1118 results about "Weld metal" patented technology

An automatic welding system for metal parts, the automatic welding system comprising a welding platform (1), wherein a fixing box (2) is provided on the welding platform (1); a first electric motor (3) is provided in the fixing box (2); a lead screw (4) is provided on an output end of the first electric motor (3); a lead screw sleeve (5) is connected to an outer side of the lead screw (4); a limiting sliding block (6) is provided at the top of the lead screw sleeve (5); a right-angle bracket (7) is provided at the top of the limiting sliding block (6); a telescopic rod (8) is provided at the bottom of the right-angle bracket (7); a welding machine (9) is provided at a movable end of the telescopic rod (8); a supporting plate I (10) and a supporting plate II (11) are provided on the welding platform (1); a right-angle plate I (12) and a right-angle plate II (13) are provided above the supporting plate I (10) and the supporting plate II (11), respectively; both the connections between the supporting plate I (12) and the right-angle plate I (13), and between the supporting plate II (11) and the right-angle plate II (13) are made by means of supporting columns (14); a second electric motor (15) is provided on the right-angle plate I (12); a rotating rod (17) is connected to the right-angle plate II (13) by means of a bearing I (16); fixing seats (18) are provided on both the rotating rod (17) and an output shaft of the second electric motor (15); and a clamping assembly (19) is provided on each fixing seat (18). The automatic welding system solves the problem of being unable to weld metal parts from multiple angles in the prior art.

The invention belongs to the technical field of metal processing, particularly relates to a multi-degree-of-freedom welding mechanical arm for processing a metal steam cabinet, and provides the following scheme aiming at the conditions that the current processing equipment cannot automatically correct the position of a welded metal plate, does not have an auxiliary cooling function of a welding point and is easy to cause welding deformation. Comprising a tool welding platform, an adjusting module is arranged above the tool welding platform, the adjusting module comprises a U-shaped supporting plate, a mounting round hole is formed in the tool welding platform, and a rotating round pipe is connected to the interior of the mounting round hole through a bearing. According to the multi-degree-of-freedom welding mechanical arm for metal steam cabinet machining, accurate cooling operation on welding points is achieved, deformation of a steam cabinet plate after welding is avoided, meanwhile, multi-angle welding on a metal cabinet plate is achieved, and therefore the labor amount of workers in the welding process is reduced, and the machining production efficiency of the welding mechanical arm is improved.

The invention discloses a clamping-adjustable metal pipe welding device, which belongs to the technical field of pipe welding, and comprises a main body mechanism for butting and welding metal pipes, and two adjusting mechanisms for adjusting the welding direction of the metal pipes are arranged on the main body mechanism; and a clamping mechanism for clamping the metal pipe is arranged on the adjusting mechanism. The arranged main body mechanism can automatically weld four butt joint faces of two metal pipes, meanwhile, the metal pipes with different splicing angles can be welded, the automation degree is high, and continuity is good; the adjusting mechanism can adjust the butt joint angle of the metal pipes, so that the device can weld the metal pipes with different postures and connection angles, and the application range is wide; the clamping mechanism can adjust the clamping position, so that the device can clamp metal pipes of different lengths, meanwhile, square pipes or round pipes of different sizes can be clamped, and use is convenient.

A method is provided for unsupervised 3D modeling and geometric measurement of additively manufactured parts. The method includes obtaining near-infrared (NIR) images for a welding process for a welded part. The welded part includes welded metal and agglomerated powder particles. The method also includes generating a multi-dimensional dataset based on the NIR images, including cropping the multi-dimensional dataset to a region of interest. The method also includes detecting melted regions in image layers of the multi-dimensional dataset to obtain an output volume. The method also includes detecting agglomerated powder in the output volume to obtain melt masks. Each melt mask indicates weld pixels for a respective image layer. The method also includes applying a multi-layer predictive model to account for multi-layer weld penetration, based on the melt masks, to obtain an output data mask that represents a 3D model and geometric measurements for the welded part.

