707 results about "Ductility" patented technology

The invention discloses a composite protective structure resistant to blast shock which is mainly a point truss honeycomb integral protective structure formed by a honeycomb tensile layer and a lattice truss-type compression resistance layer through welding spots and connecting keys, and a foam energy absorbing layer is added on the outer layer. According to the composite protective structure, theforce transmission path of a concrete protective structure under the action of blast is innovatively optimized, the resistance level of the protective structure can be greatly improved, and the structure ductility is improved; and the dispersion of concrete fragments in the structure can be restrained, and the phenomenon of blast and explosion-induced collapse of similar traditional concrete protective structures is eliminated.

The invention belongs to the technical field of metal material engineering, and relates to a light high-toughness low-cost aluminum alloy and a preparation method thereof.The alloy comprises, by mass, 7.0%-9.2% of Mg, 2.5%-4.0% of Zn, 0.06%-0.20% of Zr, 0.01%-0.03% of Sb, main impurities including Fe smaller than or equal to 0.15%, Si smaller than or equal to 0.12%, other single impurities smaller than or equal to 0.05%, the total impurity smaller than or equal to 0.15% and the balance Al. Compared with 2xxx series and 7xxx series aluminum alloys, the alloy has certain advantages in the aspects of density, specific strength, ductility, corrosion resistance and the like, and has a remarkable cost advantage compared with a low-density aluminum-lithium alloy, so that the core competitiveness of an alloy product is improved, and the alloy product has the potential of becoming a next-generation commercial aluminum alloy.

The invention provides a preparation method of laser cladding heterostructure stainless steel. According to the method, dried stainless steel pre-alloyed powder is subjected to laser melting deposition to form heterostructure stainless steel alloy with cross deposition of coarse grains and fine grains; the grain size of the fine crystal is 3-6 [mu] m, and the structure of the fine crystal layer is an equiaxed structure; the grain size of the coarse crystal is 20-50 [mu] m, and the structure of the coarse crystal layer is a columnar crystal formed along the Z axis. According to the method, the specific coarse grain / fine grain cross deposition heterostructure is presented in the stainless steel by changing the deposition layer process parameters and the scanning path, the material strength is improved while the material ductility is guaranteed, and the alloy has the excellent mechanical property.

The invention discloses a method and system for analyzing the rolling resistance of a concrete-filled steel tube combined pier column, and the method comprises the steps: applying an axial compression load to the concrete-filled steel tube combined pier column, and dividing the cross section of the concrete-filled steel tube combined pier column into three layers of regions along a radial material change part; according to corresponding total cross-section average axial strain generated by the steel pipe concrete combined pier column when different axial compression loads are applied, equivalent stress corresponding to each layer of area is calculated, total axial force corresponding to each total cross-section average axial strain is calculated, and a total cross-section average axial strain-total axial force curve is formed; searching a first total cross-section average axial strain corresponding to the maximum value of the total axial force in the total cross-section average axial strain-total axial force curve and a second total cross-section average axial strain corresponding to a first obvious inflection point of the total cross-section average axial strain-total axial force curve, and calculating a ductility coefficient, and judging whether the concrete-filled steel tube composite pier column meets the ductility design requirement or not.

Provided is a steel sheet that may be used for automobile parts and the like, and to a steel sheet having an excellent balance of strength and ductility, an excellent balance of strength and hole expansion ratio, and an excellent yield ratio evaluation index, and a method for manufacturing the same. The steel sheet includes: by wt %, C: 0.1 to 0.25%, Si: 0.01 to 1.5%, Mn: 1.0 to 4.0%, Al: 0.01 to 1.5%, P: 0.15% or less, S: 0.03% or less, N: 0.03% or less, B: 0.0005 to 0.005%, a balance of Fe, and unavoidable impurities; and as microstructures, bainite, tempered martensite, fresh martensite, retained austenite and unavoidable structures.

