68results about How to "Good welding performance" patented technology

The invention discloses a high-strength silver-free copper-based brazing filler metal which is composed of P, Sn, Ni and Cu. The high-strength silver-free copper-based brazing filler metal is low in cost, safe, environmentally friendly and good in welding effect; through the adding of Sn and Ni, the melting point of brazing filler metal alloy is reduced, and the tensile strength and wettability of the brazing filler metal alloy are enhanced.

The invention relates to the technical field of metal materials, in particular to a high-strength steel material for mine roadway support and a preparation method thereof, and the high-strength steel material comprises the following components in percentage by weight: 0.04 to 0.10 percent of C, 0.15 to 0.45 percent of Si, 1.20 to 1.80 percent of Mn, 0.20 to 0.50 percent of Cu, 0.15 to 0.40 percent of Cr, 0.10 to 0.35 percent of Ni, 0.08 to 0.25 percent of Mo, 0.015 to 0.045 percent of Nb, 0.03 to 0.08 percent of V, 0.008 to 0.025 percent of Ti, 0.005 to 0.020 percent of RE and the balance of Fe. The preparation method comprises the steps of smelting and refining, continuous casting, heating, rough rolling, finish rolling, segmented controlled cooling and medium-temperature tempering (450-550 DEG C), R is larger than or equal to 620 MPa, A is larger than or equal to 18%, the yield ratio is smaller than or equal to 0.90, KV at 0 DEG C is larger than or equal to 100 J, and the deep-well high-stress roadway support is suitable for deep-well high-stress roadway support.

This application relates to a weathering steel, its preparation method, and its application, belonging to the field of steel preparation technology. The chemical composition of the steel includes C 0.030-0.050%; Si ≤0.10%; Mn 1.25-1.70%; P ≤0.020%; S ≤0.003%; Al 0.02-0.05%; Nb 0.010-0.030%; Ti 0.03-0.07%; Ni 0.02-0.05%; Cu 0.2-0.5%; Cr 0.8-1.5%; N ≤0.0040%; Ca 0.001-0.004%. It adopts a reasonable ratio of weathering-resistant elements such as copper, chromium, and nickel added on a low-carbon, low-silicon, and low-manganese basis. The combination of Cu and Cr can form a dense α-FeOOH oxide rust layer on the surface of the steel, preventing further corrosion of the steel matrix.

This invention discloses a manufacturing process for composite 7-series aluminum alloy sheets. The composite 7-series aluminum alloy sheets are formed by laminating and rolling multiple layers of 7-series aluminum alloy sheets and multiple layers of 1-series aluminum alloy connecting plates. The 7-series aluminum alloy sheets are composed of the following components by weight percentage: Si: ≤0.22%, Cr: ≤0.23%, Fe: ≤0.35%, Cu: 2.0-3.5%, Mg: 3.5-4.5%, Zn: 6.5-10.0%, Ti: 0.015-0.2%, Zr: 0.05-0.15%, rare earth cerium alloy: 0.015-0.05%, total impurities ≤0.1%, and the remainder being aluminum. This invention uses a lamination method to roll multiple layers of 7-series aluminum alloy sheets and multiple layers of 1-series aluminum alloy connecting plates, which effectively improves plasticity, toughness, and strength. Compared with existing single 7-series materials, it has higher material strength, better impact resistance and weldability, can adapt to corrosion resistance in complex environments, and extends service life.

The application belongs to the technical field of copper-based diamond composite materials, and particularly relates to a diamond copper-based composite material and a preparation method thereof. The preparation method comprises the following steps: mixing modified diamond powder and copper powder by ball milling, and obtaining a diamond copper core material after hot-pressing sintering; activating the diamond copper core material, then magnetron sputtering a Ni / Pr alloy target material onto the upper and lower surfaces of the activated diamond copper core material to form a Ni / Pr composite intermediate layer; vacuum welding copper sheets on the upper and lower surfaces of the Ni / Pr composite intermediate layer to obtain the diamond copper-based composite material. The diamond copper-based composite material prepared by the application has high density, excellent thermal conductivity, low thermal expansion coefficient and is convenient to process.

