49results about How to "Improve high pressure performance" patented technology

The invention belongs to the technical field of pressure type water electrolysis hydrogen production, and particularly relates to a concave-convex flange type high-pressure water electrolysis hydrogen production electrode frame and an electrolysis unit.The concave-convex flange type high-pressure water electrolysis hydrogen production electrode frame comprises an electrode frame body and a bipolar plate, the bipolar plate and the electrode frame body are integrally formed in an injection molding mode, and a first boss is arranged on the outer edge of the front face of the electrode frame body; the electrolysis unit comprises two end pole plates and a plurality of concave-convex flange type high-pressure water electrolysis hydrogen production electrode frames, and each concave-convex flange type high-pressure water electrolysis hydrogen production electrode frame is located between the two end pole plates and is aligned and stacked together in the axial direction. The bipolar plate and the electrode frame are formed into an integrated structure through an injection molding process, and the bipolar plate is accurately embedded in the electrode frame in the injection molding process, so that the overall structural strength of the electrolysis unit is improved, and gas or liquid leakage possibly generated in the electrolysis process is effectively prevented; therefore, safe and efficient electrolytic reaction is ensured.

The present invention provides a trough-type solar concentrating tracking bracket, wherein the adjustable lens bracket is provided with a running wheel set, and the running wheel set is driven by a motor to drive the adjustable lens bracket to move along an arc track, so that the trough-type concentrator installed on the adjustable lens bracket can rotate according to the change of the sun's position, thereby reflecting the sunlight from the most suitable direction to the solar collector tube. In this way, only the adjustable lens bracket needs to move, thereby avoiding the frequent movement of the solar collector tube, which not only reduces the maintenance and repair work of the collector tube, but also improves the high-pressure resistance of the collector tube, and at the same time greatly reduces or even avoids possible safety hazards. Therefore, the trough-type solar concentrating tracking bracket of the present invention can conveniently track the reflection of the sun, and has good practicality and market value.

The invention discloses a fine whisker nickel-cobalt-manganese hydroxide precursor and a preparation method thereof, the product morphology can be regulated and controlled by regulating and controlling the temperature and the pH value of the particle size in the growth reaction stage on the premise of not introducing compressed air, the precursor product with fine whisker morphology and large specific surface is prepared, and the repeatability and controllability are good. And meanwhile, the lithium ion battery prepared from the precursor has excellent chemical properties, the first discharge capacity at 0.2 C is up to 207.4 mAh / g, and the first efficiency is up to 89.2%.

The invention belongs to the field of sodium-ion batteries, and discloses a high-voltage-resistant sodium-ion battery positive electrode material which comprises a core layer and a coating layer, the chemical formula of the core layer is Na < x > Ca < y > (NiFeMn) < 0.33 > x (1-z-e) Al < z > Mg < e > O < 2 >; the chemical formula of the coating layer is Na3La2 (BO3) 3. (AFm) n; 0.99 < = x + y < = 1.04, 0.01 < = y < = 0.05, 0.01 < = z < = 0.1, 0 < = n < = 0.05, 0.0023 < = e < = 0.023; a is Ca and / or Al, and m is the valence state of the A element. According to the positive electrode material, through doping and coating of the core layer, the stability of the core layer material, the coating material and the interface stability of the core layer material and the coating material are realized, particularly, the surface stability of the doped core layer is remarkably improved, and the capacity and the cycle performance under the condition of high voltage are improved. Meanwhile, the invention also provides a preparation method of the high-voltage-resistant sodium-ion battery positive electrode material.

The invention discloses a brake for mine truck parking, and belongs to the technical field of brakes, the brake comprises a base body, two piston bodies, a brake pad, a brake disc spring and a hydraulic driving system, the two piston bodies are oppositely arranged, and the two piston bodies are both in sliding fit with the base body; the number of the brake pads is two, the two brake pads are installed on the opposite sides of the two piston bodies respectively, spring sealing rings are arranged between the two piston bodies and the base body, the number of the brake disc springs corresponds to the two piston bodies, and the two brake disc springs apply elastic force to the two piston bodies to move in the direction close to each other respectively. The hydraulic driving system is used for applying driving force to the two piston bodies in the direction away from each other. The hydraulic driving system has the advantages that the sealing performance between the piston body and the base body is guaranteed, and then the hydraulic driving system can stably drive the piston body.