The invention discloses a method for reducing pores by repair welding of internal defects of a thin-wall aluminum alloy casting. The method comprises the following steps: confirming and marking X-ray positions of the internal defects of the aluminum alloy casting; internal defects at the marked position are cleaned, the defects are required to be completely eliminated, and the cleaning position is smooth and has a certain groove angle; cleaning oil stains and oxidation films at the repair welding position of the casting; preheating the whole casting; welding a reverse support and adding a blowing protection tool; manual argon arc welding filling surfacing is carried out, arc surfacing is carried out from the periphery to the center, and excess weld metal is reserved; removing redundant weld joint materials of surfacing bulges of the casting; x-ray detection is conducted on the repaired casting, whether the pore defects generated after surfacing repair can meet related requirements or not is emphatically confirmed, and if pores gathered on the surface layer of a weld joint exist, the pores can be discharged through a hot pressing method. According to the method, through hole internal defect cleaning, reverse supporting, blowing protection increasing and arc drawing surfacing methods are adopted for conducting surfacing repairing on the internal defects of the casting, the quality of aluminum alloy casting products is guaranteed, and the rejection rate and the production cost are reduced.

The invention discloses a flux-cored wire for extra-thick marine steel high heat input EGW and a preparation method of the flux-cored wire, and relates to the technical field of metal welding, the flux-cored wire comprises an outer skin of a double-layer alloy steel strip and powder filled in the outer skin, the filling rate of the powder is 20 + / -5%, and the powder comprises Fe, Mn, Si, Cr, Ni, Mo, V, B, S, Al, MgAl2O4, MgO-TiO2, ReOx and a slag former. According to the preparation method, the metal powder is positively charged, the rare earth nanoparticles are negatively charged through an electrostatic self-assembly technology, the metal powder and the rare earth nanoparticles are mixed with a slag former after being mixed, filtered and freeze-dried, an alloy steel strip is filled with the powder, and then rolling and drawing forming is conducted. In the welding process, the composite inclusions form a core-shell structure, a weld metal structure is regulated and controlled, acicular ferrite nucleation is promoted, and grains are refined, so that the low-temperature toughness and crack arrest performance of a weld are remarkably improved, the rare earth elements are beneficial for changing irregular inclusions into spheres, nucleation sites are increased, interface energy is reduced, and the nucleation rate of acicular ferrite is increased.

The invention discloses a mechanical part laser welding device and an intelligent welding system thereof, and relates to the technical field of automatic welding, the mechanical part laser welding device comprises a laser welding mechanism, the laser welding mechanism comprises an adjusting mechanism, the upper part of the adjusting mechanism is fixedly connected with a limiting mechanism, and the upper part of the adjusting mechanism is fixedly connected with a detection mechanism; the detection mechanism is located on the side face of the limiting mechanism. An included angle between a welding edge of a to-be-welded metal plate and a side line of a reference plate is measured through a visual detection system, and a plate edge adjusting system controls a first servo motor to rotate according to measured data, so that the side line of the to-be-welded metal plate is parallel to the side line of the reference plate; the welding edges of the two metal plates to be welded are adjusted to be parallel to each other and then are in butt joint and welding, so that the front and back widths of the seam are kept consistent, a laser welding gun can uniformly melt materials along the seam, the shape of the welding seam is regular and smooth, and the internal quality of the welding seam is improved.

This invention discloses a stainless steel welding wire for repair welding of martensitic stainless steel turbine runners, its preparation method, and its application, belonging to the field of metal welding material preparation technology. The chemical composition of the welding wire provided by this invention, expressed as a percentage by weight, is: C≤0.03%, Si: 0%~0.6%, Mn: 5.0%~8.0%, S≤0.010%, P≤0.020%, Cr: 12.5%~15.5%, Ni: 5.0%~7.0%, Mo: 1.0%~2.0%, with the balance being Fe and impurities. The welding wire provided by this invention is suitable for repair welding of Cr13Ni4~6 type martensitic stainless steel, and post-weld heat treatment is not required. The weld metal produced by this welding wire exhibits good strength, plasticity, and toughness, with a tensile strength ≥750MPa, elongation after fracture ≥35%, and impact absorption energy at -40℃ ≥120J.

