44 results about "Narrow face" patented technology

The utility model discloses a punching assembly and a section bar processing production line, and the punching assembly comprises a rack which is provided with a first conveying device; the two punching devices are located on the two sides of the first conveying device correspondingly, and the two punching devices are movably connected to the rack; the two punching devices are both provided with lower dies, the two lower dies are both provided with die cores opposite to each other, each die core is provided with a material hanging part, the punching devices are connected with a material pressing mechanism, the material pressing mechanism is provided with a push rod, and the moving path of the push rod passes through the horizontal plane where the corresponding material hanging part is located; a vertical die hole is formed in a die core of the punching device, and a stamping upper die is arranged at the position corresponding to the vertical die hole. And the lifting mechanism is provided with a lifting part, and the lifting part is located between the two lower dies. The punching assembly can achieve automatic punching of the narrow face of the rectangular pipe, the machining efficiency is effectively improved, the rectangular pipe can be prevented from toppling over during conveying, and the machining stability is improved.

A flow field control device and method for a slab continuous casting crystallizer includes: a traveling wave magnetic field generator arranged on the upper part of both sides of the wide face of the slab continuous casting crystallizer, near the lower part of the molten steel meniscus to the upper edge of the submerged entry nozzle outlet, wherein the electromagnetic force generated by the traveling wave magnetic field generator is parallel to the wide face of the slab; DC static magnetic field generators are respectively arranged on the lower part of both sides of the wide face of the slab continuous casting crystallizer and on the molten steel streams on both sides of the submerged entry nozzle, wherein the two static magnetic field generators are perpendicular to the wide face of the slab and the magnetic field directions are opposite; several temperature measuring points and corresponding temperature measuring elements are arranged at intervals along the height direction on the two narrow face crystallizer copper plates of the slab continuous casting crystallizer, wherein at least one temperature measuring point on each of the two narrow face crystallizer copper plates is less than 100 mm away from the upper edge of the narrow face crystallizer copper plate; the distance from each temperature measuring point to the surface of the crystallizer copper plate is the same; and a controller, wherein the traveling wave magnetic field generator, the static magnetic field generator, and the temperature measuring elements are electrically connected to the controller.

The invention provides a continuous casting slab narrow face pre-concave technology and an edge crack control method, and relates to the field of steel plate manufacturing. The continuous casting slab narrow face pre-concave technology comprises the steps that a chamfering crystallizer is used for producing a continuous casting slab; wherein the continuous casting billet produced by the chamfering crystallizer has a chamfer at the corner part; after the heating and dephosphorization procedures, a vertical rolling mill is used for conducting pre-concave side pressing on the continuous casting billet; wherein the vertical rolling mill comprises a plurality of vertical rolls; the vertical roll is of a structure with a thick middle and two thin ends, and the relation between the radius and the length of the vertical roll is expressed by a polynomial function, a trigonometric function or a normal distribution function. The continuous casting technology and the continuous rolling technology can be controlled in a coordinated mode, the side face flattening amount is reduced, and the plate yield is increased.

The present application relates to coal mining method field, especially a kind of underground mining and filling integrated mining and filling working face interphase coal mining method.Firstly, transport roadway and air return roadway are excavated;Interval arrangement filling working face and longwall working face with suitable width;Then, advancing type stoping and filling of filling working face are carried out;After the stoping and filling of filling working face on both sides are completed, and transport crossheading and air return crossheading are left for longwall working face, longwall working face is mined by retreating type full caving method;Such mining is carried out for the whole mine seam.The present application uses narrow face for filling working face, and uses wide face for longwall working face, so that coal production demand, gangue production capacity and crossheading intensity demand are matched.Filling working face uses advancing type mining, and uses filling body to form crossheading and crossheading directly, which are used for retreating type mining of longwall working face, and the whole coal mining process almost does not need to excavate crossheading, and the crossheading intensity formed by filling body is large, which reduces support workload and can ensure safety.