The application discloses a high-entropy alloy wear-resistant coating flux-cored wire, which comprises a flux core and a welding sheath; the flux core is composed of the following components: Ti: 25%-30%, Ta: 20%-25%, Al: 20%-23%, Mn: 20%-23%, Y: 5%-15%, and the sum of the atomic percentages of the above components is 100%; the welding sheath is an FeCoNi strip, and the welding sheath is composed of the following components: Cr: 0.006%, Cu: 0.011%, C: 0.1%, Co: 17.31%, Ni: 29.08%, Si: 1%, and Fe is the balance. The application further discloses a preparation method and application of the high-entropy alloy wear-resistant coating flux-cored wire. The application solves the problems of insufficient high-temperature performance, easy wear and easy corrosion of a new nuclear power turbine blade TC4 surface under a long-term working environment.

The application relates to the technical field of welding materials, and particularly discloses a high-temperature-resistant flux-cored wire containing rare earth elements and a preparation method thereof. The high-temperature-resistant flux-cored wire containing rare earth elements comprises a wire sheath and a core; the core comprises the following raw materials: dehydrated rutile, dehydrated potassium feldspar, zircon sand, metal chromium powder, metal nickel powder, electrolytic manganese, ferrotitanium, aluminiferous iron, potassium cryolite, potassium titanate, sodium titanate, iron powder, yttrium-based iron alloy powder, atomized ferrosilicon, chromium-iron nitride, bismuth oxide, an additive, and the balance of reduced iron powder; the additive is a mixture of zirconium-iron alloy, ferrotitanium alloy and aluminum-magnesium alloy. The application introduces a specific alloy additive into the core to protect the transition of the rare earth yttrium, optimizes the welding performance of the yttrium and multiple components in cooperation, matches the 253MA heat-resistant steel, adjusts the components of the molten slag and the electric arc, and reasonably processes the technology, so that the welding quality of the wire is improved.

The utility model relates to the technical field of tail lamp outer framework welding equipment, in particular to a through type tail lamp outer framework welding device, which is provided with a bidirectional swing welding device, adjusts a welding angle in two directions, is convenient to weld a tail lamp outer framework with a complex curved surface structure, and improves the welding effect of a machine. Comprising a body; the welding machine comprises a machine body and further comprises a positioning and conveying device, a stamping and shaping device, a horizontal moving device, an up-down moving device and a bidirectional swing welding device, the positioning and conveying device, the stamping and shaping device and the horizontal moving device are all installed on the machine body, the up-down moving device is installed on the horizontal moving device, and the bidirectional swing welding device is installed on the up-down moving device.

This invention discloses a hot-rolled steel sheet for vacuum train tubes that exhibits excellent yield strength, weldability, low-temperature toughness of the welded portion, vibration damping ratio, and is free from hot cracking. The hot-rolled steel sheet according to this invention is characterized in that its alloy composition, by weight percent, comprises: C: less than 0.06% (more than 0%), Si: 0.5-1.5%, Mn: 1.2-2.2%, Cu: 0.5-1.5%, Ni: more than 0.25%, Ti+Nb+V: less than 0.02% (inclusive of 0%), the balance being Fe and unavoidable impurities.