The invention provides an electrolyte as well as a preparation method and application thereof. The electrolyte comprises an organic solvent, a lithium salt, an interface additive and a fluorine-containing diluent, the interface additive comprises a boric acid disultone compound; the boric acid disultone compound has a structure as shown in a formula I; according to the electrolyte, the interface additive with a specific structure and the fluorine-containing diluent are compounded, so that the electrolyte is high in conductivity, a unique high-voltage-resistant fast-charging electrolyte system is formed, the high-voltage-resistant performance and the cycle performance of the battery are improved, and under the same condition, the charging capacity is higher, and the battery has good fast-charging performance.

The utility model relates to a sealing ring which comprises a sealing ring body, the two axial sides of the sealing ring body are respectively provided with a sealing flat gasket, the two sealing flat gaskets and the sealing ring body are of an integrated forming structure, the outer diameter of the sealing ring body is larger than that of the sealing flat gaskets, and the two sealing flat gaskets are parallel to each other and are the same. According to the sealing ring designed by the utility model, the sealing ring body and the sealing flat gasket are integrally formed, so that the durability of the sealing ring is enhanced, the service life of the sealing ring is prolonged, and the sealing ring is particularly excellent in high-pressure and abrasion environments.

The utility model discloses a high-pressure-resistant composite water pipe, which relates to the technical field of composite water pipes and comprises two water pipe bodies, a plurality of reinforcing protective sleeves are sleeved on the outer sides of the two water pipe bodies, and every two adjacent reinforcing protective sleeves are tightly attached and connected. The water pipe body is structurally reinforced and fixed through the spliced reinforcing protective sleeves, the internal structure of the water pipe body is further reinforced through the reinforcing fixing frame, and therefore the high-pressure resistance of the water pipe body is greatly improved, the using stability of the water pipe body is improved, the service life of the water pipe body is prolonged, meanwhile, the reinforcing protective sleeves can be combined and detached, and the water pipe body is convenient to use. The position can be adjusted, so that cutting use of the water pipe body is not affected, the connecting ring with the outer threaded pipe fixedly installed on the inner side in a penetrating mode is used in cooperation with the inner threaded ring in the water pipe body, the two water pipe bodies can be stably connected, the sealing performance is good, the cutting use flexibility of the water pipe body is improved, and the actual use effect is good; the practicability is high.

This invention proposes a lithium-ion battery electrolyte and its application. The electrolyte comprises at least the following components: a fluorinated solvent, including 2,2-difluoroethyl acetate, fluoroethylene carbonate, and 2,2-difluoroethyl ethyl carbonate; a lithium salt, including a first lithium salt comprising lithium hexafluorophosphate; and an additive, including a first additive comprising lithium difluorobis(oxalato)phosphate. The lithium-ion battery electrolyte and its application proposed in this invention can improve the electrolyte's high-voltage resistance and kinetic performance, reduce battery impedance, and enhance the battery's fast-charging performance and high-temperature cycle stability.

The present invention belongs to the technical field of pressure-type water electrolysis hydrogen production, specifically a concave-convex flange type high-pressure water electrolysis hydrogen production electrode frame and an electrolysis unit, the concave-convex flange type high-pressure water electrolysis hydrogen production electrode frame includes a pole frame and a bipolar plate, the bipolar plate and the pole frame are integrally injection molded, the front outer edge of the pole frame is provided with a boss one, the reverse outer edge of the pole frame is provided with a groove two, the electrolysis unit includes two end plates and a plurality of the above-mentioned concave-convex flange type high-pressure water electrolysis hydrogen production electrode frames, each concave-convex flange type high-pressure water electrolysis hydrogen production electrode frame is located between the two end plates, and is aligned and stacked together along the axial direction. The bipolar plate and the pole frame are formed into an integrated structure by an injection molding process, and during the injection molding process, the bipolar plate is precisely embedded in the interior of the pole frame, which not only improves the overall structural strength of the electrolysis unit, but also effectively prevents the leakage of gas or liquid that may be generated during the electrolysis process, thereby ensuring the safety and efficiency of the electrolysis reaction.