The application discloses a method for protecting connecting roadways and large roadways by means of a handle type working face partitioned double-order fracturing, and belongs to the technical field of mine surrounding rock control. Target fracturing layer position and influence boundary are determined according to roof stratum structure, working face width and narrow conversion position and spatial relationship of connecting roadways and large roadways. In the working face wide face mining stage, when the distance between the working face mining line and the connecting roadway reaches the first advanced starting distance, the first fracturing borehole is arranged; in the working face narrow face mining stage, when the distance between the working face mining line and the large roadway reaches the second advanced starting distance, the inner side fan-shaped borehole and the outer side fracturing borehole facing the outside of the working face are arranged, the inner side and outer side fracturing boreholes are subjected to the second hydraulic fracturing, and a three-dimensional fracture network is formed. The boreholes with insufficient fracture closure, extension or non-connection are subjected to re-pressurization, and the two-stage fracturing effects are verified. The application can weaken the mining stress transmission in stages, reduces the deformation of the connecting roadway and the large roadway surrounding rock, and improves the roadway stability and the coal recovery rate.

The invention discloses a method and device for controlling the reverse taper of a continuous casting crystallizer. The method comprises the steps that the running state of a continuous casting machine and the steel type of a casting blank are obtained; according to the running state of the continuous casting machine and the steel type of the casting blank, the corresponding reverse taper of the narrow face of the crystallizer of the casting blank in different running states is determined; and controlling the operation of the crystallizer in the continuous casting machine according to the reverse taper of the narrow surface of the crystallizer. In this way, the situation that casting cannot be continued due to casting blank width defects and precision deviation caused by abnormal operation conditions such as casting starting, shutdown and casting speed reduction in the continuous casting process can be reduced, and the production quality of the casting blank is guaranteed.

The invention relates to the technical field of clean steel smelting, in particular to a continuous casting crystallizer slag entrapment evaluation method which comprises the following steps: constructing a crystallizer three-dimensional model, taking a pipeline section at a crystallizer nozzle outlet, and calculating the molten steel flow at the nozzle side outlet; selecting an impact area formed after the fluid impacts the narrow surface of the crystallizer, and calculating the coordinates of an impact point; calculating the included angle between the jet flow of the nozzle side outlet and the horizontal plane according to the impact point coordinates, and obtaining the molten steel flow of the impact slag-metal interface according to the molten steel flow of the nozzle side outlet; the molten steel impact force is calculated according to the molten steel flow of the impact slag-metal interface; and the ratio of the impact force of the molten steel to the tension of the half slag-metal interface serves as a slag entrapment evaluation index and is used for judging whether slag entrapment occurs or not. According to the method, the slag entrapment phenomenon is judged through objective quantitative indexes, the stability of the casting quality can be effectively improved by accurately evaluating the slag entrapment risk, and the production cost of cast steel is reduced.

The utility model relates to the field of automatic welding devices, in particular to a flexible nozzle for self-adaptive narrow gas shielded welding. Comprising an annular inner layer and a first fabric layer, the first fabric layer wraps the outer side of the annular inner layer, the outermost end of the first fabric layer exceeds the end of the annular inner layer, and the edge of the outermost end can elastically abut against the narrow side face of the workpiece. A physical space is formed by the annular inner layer and the first fabric layer, protective gas is limited, so that the welding core is always located in the protective gas, meanwhile, the end of the structure can make contact with the narrow face to generate flexible deformation and can generate relative sliding, and the structure can be suitable for narrow-space welding of the nonlinear face.

The invention provides a method for overcoming the slab narrow face transverse crack defect and application. A method for overcoming slab narrow face transverse crack defects comprises the steps that S1, the taper coefficient of a crystallizer is set to be 1.20%-1.40% for positive peritectic steel with the carbon content being 0.08%-0.12%, S2, in the pouring process, the heat flux density of a wide face and the heat flux density of a narrow face are calculated based on the flow of cooling water of the wide face and the narrow face of the crystallizer and the water inlet and outlet temperature difference, and the ratio of the heat flux density to the heat flux density is controlled to be maintained to be 0.8-0.9; s3, the cast slab meeting the taper and the heat flux ratio is subjected to release rolling, the method for solving the slab narrow face transverse crack defect and the application mainly aim to overcome the defects that in the prior art, due to the fact that the defect is high in concealment and difficult to detect, the slab with the defect often flows into the rolling procedure and develops into a hot-rolled coil broken edge, and the defect cannot be detected easily. And the problems that the yield is reduced, the grinding cost is increased, and the hot charging rate is reduced are solved.