The invention relates to the technical field of glass welding, in particular to a clamping device for metal-glass laser welding and a welding method. The device comprises a bottom plate, a cover frame and supporting columns connecting the bottom plate and the cover frame, and a lifting part is formed between the cover frame and the bottom plate. A mechanical lifting assembly with an adjusting rocker and a graduated scale is installed on the bottom plate in the lifting part, the lower end is connected with the bottom plate, and the upper end is connected with the machining table to drive the machining table to ascend and descend. And the center of the cover frame is provided with a quartz glass pressing plate plated with a magnesium fluoride antireflection film. A cylindrical metal mounting base coaxial with the glass pressing plate is arranged on the machining table and used for mounting metal to be welded. During welding, the adjusting rocker is rocked to lift the machining table so that to-be-welded glass can make contact with the glass pressing plate, and optical contact is achieved by observing the situation that an interface Newton ring disappears from appearing; the whole clamping device is moved to a laser machining platform, and welding is conducted through a glass pressing plate; and after completion, the machining table is lowered to disassemble the weldment.

The invention discloses a high-strength steel welding rod for 1000 MPa water and electricity and a preparation method and application of the high-strength steel welding rod. The invention belongs to the technical field of welding materials. The technical problems that the low-temperature impact toughness of an existing welding material for 1000 MPa-grade high-strength steel needs to be improved, and the welding cold crack sensitive index is too large are solved. The welding rod is composed of a core wire and a coating wrapping the surface of the core wire. Powder of the coating is formed by mixing marble, fluorite, rutile, silica powder, electrolytic manganese, ferrosilicon, graphite, ferromolybdenum, chromium metal, iron powder, nickel powder, sodium carbonate and sodium alginate. The welding rod has the advantages of good all-position welding process performance, stable electric arc, small flying speed, uniform coating melting, beautiful weld joint forming and good operability of welders. And weld metal has good mechanical properties. And the method is used for welding the high-strength steel for the 1000MPa-grade water

The invention discloses a method for predicting the phase content and the hardness of a titanium alloy welding joint, which comprises the following steps of: 1, constructing a welding temperature field model, and correcting a Gaussian cylinder heat source model in welding simulation by comparing the morphology of a welding joint molten pool; 2, a solid-state phase change model is introduced, and a weld metal phase change model is constructed; and step 3, inputting the solid-state phase change model obtained in the step 2.4 into the three-dimensional solid model to obtain the phase content of the welding joint as a field variable in an output hardness field, and predicting the hardness of the joint through the phase content of the welding joint. According to the method, by introducing a solid-state phase change model and optimizing heat source parameters, high-precision prediction of the phase content and hardness of the welding joint is achieved, and rapid optimization of process parameters is guided.

The invention belongs to the technical field of three-dimensional measurement and weld joint processing, and discloses a weld joint feature recognition and path extraction method based on line laser measurement. According to the full-automatic welding seam shape extraction method, an automatic measurement part before welding seam polishing and other machining steps can be achieved, after a robot measures the position of a welding seam, welding seam shape extraction can be achieved, the position of the center line of the welding seam can be calculated, and therefore a machining path is obtained; and the robot can be directly guided to process the welding seam through the hand-eye matrix. In addition, the welding width and surplus height characteristics before and after welding seam machining can also be calculated and compared. After the welding width and the excess weld metal are calculated, the machining parameters can be further calculated, and the whole method provides technical support for automatic welding seam machining.

The utility model discloses a main-grid-free back contact battery string and a photovoltaic assembly, the main-grid-free back contact battery string comprises a plurality of back contact battery pieces arranged along a first direction, and the back surface of each back contact battery piece is provided with first fine grids and second fine grids which are alternately arranged along the first direction; the first welding strips and the second welding strips are alternately arranged in the second direction; wherein for the same back contact battery piece, the first welding strip is electrically connected with the first fine grid, and is insulated from the second fine grid; the second welding strip is insulated from the first fine grid and is electrically connected with the second fine grid; welding layers are arranged at the contact positions of the first fine grid and the first welding strip and the contact positions of the second fine grid and the second welding strip; the welding layer comprises a welding metal layer and a bonding glue layer, and the bonding glue layer covers the welding metal layer. According to the utility model, the welding quality of the welding strip can be improved, and the connection stability and reliability of the welding strip and the fine grid are ensured.