The invention discloses an Al-Mg-Zn aluminum alloy plate with excellent strong plasticity and light weight characteristics as well as a preparation method and application of the Al-Mg-Zn aluminum alloy plate. The alloy comprises the following components in percentage by mass: 5.0%-5.5% of Mg, 1.5%-2.0% of Zn, 0.4%-0.5% of Mn, 0.1%-0.3% of Cu, 0.15%-0.25% of Sc, 0.1%-0.15% of Zr, 0.05%-0.15% of Ag, less than or equal to 0.1% of impurities and the balance of Al. The density is not more than 2.63 g / cm < 3 >, the tensile strength is not less than 470 MPa, and the ductility is not less than 23%. The preparation method comprises the steps of high-purity raw material smelting and casting, two-stage homogenization, hot rolling, intermediate annealing, cold rolling, solid solution treatment and single-stage aging. Wherein the total pressing amount of hot rolling is 80-85%, the total pressing amount of cold rolling is 20-35%, and the single-stage aging time is 120-140 DEG C * 16-24 h. The microstructure of the alloy is characterized in that the average size of dispersed AlSc particles is smaller than or equal to 100 nm, the area fraction of deformed grains is larger than or equal to 70%, the average size of nanometer beta-AlMg and T-Mg (Al, Zn) composite precipitated phases is smaller than or equal to 20 nm, the number density is larger than or equal to 1 * 10 < m >, the area fraction of micron-order second phases is smaller than or equal to 0.5%, and the alloy is only formed by impurity Fe. According to the method, the traditional two-stage aging process is simplified, low density, high strength and high plasticity are synchronously improved, and the method is suitable for large-scale industrial application.

This invention provides a high-strength, high-ductility austenitic stainless steel and its production method. The composition is: C 0.045%-0.085%, N 0.10%-0.40%, Si 0.90%-1.55%, Cr 16%-20.1%, Ni 7.5%-12.5%, Mn 1.5%-3.5%, Mo 1.5%-3.0%, Nb 0.08%-0.22%, Ti 0.015-0.065%, O≤0.005%, P≤0.003%, S≤0.003%, with the remainder being Fe and unavoidable impurities. Compared with existing technologies, this invention obtains a reasonable grain size and second-phase particles through nitrogen, titanium, and niobium alloying, combined with low-temperature rolling and appropriate annealing and aging heat treatment, thus developing an austenitic stainless steel with excellent mechanical properties. It achieves excellent ductility at a high strength level, with a strength-ductility product as high as 60 GPa·s.

The invention relates to the technical field of maritime work steel production, in particular to an ultrahigh-toughness wear-resistant maritime work steel plate based on gradient structure design and a manufacturing method thereof, and the steel plate comprises the following chemical components in percentage by mass: 0.03%-0.09% of C, 0.85%-1.45% of Si, 1.4%-2.0% of Mn, 0.5%-0.9% of Cr, 5.0%-8.5% of Ni, 0.2%-0.6% of Mo, 0.6%-1.2% of Cu, 0.012%-0.025% of Ti, 0.02%-0.06% of Nb, 0.03%-0.07% of Al, 0.010%-0.018% of Ce, 0.003%-0.006% of B, less than or equal to 0.005% of P, less than or equal to 0.002% of S and the balance of Fe and inevitable impurities. The integrated performance upgrading that one side of the steel plate is wear-resistant and the other side is tough is realized. And the wear resistance, the ductility and the low-temperature toughness of the ultrahigh-strength steel plate are greatly improved.

The invention belongs to the technical field of metal materials, and relates to a CoNiVAlX (x is greater than or equal to 0 and less than or equal to 0.5) multi-principal-element heterostructure entropy alloy system and a preparation method thereof. The chemical composition (atomic percent) of the alloy contains Co, Ni, V, Al and a trace regulator, flexible matching of strength and toughness is realized in a wide temperature range of-263 DEG C to 800 DEG C by regulating the Al content and a thermal mechanical treatment process, and various mechanical states such as'high ductility-medium strength 'and'high strength-medium ductility' can be obtained; the preparation process is based on a mature metallurgical technology and does not depend on special equipment, and large-size stable preparation can be achieved. Tests prove that the alloy system is wide in toughness and adjustable, the toughness balance in a wide temperature range is realized, the application requirements in an extreme environment are met, and the alloy system has a good industrial popularization prospect.