The invention provides a crystallizer narrow-face copper plate for improving casting blank quality, which relates to the technical field of crystallizers and comprises a copper plate body, a plurality of vertical grooves are arranged on the back of the copper plate body, a flat cooling cavity extending transversely is arranged at the top of the back of the copper plate body, the depth of the flat cooling cavity is larger than that of the vertical grooves, and the bottom of the flat cooling cavity is communicated with the upper ends of the vertical grooves. A step is arranged on the side wall of the flat cooling cavity and is covered and sealed by a pressing plate to form an independent sealed cooling groove; the pressing plate is provided with a notch corresponding to the top of the cavity to form a water outlet channel, and the edge of the pressing plate is further provided with a concave sealing groove with a sealing strip. Cooling water enters from the narrow-face water tank, flows through the vertical groove from bottom to top, then is converged into the flat cooling cavity to be mixed and equalized in pressure, and then flows out from the water outlet channel to form inverted-T-shaped circulation. The independent pressure equalizing buffer cavity is formed in the top of the copper plate, so that the cooling uniformity of a meniscus area is remarkably improved, uniform formation of an initial blank shell is effectively promoted, cracks on the surface of a casting blank are reduced, and the product quality and the production stability are improved.

The utility model discloses a narrow-face control arm precise bidirectional trimming tool which comprises an upper die and a lower die which are matched with each other, the lower die comprises a lower supporting block used for supporting the trimming position of a workpiece, a left cutter and a right cutter, the left cutter and the right cutter can be close to each other, and the upper die comprises a left drive and a right drive. The left drive and the right drive are matched with the left cutter and the right cutter correspondingly and used for driving the left cutter and the right cutter to get close to each other to achieve edge cutting of a workpiece. The upper surface of the lower supporting block is provided with a curved surface consistent with the lower surface of a workpiece in a profiling mode, and the left drive and the right drive are wedge-shaped pieces respectively. The precise bidirectional trimming tool for the narrow-face control arm comprises a left cutter and a right cutter which can be close to each other, and the two sides of a workpiece can be trimmed at the same time through the mutual approaching of the left cutter and the right cutter.

The utility model discloses a vertical lathe narrow face large workpiece clamping auxiliary tool in the technical field of workpiece lathe machining, which comprises a base, a fastening structure is arranged at one end of the base, a supporting structure is arranged at the other end of the base, and the fastening structure is matched with a locking groove arranged on a working platform. The lower portion of the fastening structure is inserted into the locking groove, the base is located on the working platform, the base is locked and fixed to the working platform through the fastening structure after the base moves to a designated position along the locking groove, and then the supporting structure can abut against the narrow face of the bottom of a workpiece and is matched with the clamping mechanism to clamp and fix the workpiece. And the narrow surface of the bottom of the workpiece can be supported and cannot exceed the range, so that contact with a turning tool is avoided, and the safety is high.

The axle structure for the four-way shuttle vehicle comprises a transmission shaft and a walking wheel, a middle shaft body of the transmission shaft is installed on a wheel carrier plate through a bearing assembly, a shaft body on one side of the transmission shaft is a power part, and a shaft body on the other side of the transmission shaft is connected with a hub hole of the walking wheel through an expansion connecting sleeve. The bearing assembly comprises a bearing sleeve and angular contact ball bearings, the bearing sleeve is installed on the wheel carrier plate, the two angular contact ball bearings with the wide face facing the wide face or the narrow face facing the narrow face are installed between the transmission shaft and the bearing sleeve, and a spacer bush is arranged between the two angular contact ball bearings. Limiting check rings are coaxially installed at the side ends, facing the wheel carrier plates, of the walking wheels, and a power part of the transmission shaft is in key connection with a driving chain wheel. According to the utility model, an original deep groove ball bearing is replaced by the angular contact ball bearings, so that the distance between the two angular contact ball bearings is increased, and the bearing capacity of the bearing assembly is improved; original key connection is replaced with expansion connection sleeve connection, and the problem that key connection is difficult to disassemble and reset is solved.