This invention discloses a method for preparing a composite solid electrolyte, comprising the following steps: S1: dispersing modified sulfide electrolyte particles in an organic solvent, adding ethylene glycol diglycidyl ether and trifluoropyridine diamine for polymerization; S2: reacting the reaction product with added bromoalkane, then adding a fluorinated anion solution for ion exchange reaction to obtain a polyionic liquid-coated electrolyte intermediate; S3: placing it in a reactor containing acrylate, swelling under supercritical conditions, and then adding polyethylene glycol acrylate and lithium salt; after the reaction, a composite solid electrolyte with an interpenetrating or semi-interpenetrating network structure polymer coating is obtained. The preparation method of this invention not only effectively suppresses side reactions between the sulfide electrolyte, organic solvent, and lithium metal anode, but also significantly improves the interfacial stability and ionic conductivity of the electrolyte through the interpenetrating or semi-interpenetrating network structure polymer coating layer.

The present invention relates to the technical field of secondary batteries, and in particular to a solid electrolyte, a composite electrolyte and a secondary battery. It comprises at least one of the polymers shown in structural formulas I and II; wherein R is selected from H, a C1-C3 alkyl group or a C1-C3 fluoroalkyl group; m is an integer of 1-1000, and n is an integer of 5-2000. The secondary battery based on the solid electrolyte provided by the present invention has high cycle stability and high energy density, and can inhibit the growth of lithium dendrites and the shuttling effect of polysulfides.

The filter element comprises an end cover, a first sleeve and a second sleeve, a through hole penetrating up and down is formed in the center of the top of the end cover, the first sleeve and the second sleeve are both fixedly installed at the bottom of the end cover, and the first sleeve is located in the second sleeve; a gap is formed between the bottom end face of the first sleeve and the top end face of the second sleeve, a sealing gasket is arranged in the gap, the wall of the first sleeve and the wall of the second sleeve are each of a hollow structure, the wall of the first sleeve and the wall of the second sleeve are filled with multiple layers of filter cotton, and multiple layers of steel wire meshes are arranged in the wall of the first sleeve and the wall of the second sleeve. During use, the first sleeve is mounted at the bottom of the end cover, then the second sleeve is mounted at the bottom of the end cover, and high-pressure liquid enters the first sleeve through the end cover, impacts the first sleeve and then overflows the second sleeve, so that the pressure is borne in a graded manner, and the high-pressure resistance is improved.

The present invention proposes a wiring structure for pressure-bearing equipment, including a pressure-bearing equipment housing, a protective cover, a terminal, a power cord, a cover plate and a terminal connection plate. The cover plate is sealed on the protective cover and connected with the protective cover to form a protective box with a wiring cavity inside; the protective cover is welded to the outer wall of the pressure-bearing equipment housing, and the terminal connection plate is arranged in the protective cover, with its back abutting against the bottom of the protective cover, and the terminal connection position thereon is arranged one-to-one with the external connector of the terminal and the power cord connector of the power cord; the power cord connector of the power cord, the external connector of the terminal and the terminal connection plate are fastened and connected by terminal bolts, power cord connector perforations, external connector perforations of the terminal and the mounting holes of the terminal connection plate. The present invention has a simple structure and is easy to produce. It not only meets the high reliability requirements of waterproof, dustproof and electric shock proof, but also is suitable for use in relatively harsh environments, greatly prolonging the service life of the core components of the pressure-bearing equipment and improving the stable operation time of the pressure-bearing equipment.

The invention discloses an electrical equipment insulating liquid and a preparation method thereof, and belongs to the technical field of insulating liquid preparation, the preparation method comprises the following steps: sequentially adding trimethylolpropane, caprylic acid, capric acid and oleic acid into a reaction container, then adding toluenesulfonic acid as a catalyst, and carrying out an esterification reaction to obtain a substrate after the esterification reaction; removing the unreacted substrate from the substrate after the esterification reaction by using a vacuum distillation method to obtain a distilled product; and naturally cooling the distilled product, carrying out alkali refining treatment by using a sodium hydroxide solution, washing by using ultrapure water to remove sodium salt in the alkali refining process, adsorbing by using an adsorbent to remove moisture and polar impurities, carrying out vacuum drying, and finally filtering by using a filter membrane to generate the trimethylolpropane caprylic / capric trioleate insulating liquid. The problem of low ignition point of the trimethylolpropane ester insulating liquid can be solved, and the insulating liquid has excellent electrical performance and is suitable for electrical equipment such as transformers.