A process for forming extruded products using a device having a scroll face configured to apply a rotational shearing force and an axial extrusion force to the same preselected location on material wherein a combination of the rotational shearing force and the axial extrusion force upon the same location cause a portion of the material to plasticize, flow and recombine in desired configurations. This process provides for a significant number of advantages and industrial applications, including but not limited to extruding tubes used for vehicle components with 50 to 100 percent greater ductility and energy absorption over conventional extrusion technologies, while dramatically reducing manufacturing costs.

The invention discloses a method and system for determining the optimal stress orientation of a concrete special-shaped sheet column, and relates to the technical field of constructional engineering. According to the method, a correlation model of special-shaped contour parameters and load conditions is constructed, a mechanical property key direction set is extracted, the screening range is narrowed, the optimal orientation determination efficiency is greatly improved, the design period is shortened, and the optimal orientation determination efficiency is improved based on multi-dimensional screening of all-circumferential inertia moment distribution, a rigidity curve and a bending moment contribution ratio. Core indexes such as section ultimate bearing capacity and ductility are comprehensively evaluated by combining stress simulation of a concrete nonlinear constitutive relation; through overall structure collaborative checking calculation and node stress analysis, it is ensured that the orientation meets the mechanical requirements of components and adapts to lateral force resistance and stress continuity of the overall structure, in combination with building construction requirements and node compressive strength redundancy optimization, the scheme of optimal mechanics but construction conflicts is eliminated, safety redundancy is reserved, the structure anti-disaster stability is guaranteed, and the construction safety is improved. And meanwhile, the method adapts to complex working conditions and specification requirements and ensures that the scheme can be directly applied.

According to the 3D printing concrete truss girder structure based on three-dimensional steel bar reinforcement and the construction method, through space welding connection of the three-dimensional conical steel bars and the top plane steel bars, the interlayer bonding performance and the overall stress performance of a 3D printing concrete truss girder are remarkably improved. The three-dimensional conical steel bars comprise plane steel bars matched with the truss girder in length and width and a plurality of three-dimensional conical steel bar units, the three-dimensional conical steel bar units are arranged in the mode that the height of a three-dimensional space component formed by bending metal steel bars crosses over at least one or more concrete printing layers, and the plane steel bars are buried in the lower layer concrete. And the upper ends of the three-dimensional conical steel bar units are fixedly connected with the top vertical rod section steel bars of the top plane steel bars on the upper layer or the higher layer or the vertical bars of the next plane steel bars, so that an integral space steel bar framework is formed. The steel plate has higher shear bearing capacity, better ductility and a better failure mode, and is suitable for load-bearing components in various building and bridge engineering.

The invention discloses a multi-cavity aluminum alloy battery pack shell extrusion-bending process optimization method, and relates to the technical field of aluminum alloy machining. According to the method, 6000 series aluminum alloy serves as a base material, and the problems of cracking, resilience, section deformation and uneven performance of a profile in the traditional process are solved through the six-step core process of compound trace element regulation and control, gradient heating ingot casting, PID temperature control extrusion, segmented quenching temperature control, multi-roller cooperative bending and online structure monitoring. The strength and plasticity of the alloy are improved through Mn / Zr or Cu / Ag composite microalloying, extrusion-bending continuous forming and real-time grain boundary migration and dislocation density monitoring are combined, and the multi-cavity structure size precision (the broad side error is + / -1.87 mm, and the narrow side error is + / -0.40 mm) and the mechanical property (the tensile strength is larger than or equal to 200 MPa, and the percentage elongation after fracture is larger than or equal to 8%) both reach the standard. The process shortens the processing period by more than 30%, improves the material utilization rate to 92%, is suitable for large-scale mass production of new energy automobile battery pack shells, and provides key technical support for automobile lightweight.

