793results about "Roll force/gap control device" patented technology

The present invention provides a weather resistant steel plate, which comprises components of, by mass percent, 0.02 to 0.10 of C, 0.10 to 0.40 of Si, 1.0 to 1.6 of Mn, less than or equal to 0.025 of P, less than or equal to 0.015 of S, 0.20 to 0.50 of Cu, 0.30 to 0.60 of Cr, 0.10 to 0.50 of Ni, less than or equal to 0.40 of Mo, less than or equal to 0.060 of Nb, less than or equal to 0.060 of V,0.010 to 0.035 of Ti, less than or equal to 0.0030 of B, less than or equal to 0.0050 of Ca, 0.015 to 0.050 of Al, and the balance Fe and other unavoidable impurities. Correspondingly, the present invention also provides a manufacturing method of the weather resistant steel plate. Through reasonable distribution ratio of alloy components, the method provided in the invention can obtain a high-strength and high-toughness weather resistant steel plate with good corrosion resisting performance, high yield strength and tensile strength, and excellent low temperature impact toughness. The steel plate also possesses good weldability, being able to carry out welding without preheating or employ lower preheating temperature welding. The steel plate provided in the invention can be widely applied to large-scale steel structure engineering such as building structures, bridges, etc.

A robot apparatus having a multi-link structure including a plurality of links and joints serving as link movable sections, and in which at least some of the links are driven by combination of position control and force control is disclosed. The apparatus includes: position control means for performing the position control on the links, which are driven by position control and force control; position control means with force constraint for placing the force control before the position control so as not to cause the magnitude of an external force to exceed a set value; force control means for performing the force control on the links; and integrated force/position control means for controlling driving of the joints by switching the position control means, the position control means with force constraint, and the force control means, and unifies the position control and the force control.

A cold rolling method for preparing high-Si steel sheet containing Fe (85-96 Wt%) and Si (4-15) includes such steps as providing raw material containing Si, B and Fe, smelting, casting, forging, hot rolling, warm rolling, heat treating and cold rolling.

The invention discloses a dynamic roll gap compensation method during cold continuous rolling flying gauge control and belongs to the technical field of automatic control of cold continuous rolling. The method includes a part of roll gap compensation for a welding gap position at the position of a rolling mill inlet front thickness gauge and a part of roll gap compensation for the welding gap position at the positions of all rolling mill outlet thickness gauges. A roll gap adjustment value is determined by a model system of a process computer to a great degree due to the fact that a large part of AGC functions are not introduced during flying gauge control. Therefore, computational accuracy of the model system can directly affect thickness control accuracy during flying gauge control. A practical inlet thickness acquired by using a practical thickness gauge at the position of the rolling mill inlet front thickness gauge is adopted to replace a raw material thickness to improve initial data accuracy for setting a model, and a set value of a roll gap during FGC is corrected according to calculated deviation between a front steel coil roll gap and a back steel coil roll gap so as to improve setting accuracy of the roll gap. More accurate roll force is acquired in the method of dynamic self-adapting at the positions of all the rolling mill outlet thickness gauges, setting accuracy of the roll gap is improved, and then the roll gap value can be compensated during flying gauge control.

The invention relates to a titanium alloy, in particular to a titanium alloy TC4 cold-rolled tube and a production method thereof. By weight, the composition of the alloy is as follows: the balance of Ti, 5.5 percent to 6.75 percent of Al, 3.5 percent to 4.5 percent of V, less than or equal to 0.1 percent of Fe, less than or equal to 0.1 percent of C, less than or equal to 0.03 percent of N, less than or equal to 0.015 percent of H and less than or equal to 0.15 percent of O. The specification of the TC4 cold-rolled tube is outer diameter multiplied by wall thickness (however, the ratio of the outer diameter to the wall thickness is larger than 2). In the process of cold-rolling the titanium alloy tube, lubricant is added on the inner and the outer surfaces of the tube blank and the semi-finished tube, rolling is then carried out, the tube is annealed in oxygen after each rolling pass, a single edge is inwardly sheared by 0mm to 0.8mm, scale cinder and flaws are completely removed before the last one to two passes, the tube is washed by alkali and acid or acid and then by water and then rolled before a finished product is produced after 1 to 16 rolling passes, the rolled finished product is annealed in oxygen or vacuum, and the annealed finished product is washed by alkali and acid or acid again. The performance of the titanium alloy (TC4) cold-rolled tube is good, the metallographic structure is uniform, and the surface quality of the tube is good.