The invention provides a welding method for a floating ship plate of a large oil storage tank, which belongs to the technical field of electric digital data processing and comprises the following steps: firstly, acquiring three-dimensional point cloud data through a sensor group on a crawler-type welding robot, and acquiring a feature image of a to-be-welded area by using a camera; a welding coordinate system is established based on the data, a groove contour is calculated, and an initial welding track is generated. And in combination with welding process parameters and environmental conditions, an Euler angle sequential sequence calculation equation set is established, and the posture of a welding head is adjusted in real time. Groove forming data in the welding process are monitored in real time through a sensor, when the fusion depth or the excess weld metal of a connector does not meet the requirement, a system can automatically recalculate the Euler angle sequence and adjust welding parameters till the technological standard is met, and therefore high-quality automatic welding is achieved, and the welding efficiency is improved. The technical problem that in the prior art, welding parameters and the motion trail of the welding robot are difficult to automatically adjust according to the welding state sensed in real time in the welding process is solved.

The invention belongs to the technical field of welding positioning fixtures, and particularly relates to a welding positioning fixture for an electric welding machine, which comprises a worktable, supporting blocks are symmetrically arranged on the worktable, clamping assemblies for limiting workpieces are arranged on the supporting blocks, driving assemblies are arranged on the side surfaces of the supporting blocks, and a frame is arranged in the worktable. A mounting groove is formed in the frame, exhaust fans are symmetrically mounted in the mounting groove, a heat recovery assembly is arranged in the frame, and an adsorption assembly used for purifying waste gas is arranged in the flowing groove. According to the welding positioning clamp for the electric welding machine, flue gas particles generated during welding can be conveniently and rapidly filtered and purified through the ventilation grooves, an exhaust fan works to extract air in the flowing groove, and then flue gas generated during metal plate welding can flow into the flowing groove through air inlet holes; particulate matters carried by the air can enter the ventilating slot, and the filter screen can intercept and adsorb the flue gas particulate matters carried by the air, so that the aim of purifying the air is fulfilled.

The invention discloses welding equipment for a high-strength steel plate welding structural part, and relates to the technical field of high-strength steel plate welding. Welding seam metal between the two high-strength steel plate bodies is hammered and rotated through the spherical hammer head, the welding seam metal can generate plastic deformation through the hammering effect, crystalline grains of the welding seam metal can be refined through the plastic deformation, pressure stress is generated in a welding seam, the possibility of cold crack generation is reduced, and the welding quality is improved. In the knocking process, along with rotation of the spherical hammer head, hammering force generates a tangential stress component on the surface of the weld joint, the tangential stress can enable weld joint metal to be subjected to certain compression and rubbing effects in the horizontal direction, the weld joint and base metal can be better combined more tightly, and the welding quality is improved. And the situation of cold cracks possibly caused by interlayer tearing and the like is further avoided.

The utility model relates to the technical field of metal welding, and discloses a liftable welding table for welding metal parts, which comprises a box body, the upper surface of the box body is open, a protective inner frame is slidably connected to an inner cavity of the box body, a table plate is fixedly connected to the upper end of the protective inner frame, and two groups of adjusting mechanisms are symmetrically arranged on the upper surface of the table plate; through cooperation of a box body, a table plate, a protective inner frame and a lifting mechanism, first two-way screws are driven by a first motor to rotate, the two first two-way screws synchronously rotate under the action of a chain and a chain wheel, then moving blocks on the two first two-way screws move relatively, and therefore the included angle between a supporting rod and the horizontal plane is increased; the height of the table plate is adjusted, the table plate is suitable for operators with different heights to use, the operation convenience is improved, the application range is wide, the welding efficiency of metal parts is improved, and the welding quality of the metal parts is improved.

The invention discloses an austenitic stainless steel welding wire for a liquid hydrogen storage tank and a preparation method and application of the austenitic stainless steel welding wire, and belongs to the technical field of welding materials and preparation of the welding materials. The welding wire solves the problem that the low-temperature performance of a welding seam is poor when the current welding wire for the liquid hydrogen storage tank is used for welding. The welding wire comprises the following chemical components in percentage by mass: less than or equal to 0.02% of C, 0.4-1.5% of Si, 5.0-7.5% of Mn, less than or equal to 0.020% of S, less than or equal to 0.030% of P, 16.0-22.0% of Cr, 15.0-18.0% of Ni, 2.0-5.0% of Mo, 0.05-0.2% of N, less than or equal to 0.01% of O and the balance of Fe and inevitable impurities. According to the welding wire, deposited metal is low in low-temperature embrittlement tendency, high in low-temperature strength and excellent in low-temperature impact and fracture toughness. The welding wire is used for welding the austenitic stainless steel liquid hydrogen storage tank and is wide in application range, and the mechanical property of deposited metal is good.