The invention relates to the technical field of ferrous metallurgy, in particular to a process method for controlling the occurrence rate of longitudinal cracks on the surface of a continuous casting sheet billet, which specifically comprises the steps of controlling the uniform growth of an initial billet shell in a crystallizer, optimizing the flowing state of molten steel in the crystallizer, adjusting the vibration parameters of the crystallizer and controlling the thickness of a casting powder liquid slag layer. And the carbon content in the steel is controlled to avoid a peritectic zone, the sulfur content and residual elements are limited, and the manganese-sulfur ratio is increased. By means of the narrow face and wide face differentiated cooling ratio and combination of the reasonable taper and heat flux ratio, heat transfer of the wide face and the narrow face is effectively balanced, local stress concentration is restrained, it is ensured that an initial blank shell evenly grows, the hot crack risk is reduced, the occurrence rate of continuous casting surface longitudinal cracks is controlled, and the stable and reliable quality of continuous casting slab production is achieved.

The present invention relates to the technical field of clean steel smelting, and in particular to a method for evaluating slag entrainment in a continuous casting mold, which includes: constructing a three-dimensional model of the mold, taking a pipe cross-section at the outlet of the mold nozzle, and calculating the molten steel flow rate at the outlet on the nozzle side; selecting the impact zone formed after the fluid impacts the narrow face of the mold, and calculating the impact point coordinates; calculating the angle between the jet flow at the outlet on the nozzle side and the horizontal plane according to the impact point coordinates, and then obtaining the molten steel flow rate impacting the slag-metal interface based on the molten steel flow rate at the outlet on the nozzle side; calculating the molten steel impact force according to the molten steel flow rate impacting the slag-metal interface; using the ratio of the molten steel impact force to half of the slag-metal interfacial tension as the slag entrainment evaluation index to determine whether slag entrainment occurs. The present invention uses an objective quantitative index to judge the slag entrainment phenomenon, and can effectively improve the stability of the casting quality and reduce the production cost of cast steel by accurately evaluating the slag entrainment risk.

The utility model provides a combined range hood. The combined range hood comprises a smoke suction module and a fan module which are mutually independent, the smoke suction module comprises a wide face area in the front-back direction and a narrow face area in the left-right direction, a vertical air channel is formed in the smoke suction module, a smoke inlet is formed in the lower portion of the wide face area and communicates with the lower end of the air channel, and the size of the upper end of the air channel in the front-back direction is gradually increased from bottom to top. The draught fan module is connected to the upper portion of the smoke suction module, the lower side of the draught fan module is provided with an air inlet in butt joint with the upper end of the air duct, and an exhaust fan right opposite to the air inlet is arranged in the draught fan module. Compared with the prior art, the scheme has the advantages that occupation of operation space is reduced as much as possible, and meanwhile the suction effect of the exhaust fan on the air duct is ensured.

This invention belongs to the field of steel production technology and discloses an effective production method for controlling edge defects in hot-rolled high-strength steel. The process includes converter smelting → LF refining → continuous casting → soaking furnace heating → hot continuous rolling → cooling and coiling. Specifically: the LF refining process controls the nitrogen content in the molten steel to be ≤40ppm at the end point; the continuous casting uses a funnel-shaped crystallizer with a taper ratio of 1.1%~1.3%, and the narrow face taper is adjusted during casting to maintain the heat flux density of the narrow face at 55%~85% of the heat flux density of the wide face; the secondary cooling intensity is controlled to ensure that the corner temperature of the billet is >900℃ in the straightening zone; the soaking furnace heating temperature is ≥1150℃, and the time in the furnace is ≥30min; in the vertical roll fixed-width side pressing pass of hot continuous rolling, the rolling force of the vertical roll mill is controlled to be >300kN. This invention significantly reduces the incidence of edge quality defects such as edge cracks, burrs, and broken edges in high-manganese and high-titanium series high-strength steel by optimizing the steel composition, continuous casting, and hot rolling processes.