The invention discloses a preparing method of electrostatic enamel hot-roller fine-grained steel, which is characterized by the following: allocating mass percent as 0. 02-0. 10 carbon, not more than 0. 10 silicon, 0. 4-1. 0 manganese, not more than 0. 05 phosphor, 0. 02-0. 05 sulfur, 0. 01-0. 10 aluminum, 0. 003-0. 010 nitrogen, 0. 03-0. 10 titanium, surplus ferric and unavoidable impurity; setting the content of TiN at 0. 013-0. 044; setting ferrite tissue grain fineness number not less than 10 grade. This invention possesses good enamel adherence property and against squama knock property.

The invention belongs to the fields of metallurgical technology and material science, and in particular relates to a high-silicon-steel thin belt and a preparation method thereof. High silicon steel is mainly applied to manufacture iron cores in a high-frequency motor, a transformer and a high-frequency choke coil and comprises the following chemical components in percentage by weight: 6.5 percent of Si, 0.01-0.6 percent of Al, 0.4-0.8 percent of Mn, no more than 0.003 percent of N, no more than 0.005 percent of S, no more than 0.01 percent of P, no more than 0.003 percent of O, no more than 0.004 percent of C and the balance of Fe and unavoidable impurities. The content of the impurities and harmful gases is reduced in the high silicon steel by vacuum melting to ensure the purity of molten steel, then, the high silicon steel is cast and rolled with the casting temperature of 1470-1510 DEG C, and the thickness of a cast belt is 1.5-2.0mm; after being taken out of a cast roll, cooling by spraying water, heat insulating and warm rolling are carried out on the cast belt, and finally, a product is obtained by recrystallization annealing. When being used for producing the high silicon steel, the technology of the invention has the advantages of small investment, energy saving, environmental protection, high lumber recovery and good product magnetism.

The invention discloses an on-line coordination control method for the plate shape and plate thickness of a strip tandem hot continuous rolling mill, belonging to the technical filed of hot continuous rolling of sheets and strips. The method is characterized by comprising the following steps: (1) collecting n rack hot continuous rolling mill equipment and rolling schedule parameters; (2) collecting the roll force and the convexity offset value of a last rack plate in situ; (3) calculating the plate shape stiffness of each rack; (4) keeping the thickness of the outlet of the tail rack to be constant; (5) inversely calculating the convexity variable quantity of the mechanical plate of the i rack from the tail rack; (6) calculating the roll force and the variable quality of the thickness of the inlet of the i rack; (7) calculating the thickness of the new inlet and outlet of the i rack; (8) calculating the rolling reduction and adjusted quantity of the i rack; (9) calculating the convexity variable quantity of the outlet plate of the (i-1) rack according to the equi-proportional convexity condition; (10) repeating steps from (5) to (9) to obtain the rolling reduction and adjusted quantities of 2nd to n racks; (11) calculating the rolling reduction and adjusted quantity of the first rack; and (12) carrying out on-line coordination control according to the rolling reduction and adjusted quantities, thereby achieving the purpose of coordination control on the plate shape and plate thickness.

The invention relates to a method for producing high-strength low-alloy steel. Wherein, it comprises smelting, refining, casting sheet blank, heating blank, removing phosphor, cooling and flattening; the smelting step uses pure steel, low phosphor, and low sulfur; in the casting step, the loose of blank and the aliquation are lower than B0.5level; in the heating step, vanadium+niobium+ titanium0.15%, nickel+chromium+copper<=0.50%, and the heating temperature is 1180-1220Deg. C; in the thermal rolling step, in the crystallize process, the deformation temperature is 1070-1000Deg. C, the deformation amount is 40-60%, and the rolling speed is 1.5-2.5m/s, and in the second step that rolling the non-crystallized area, the pressure is 200-400MPa, the rolling speed is 5-1.5m/s, and the deformation amount is 60-75%; and the interlayer cooling speed in the cooling step is 15Deg. C/s-25Deg. C/s.