The invention provides a pipeline all-position laser rotating electric arc composite automatic welding device and method. The device comprises a flexible guide rail, a welding trolley, a rotating electric arc welding gun module, a laser module, a sensor module and a controller. The flexible guide rail is annularly arranged and tightly attached to the pipeline and provides a moving path for the welding trolley. The welding vehicle is movably arranged on the flexible guide rail; the rotary arc welding gun module, the laser module and the sensor module are sequentially and adjustably arranged at the front end of the welding vehicle in the circumferential direction of the pipeline; the welding trolley, the rotary arc welding gun module, the laser module and the sensor module are electrically connected with the controller. Two heat sources of laser and rotating arc synergistically act on the same molten pool, the molten pool is deepened by the laser, the melting width is widened by the rotating arc, a large weld depth-to-width ratio is jointly molded, and the distribution uniformity of weld alloy elements is improved through the quenching and tempering treatment of the laser on weld metal and the stirring effect of the molten pool of the rotating arc. And the welding speed and the welding quality are greatly improved.

The invention provides an ultra-low carbon duplex stainless steel all-position welding flux-cored wire and a welding method thereof.The outer skin of the flux-cored wire is a stainless steel strip, the flux-cored wire is filled with powder, and the powder comprises, by mass, 18-25% of natural rutile, 20-30% of stainless steel powder, 20-30% of stainless steel powder, 20-30% of stainless steel powder and the balance stainless steel powder. 3-5% of sodium titanate; 5-10% of quartz sand; 0.5 to 4 percent of zircon sand; 1-3% of sodium fluoride; 15 to 25 percent of ferromolybdenum; 3-6% of nitrided ferrochrome; 2-4% of electrolytic manganese; 5-8% of nickel powder; 27 to 32 percent of metal chromium; 0.5-2% of magnesium powder; 0.5 to 1.5 percent of bismuth oxide; and 1-4% of silicon iron. The flux-cored wire is used for all-position welding of third-generation duplex stainless steel, welding spatter is small, and weld joint forming is good; the carbon content of a weld joint is extremely low, and through component and welding process control, weld joint metal has strength, plasticity, toughness and corrosion resistance equivalent to those of base metal. And the double requirements of high strength and toughness and high corrosion resistance in the manufacturing fields of submarine pipeline laying, shipbuilding, marine gas field exploitation and the like are ensured.

The invention provides a coal mine hydraulic support gas shield welding wire with the strength higher than 900 MPa and a preparation method of the coal mine hydraulic support gas shield welding wire. The gas shield welding wire comprises, by mass, 0.03%-0.06% of C, 0.51%-0.70% of Si, 1.35%-1.64% of Mn, smaller than or equal to 0.010% of P, smaller than or equal to 0.005% of S, 0.20%-0.38% of Cr, 2.35%-2.65% of Ni, 0%-0.09% of Cu, 0.45%-0.70% of Mo, 0.015%-0.030% of Ti, 0.025%-0.035% of Nb, 0.002%-0.006% of Ce, 0.0005%-0.0012% of B, smaller than or equal to 0.004% of O, smaller than or equal to 0.006% of N and the balance Fe and The invention has the following beneficial effects: (1) through reasonable design of chemical components, the yield strength of weld metal is greater than or equal to 820 MPa, the tensile strength is greater than or equal to 900 MPa, the ductility is greater than or equal to 21%, and the low-temperature impact toughness at-40 DEG C is greater than or equal to 75 J; (2) inclusions in a weld joint are dispersed and refined after the welding wire is welded, refined acicular ferrite instead of bainite and martensite is taken as a main structure, and the strength and toughness of the weld joint are excellent; and (3) the composition proportion of the welding wire is optimized, a stable welding wire preparation process is developed according to the components, and the comprehensive performance of the high-strength coal mine hydraulic support welding seam is considered.