The utility model discloses a spiral duct convenient to install, which relates to the technical field of ventilation duct connection and comprises a spiral duct body, and an internal connection structure and an external connection structure are respectively arranged at two ends of the spiral duct body. The internal connection structure comprises a limiting rod and an arc-shaped sealing strip, the external connection structure is provided with a limiting groove and a wedging groove which are matched, and rapid butt joint is achieved through a hasp structure. The sealing structure comprises an air guide ring, an annular air bag and a one-way valve, and the contact pressure between the sealing ring and the narrow face end is dynamically controlled by adjusting the air pressure of the air bag to adapt to environment temperature changes. By means of the design, the problems that a traditional air pipe is complex in installation and nonadjustable in sealing are solved, and the advantages of efficient butt joint, double sealing and pressure self-adaption are achieved.

This invention discloses a high-manganese steel production apparatus for improving the quality of high-manganese steel, belonging to the field of steel production technology. The apparatus includes a casting furnace and a casting pipe. A pipe seat that mates with the casting pipe is provided at the casting furnace. The casting pipe is inclined downwards at an angle f. In this high-manganese steel production apparatus, the casting pipe is inclined downwards at an angle of 12°, compared to the previous 15° angle. This shortens the distance between the steel stream and the narrow copper plate of the crystallizer, and places it higher up. The time for the stream to reach the meniscus is shortened, and the steel flow is increased. The stream exiting the nozzle experiences a smaller temperature drop as it flows upwards to the meniscus after hitting the narrow face. This maintains a higher superheat at the meniscus, which is beneficial for promoting the stability of the slag layer, uniform heat transfer, and improving the surface quality of the slab. It also reduces the probability of adhesion and longitudinal cracks.

The utility model provides a device for measuring the abrasion loss of a narrow chamfered copper plate of a crystallizer, which relates to the technical field of continuous casting and comprises a positioning mechanism, a clamping mechanism and a measuring device. The positioning mechanism is a planar substrate with a guide clamping groove; the clamping device is mounted at the tail part of the planar base plate and is used for clamping the narrow-surface chamfering copper plate of the crystallizer placed in the guide clamping groove; and the measuring device is arranged at the side part of the planar substrate and is used for acquiring data for calculating the abrasion loss of the narrow-surface chamfered copper plate of the crystallizer. According to the utility model, the narrow-surface chamfered copper plate of the crystallizer is placed on the plane base of the positioning mechanism for positioning, and the positioning mechanism is placed on the measuring platform for use, so that the levelness and flatness of a detection surface are ensured, and the reliability of a measuring result is ensured; through base fixation of the universal rod and adjustment of the universal rod, flexible mobility of the dial indicator is ensured, it is ensured that the abrasion loss of each point of the copper plate can be measured, and the measurement accuracy of the dial indicator ensures the accuracy of a measurement result.

The invention relates to the technical field of slab continuous casting, in particular to a crystallizer foot roller for eliminating casting blank narrow face indentations, a crystallizer and a continuous casting machine. The invention provides a crystallizer foot roller for eliminating casting blank narrow surface indentations, which is characterized in that the crystallizer foot roller comprises a segmented roller and a plurality of flat rollers, the segmented roller and the plurality of flat rollers are arranged at intervals to form a casting blank bearing surface, the segmented roller is arranged at a casting blank outlet of a crystallizer, and the segmented roller comprises a first roller body and a second roller body, the first roller body and the second roller body are connected through a connecting shaft, and the edges of the ends, close to the connecting shaft, of the first roller body and the second roller body are arranged to be fillets. A curve transition section is arranged on the edge of a roller body of the flat roller, extends in the axial direction of the roller body and is smoothly connected with the end face of the roller body and a roller face. According to the technical scheme, sharp contact between the narrow-face blank shell and the edge of the foot roller can be reduced, the industrial problem of corner indentation of a small-chamfer crystallizer casting blank is solved, and quality improvement of the small-chamfer casting blank is facilitated.