This utility model discloses a moving spring assembly and a relay, including a moving spring body. The moving spring body includes a main body segment and a bent portion connected to the free end of the main body segment. A moving contact corresponding to the stationary contact on the stationary spring assembly of the relay is installed on the bent portion. The bent portion is configured to bend away from the stationary spring assembly to increase the breaking gap between the moving contact and the stationary contact. Because the bent portion is provided at the free end of the main body segment and the moving contact is installed on the bent portion, compared to the existing straight, elongated moving spring structure, the space occupied in the corresponding contact breaking direction within the operating stroke is relatively small. This facilitates the compact installation of relay components within a limited space, and further improves the design effect of small size, large contact, and large gap of the relay, thereby improving the high voltage resistance performance of the relay.

The utility model relates to a contact fixing structure, a high voltage connector and a high voltage connector assembly, the contact fixing structure comprises an insulator, a contact and a contact fixing sleeve, the outer wall of the contact is provided with a first groove and a first boss, the inner wall of the insulator is provided with a second boss, the contact fixing sleeve is installed in the first groove, and the second boss is installed in the second groove. The front side of the contact fixing sleeve is provided with an inclined plane structure, so that the contact fixing sleeve is convenient to mount and dismount. After the contact piece is installed from the tail of the insulator and assembled in place, the contact piece fixing sleeve is bounced off and clamped at the front end of the second boss, the first boss is located at the rear end of the second boss, and axial positioning of the contact piece is achieved.

The present invention relates to an electrolyte additive, its preparation method and application, belonging to the field of battery technology, and is used to solve at least one of the problems such as low conductivity of the existing electrolyte, poor cycle performance and high-voltage resistance performance of the battery. The electrolyte additive of the present invention grafts an ionic liquid group onto a cyclic ester compound, improving the ion transport channel and further enhancing the ionic conductivity of the SEI after film formation; in addition, during the formation of the SEI film, the oxacyclic group undergoes a ring-opening polymerization reaction to form a more stable SEI film, improving the cycle performance and high-voltage resistance performance of the battery, etc.

The utility model discloses a lip-shaped pad for a quick-opening blind plate, which belongs to the technical field of quick-opening blind plate sealing, is matched with the quick-opening blind plate for use, and comprises a lip-shaped pad body, a sealing lip, a pressure equalizing hole and a second pressure groove. By arranging the second pressure groove, expansion is generated under the pressurizing effect, the lip-shaped pad body is pressurized towards the two sides to form attached sealing with the sealing groove, sealing of the quick-opening blind plate is formed, and the problem that an existing quick-opening blind plate can only achieve the sealing effect under the condition of high-precision matching, and the sealing effect is poor is solved. The quick-opening blind plate can be suitable for being used in very complex environments with impurities, dust and the like, and the sealing performance of the pipeline in the complex environments is improved.

The utility model relates to the photovoltaic field, and discloses a photovoltaic module which comprises an insulating layer, a first substrate, a first packaging adhesive film layer, a battery piece layer, a second packaging adhesive film layer and a second substrate, the first substrate, the first packaging adhesive film layer, the battery piece layer, the second packaging adhesive film layer and the second substrate are sequentially stacked from bottom to top, and the insulating layer is located between the first packaging adhesive film layer and the second packaging adhesive film layer. The insulating layer is distributed on the edge area of the upper surface, the side surface and the edge area of the lower surface of the battery piece layer, and the width of the covering area of the insulating layer on the upper surface of the battery piece layer is different from that of the covering area of the insulating layer on the lower surface of the battery piece layer; or, the insulating layer is in a bag shape, and the battery piece layer is completely wrapped in the insulating layer. The creepage distance of the photovoltaic module is increased, and the increased creepage distance is the width of the insulating layer located on the upper surface or the lower surface of the battery piece layer. Therefore, the area of the photovoltaic module can be fully utilized, and the utilization efficiency of the photovoltaic module is improved. The widths of the insulating layers on the upper and lower surfaces of the cell layer are different, thereby reducing the manufacturing difficulty.