The invention provides a double-shaft-shoulder friction stir welding device with an adjustable shaft shoulder distance and a friction stir girth welding method of the double-shaft-shoulder friction stir welding device. The device comprises an adjustable double-shaft-shoulder stirring tool (1), a rotating main shaft (3), a withdrawing shaft (4), a clamp (5), a positioning platform (6) and a workbench (7), the adjustable double-shaft-shoulder stirring tool (1) is composed of an upper shaft shoulder, a lower shaft shoulder and an adjustable stirring needle, and the rotating main shaft (3) is adopted for controlling rotation of the adjustable double-shaft-shoulder stirring tool (1); and the withdrawing shaft (4) is adopted to adjust the length of the stirring needle. According to the adjustable stirring device, the adjustable stirring needle can freely stretch out and draw back through the withdrawing shaft (4), so that the distance between the shafts can be controlled, and the adjustable stirring device can adapt to welded workpieces (2) with different plate thicknesses. In addition, the press-in amount of the upper shaft shoulder and the lower shaft shoulder can be adjusted in the welding process, and welding forming is better facilitated. The adjustable double-shaft-shoulder stirring tool (1) is not only suitable for common welding seams, but also suitable for closed circumferential welding seams.

This invention discloses a ship plate steel with high plasticity, excellent impact toughness, and excellent weldability, and its production method. The composition of the ship plate steel includes C, Si, Mn, Als, P, S, Re, and the balance Fe and impurities. The preparation method includes: heating the billet at a temperature of 1150–1250℃, a heating rate of 8–12 min / cm, and a furnace exit temperature in the range of 1170±30℃; rolling: the first-stage rolling temperature is ≥1050℃, the intermediate billet thickness is 3 times the thickness H of the finished steel plate, and the second-stage rolling temperature is ≤960℃. The final rolling temperature is 830±30℃; the red-hot temperature after rolling is determined according to the thickness H of the finished steel plate. When H≤16mm, the red-hot temperature after rolling is 620±40℃; when 16<H≤25mm, the red-hot temperature after rolling is 640±30℃. The maximum thickness of the finished steel plate obtained by this invention is 25mm, the yield strength ReH≥320MPa, the tensile strength Rm≥420MPa, the elongation A≥30%, the longitudinal impact energy KV2≥200J at 0℃, and the steel plate microstructure is ferrite + pearlite. It is an economical high-plasticity ship plate steel.

The utility model relates to glass welding technical field and disclose a kind of glass welding vacuum jig, including base, the top of base is equipped with fixed base, the both sides outer wall of fixed base is fixedly connected with the connecting block of symmetrical distribution, when installation, the output shaft rotation of motor drives bidirectional screw rod rotation and further drives movable plate to move, movable plate moves through connecting rod and drives pressing plate, and further make pressing plate close to fixed base, when positioning plate and fixed base contact, fixed base makes positioning plate move and enter into recess, first spring deformation, glass body along positioning plate enters fixed base, until two groups of glass body are pasted, at this time, the cavity is sealed by first sealing gasket and second sealing gasket, start vacuum pump, vacuum pump carries out vacuumizing in the cavity through conduit, it is convenient to install, ensure that the glass to be welded between is vacuum state, make two layers of glass to be welded stick tighter to reach better welding effect.

This invention relates to a method for producing low-density, high-strength, and high-toughness protective steel plates from continuously cast billets, belonging to the field of metallurgy. The steel plate is an Fe-Mn-Al-C series austenitic low-density steel plate with an austenitic matrix supplemented by dispersed fine precipitated carbides, achieving high strength and high toughness, thus meeting the requirements for ballistic protection. The steel plate has a production thickness of 6-12 mm, a width of 1600-3000 mm, and a density of 6.75-7.05 g / cm³. 3 It has a density 7.85 g / cm³ higher than that of conventional steel. 3 The steel plate exhibits at least a 10% reduction in weight, good machinability and weldability, and excellent ballistic protection performance. A 6mm thick steel plate meets the NATO AEP STANAG 4569 standard Level I ballistic protection requirements, while a 12mm thick steel plate meets the NATO AEP STANAG 4569 standard Level II ballistic protection requirements. Production process: smelting—continuous casting—slow cooling—rolling—heat treatment—finishing—inspection—warehousing.