The invention belongs to the technical field of metal door and window machining, particularly relates to positioning welding equipment and method for metal door and window machining, and aims to solve the problems that the welding efficiency and effect of a metal door frame are reduced due to tedious manual fixing and positioning operation during welding of the metal door and window. A positioning welding module is arranged above the tool supporting bottom plate and comprises two tool supporting plates, first round holes are formed in the side faces of the two tool supporting plates correspondingly, and overturning cylinders are connected to the interiors of the two first round holes through bearings correspondingly. According to the positioning and welding equipment and method for metal door and window machining, the situation that a person manually fixes and positions door and window frames is avoided, meanwhile, the door and window frames of different sizes are fixed and positioned, the two sides of the door and window frames are welded, and therefore the welding efficiency and effect of the metal door and window are improved.

The utility model discloses a precision metal piece laser welding device which comprises a base, a cavity is formed in the base, a transmission motor is fixedly connected in the cavity, an output shaft of the transmission motor is fixedly connected with a first bevel gear, the top of the cavity is rotationally connected with a second bevel gear, and the second bevel gear is fixedly connected with a second bevel gear. A rotating plate is fixedly connected to the upper end of the second bevel gear, a plurality of mounting grooves are formed in the rotating plate, a double-head motor is fixedly connected to the interior of each mounting groove, threaded rods are fixedly connected to two output shafts of each double-head motor, and threaded blocks are in threaded connection to the outer surfaces of the two threaded rods. A transmission motor, a first bevel gear and a second bevel gear are arranged to drive a rotating plate to rotate, a clamping plate is driven to move through a double-end motor, a threaded rod and a threaded block, a metal piece is clamped and fixed, when one metal piece is welded, the other metal piece is conveniently clamped and installed, and the welding efficiency is improved.

The invention provides a method for improving fluidity of weld metal in friction stir welding of dissimilar aluminum alloy, and belongs to the technical field of friction stir welding of dissimilar metal. The method comprises the following steps that 7075 and 6061 aluminum alloy plates are in butt joint and fixed, and friction stir welding is conducted; and the ratio of the length of a stirring needle for friction stir welding to the thickness of the aluminum alloy plate is 0.675-0.725. The metal fluidity and hardness distribution uniformity of a welding joint of dissimilar aluminum alloy friction stir butt welding are influenced by regulating and controlling the needle length of the stirring needle. And when the ratio of the length of the stirring needle to the thickness of the plate is 0.7, the elliptical onion ring formed in the nugget zone of the welding joint is complete in structure, the number of circles is large, and the whole position is moderate, so that the weld metal fluidity of the welding joint is better, and the hardness distribution is more uniform.

The invention relates to the technical field of welding monitoring, and discloses an online monitoring method for the welding quality of a joint of an ultrasonic welding metal sheet, which comprises the following steps: S1, detecting the friction coefficient of a welding interface of the metal sheet in real time through a friction coefficient detection unit; s3, dividing the real-time friction coefficient detected in the step S1 into three stages, namely a pre-welding stage, a welding process stage and a post-welding cooling stage according to the welding process, and S4, performing statistical analysis on the real-time friction coefficient of each stage in the step S3 by adopting an average value and an extreme value, and during calculation, at least obtaining the real-time friction coefficient of each stage during five times of welding. The method has the following advantages and effects that by dynamically monitoring the friction coefficient of the interface of the ultrasonic welding metal sheet in real time, detecting the quality of a welding joint in real time and optimizing welding process parameters in time, the percent of pass of products can be greatly increased, and the operability and accuracy of quality control are remarkably improved.

The butt-welding machine comprises a welding machine frame, an electric push rod is fixedly installed on the outer surface of one end of the welding machine frame, and a guide sliding mechanism is arranged on the outer surface of the side, away from a positioning push-out rod, of the welding machine frame. Through the guide sliding mechanism, parts can stably move forwards, backwards and leftwards and rightwards in the same direction during butt-welding. According to the butt-welding machine with the guiding and clamping structure, when metal sheets are welded, only multiple metal sheets need to be placed between the upper sliding seat and the clamping plate, then the longitudinal measuring scale can be observed, the position of the middle adapter can be adjusted and fixed, the metal needing to be welded is located between the touch needle and the bottom welding supporting table, and welding of a first welding spot is conducted; then the grab handle is grabbed to move the upper sliding seat, and the scale of the transverse measuring scale is observed to control the transverse distance between the welding spots, so that the welding spots can be quickly found during multi-row welding, accurate positioning butt-welding is performed, and meanwhile, neat and attractive welding is ensured.

