175results about How to "Avoid Weld Cracking" patented technology

The invention relates to an overlaying welding technology of an iron casting, in particular to an overlaying welding technology of a ductile cast iron roller. The technology comprises the following steps: (1), post-welding preparation: a, detecting cracks; b, controlling a welding material; and c, selecting a welding beveling; (2), welding: a, preheating the beveling within a range of 120mm to 180mm at a temperature range of 130 DEG C to 170 DEG C; b, adopting a DC reverse-connected arc welding machine for welding, using welding rods with the diameter of 3.2mm for welding a first-layer welding line and using welding rods with the diameter of 4mm for welding lines on subsequent layers; and (3), post-welding detection. The invention adopting the technologies, such as small currents, a plurality of stages, sectional welding, welding line hammering after welding, cooling speed reduction, and the like prevents welding line cracks and fusion region cracks from generating, prolongs the service life of products, obtains favorable economic benefits and solves the problems for the overlaying welding of mid-small cracks, and the like on the surface of the ductile cast iron roller.

The invention provides an electric welding rod with ultra low hydrogen and high toughness. The electric welding rod comprises core welding-wires and electrode coating composition. The electrode coating composition comprises the following components (weight percentage): 38-42 percent of marble, 21-28 percent of fluorspar, 1-3 percent of white titanium pigment, 6-10 percent of ferrotitanium, 0.5-1.5 percent of low-carbon ferromanganese, 3-7 percent of ferrosilicon, 3-6 percent of manganese metal, 2-4 percent of metallic chromium, 1-3 percent of mica, 1-3 percent of ferromolybdenum, 1.5-3.5 percent of ferrovanadium, 1-4 percent of nickel powder and 2-4 percent of rare earth metal. H08A is adopted as the core welding-wires, and water glass is used as the cementing agent. The electric welding rod fills the blank of electric welding rod needed for an ultra-thin large diameter circular saw blade, and simultaneously the electric welding rod can also be used for the welding of products in structures of carbon tool steel, alloy tool steel and spring steel material. The electric welding rod has good welding processing property and crack resistance, and simultaneously has very high welding strength, rigidity, plasticity and toughness, and the color of the welding seam is identical with the color of the base material.

The composite rotary double focus laser-MIG electric arc welding head includes mainly two parts, the rotary double focus laser welding head and the MIG electric arc welding wire feeding welding gun, connected via a connecting plate. It has welding wire feeder fixed on the connecting plate, welding wire feeding hose connected to the feeder, conducting nozzle and goose neck for welding wire to pass through; protecting nozzle in the end of the goose neck; and rotating table with reflecting cavity, regulating frame, reflector, connecting barrel and welding laser head. The present invention combines the rotary double focus laser welding and the MIG electric arc welding, and has greatly raised welding performance and lowered assembling precision requirement for even wide application.

The invention discloses a method for overlaying a wear-resistant layer of a blade shroud of a turbine working blade. In the method, manual tungsten electrode argon arc welding is used, and the specific process parameters meet the requirements that: welding wires are selected from a T800 cobalt-based wear-resistant alloy welding wire which is researched according to a B50TF193 standard of AmericanGeneral Electric Company and an S-6 cobalt-based wear-resistant alloy welding wire which is researched according to an American metal society standard AMS5788; the diameters are phi 1.6mm and phi 1.2mm respectively; a mark and the diameter of a tungsten electrode are WCe20 and phi 2.0mm; the diameter of a nozzle is phi 12mm; welding current is between 20 and 25A; and the flow rate of protective gas is between 10L/min and 12L/min. By the method, the condition of incomplete penetration or over-melting of a Z-shaped gear switching part R is avoided, the problem of overheating of welding is also solved, and the occurrence probability of welding cracks is greatly reduced or avoided. The method completely meets the requirements of the wear-resistant layer in a high-temperature working state after welding.