This invention relates to a method for welding the ends of an aluminum rotating target. The method includes the following steps: (1) assembling both ends of the aluminum target tube with a flange and a cap respectively to obtain an aluminum target tube with a welded joint; (2) performing friction stir welding on the welded joint in step (1), and machining it after cooling to obtain the aluminum rotating target; the friction stir welding in step (2) includes a first weld, a second weld, and a third weld performed sequentially. This invention, by dividing the friction stir welding process into three sequential welds, achieves excellent weld joint performance, eliminates crack defects, and significantly improves sealing performance.

This utility model relates to the technical field of welding positioning equipment, and discloses a gearbox welding positioning device with a positioning structure. It includes a welding platform, a storage box fixedly mounted at the lower end of the welding platform, a support base fixedly mounted at the lower end of the storage box, a telescopic leg fixedly mounted at the lower end of the support base, a movably mounted stabilizing leg pad at the lower end of the telescopic leg, a convenient handle fixedly mounted at the other end of the storage drawer, and a locking block fixedly mounted at the other end of the storage drawer. This gearbox welding positioning device with a positioning structure improves the device's movable positioning and welding capabilities. In actual use, the workpiece can be rotated, positioned, and clamped as needed, facilitating welding and improving the welding positioning effect of the gearbox welding positioning device with a positioning structure.

This invention discloses an electromagnetic pulse welding coil for welding tubular metals. The electromagnetic pulse welding coil is arranged circumferentially along a driving tube. The driving tube can obtain Lorentz force through electromagnetic induction of the electromagnetic pulse welding coil, providing the impact velocity for welding. The electromagnetic pulse welding coil is composed of several circumferentially connected "convex"-shaped structures. The "convex"-shaped structures are arranged with an inward rotation of 90°, and the wide end at the outer end has a notch. One side of the notch is connected to the other side of the notch of the adjacent "convex"-shaped structure through a connecting block, thereby connecting all the "convex"-shaped structures into a whole, forming a ring structure around the driving tube. This invention has the advantages of significantly improving the electromagnetic energy utilization efficiency, increasing electromagnetic energy, and being applicable to electromagnetic pulse welding of difficult-to-deform metals.

The application provides an acid core wire and a preparation method and application thereof, and particularly relates to the technical field of welding materials. The core wire comprises a steel belt sheath and a core filled in the steel belt sheath. The core comprises the following components in percentage of mass: 35-50% of rutile, 2.5-5% of zircon sand, 2.5-5% of potassium feldspar, 1.5-3% of potassium fluozirconate, 1.5-3% of quartz, 15-20% of metallic manganese, 3-5% of ferrosilicon, 15-20% of nickel powder, 1-2% of cobalt powder, 1-2% of molybdenum powder, 1-2% of aluminum-zirconium alloy, 1.5-3.5% of magnesium powder, 1-2% of perovskite, and the rest is atomized iron powder. The acid core wire has good welding process, good arc stability, less spatter, good appearance of weld formation, good deslagging property, high deposition rate and deposition rate, and the weld has the characteristics of high strength, high low-temperature impact toughness and corrosion resistance, and can meet the use requirement of high-strength Q690 rack steel.

The getter activation type vacuum welding furnace comprises a rack assembly and a cavity assembly borne by the rack assembly, and the cavity assembly comprises a cavity assembly body, a pressing module, a movable partition plate assembly and a clamp assembly; a process chamber is formed in the cavity assembly; the pressing module is arranged in the cavity assembly; the movable partition plate assembly comprises a first partition plate, a second partition plate and a partition plate driving assembly used for driving the first partition plate and the second partition plate to rotate to be separated and folded. The clamp assembly comprises a lower clamp and an upper clamp, the lower clamp is fixed to the cavity assembly, and the upper clamp is configured to move close to the lower clamp under driving of a downward pressing head of the downward pressing module so that a first workpiece on the upper clamp can make contact with a second workpiece on the lower clamp. According to the scheme, by means of the scheme that physical isolation is activated firstly, then isolation is removed, and pressing welding is conducted, partitioned heating of the upper clamp and the first workpiece on the upper clamp and partitioned heating of the lower clamp and the second workpiece on the lower clamp are achieved.