The invention relates to the technical field of high-speed cable shielding materials, and discloses a manufacturing method of rolled copper foil for high-speed cable shielding. The method comprises the following steps: preparing a copper plate; performing multi-pass cold rolling on the copper plate to form an elongated grain structure oriented along the rolling direction; performing controlled annealing on the cold-rolled copper foil to recover plasticity and inhibit complete recrystallization; the target thickness is obtained through finish rolling; carrying out finishing rolling on at least one surface of the copper foil by adopting a mirror surface working roller so as to reduce the surface roughness; and performing surface smoothing or passivating treatment to inhibit oxidation and performance degradation. Therefore, the obtained rolled copper foil has good ductility, structural stability and high-frequency performance.

The invention discloses an interface enhanced composite shear wall based on a high-ductility cement-based material. The high-ductility cement-based composite materials are formed in edge constraint areas on the two sides of the shear wall, and the common concrete is formed in a core area in the middle of the shear wall. The interface separation net is a high-strength ribbed non-dismantling formwork net and is vertically arranged at the junction of the edge constraint area and the core area, the section of the interface separation net is in a periodic concave-convex wave shape or a stepped shape, and a macroscopic mechanical meshing interface is formed. The interface seaming ribs are U-shaped ribs and are horizontally arranged at the positions of the inter-rib slurry penetrating nets of the interface separation net in a penetrating mode, one ends of the interface seaming ribs are anchored to the edge constraint area common steel bars, and the other ends of the interface seaming ribs extend into the core area and are connected with longitudinal and transverse rib cross joints of the composite material grid ribs in a hooked mode; the problems of rigidity mutation and slippage of the heterogeneous material interface are solved by utilizing the geometric occlusion effect of the interface separation net and the anchoring effect of the deep bolt pins and joints of the interface sewing ribs, cooperative work of a high-ductility material and common concrete is achieved, and good anti-seismic performance is achieved.

The invention discloses a method for preparing a high-toughness titanium alloy pipe through precision forging and the pipe prepared through the method. The pipe prepared through the method is small in anisotropy, the strength in all directions reaches 1100 MPa or above, the ductility reaches 10% or above, the impact toughness reaches 25 J / cm < 2 > or above, and the structure and performance uniformity is good.

This invention relates to the field of metallic materials technology, and more particularly to a negative enthalpy duplex stainless steel material and its preparation method, which possesses high strength, high plasticity, and high corrosion resistance. The negative enthalpy duplex stainless steel material is Fe... a Cr b Ni c Mo d Mn e C f Si g Ti h Al i V j Wherein, a, b, c, d, e, f, g, h, i, and j correspond to the mass percentages of each element: a = 60-70 wt%, b = 15-20 wt%, c = 10-15 wt%, d = 0-5 wt%, e = 1-5 wt%, f = 0.015 wt%, g = 0-1 wt%, h = 0-3 wt%, i = 0-0.5 wt%, j = 0-0.5 wt%, and d, g, h, i, and j are not zero. This series of negative enthalpy duplex stainless steel materials all contain ferrite and austenite in their structure, and the microstructure and mechanical properties of the alloy can be controlled by adjusting the proportions of different metal elements. This series of negative enthalpy duplex stainless steel materials exhibits high strength and high ductility. Simultaneously, negative enthalpy duplex stainless steel materials exhibit excellent corrosion resistance.

The invention provides a high-strength and high-ductility damage self-repairing cement-based composite material based on spiral memory alloy fibers and a preparation method of the high-strength and high-ductility damage self-repairing cement-based composite material, and belongs to the technical field of underwater engineering concrete structures. According to the invention, the matrix mix proportion of the cement-based composite material and the hybrid reinforcement effect of the three fibers on the matrix are redesigned, so that the tensile strain capacity is also remarkably improved while the strength of the UHPSC is improved, and the deformation ductility and the cumulative energy dissipation capacity of the cement-based composite material are further remarkably enhanced; as the spiral superelastic SMA fibers have self-resetting capacity, restoring force can be provided for the unloaded cement-based composite material, tensile cracks of the cement-based composite material are promoted to be automatically closed or the width of residual cracks of the cement-based composite material is obviously reduced, and on the basis, the self-healing capacity of an incompletely hydrated cementing material in the cement-based composite material is matched, so that the self-healing performance of the cement-based composite material is improved. And the UHPSC material can present a good damage self-repairing effect.