The invention belongs to the technical field of railway steel, and particularly discloses a high-performance low-alarm-rate turnout rail and a production method thereof. The method comprises the following steps that S1, a rectangular square billet is smelted and cast; s2, the smelted and cast rectangular square billet is heated and rolled, in the rolling process, the wide face of the rectangular square billet is rolled into a rail head, and the narrow face of the rectangular square billet is rolled into a rail waist; s3, rolling waste heat is used for online heat treatment; and S4, straightening and processing the turnout rail subjected to online heat treatment to obtain the high-performance low-alarm-rate turnout rail. According to the scheme, by means of the turn-over rolling technology, original casting blank narrow face rolling is changed into rail head rolling and wide face rolling is changed into rail waist rolling, the rail waist metal amount is increased, the rail waist deformation amount is increased, the rail waist density is improved, the rail waist non-metallic inclusion distribution rule is changed, and therefore the rail waist alarm rate is reduced.

The invention discloses a chamfering crystallizer width adjusting oil cylinder control method and related equipment, relates to the field of continuous casting billet manufacturing, and mainly aims to solve the problem of casting interruption caused by taper alarm in the casting process. The method comprises the steps that in the pouring process of the chamfering crystallizer, the taper of the chamfering crystallizer is selected based on steel grade parameters; a dummy bar head is assembled in advance in a centering mode, so that the dummy bar head and the chamfering crystallizer are arranged in a centering mode; and the dummy bar head is separated from the chamfering crystallizer and then assembled again, and if the distances between the dummy bar head and the narrow faces of the copper plates on the two sides of the chamfering crystallizer are different, the dummy bar head is subjected to centering adjustment relative to the chamfering crystallizer. The control method is used for the control process of the width adjusting oil cylinder of the chamfering crystallizer.

The present application relates to a kind of methods for removing inclusions and slag entrapment in steel in crystallizer, comprising S1, the outside of copper plate of the front and rear sides of crystallizer is provided with electromagnetic device;S2, after continuous casting and the molten steel state in crystallizer is stable, electromagnetic device is opened to the molten steel in crystallizer is treated, until pouring is finished;S3, after the cast blank is out of crystallizer, the surface of the front and rear sides of cast blank is treated or the cast blank is taken off line after skinning treatment is carried out.The present application is by the outside of the wide face of crystallizer is provided with electromagnetic device, in the continuous casting process of molten steel, using inclusion and the protective slag entrapment in molten steel flows in the process of flow due to friction and has electric charge, when charged particle moves in magnetic field, will receive the action characteristics of Lorentz force, promote inclusion and slag entrapment to the narrow face of crystallizer or the liquid protective slag on top gathers, again through the cast blank is out of crystallizer, the narrow face of cast blank is treated, finally obtains the cast blank of high quality of purity.

The invention discloses a method for judging the length of a mixed area of different steel grades under different conditions in the continuous casting and mixed pouring process, which comprises the following steps of: (1) acquiring the speed distribution of the narrow surface center line position of a continuous casting slab along the throwing direction based on a flow field numerical model in the continuous casting process; (2) determining minimum value points of the speed, determining the area length corresponding to the second minimum value point as the mixing area length corresponding to the surface position of the continuous casting slab, and determining the area length corresponding to the third minimum value point as the mixing area length corresponding to the center position of the continuous casting slab, the average value of the lengths of the mixing areas corresponding to the surface position and the center position of the continuous casting slab is determined as the length of the mixing area at the 1 / 4 position of the thickness direction of the continuous casting slab; and (3) calculating the length of the mixing area under different continuous casting process conditions according to the steps, and obtaining a calculation formula of the length of the mixing area under different conditions through a fitting method.

