality of the casting blank is greatly improved, the crack occurrence rate of crack-sensitive steel is lowered to 3.5%, the commuted amount is effectively reduced, and the fault time is effectively shortened. The withdrawal and straightening force fault diagnosis method of the sector segment of the continuous casting machine is simple in operation, high in sensitivity, timely in detection and precise in positioning.

The invention discloses a green body for testing the cracking performance of a slurry wet blank, a casting mold and a method. The green body is provided with at least a detection module, each detection module comprises a connecting part and stretching parts arranged at the two ends of the connecting part, the connecting part and the stretching parts at the two ends of the connecting part for eachdetection module are connected into a whole, and an unfilled corner is arranged between the connecting part and the stretching part at the at least one end; and the unfilled corners are arranged in anacute angle mode and arranged towards the axis direction. According to the green body for testing the cracking performance of the slurry wet blank, the casting mold and the method, slurry is poured into the mold to form the green body, two or more detection modules with connecting parts with different lengths are included in each of all the green bodies, the mold is opened after time is manuallyset so that the cracking performance of the slurry wet blank can be tested, measured and evaluated more objectively according to the number of cracks of the green body and the situation that the detection module with the specific length in which the cracks occur is determined, and then the crack incidence rate of the green body is reduced.

The invention relates to a test method for improving the surface quality of a microalloyed steel continuous casting billet. The method comprises the following steps that an unconventional high-temperature tensile test is designed through a thermal simulation testing machine by mastering the temperature fluctuation of the continuous casting billet in a withdrawal and straightening process; and the continuous casting process is adjusted by simulating data of the casting blank in two states of temperature fluctuation and stretching in the withdrawal and straightening process, the obtained data better conforms to the actual rule, and the method has higher reference value for casting blank crack control. The temperature fluctuation period t is determined according to the casting blank pulling speed and the roller diameter, the temperature fluctuation T is determined according to a continuous casting tool, +/-T up-and-down fluctuation circulation is achieved within the time t at different stretching temperatures, and therefore data closer to the actual production technology is obtained to adjust the straightening temperature and the like. And finally, the continuous casting straightening temperature is formulated by analyzing and comparing high-temperature thermoplasticity under different parameters and according to the principle that the area shrinkage is higher than 60% and is a plastic area, and the area shrinkage is lower than 40% and is a brittle area.

The invention discloses a method for controlling a triangular area crack of a continuous casting plain carbon steel slab, which belongs to the technical field of continuous casting slabs, and comprises the following steps: S1, keeping the wide surface water flow of a crystallizer at 3200L/min, controlling the narrow surface water flow of the crystallizer at 510L/min-600L/min, calculating the narrow side and wide surface heat flux according to a heat flux formula of the crystallizer in combination with the water inlet and outlet temperature difference of the crystallizer, meanwhile, the cooling water flow of the foot roller section of the crystallizer is increased by 10-30 L/min, a database is established, and data with the heat flux density ratio of the narrow side to the wide side being 0.8-1.0 MW/m < 2 > is selected; s2, measuring the surface temperature of an inlet and an outlet of the straightening section of the casting blank, firstly, establishing a database according to the measured temperature and the optimized secondary cooling water specific water flow, and selecting data of the straightening section at the temperature of 910-930 DEG C from the database; secondly, an arc-shaped section nozzle of the casting machine is changed into a backwashing nozzle, so that the temperature return amount is less than 20 DEG C;

The invention provides a MnCoZn-based ferrite and a manufacturing method thereof. The MnCoZn-based ferrite has excellent mechanical properties in which a flat plate-shaped magnetic core has a fracture toughness value of 1.00 MPa.m1/2 or more as measured in accordance with JIS R1607, and excellent magnetic properties in which the resistivity is 30 [Omega] .m or more, the Curie temperature is 100 DEG C or more, the coercive force of a toroidal magnetic core produced under the same conditions is 15.0 A/m or less, and the initial permeability value at 23 DEG C and 10 MHz is 150 or more. The MnCoZn ferrite is composed of a basic component, an auxiliary component and unavoidable impurities, and the contents of P, B, Na, Mg, Al and K in the unavoidable impurities are respectively controlled to be as follows: P: less than 10 ppm by mass; b: less than 10 ppm by mass; less than 200 ppm by mass of Na; mg: less than 200 mass ppm; al: less than 250 ppm by mass, and K: less than 100 ppm by mass.

The invention relates to the technical field of metallurgy, in particular to continuous casting crystallizer casting powder for high-grade silicon steel as well as a preparation method and application of the continuous casting crystallizer casting powder. The continuous casting crystallizer casting powder provided by the invention comprises the following chemical components in percentage by mass: 40 to 45 percent of SiO2, 20 to 27 percent of CaO, 1.0 to 2.5 percent of MgO, 1 to 3 percent of Al2O3, 12 to 16 percent of Na2O, 10 to 13 percent of F, 1 to 3 percent of C and the balance of inevitable impurities. The binary alkalinity CaO/SiO2 of the casting powder ranges from 0.5 to 0.6, the melting point of the casting powder ranges from 950 DEG C to 1000 DEG C, and the viscosity of the casting powder at the temperature of 1300 DEG C ranges from 0.25 Pa.s to 0.35 Pa.s. According to the continuous casting crystallizer casting powder provided by the invention, through the low-alkalinity, low-melting-point and low-viscosity casting powder, the phenomenon that the surface of a casting blank is easy to sink and crack during continuous casting of a high-grade silicon steel material can be effectively inhibited.