The invention discloses high-strength heat-resistant aluminum-copper alloy powder, a 3D printing application method and an aluminum product. Relates to the technical field of metal material and additive manufacturing, in particular to a high-strength heat-resistant aluminum alloy material suitable for selective laser melting. The alloy powder is composed of Cu, Sc, Ni, Ce, Si, Mn, Ti, Fe and Al, the content of Cu ranges from 5 wt% to 15 wt%, the content of Sc ranges from 0.3 wt% to 2 wt%, the content of Ni ranges from 0.5 wt% to 5.5 wt%, the content of Ce ranges from 0.5 wt% to 5.5 wt%, and an Al7Cu4Ni eutectic phase is generated in situ in the printing process. And through a multi-element synergistic strengthening mechanism, the solidification interval is effectively reduced, cracks are inhibited, and meanwhile fine grain strengthening and precipitation strengthening are achieved. After SLM forming and low-temperature heat treatment, the obtained aluminum product has ultrahigh strength, good plasticity and excellent heat resistance, the tensile strength exceeds 650 MPa, the hardness exceeds 180 HV0.2, the ductility exceeds 7%, and the aluminum product meets the requirements for light high-strength heat-resistant components in the high-end fields such as aerospace and the like.

The invention discloses a magnesium-rare earth alloy with a grinding tooth-shaped interface structure and a preparation method and application thereof, and belongs to the technical field of magnesium alloy material processing. According to the magnesium-rare earth alloy with the meshed tooth-shaped interface structure, a W phase is directionally separated out around the boundary of an Al2 (Gd, Y) phase. The Mg-Gd-Y-Zn-Al alloy serves as a base, a high-modulus Al2 (Gd, Y) phase is introduced, directional precipitation of a W phase around the boundary of the Al2 (Gd, Y) phase is achieved through multiple times of ultrasonic vibration composite multi-axial vibration coupling and secondary solution treatment, the Al2 (Gd, Y) phase with a tooth-shaped microcosmic interface structure is constructed, compatible deformation with a magnesium matrix is achieved, the Al2 (Gd, Y) phase is refined through composite deformation machining, stress concentration is relieved, and the mechanical property of the alloy is improved. And meanwhile, the strength and plasticity of the alloy are improved through torsional deformation of the LPSO phase. Through the formation of the special microstructure, the high strength, the high modulus and the high ductility of the magnesium-rare earth alloy are synchronously improved.

The invention provides a manufacturing method of a copper-nickel alloy pipe with excellent high-temperature plasticity. The manufacturing method comprises the following steps that S1, Ni, Fe, Mn, Ti, CuMg20 and Cu raw materials are weighed according to components of a nickel-based alloy pipe; s2, raw materials of Cu, Ni, Fe, Mn and Ti are smelted, CuMg20 is added for deoxidation, and an alloy round ingot is obtained through casting; s3, the alloy round ingot is subjected to homogenizing annealing; s4, forging and upsetting the alloy round ingot to obtain an upset round ingot; s5, performing hot extrusion on the upset round ingot to obtain a tubular billet; s6, the tubular billet is subjected to cold rolling, and annealing is conducted between pass cold rolling; and S7, the tubular billet is subjected to heat treatment, and the copper-nickel alloy pipe is obtained. According to the method, the uniformity and thermoplasticity of the alloy structure are improved, the plasticity and comprehensive mechanical performance of the copper-nickel alloy pipe in the high-temperature environment are remarkably improved, and the method is stable, high in repeatability and beneficial to large-scale production of the high-quality copper-nickel alloy pipe.