The invention discloses a spiral molded large-deformation-resistant submerged-arc welding pipe and a manufacture method thereof. A large-deformation-resistant hot rolled coil plate is unrolled and straightened, a welding groove is respectively machined on two sides of the plate, then the plate is placed into a spiral steel pipe molding unit to be molded and bent into a pipe shape gradually, the submerged-arc welding process is adopted to conduct welding pipe welding, and the welding pipe is subjected to following treatment such as hole enlargement, detection, hydraulic test and ultrasonic detection to form a product. The submerged-arc welding pipe has low yield ratio, larger even elongation, high deformation hardening exponent and Round-House type stress-strain curve under the premise that the welding pipe meets the requirement for high strength and high flexibility. The welding pipe is mainly applied to regions such as frozen earth zones, landslide zones, earthquake zones and the like where geological movement happens easily, serves as a steel pipe in oil and gas delivery pipes which can bear large deformation and stress, and ensures safe service of the pipes.

The invention discloses a production process of a laminated-rolled wide sheet. The production process specifically comprises the following steps that (1) a blank is selected, the selected blank is bloomed to 70-75 mm, and then a bloomed sheet is subjected to flame cutting and sizing; (2) milling is carried out on the blank sheet subjected to primary sizing; (3) a groove is formed in the surface ofa lower blank, an isolating agent is sprayed in the groove, and the isolating agent is dried; (4) aligning and compounding are carried out on the dried lower blank and upper blank, and welding is carried out; (5) a blank boss is machined; (6) the blank sheet is placed in a stepping type heating furnace for heating; (7) descaling is carried out with high-pressure water; (8) broadening rolling is carried out by a 5000 mm rolling mill; (9) straightening is carried out; and (10) plasma cutting and sheet separating are carried out. According to the production process of the laminated-rolled wide sheet, limitation on a roll gap of a 5m rolling mill in producing wide sheets with the thickness of 6 mm or below by using the CVC technology can be solved, and meanwhile, the problems that a wide sheet with the thickness of 8 mm or below is high in curvature and large in plate projection degree are solved.

A welding method for a vertically spliced super-thick steel plate is a welding method for a super-thick steel plate with the thickness ranging from 60mm to 120mm. The method is characterized by including: hoisting a primarily spliced super-thick steel plate onto a special jig frame for horizontal welding, fixing the super-thick steel plate with a waler of the jig frame by welding prior to fastening the super-thick steel plate with a ground abutting floor stand by the aid of a wedge, then using carbon dioxide arc welding for sequential symmetry horizontal welding on the front side and the back side of the super-thick steel plate respectively by even welders until spliced plate welding is finished, and finally performing postheat treatment to prevent cracks. The method has the advantages that welding deformation of the spliced super-thick steel plate can be well controlled, welding deformation correction is avoided, welding cracks are prevented, welding quality is improved, and construction requirements are met. The carbon arc air gouging process for back gouging is omitted, welding procedure is simplified, turnover times of the super-thick steel plate are decreased, workload is reduced, labor intensity is relieved, and production efficiency is improved.

The invention discloses a process for manufacturing a spoke plate of a wheel type construction machinery vehicle and a special vertical winding machine therefor, and belongs to the technical field of construction machinery. The process comprises the following working procedures: heating, wherein strips are heated to be between 650 and 750 DEG C to form heating strips; winding, wherein the heating strips are fed into the vertical winding machine and the strips are wound into vertical spiral blanks; cutting, wherein the spiral blanks are cut into separate blanks according to the specification of a prefabricated spoke plate; pressing spots, wherein cuts of the separate blanks are aligned for spot welding; welding, wherein the separate blanks after the spot welding are welded to form a spoke plate blank; finishing, wherein the dimensional precision of the welded blank is finished to form the spoke plate blank; and machining, wherein the spoke plate blank is machined to manufacture a spoke plate finished product. The invention is suitable for manufacturing the spoke plate of the wheel type construction machinery vehicle.