The invention relates to the field of production and control of a finish-rolled band steel, in particular to a method for controlling a thickness of a finish-rolled band steel. An adaptive control method for increasing the thickness precision of a finish-rolled steel band by utilizing a roll gap is characterized in that the method comprises the following steps of establishing a roll gap modification quantity static table which performs indexing according to the layers of band steels; before rolling the band steels, identifying the layer of the current rolling band steel, determining the roll gap modification current value, summing the roll gap modification current value with the zero point modification current values of racks, obtaining a roll gap model learning coefficients of the racks used for rolling setting pre-calculation; after rolling the band steels, detecting the obtained band steel final rolling thickness value and the actual roll gap value of the rack at the finish-rollingend, calculating the values, obtaining the band steel final rolling thickness deviation, the initial roll gap deviation value and the roll gap modification update value, for example, when the layer of the same coil of band steel is different with that of the former coil of band steel, the roll gap modification update value is saved in the roll gap modification quantity static table; and collecting the roller speed, roll gap, rolling force and final rolling thickness actually measured data of each rack, and then performing zero point modification of the roll gap. According to the method provided by the invention, the roll gap modification value and zero point modification are used jointly, so that the adaptive capability of the roll gap model under the condition that the rolling planning specification is variable can be improved, thereby improving the setting precision of the model and realizing accurate control to the thickness of the band steel.

The invention discloses a hydraulic servo rolling mill for producing battery pole sheets, which comprises a pedestal, a frame arranged on the pedestal, a lower mill roller and an upper mill roller both arranged inside the frame, a computer-controlled press-down servo hydraulic cylinder connected on a bearing seat for holding the rollers, and computer-controlled roller-bending hydraulic cylinders respectively arranged outside the lower bearing seat of the lower mill roller and the upper bearing seat of the upper mill roller to adjust the bearing clearance between the lower and the upper mill rollers. The invention has three control modes of constant-pressure, constant-clearance and constant-thickness rolling of battery pole sheets, achieves on-line real-time control of position and pressure of the roller and the thickness of the battery pole sheet, ensures the arbitrary switch among the three control modes, thereby meeting higher requirement for the accuracy of battery pole sheets.

The invention discloses a slab sickle bending control system and a slag sickle bending control method used for a roughing mill, and belongs to the field of mechanical automatic control. The control system comprises a slab width detecting module, two side roller beam leveling modules, a computer control module and a storage unit. The slag width detecting module is used for processing centre line offset data detected by a width detector and sending the processed centre line offset data to the computer control module; the computer control module is used for calculating a leveling value of each gate by collecting a set value of slag and practically measured value data, and sending the leveling value to the two side roller beam leveling modules; and the two side roller beam leveling modules are used for regulating two side roller beams of the roughing mill according to the leveling value, and controlling the slab sickle bending. The control system is applicable on the roughing mill, capable of calculating the leveling value of each gate more accurately, and capable of effectively controlling slag sickle bending and guaranteeing stability of finishing rolling unit production, thereby relieving steel scrap caused by off-tracking, shifting and the like, increasing yield and bringing direct economic benefits for enterprises.

An apparatus comprises a platform, a stylus, and a heating system. The platform is capable of holding a sheet of material. The stylus is capable of impinging the sheet of the material to incrementally form a shape for a part. The heating system is capable of heating at least a portion of the sheet of material in a location on the sheet of material prior to the stylus impinging the location.

The invention relates to a steel plate used for a large-thickness hydro-device which belongs to the technical field of steel-making. Counted by weight percentage, the steel plate consists of the following elements: 0.13 to 0.15 percent of C, equal to less than 0.10 percent of Si, 0.50 to 0.60 percent of Mn, equal to or less than 0.008 percent of P, equal to or less than 0.007 percent of S, 0.14 to 0.18 percent of Ni, 2.30 to 2.50 percent of Cr, equal to or less than 0.15 percent of Cu, 0.95 to 1.10 percent of Mo, 0.015 to 0.020 percent of Nb, 0.010 to 0.020 percent f Ti, 0.020 to 0.045 percent of Al, equal to or less than 0.016 percent of As, equal to or less than 0.015 percent of Sn, equal to or less than 0.003 percent of Sb and the rest is Fe as well as unavoidable impurities. The delivery state of the steel plate is normalizing plus annealing; the quality of the steel is pure; the capacity for resisting the corrosion of hydrogen is excellent; besides, the steel plate has excellent weldability and comprehensive mechanical properties.