Provided are a gas-shielded metal arc welded joint of high-Mn steel, which is simple, has high strength and excellent extremely low-temperature toughness, and a method for producing the same. A gas-shielded metal arc-welded joint in which a welding metal is formed from a steel material of a high-Mn-content austenitic steel containing, in mass%, 18.0-30.0% of Mn using a shielding gas and a solid welding wire, the welding metal having a chemical composition containing, in mass%, 0.15-0.80% of C, 0.10-1.00% of Si, 17.0-30.0% of Mn, 0.030% or less of P, 0.030% or less of S, 0.001-0.100% of Al, 0.4-5.5% of Cr, 0.01-3.50% of Mo, 0.01-10.00% of Ni, and 0.0200-0.1500% of N, with the remainder being Fe and unavoidable impurities. Methods of making a gas shielded metal arc welded joint by incorporating a given concentration of nitrogen in a shielding gas, or increasing the N content of a solid wire.

The utility model discloses a subway door leaf glide way which comprises a long-strip-shaped bottom plate, a side wall and a limiting block, the side wall is perpendicularly arranged on the edge of one side of the long edge of the bottom plate, and the limiting block, the bottom plate and the side wall are perpendicular at the same time and intersect at the same vertex. The bottom plate, the side walls and the limiting blocks are integrally formed; the limiting block is provided with a transition arc face tangent to the inner side face of the side wall. According to the utility model, an integral forming process is adopted, only one step of casting is needed in the preparation process, cutting, welding and the like of plates are not needed, and the defects of plate deformation caused by thermal cutting, welding metal melting and out-of-tolerance of size and form and location caused by material forming after condensation shrinkage and insufficient yield can be effectively overcome in the preparation process; the product yield is improved; the efficiency is high in the preparation process, and the construction period can be effectively shortened; and in the aspect of personnel allocation, only one type of work needs to be cast, personnel allocation is relatively simple, and the management cost is relatively low.

Provided is an austenitic stainless steel alloy welded joint containing a weld metal having excellent welding hot cracking resistance, polythionate SCC resistance, naphthenic acid corrosion resistance, and aging toughness. The welding metal (20) contains, in mass%, 0.020% or less of C, 0.01 to 1.00% of Si, 0.20 to 2.00% of Mn, 0.030% or less of P, 0.010% or less of S, 16.0 to 25.0% of Cr, 15.0 to 40.0% of Ni, 2.5 to 5.0% of Mo, 0.10 to 2.00% of Nb, 0.05 to 0.30% of N, 0.001 to 0.100% of sol.Al, and 0.0010 to 0.0050% of B, with F1 as defined by formula (1) being 2.30 or less and F2 as defined by formula (2) being 2.5 or less. F1 = 130B + 8C + 0.025 Cr + 0.25 Mn + 0.08 Mo + 0.6 Nb + 12P + 7.6 S + 0.78 Si + 0.012 W (1), and F2 = [Mo] H / [Mo] L (2).

The invention discloses a heat-treatment-free control method for inhibiting hydrogen-induced cracks in ultrahigh-strength steel welding, which belongs to the technical field of welding, and enables weld metal to obtain a low-phase-transition-temperature characteristic and a double-phase structure containing retained austenite under a specific dilution rate window by cooperatively regulating and controlling components of a welding material and welding process parameters. Therefore, preheating-free and post-heat-treatment-free efficient welding of the ultrahigh-strength steel is achieved. According to the method, the volume expansion effect generated by low-temperature martensite phase transformation of weld metal is utilized to actively counteract restrained tensile stress formed by welding cooling shrinkage; on the other hand, the effect of the retained austenite serving as an efficient'hydrogen trap 'is fully played, migration and enrichment of hydrogen to crack sensitive areas such as a heat affected zone or a fusion line are effectively blocked, and finally effective inhibition of hydrogen-induced cracks in ultrahigh-strength steel welding is achieved; the obtained welding joint is free of hydrogen-induced cracks and has the mechanical property level well matched with base metal.