The invention discloses a dissimilar metal welding method of titanium alloy and austenitic stainless steel, comprising the following steps of: carrying out grinding and assembling before welding; and carrying out welding by using a method of filler wire pulsed TIG welding. With the dissimilar metal welding method of the titanium alloy and the austenitic stainless steel of the invention, by welding parameter adjustment, preheating before the welding, thermal insulation and slow cooling after the welding and control of melting and solidification conditions of a titanium alloy and stainless steel welding pool, a welding joint which has nice weld formation, and has no defects of cracks and air holes is obtained. The welding method of the invention has high welding efficiency, low cost, convenient and flexible operation, and can meet requirement of the welding joint of welding the dissimilar metals of the titanium alloy and the austenitic stainless steel.

The present invention relates to steel rail welding and is especially the welding process of steel rail for portal crane. The welding process includes selecting welding rod for high carbon manganese steel rail; regulating the assembly interval between two rails to 15-25 mm, fixing with arched fixture and backing with copper cushion; welding single side of the copper cushion via manual arc welding and right-angle bevel butt welding. The welding process has preheating temperature not lower than 300 deg.c, interlayer temperature not lower than 200 deg.c and after-welding heating temperature not lower than 600 deg.c with the temperature being measured in the point away from the welding seam center by 100 mm. All the welding seams are inspected via magnetic powder flaw detection for welding crack and other flaws.

The invention discloses a welding wire special for 7XXX series aluminum alloy and a manufacturing method thereof. The special welding wire is composed of, by mass, 2.0%-6.0% of Ni, 0-5.0% of Mg, 0.1%-0.3% of Zr, 0.1%-0.3% of Ti, 0.1%-0.3% of Cr, 0-0.1% of Fe, 0-0.1% of Si, and the balance Al. The manufacturing steps comprise burdening, smelting, sampling analysis, semicontinuous casting, homogenizing heat treatment, extruding, wire drawing, surface treatment, cleaning, drying and packaging. According to the welding wire, the element Ni which can be subjected to the eutectic reaction with the Al is selected, so that the hot tearing tendency of welds is reduced by forming eutectic structures. The welding wire is suitable for all 7XXX series aluminum alloy and is mainly specific to welding of the high-strength 7XXX series aluminum alloy with poor welding performance. By adopting the welding wire for fusion welding of the 7XXX series aluminum alloy, welding cracks can be effectively avoided, and the weldability of the high-strength 7XXX series aluminum alloy is improved. Through proper heat treatment of welding joints, the strength of the welds is not lower than 260 MPa, and elongation is not lower than 3%.

The invention discloses a technique for preventing defects of a surfacing wear-resistant layer of a part. By the technique, the surfacing quality of parts such as pistons is improved, the number of rework is reduced, the one-step delivery-check qualified rate of the parts is improved, and the production cost is reduced. According to the technical scheme, the technique comprises the following steps of (1) roughly turning outlines of a piston part to obtain a part with a cylindrical boss structure and forming an annular groove with the inverted-isosceles-trapezoid-shaped section in a cambered surface of a large end of the part; (2) surfacing a nickel-base superalloy auxiliary layer in the annular groove, performing crossing symmetrical welding, transversely welding the annular groove along the axial direction, sequentially welding the annular groove until surfacing on the whole annular groove of the part is finished and machining the auxiliary layer; (3) surfacing an aluminum bronze layer on the auxiliary layer and performing crossing symmetric welding; and (4) sequentially performing destressing treatment and finish machining on the piston part after the piston part is subjected to surfacing so as to obtain a finished product of a piston.

The invention provides a non-preheating submerged-arc welding method of an EH36 high strength steel thick plate. The non-preheating submerged-arc welding method includes the following steps of processing an X-shaped welding groove in the welding point of the EH36 high strength steel thick plate; completing positioned welding at the X-shaped welding groove through semi-automatic CO2 gas shielded welding; welding a starting weld tab and a run-off tab at both ends of the X-shaped welding groove through the method of semi-automatic CO2 gas shielded welding correspondingly; and selecting solderingflux and a welding wire with the diameter being 5mm to weld a welding plate at the positioned weld joint. The interpass temperature is kept at 230 DEG C or below in the welding process and slag removal work is carried out after each weld joint is welded; and the groove root is cleaned after welding filling of a front groove is completed through carbon arc air gouging matched with mechanical grinding,and then the back weld joint is filled filling. According to the non-preheating submerged-arc welding method of the EH36 high strength steel thick plate, generation of a welding crackcan beeffectively avoided to ensurethe quality of the weld joints. At the same time, input of preheating equipment, energy, labor and the like before weldingis reduced, the production cost is reduced, and a production cycle is shortened.