The invention discloses a steckel mill rolled piece head-and-tail deviation control method which comprises the following steps that: based on existing equipment configuration, different modes are distinguished by integrating the rolling information of a steckel mill according to the rolled piece deviation and rough rolling force in the final step of rough rolling, then the deviation controlled by roll gaps on both sides of the steckel mill is determined, and roll gap setting control for preventing deviation is carried out. Through the method, the hand-and-tail deviation of strip steel can be reduced, shut-down accidents caused by the deviation of strip steel can be prevented, and the rolling stability of the steckel mill can be improved.

The invention relates to an easily welded, hardened and tempered high-intensity steel plate and its producing method, which comprises the following part: C<=0.15%, 0.15%-0.50% Si, 0.80%-1.80% Mn, P<=0.02%, S<=0.01%, Mn<=0.6%, Nb<=0.07%, B<=0.003%, Ni<=1.20%, Cr<=0.80%, Ti<=0.03%, V<=0.08%, the rest Fe and unavoidable impurity. The invention smelts with the electric furnace, which is provided with the low quantity P, S and the pure steel, gets the users' favor, has the low cost and the market competitive ability, solves the problem of big crystal grain and low dynamic ductility, and is fit for producing the high-intensity steel with low draught pressure rolling mill in the other steel factory. The invention also reduces the labor strength, which saves the time of the work, improves the availability ratio of the material, and reduces the leveling expense of making the steel plate.

The invention relates to a modified method for preparing ferrite non-corrodible steel, comprising heating casting blank, phosphorus removing, roughing down, phosphorus removing, fine rolling, cooling, spiraling, acid washing and cold reducing. The heating temperature is controlled between 1000- 1200 Deg. C; the outlet for roughing down is controlled between 900- 1100 Deg. C, and the relative pressing rate for roughing down is distributed backwards to increase break deformation energy restoration and promote break recrystallization; increase swing steel of middle roller way of 10- 100s between roughing down and fine rolling to ensure the time and condition for middle blank recrystallization; the temperature for fine rolling inlet is controlled between 850- 1050 Deg. C, for outlet the temperature is controlled between 750- 950 Deg. C, the relative pressing rate for fine rolling is distributed backwards to increase break deformation energy restoration and promote break recrystallization; the break after rolling is cooled to 600- 800 Deg. C for batching.

The invention discloses a method for preparing a metal layered micro-gradient composite material. The method is mainly characterized in that the micro-gradient composite material is obtained through interface diffusion of alloy elements with the homologous-series heterogeneous multi-layer metal rolling bonding and heat processing technology. Metal with two kinds of alloy content is adopted for rolling bonding, and the to-be-bonded surfaces are grinded and washed; after the ends are fixed, rolling bonding is carried out, and a multi-layer heterogeneous metal composite board is prepared; then heat processing is carried out on the composite board, the temperature is kept for a certain period of time according to requirements, the alloy elements are diffused on interfaces, and therefore the layered micro-gradient composite material is obtained. According to the metal layered micro-gradient composite material prepared with the method, obvious micro-gradients in chemical components and performance exist nearby the interfaces, and the good interface bonding strength can be achieved; the number of the micro-gradient interfaces and the thickness of micro-gradient layers can be adjusted and controlled by changing the rolling bonding technology, the laminating order and the heat processing technology.

The invention discloses a rolling force presetting method of an ultra-thin plate tempering machine. The specific steps of the presetting method are: firstly, a calculation model of rolling force is established; Bring the collected data into the rolling force calculation model, and obtain the value of the correction coefficient according to the principle of the smallest mean square error; finally, substitute the correction coefficient value into the rolling force calculation model to obtain the rolling force determination calculation model. The rolling force presetting method of the present invention is aimed at the characteristics of temper rolling of ultra-thin strip steel, has fast calculation speed and strong applicability, and is especially suitable for presetting the rolling pressure of an ultra-thin plate temper mill.

A method for automatically optimizing the technological parameters in rolling metallic plate or band features use of an automatic control system composed of an in-line automatic measuring unit, a network communication unit and a data processing unit with computer. It includes measuring the rolling force F and advancing value fs, inserting them in a dyadic high-order non-linear equations to find out deforming resistance K and friction coefficient Mu, adaptive learning of the calculation module, and optimizing.