The invention discloses a building component and a building structure, and relates to the technical field of buildings. Wherein a cavity is limited in the framework, and a plurality of communicating holes capable of communicating with the cavity are formed in the cavity wall of the framework; and the concrete body covers the periphery of the framework and is filled in the cavity. The excellent compression resistance of the concrete body can be used for bearing the load of a pressure area, meanwhile, restraining force can be generated on the framework, local yielding of the framework is prevented, the fireproof and anti-corrosion effects can be achieved, the framework can bear tensile force to make up for the tensile weakness of the concrete body, shear force can be borne, ductility is improved, and the service life of the concrete body is prolonged. And the bearing capacity and the stability of the building component are improved. Besides, the mechanical occlusal force between the framework and the concrete body can be increased through the communicating holes, interface slippage and cracking are effectively avoided, and the cooperative work capacity and durability of building components under long-term loads are guaranteed.

Provided are a solder alloy, a solder paste, a solder ball, and a solder joint which have a low melting point, are excellent in ductility, shear strength, and heat cycle resistance, further suppress the occurrence of open defects, and in addition, have reduced residual voids even at the time of joining in a large area. A solder alloy has an alloy composition of, by mass %, Bi: 35.0 to 68.0%, Sb: 0.1 to 2.0%, Ni: 0.010 to 0.050%, Ge: 0.007 to 0.090%, with the balance being Sn. Preferably, the alloy composition further contains, by mass %, at least one of Co, Ti, Al, Mn, As, Fe, Pd, Zn, Zr, Pb, In, Ce, P, and Ga: 0.1% or less in total. Further, this solder alloy can be suitably used for solder pastes, solder balls, and solder joints.

Provided are a high-strength hot-rolled steel sheet having high strength, high ductility, excellent strain dispersibility, high stretch flangeability, and bendability, a member, and methods for manufacturing the same.　The high-strength hot-rolled steel sheet has a prescribed component composition, and has a steel structure in which, in terms of area ratio, the total of bainite and tempered martensite is 80.0% or more, pearlite is 10.0% or less, retained austenite is 15.0% or less, the total of retained austenite and pearlite is 1.0% or more, the total of tempered martensite and bainite having a circle-equivalent diameter of 5.0 μm or more is 10.0% or less, and the proportion of line segments having a hard phase fraction of 20.0% or more among line segments having a length of 200 μm parallel to the rolling direction is 30.0% or less, the tensile strength TS (MPa) and the component composition (mass%) satisfy the expression 0 ≦ 730 + 2000 × (C + Si / 16 + Mn / 40 + Al / 18 + Cr / 40 + Ni / 40 + Mo / 20 + Ti / 3) – TS ≦ 250, where each element symbol in the formula represents the content (mass%) of each element, and the high-strength hot-rolled steel sheet has a tensile strength of 980 MPa or more.

The invention relates to high-strength and high-ductility wear-resistant medium manganese steel and a preparation method thereof, belongs to the technical field of ferrous metallurgy, and aims to solve at least one of the problems that in the prior art, medium manganese steel is low in initial yield strength and difficult to meet the application requirements of high-wear-resistant parts, high plasticity and high wear resistance are difficult to consider, and long-term stable service is difficult to realize in a high-wear environment. The invention relates to wear-resistant medium manganese steel with high product of strength and elongation. The medium manganese steel comprises the following chemical components in percentage by mass: 0.35%-0.45% of C, 0.75%-1.25% of Si, 8.5%-11.5% of Mn and the balance of Fe and inevitable impurities. By optimizing the alloy design of the medium-manganese wear-resistant steel, the limitation of insufficient initial hardness of the traditional medium-manganese steel is overcome, so that the medium-manganese steel can have higher surface hardness in a non-work-hardening stage, thereby showing excellent wear resistance in the initial service stage of a structural part; and the problem of high wear rate caused by insufficient hardness of the traditional high / medium manganese steel at the initial stage of wear is effectively avoided.