This application relates to a hot-rolled pickled duplex steel and its preparation method, belonging to the field of strip steel production technology. The chemical composition of the duplex steel, by mass fraction, is: C: 0.05%~0.15%, Si: 0.15%~1.50%, Mn: 1.0%~2.0%, Al: 0.02%~0.10%, P≤0.015%, S≤0.006%, Cr: 0.1%~0.5%, Nb: 0.01%~0.05%, Ti: 0.01%~0.03%, Ni: 0.01%~0.40%, V: 0.001%~0.050%, with the remainder being Fe and unavoidable impurities. Through optimized C-Si-Mn-Cr-Nb-Ni composition system design, combined with controlled rolling and staged laminar flow cooling processes, a multiphase microstructure composed of ferrite and martensite was successfully obtained in the hot-rolled pickled duplex steel. This multiphase microstructure enables hot-rolled and pickled duplex steel to maintain high strength while retaining high elongation. Furthermore, a specific component ratio effectively suppresses softening in the weld heat-affected zone. This hot-rolled and pickled duplex steel is particularly suitable for passenger car chassis manufacturing, achieving a balance between lightweight design, high safety performance, and good manufacturability.

The invention discloses a production method of seawater corrosion resistant steel Q345qNHY-I. The technological process comprises the steps of converter smelting, refining, continuous casting, heating and rolling, cooling and checking and warehousing. The steel comprises the following chemical components in percentage by mass: 0.03 to 0.05 percent of C, 0.15 to 0.30 percent of Si, 0.8 to 0.9 percent of Mn, less than or equal to 0.012 percent of P, less than or equal to 0.0015 percent of S, 0.020 to 0.030 percent of Nb, 0.015 to 0.02 percent of Ti, 0.015 to 0.025 percent of Al, 1.32 to 1.45 percent of Ni, less than or equal to 0.06 percent of Cr, 0.23 to 0.27 percent of Mo, less than or equal to 0.01 percent of V, 0.45 to 0.50 percent of Cu, 0.9 to 2.0 percent of Ca / S, more than or equal to 1.29 percent of V and the balance of Fe and inevitable impurities. The steel produced by the method has moderate strength, good toughness, excellent low-temperature toughness, excellent processability and excellent welding performance.

This invention discloses a low-carbon equivalent, high-toughness, ultra-high-strength marine engineering steel, FH550, and its production method, belonging to the field of metallic materials technology. The chemical composition of this steel, by mass percentage, is: C: 0.06~0.12%, Si: 0.20~0.40%, Mn: 1.30~1.70%, P≤0.015%, S≤0.003%, Al: 0.02~0.05%, Nb: 0.030~0.06%, V: 0.010~0.040%, Ti: 0.010~0.025%, Cr: 0.10~0.30%, B: ≤0.0005%, with the balance being Fe and impurities, and a carbon equivalent (Ceq) ≤0.44%. The production method includes: hot metal pretreatment → BOF smelting → LF refining → RH vacuum treatment → thick slab continuous casting → slow cooling with cover → billet heating → two-stage rolling → accelerated cooling → flaw detection → inspection. The two-stage rolling adopts a strong reduction process, and accelerated cooling after rolling replaces the quenching and tempering treatment. The FH550 steel plate of this invention has a yield strength ≥550MPa, an average KV2 impact energy ≥260J at -60℃, and combines ultra-high strength, low-temperature high toughness, and excellent weldability. The production process is simple, has a short cycle, and low cost, and can be widely used in deep-sea marine engineering, bridges, and other fields.