This invention belongs to the field of steelmaking continuous casting technology, and relates to an online diagnostic method for the crystallizer of a slab continuous casting machine. The method involves inspecting and measuring the crystallizer body during the casting interval. The diagnostic criteria are as follows: the corner gap of the crystallizer copper plate ≤ 0.3mm; the absolute value of the difference between the length of one side of the inner and outer arcs of the crystallizer copper plate and the standard length of one side of the inner and outer arcs of the crystallizer copper plate ≤ 1mm; the absolute value of the relative thickness difference between the inner and outer arcs and the left and right sides of the crystallizer copper plate ≤ 3mm; the wear value of the narrow face of the crystallizer copper plate ≤ 1mm; the straightness of the crystallizer copper plate ≤ 0.5mm; within 450mm of the top edge along the length direction of the crystallizer copper plate, each crack or scratch must be ≤ 3.0mm wide, ≤ 10mm long, and ≤ 0.5mm deep, with a number of cracks or scratches ≤ 2; outside this area, each crack or scratch must be ≤ 3.0mm wide, ≤ 50mm long, and ≤ 0.5mm deep, with a number of cracks or scratches ≤ 2; and the area of ​​plating cracks at the meniscus ≤ 30×30mm. 2 If the area of ​​coating peeling off at the meniscus is 0, it meets the diagnostic criteria and is considered qualified; otherwise, it is considered unqualified.

The invention relates to a device and method for regulating and controlling bias current in a crystallizer through electromagnetic braking, and belongs to the technical field of ferrous metallurgy continuous casting. The device comprises a regional electromagnetic braking device, a full-width two-section electromagnetic braking device, a liquid level wide-width nozzle local electromagnetic braking device and a narrow-width regional electromagnetic braking device, each electromagnetic braking device is composed of an iron core, a magnetic induction coil and a magnetic pole, a static magnetic field is applied to the wide face of a crystallizer, magnetic lines of force on the two sides of the submersed nozzle perpendicularly penetrate through the wide face of the crystallizer, and molten steel flowing is regulated and controlled; liquid level fluctuation and meniscus flow are inhibited, the impact depth of molten steel and the impact strength on a narrow surface are reduced, the problem of bias flow caused by nozzle nodulation is solved, the quality of a casting blank is improved, and smooth production is guaranteed; the method comprises the steps of monitoring a bias current phenomenon, selecting a proper device, and adjusting magnetic pole parameters to stabilize a flow field; the nozzle can effectively improve the flowing state of molten steel in the crystallizer, reduce slag entrapment and surface defects, prolong the service life of the nozzle, adapt to different nodulation degrees and pulling speed conditions, and have remarkable technical advantages and application prospects.

The utility model belongs to the technical field of grading wheels, and particularly relates to a mechanical mill grading wheel sprayed with tungsten carbide, which comprises two flange plates arranged oppositely, a rotor opening arranged at the circle center of the flange plates and an impeller assembly arranged between the two flange plates, the impeller assembly comprises a plurality of grading blades connected between the two flange plates, and the grading blades are arranged in an antiparallelogram structure, so that the contact area between the grading blades and material particles is increased by designing the grading blades in the antiparallelogram structure; according to the grading wheel, the bearing capacity of the grading blades to material particles is effectively improved, the abrasion risk is reduced, friction of small-particle materials to the narrow face is reduced through the gap structure with the narrow inside and the wide outside, the grading blades are further protected, meanwhile, circulation of airflow is accelerated through the structure, the grading efficiency of the grading wheel is improved, and the grading efficiency of the grading wheel is improved. The wear resistance of the grading blade is further improved; and the service life is prolonged.

An electric contact element for use in a printed circuit board plug connector is formed with at least two opposing narrow faces and at least two opposing wide faces. At least one narrow face is designed to be used as a contact surface in order to be brought into an electrically conductive connection with a counter contact element. At least the contact surface of the contact element and of the counter contact element are designed to have identical structures, and the wide face has at least one rigid region and a flexible region.

The cylinder hole reverse chamfering cutter for machining comprises a cutter handle and a cutter holder, the cutter handle is located below the cutter holder, and the diameter of the cutter holder is larger than that of the cutter handle. The tool bit further comprises a tool bit narrow face and a tool bit wide face, the tool bit narrow face and the tool bit wide face are integrated, the radius of the tool bit narrow face is smaller than that of the tool bit wide face, and the tool bit narrow face and the tool bit wide face are both located above the tool apron. The reaming and reverse chamfering processes are integrated, so that the working efficiency is improved, and the cost is saved.