The application provides a steel plate heat treatment method and a steel plate obtained by the method, and the preparation method comprises the following steps: sequentially performing shot blasting, straightening and tempering on a hot-rolled steel plate to obtain a dust-free steel plate; in the shot blasting step, the shot blasting current is 40-50 A, the shot blasting speed is 5-10 m / min, and the shot diameter is 0.6-0.8 mm. The shot blasting step removes the oxide layer on the surface of the hot-rolled steel plate, so that the alloy part with better plasticity is exposed, so that the ductility of the surface of the steel plate is uniform in the subsequent straightening process, the generation of dust is reduced, on the other hand, the internal stress in the steel plate can be eliminated through the final tempering step, the ductility or toughness of the steel plate is improved under the condition that the hardness and strength of the steel plate are not reduced or are appropriately reduced, and the final use performance of the steel plate is improved.

The invention relates to low cost high ductility cast aluminum alloys. Recycled (recycled) aluminum alloys are provided for casting into structural components, such as vehicle components. The aluminum alloys include at least 80 wt. % aluminum, 0.1 wt. % to 0.6 wt. % copper, 6.0 wt. % to 8.0 wt. % silicon, 0.10 wt. % to 0.60 wt. % magnesium, 0.10 wt. % to 0.50 wt. % zinc, 0.12 wt. % to 0.30 wt. % iron, 0.2 wt. % to 0.6 wt. % manganese, not greater than 0.15 wt. % titanium, 0.015 wt. % to 0.03 wt. % strontium, other elements in amounts not greater than 0.05 wt. % each and not greater than 0.15 wt. % total.

The invention discloses a welding process of a high-strength onboard load training device, which adopts a structural combination of a plurality of layers of steel plates and a high-ductility alloy connecting piece, and utilizes a composite welding device consisting of a welding head, a gas generating ring, a tempering heating ring and a slow cooling gas curtain ring which are coaxially arranged. The synergistic effect of an electric arc heat source and a laser heat source can be achieved in the welding process, a deep penetration weld joint is formed, and sufficient metallurgical bonding of the multi-layer steel plate and an alloy connecting piece is ensured. And in cooperation with annular protective gas, local tempering and slow cooling control, the welding seam structure can be effectively improved, the residual stress can be reduced, cold cracks and fatigue cracks are prevented, and therefore the strength and stability of a welding joint are remarkably improved.

The application discloses a Ti-55531 titanium alloy with high toughness and plasticity and a preparation method thereof. The preparation method specifically comprises the following steps: (1) placing the Ti-55531 titanium alloy into a muffle furnace or a resistance box-type heating furnace, and heating the Ti-55531 titanium alloy to 880 DEG C to 910 DEG C with the furnace, and keeping the temperature for 1 h to 2 h; (2) transferring the Ti-55531 titanium alloy treated in the step (1) into a heating furnace with a furnace temperature of 660 DEG C to 680 DEG C, keeping the temperature for 10 h to 15 h, and then air cooling the Ti-55531 titanium alloy to room temperature, so that the Ti-55531 titanium alloy with high toughness and plasticity is obtained. The lamellar structure of the obtained Ti-55531 titanium alloy has a multi-level structure, the multi-level structure comprises original beta grains, alpha beam sets, lamellar alpha, nanometer twinning structures and discontinuous grain boundary alpha, so that the Ti-55531 titanium alloy has high toughness and high plasticity.

According to the compression-resistant precision steel pipe, two positioning rings are symmetrically arranged in a steel pipe body, two butt-joint rings are symmetrically arranged at the two ends of the steel pipe body, butt-joint plates are arranged at the outer ends of the butt-joint rings, and the butt-joint rings can be inserted into the steel pipe body and make contact with the positioning rings; a plurality of grooves and reinforcing ribs are arranged on the outer wall of the steel pipe body, the reinforcing ribs are located in the grooves, a plurality of limiting holes are formed in the peripheral side of the butt joint plate, the two ends of each reinforcing rib can be inserted into the corresponding limiting hole, the steel pipe body is composed of an inner reinforcing layer and an outer toughness layer, the reinforcing layer made of alloy steel provides high-strength support, and the reinforcing ribs are made of steel. External pressure can be effectively resisted, and steel pipe deformation is prevented; the ductile layer made of low-carbon steel endows the steel pipe with good toughness, pressure impact can be buffered, brittle fracture is avoided, and the compressive property of the steel pipe is essentially improved through combination of the ductile layer and the steel pipe.