This invention relates to a 3D printing additive manufacturing method for die-casting mold steel metal powder. The metal powder has the following mass percentage content: carbon: 0.20-0.28%, silicon: <0.1%, manganese: 0.20-0.5%, molybdenum: 1.30-1.80%, chromium: 1.50-2.50%, vanadium: 0.10-0.50%, tungsten: 0.3-0.6%, nickel: 2.00-3.00%, copper: 0.80-1.00%, sulfur: ≤0.02%, phosphorus ≤0.025%, oxygen ≤0.025%, with the remainder being Fe and unavoidable impurities. The additive manufacturing method employs selective laser melting, with a laser power of 200W-320W, a laser scanning speed of 800-1100mm / s, a scanning spacing ≤0.1mm, and a laser energy density of 68.17-127.08J / mm². 3 The powder layer thickness is ≤0.03mm, the scanning strategy is 65~70°, and the substrate preheating temperature is 120~150℃ to obtain the alloy. Its beneficial effects are: through alloy composition design and selective laser melting, the prepared alloy exhibits low crack sensitivity and high thermal conductivity, achieving a dual improvement in strength and toughness. It ensures the formation of high-toughness, low-expansion lath martensite, providing excellent toughness while possessing extremely good weldability and being less prone to cracking.

The application discloses a building steel bar welding device and belongs to the technical field of steel bar welding. The building steel bar welding device comprises a supporting base, the upper surface of the supporting base is provided with cleaning mechanisms at both ends, the cleaning mechanisms comprise cleaning assemblies for cleaning steel bars, limiting driving assemblies for fixing the steel bars and supporting and position adjusting the cleaning assemblies, the cleaning assemblies are arranged at one end of the limiting driving assemblies, and the upper surface of the supporting base is provided with first limiting supporting plates for supporting the limiting driving assemblies at both ends. The steel bar is cleaned multiple times through the cooperation of multiple structures, the welding quality of the steel bar welding device is not affected by the residual sundries on the steel bar, the welding effect of the steel bar welding device on the steel bar is better, and secondly, the application can be applied to different types of steel bars, so that the application range of the steel bar welding device is wider.

This invention discloses a method for producing hot-rolled pickled steel strip for CT70 grade coiled tubing, comprising: smelting and continuous casting, wherein the chemical composition and weight percentage of the continuously cast billet are: C: 0.06~0.10%, Si: 0.10~0.30%, Mn: 0.60~0.90%, P: ≤0.018%, S: ≤0.005%, Cu: 0.20~0.30%, Ni: 0.10~0.25%, Cr: 0.45~0.65%, Mo: 0.10~0.30%, Nb: 0.008~0.015%, with the remainder being Fe and impurities; heating the continuously cast billet; hot rolling; cooling and coiling. This invention, by adding appropriate amounts of Mn, Cu, Cr, Ni, Mo, and Nb, ensures that the product is matched with a reasonable controlled rolling and cooling process and pickling process, resulting in a product with uniform and fine microstructure, stable performance, and good surface quality and strip shape.

This invention relates to the field of hot extrusion manufacturing technology, specifically to a high-strength weldable 6xxx series aluminum alloy profile, its manufacturing method, and its application. The aluminum alloy profile is composed of the following weight percentages: Si: 0.80%~1.2%, Fe≤0.20%, Cu: 0.40%~0.80%, Mn: 0.30%~0.70%, Mg: 0.70%~1.1%, Cr≤0.25%, Zn≤0.10%, Ti≤0.10%, Zr: 0.05%-0.20%, Pb<0.01%, with the balance being Al and unavoidable impurities. The profile meets the following performance requirements: tensile properties, R... m ≥420MPa, R p0.2 ≥330MPa, A 50mm ≥8.0%; Fatigue performance: at r=0.1, N=1×10 7 Under the same conditions, the fatigue strength σ of the smooth sample is ≥145MPa, realizing the lightweight manufacturing of high-speed trains.