The invention discloses a molding method of ultra-thin magnesium alloy plank stuff, which firstly carries out heat preservation of magnesium alloy cast ingots at the temperature of 648 to 688 K for 22 to 25 hours under the protection of inert gases, implements the homogenization treatment of ingot blanks, directly cogs the ingot blanks with heat extrude until the total deformation degree of the heat-extruded and cogged ingot blanks reaches over 40 percent and then implements annealing; the molding method trims the plate blanks after the heat-rolled cogging into required width dimension, implements transverse rolling in a thermal treatment status and controls the heat rolling deformation degree between 20 and 30 percent at the first time, implements longitudinal rolling after the middle annealing, and then implements a plurality of times of transverse rolling, longitudinal rolling, repeated transverse rolling and repeated longitudinal rolling in the thermal treatment status with the assisted middle annealing until the thickness of the plank stuff is 1mm; the molding method implements the cold rolling of the plank stuff with the reduction of 5 percent in each pass, the total deformation degree of the cold rolling between two middle annealing is controlled at 30 percent, and the thickness of the plank stuff after the cold rolling is 0.1mm; the molding method finally implements the flattening and the finishing operation of the plank stuff. The plank stuff produced by the molding method of the invention has tiny crystal grains, even tissue, little defects, lessening cardinal area texture, and improving mechanical, corrosion resistant and electrochemical performance, etc..

The invention discloses a method for preventing strip breakage on startup. The method includes, before strip winding, processing sheets with broken strips at first after stopping of a cold rolling mill due to strip breakage, compressing roll gaps of various frames and regulating the minimum rolling force of the roll gaps of the different frames after finishing the strip winding, generating exit tension of the different frames prior to regulating roll bending force of working rolls and intermediate rolls after finishing compressing of the roll gaps, and then, starting the cold rolling mill. The method for preventing strip breakage on startup includes control of the roll gaps of the cold rolling mill, selection of rolling force and tension and generation of tension, regulation of actual inclination and tension deviation of different frames, control of bending conditions of the working rolls and the intermediate rolls after startup, thereby effectively controlling times of startup strip breakage of sheets with the thickness lower than 0.6mm and improving production efficiency.

The invention discloses a direct forming manufacturing method of a metal-based multilayer/gradient composite board and a process unit of the direct forming manufacturing method. Scale, corrosion materials and other impurities on the joint surface of a base board are removed through chemical cleaning, the cleaned surface is subjected to gradient power electromagnetic induction heating or laser bombardment surface treatment, all phases near the joint surface are fully dissolved, a solid solution is enhanced, toughness and corrosion resistance are improved, the surface stress of the board is eliminated, and surface laser treatment is conducted to improve the binding property of a composite layer; raw materials of the composite layer are added and injected through powder laying, a high-energy heat source is adopted for irradiation or induction heating to melt powder, metallurgical bonding is formed between the composite layer and a base, and control over the final shape of a cold/hot-rolled board is conducted. The obtained multilayer/gradient composite board is compact in surface structure, bonding between the composite layer and the base and between layers is good, and the interlayer bonding performance of the composite board is remarkably improved. The process is high in flexibility, and the production period of the metal-based composite board can be greatly shortened after the process is combined with an existing continuous casting technology.

The invention discloses a method for producing a metallic titanium plate by adopting a medium-wide band heat rolling set. The method comprises the following steps: heating a titanium plate blank with a thickness of between 50 and 90 millimeters in a roller-hearth type soaking furnace to between 800 and 1,000 DEG C, controlling inlet temperature of the titanium plate blank entering the medium-wide band heat rolling set at a temperature of between 800 and 950 DEG C, controlling process temperature to between 700 and 950 DEG C, and keeping final rolling temperature at a temperature of between 700 and 800 DEG C after fine rolling for seven times; and well controlling roll gap width, depressing rate, roll force and roll (rolling) speed of each stander of the heat rolling set, controlling the rolling speed of the titanium plate rolled by the tail stander of the heat rolling set at between 4.0 and 8.0 meters per second, and coiling the titanium plate by a coiling machine after cooling the titanium plate by water, wherein the coiling temperature is between 550 and 680 DEG C. The method uses a CSP production line to produce the non-ferrous metallic titanium plate (coil) for domestic initiation, and has extremely great economic and social benefits.