The invention provides a repair welding method of an austenite stainless steel casted nuclear pump shell. The repair welding method comprises the specific steps of defect detection and treatment; welding slot treatment; welding rod treatment: baking a welding rod at the temperature of 150 DEG C, and keeping the temperature for standby application; preheating of a to-be-welded zone; repair welding of the to-be-welded zone: carrying out repair welding layer by layer and pass by pass; confirmation of the repair welding effect: carrying out flaw detection on a repair welding zone of a pump body through rays, confirming the repair welding effect, and guaranteeing that the repair welding zone does not have weld defects; and solution treatment: carrying out solution treatment on workpieces subjected to repair welding. According to the repair welding method, samples do not have relatively large welding deformation through adoption of symmetrical arc-shaped welding slots, pre-welding preheating and postwelding thermal treatment; stress after repair welding is reasonably distributed through requirements on shape and radian of the welding slots and pre-welding thermal treatment; the content of impurity elements can be controlled and weld joints do not have obvious defects through surface roughness control and cleaning for the welding slots, and baking treatment for the welding rod; and intergranular corrosion resistance of austenite of the repair welding zone of a nuclear pump can be improved through postwelding solution treatment for a corresponding zone of the nuclear pump body.

The invention discloses a welding method of maritime work high-strength steel plates. An asymmetric X-shaped or K-shaped groove is formed in the welded position. A gap of 2+/-1 mm is reserved in the root portion of the groove. When the asymmetric X-shaped groove is adopted, the angle of the groove is 40+/-5 degrees, and CO2 protects multi-layer and multi-pass welding of flux-cored wires. When the K-shaped groove is adopted, the angle of the groove is 45+/-5 degrees, and CO2 protects multi-layer and multi-pass welding of flux-cored wires. Besides, the welding thickness on the two sides is set in the mode that the plate thickness is D mm, the distances between the section, parallel to the plane of each steel plate, of the root portion of the groove and the two planes of the steel plate are T1 and T2, the groove portion on the T1 side is shallow, the groove portion on the T2 side is deep, T1 is smaller than T2, T1 is equal to 1/2D-3 mm, and T2 is equal to 1/2D+3mm. By the adoption of the welding method, the welding workload can be lightened, heat energy dissipation is reduced, unexpected welding deformation and welding cracks of welded components are avoided, the welding stress is rapidly eliminated, and a welded structure meets expected requirements.

The invention discloses a reinforced high-pressure GIS (gas insulated switchgear) shell. The reinforced high-pressure GIS shell comprises a barrel and flanges at two ends of the barrel. An inner seam allowance is arranged on the end face of one side of an inner hole of each flange; an inner groove is arranged in the orifice of an inner hole at each of two ends of the barrel; the inner seam allowances sleeve the barrel at intervals and are fixedly connected with the same by welding; the depth L1 of each female end is 0.9-1 times of the wall thickness of the barrel; the upper end face of each inner seam allowance is provided with a chamfer 45 degrees to 55 degrees in angle alpha, and the depth L2 of the chamfer is 0.4-0.5 times of the wall thickness of the barrel; the lower end face of each inner seam allowance is provided with another chamfer 35 degrees to 40 degrees in angle beta, and the depth L3 of the chamfer is 0.5-0.7 times of the wall thickness of the barrel; the length L4 of the truncated edge of each inner groove is 0.2 to times of the wall thickness of the barrel; further, gaps are reserved between the end face of the barrel and the lower end faces of the inner seam allowances. The reinforced high-pressure GIS shell is convenient to clean before welding, small in welding stress and welding deformation and small in allowance of secondary machining of the flanges.