The present application relates to a kind of bridge bent cap reinforcement cage processing welding equipment, it includes positioning device and gantry welding device;Positioning device includes bottom plate, bottom plate is equipped with the placement plate for placing reinforcement cage, placement plate is equipped with the locking mechanism and fixed assembly for fixing reinforcement cage, the turnover mechanism for overturning placement plate, the support mechanism for supporting reinforcement cage;The upper surface before the turnover of reinforcement cage is the front of reinforcement cage, at this time also the front of placement plate, the upper surface after the turnover of reinforcement cage is the back of reinforcement cage, at this time also the back of placement plate;Each welding position corresponds a set of locking mechanism, each locking mechanism is equipped with the slot for the welding position of the back of reinforcement cage to expose, fixed assembly is used to assist fixing straight steel one and straight steel two;Gantry welding device includes gantry, three-axis module and laser welding head.The technical scheme improves the welding efficiency and welding effect of reinforcement cage.

The invention discloses a production method of a Q355B, C and D grade steel plate with the thickness of 81-120mm. A normalizing rolling and immersion type rapid cooling process is adopted, a casting blank is rolled in a recrystallization area, a large reduction process is adopted to crush, flatten and lengthen original austenite, in order to avoid growth of uncrushed austenite grains, Nb elements in the steel plate induce separation of Nb (C and N) at a grain boundary, and the thickness of the Q355B, C and D grade steel plate is increased. The pins are used for preventing growth of woven grains, the steel plate is rapidly cooled in water after being rolled, the temperature of the core part of the steel plate is reduced to be below Ar3, the steel plate is converted into 60% ferrite and 40% pearlite structures, incompatibility of strength and low-temperature impact caused by growth of internal structure grains of the steel plate is avoided, the production process is simple, the cost is low, industrial batch production is easy to achieve, and the production cost is low. The produced steel has good obdurability matching and welding performance.

The invention discloses a welding method for a thin-walled pipe and a thick-walled part. The welding method aims at overcoming the defects that the welding difficulty of the thin-walled pipe is large, and the welding effect is poor. The method comprises the following steps that S1, the end of a thin-walled pipe is inserted into a mounting hole in a thick-walled part, and the thin-walled pipe is sleeved with a welding ring; s2, the welding ring abuts against the opening of the mounting hole; and S3, a circle of welding seam is formed at the welding ring through welding, and the welding ring, the outer wall of the thin-walled pipe and the opening of the mounting hole are welded together. The welding operation of the thin-wall pipe fitting and the thick-wall pipe fitting is convenient, the thin-wall pipe fitting does not need to be machined in the welding process, the thin-wall pipe fitting is a standard part which can be bought in the market, the production period is shortened, the cost is reduced, and the welding effect of the thin-wall pipe fitting and the thick-wall pipe fitting is good.

The invention discloses low-C-high-Mn-Ni-Cu corrosion-resistant L555-grade subsea pipeline steel and a preparation method thereof, belongs to the technical field of subsea pipeline steel manufacturing, and aims to solve the technical problem that existing L555-grade pipeline steel is poor in corrosion resistance and low-temperature toughness. The low-C high-Mn-Ni-Cu corrosion-resistant L555-grade subsea pipeline steel provided by the invention is prepared from the following components in percentage by mass: 0.031 to 0.045 percent of C, 2.00 to 2.10 percent of Mn, 0.15 to 0.22 percent of Si, 0.60 to 0.80 percent of Ni, 0.31 to 0.40 percent of Cu, 0.15 to 0.20 percent of Cr, 0.020 to 0.030 percent of Nb, 0.010 to 0.015 percent of Ti, less than or equal to 0.008 percent of P, less than or equal to 0.002 percent of S, less than or equal to 0.004 percent of N and the balance of Fe and inevitable impurities. The L555-grade subsea pipeline steel provided by the invention has good corrosion resistance and low-temperature toughness, and is suitable for deepwater drilling riser main pipes and other pressure-bearing service components.