The invention relates to a production method of ultra-fine crystal magnesium/titanium laminated composite panel, which comprises the following steps: firstly, cleaning the surfaces of the metal materials; secondly, stacking the metal materials; thirdly, annealing the stacked sheets; fourthly, rolling the sheets after annealing; fifthly, cutting the rolled sheets into two identical parts, trimming and deburring; repeating the first step to the fourth step for lamination and ply rolling; sixthly, annealing the composite panel obtained from lamination and ply rolling to obtain the ultra-fine crystal magnesium/titanium laminated composite panel. The production method solves the problems of complicated technology, high cost, poor corrosion resistant performance of material and poor interface binding performance of the magnesium/titanium laminated composite panel existing in the prior art. The production method has the advantages of simple technology, low cost as well as good corrosion resistant performance and good interface binding performance of the composite panel.

A method of controlling a continuous skin-pass and reduction operation for a metal strip includes the steps of passing a strip through a gap between working rollers of at least two successive rolling stands, only an upstream one of the stands providing substantial thickness reduction of the strip; determining an extension rate of the strip provided by the upstream stand; determining a tension of the strip downstream of the upstream stand; adjusting the speed of the working rollers of the upstream stand compared to the speed of the working rollers of a downstream one of said stands according to the determination of the extension rate; and adjusting the squeezing force of the upstream stand according to the downstream tension determination. A response time to the step of adjustment of the squeezing force is longer than a response time to the step of adjusting the speed of the working rollers.

The invention discloses a belt steel flattening elongation and slab-shaped complex control method, which is characterized by the following: the invention can choose draught pressure mode by comparing draught pressure adjusting elongation algebraic system and tension adjusting elongation algebraic system or use tension mode to control elongation, which can control rolling process of planisher according to set point of every processing parameter and relevant on-line measured value; the tension is controlled in draught pressure control mode, when the draught pressure accumulation regulating variable is over finite limit and the draught pressure keeps constant; the draught pressure is adjusted in tension control mode, when the tension accumulation regulating variable is over finite limit and the tension keeps constant; the curve roll force is adjusted when adjusting draught pressure.

The invention relates to a hard tinned plate which is suitable for stamping processing and is produced from low carbon Al-killed steel. The original plate comprises the chemical components by weight percentage: 0.08 to 0.13 percent of C, less than or equal to 0.025 percent of Si, less than or equal to 0.65 percent of Mn, less than or equal to 0.020 percent of P, less than or equal to 0.020 percent of S, 0.02 to 0.06 percent of solAl, less than or equal to 0.03 percent of Ti, less than or equal to 0.005 percent of N, and Fe and unavoidable impurities accounting for the margin. The production process adopts the steps of steelmaking with molten iron->continuous casting-hot rolling->push-pull mode pickling->HC rolling mill cold rolling->electrolytic degreasing->hydrogen bell furnace annealing(BA)->double-machine leveling->electrolytic tinning, and finally the hard tinned plate can be obtained. The hard tinned plate of the invention has the advantages of low cost, high hardness, favorable stamping processability, and the like, and can be widely used as packing materials for food, drinks, etc.

In a process in roller folding a folding roller is moved against a workpiece. The urging force of the folding roller against the workpiece is resilient, and the folding roller moves in a path along the workpiece by means of a movement device provided with a control system. The urging force is sensed by a sensor, which is integral in or included in the movement device, and the output signal of the sensor is fed to the control system.

The invention discloses a Ni-base alloy composite base band prepared by a hot isostatic pressing method, belonging to the technical field of a high-temperature coating superconductivity base band. The preparation method comprises the following steps: putting NiW powders (code A) and NiW alloy powders (code B) into a die according to an A-B-A sequence, wherein the atom percent of W of the NiW powders is 3-7%, and the atom percent of W of the NiW alloy powders is 9-12%; pressing and sintering by the hot isostatic pressing to obtain an initial composite billet with even diffused ingredients and favorably combined inner and outer layers and; cold rolling the composite billet with the pass distortion of 3-15% and the total distortion of more than 95%; and obtaining a cold rolling base band with a thickness of 80-150 mu m; annealing the base band for 0.5-2 hours under the protection of an Ar/H2 mixed gas at the temperature of 1000-1400 DEG C to obtain the Ni-based alloy composite base band. The composite base band has high mechanical strength and strong double-shaft texture.