The utility model discloses a kind of high-purity high-pressure-resistant soft sealing ball valves, including valve body assembly, ball core and soft sealing structure, valve body assembly is equipped with valve core cavity and is equipped with the medium channel in the both sides of valve core cavity, medium channel is communicated with valve core cavity, ball core is rotatably arranged in valve core cavity, soft sealing structure is arranged between medium channel and valve core cavity and includes valve seat, compression ring and elastic member, valve seat is annular and has hard shell and soft sealing body, hard shell is equipped with annular groove, the side of annular groove towards ball core is open structure, soft sealing body is arranged in annular groove and part from the open structure of annular groove Stretches out, elastic member is acted on valve seat by compression ring, so that the part of soft sealing body from the open structure of annular groove abuts on ball core.The utility model by hard shell part cladding soft sealing body, can improve the high-pressure resistance of valve seat, reduce its possibility of deformation due to high-pressure medium, ensure sealing performance, improve adaptability.

The present invention provides an electrolyte and a lithium ion battery containing the same, wherein the electrolyte comprises a lithium salt, an organic solvent and an additive, wherein the additive comprises a silicium imidazole compound and a sulfonate compound, wherein the silicium imidazole compound has a structure shown in Formula I, and the sulfonate compound has a structure shown in Formula II. The electrolyte provided by the present invention contains both the silicium imidazole compound and the sulfonate compound, and the two additives act synergistically to improve the first cycle efficiency of the lithium ion battery, improve the disadvantage of poor cycle performance of high specific energy silicon-based negative electrode batteries, and also inhibit the volume expansion of the silicon-based negative electrode to a certain extent.

The present invention discloses a high-pressure and high-temperature resistant automotive proximity inductive sensor and its manufacturing process, which relates to the field of laser sensors. In view of the fact that the existing inductive sensor has the problem that the injection glue will be broken into slag after working for a long time at high temperature, thereby affecting the stability of the internal oscillation coil of the inductive sensor, and the temperature change from high temperature to normal temperature may cause the coil and electronic components to be pulled by the glue to break and fall off, thereby affecting the product function, the following scheme is proposed, which includes an LC oscillation part, a signal processing part and an output part, the LC oscillation part includes an anti-interference module, an LC oscillation module and a high-temperature compensation network, and the LC oscillation module is connected to the anti-interference module, the high-temperature compensation network and the signal amplification and processing module. The present invention has a novel structure, can be used at an operating temperature of up to 120°C, has a strong transient anti-interference ability, a wide range of applications, has the ability to withstand 50Mpa oil pressure, and has high stability in use.

The utility model discloses a cathode shield, a high-voltage socket and an X-ray generator, the cathode shield is used for reducing the electric field intensity of a welding seam formed by a connecting ring in the high-voltage socket and a socket body, the cathode shield is sleeved at one end of the socket body and outside the connecting ring, and a vacuum gap is defined between the cathode shield and the welding seam; a protruding part which protrudes towards the welding seam and surrounds the welding seam is defined by the inner wall face, close to one end, of the cathode cover, and the protruding part is used for reducing the radial distance between the inner wall face, at the protruding part, of the cathode cover and the welding seam so as to reduce the electric field intensity at the welding seam. According to the cathode cover provided by the embodiment of the utility model, the inner wall surface of the cathode cover is provided with the lug boss corresponding to the welding seam, so that the intensity of an electric field near the welding seam is reduced, and the insulation level and the high-voltage resistance of a high-voltage socket are improved.

The present application discloses a diode structure and a method for preparing the diode structure. The diode structure includes a first epitaxial layer and a second epitaxial layer arranged in a stacked manner, wherein the second epitaxial layer includes a first sub-epitaxial portion and a second sub-epitaxial portion arranged alternately in a first direction and having different doping types, the first direction being a direction parallel to the surface where the first epitaxial layer and the second epitaxial layer contact, and the diode structure further includes: an injection region, the injection region being arranged on a surface of the first sub-epitaxial portion away from the first epitaxial layer, wherein the doping type of the first sub-epitaxial portion is the same as the doping type of the first epitaxial layer, and the doping type of the injection region is the same as the doping type of the second sub-epitaxial portion. The invention solves the problem in the related art that the diode device structure has no obvious product performance advantage in terms of parameters, a complex process flow, and high production costs.

The invention provides a miniature high-voltage transmission-type X-ray ceramic tube which comprises a ceramic tube, and a cathode assembly and an anode assembly are installed at the upper end and the lower end of the ceramic tube respectively. The cathode assembly comprises a core column assembly, a cathode seat, a getter, a lamp filament and a focusing head, the cathode seat is hermetically welded at an upper end tube opening of the ceramic tube, the focusing head is hermetically welded in the cathode seat, the lower end of the focusing head extends into the upper end tube opening, and the core column assembly is hermetically inserted in the focusing head; the lamp filament is installed at the lower end of the core column assembly and located in the extending section of the focusing head. The core column assembly comprises a core column kovar sleeve, a core column ceramic chip, a pair of core columns and an exhaust pipe, and the core column kovar sleeve is welded in the focusing head in a sealed mode. The ceramic tube solves the problem that in the prior art, small size and large voltage cannot be achieved, the structural layout and material selection are reasonable, the size of the X-ray tube is shortened under the condition that high voltage is kept, and the ceramic tube is good in insulation and heat dissipation performance and easy to produce.

This invention provides a diode structure, comprising: a substrate; multiple filling trenches disposed on the substrate, extending along the length or width direction of the substrate and spaced apart along the length or width direction of the substrate; an epitaxial filling layer disposed within each filling trench; a first metal layer connected to at least one epitaxial filling layer within the multiple filling trenches to form a first ohmic contact; and a second metal layer disposed on the substrate and forming a Schottky contact with the substrate. This application solves the problem of low high-voltage withstand capability in existing SiC diodes.

The resonator comprises a glass substrate, a first conductive layer and a second conductive layer, and the glass substrate is provided with a first surface and a second surface which are opposite to each other; the first conducting layer is arranged on the first surface and comprises a first pole plate and an inductance coil surrounding the periphery of the first pole plate, and the inductance coil is provided with an inner connecting end and an outer connecting end; the second conducting layer comprises a second polar plate arranged on the second surface, and the second polar plate is opposite to the first polar plate; the inner connecting end is electrically connected with the first polar plate, and the outer connecting end and the second polar plate are used for connecting an external circuit, or the inner connecting end is electrically connected with the second polar plate, and the outer connecting end and the first polar plate are used for connecting the external circuit. According to the resonator, the glass substrate is used as the substrate of the capacitor formed by the first polar plate and the second polar plate, so that the substrate loss and the substrate parasitic capacitance can be reduced, the isolation performance of the capacitor can be greatly improved, and the high-voltage resistance of the resonator can be effectively improved.

The utility model relates to PET polyester bottle technical field discloses a kind of light PET polyester bottles with high-pressure-resistant structure, comprising: light PET polyester bottle body;High-pressure-resistant structure, the high-pressure-resistant structure is arranged on light PET polyester bottle body, the high-pressure-resistant structure is used to improve the compression resistance of light PET polyester bottle body;Convenient operation structure, the convenient operation structure is arranged at the top of light PET polyester bottle body, the convenient operation structure is used to improve the convenience of opening opening and closing.The utility model is designed by arc convex part and hemispherical convex part, so that the bottom of bottle forms hemispherical groove and arc groove, which can uniformly disperse the impact force of medium in the inner cavity bottom of light PET polyester bottle body, disperse internal pressure stress, enhance the load-bearing and compression resistance of bottle bottom, by the design of lower reinforcing ring, connecting rod one, middle reinforcing ring, connecting rod two and upper reinforcing ring, frame structure can be formed on the outer wall of light PET polyester bottle body, to prevent lateral expansion.

According to the technical scheme, the seamless tube comprises an outer tube, a seamless tube body and a lining column, a carbon fiber tube is installed on the outer surface of the seamless tube body through a supporting tube, the outer tube body is installed on the outer surface of the carbon fiber tube through a clamping table, and a ceramic heat-resisting layer is arranged on the outer surface of the outer tube body. A supporting column is installed on the outer surface of the lining column, a supporting rod is installed on the outer surface of the supporting column, a supporting plate is installed at the tail end of the supporting rod, a supporting groove is formed in the position, located on the supporting plate, of the inner surface of the seamless pipe, and the supporting plate is clamped in the supporting groove. The high-temperature-resistant and high-pressure-resistant seamless tube solves the problems that the supporting performance of seamless steel is reduced and the service life of the seamless tube is affected due to the fact that an existing seamless tube is greatly affected by pressure and temperature in a high-temperature and high-pressure environment, the supporting performance of the seamless steel is guaranteed, and therefore the service life of the seamless tube is prolonged.