12results about How to "Reduce hot cracks" patented technology

The invention discloses a zirconium-nickel dissimilar metal welding method based on active regulation and control of a temperature field. The zirconium-nickel dissimilar metal welding method comprises the following steps that S1, base metal is cleaned; the butt-joint end faces and the welding surfaces of the zirconium and nickel alloy pipes are polished and cleaned, and clean zirconium and nickel base materials are obtained; s2, a to-be-welded part is assembled; the to-be-welded end face of the clean base metal is assembled in a protective gas cavity of the rotary clamping device; s3, welding is conducted; a laser scanner is adopted for welding at a preset welding position, heat source gradient distribution of base metal at the two ends of a welding seam is controlled by regulating and controlling laser power, welding seam temperature field feedback is established through an infrared temperature sensor, and real-time monitoring and laser power regulating and controlling are conducted; s4, postweld heat treatment; and the laser power is adjusted in real time according to welding seam temperature field feedback so as to adjust and control the welding seam cooling process. According to the method, effective connection of zirconium-nickel indissolvable metal is achieved by controlling the regional welding temperature field, the temperature range for forming brittle compounds is avoided, the uniformity of a molten pool between Zr and Ni materials is ensured, and welding defects such as hot cracks and air holes are reduced.

The invention provides a preparation method and device of a nickel-based corrosion-resistant alloy thin strip, and relates to the technical field of nickel-based corrosion-resistant alloys, and the preparation method comprises the following steps: S1, forging, hot rolling and cold rolling a cast nickel-based corrosion-resistant alloy original cast ingot to form a relatively thin strip I; s2, the first thin strip obtained in the step S1 is subjected to rolling machining through first rolling equipment, and a second thin strip is formed; s3, the second thin strip obtained in the step S2 is subjected to rolling machining through second rolling equipment, and a third thin strip is formed; wherein in the rolling process, the rolling speed of the second rolling device is controlled to be smaller than that of the first rolling device. According to the method, hot cracks and burns generated on the surface of the nickel-based corrosion-resistant alloy thin strip can be reduced, and the surface quality of the finished nickel-based corrosion-resistant alloy thin strip is guaranteed.

The present invention discloses a gradient tool material for machining vermicular graphite cast iron, which is made of the following raw materials: surface layer: WC87-94 parts, Al2O33-7 parts, Co2-6 parts, Y2O30-1 parts; sub-surface layer: WC87-94 parts, Al2O31-5 parts, Co4-8 parts, Y2O30-1 parts; middle layer: WC87-94 parts, Al2O30-3 parts, Co6-10 parts, Y2O30-1 parts; according to the proportion of each layer component, they are respectively loaded into a ball mill, ball milled, dried, and sieved; they are layered in a graphite sleeve and sintered in a vacuum sintering furnace. The present invention makes the metal phase and the ceramic phase symmetrically distributed in a gradient, the surface layer of the tool has high hardness and wear resistance, the middle layer has strong toughness and plasticity, and can withstand high impact loads; the thermal expansion coefficient and thermal conductivity coefficient between each layer of material gradually increase from the surface to the inside, effectively relieving thermal stress concentration, reducing thermal crack initiation, and improving tool life.

The present application belongs to the technical field of preparation of multi-curved surface silicon carbide, and discloses a preparation method of reaction sintering multi-curved surface silicon carbide whole plate, comprising: mixing 100 parts of alpha-SiC powder, 15-20 parts of composite carbon source, 1-2 parts of silicon carbide fiber, 2.3-3.8 parts of dispersing agent, 8-12 parts of water-soluble phenolic resin, 2-4 parts of additive and 42-46 parts of water according to weight parts, pre-dispersing, ball-milling, spray granulating, pressing into multi-curved surface green body; the green body is stacked with graphite support parts and filled with graded silicon particles, and is subjected to step-by-step degreasing and step-by-step reaction sintering under vacuum argon, and then is cooled after temperature control to obtain the product. Through the synergistic effect of formula control of composite carbon source, specific ternary additive and fine sintering process, the technical problem of sintering cracking and cracking of multi-curved surface whole plate is eliminated, and the product density, bending strength and fracture toughness are effectively improved.

The invention relates to a material adding device and method for ultrasonic resonance assisted direct deposition of a high-melting-point metal wire. The device comprises a wire feeding system, a control system, an ultrasonic resonance system, an electromagnetic induction heating device, a three-axis moving device, a substrate preheating device and a shear strain transmission device. For a high-melting-point metal wire, a wire feeding system drives the metal wire to be conveyed downwards along a high-temperature wire feeding pipe, an electromagnetic induction heating device at the lower end of the high-temperature wire feeding pipe softens the metal wire, the metal wire and the wire feeding pipe penetrate through a shear strain transmission device together, and a hollow connecting rod loaded with piezoelectric ceramics transmits ultrasonic vibration to the metal wire; the metal wire is extruded through a shear strain deposition head, and the ultrasonic resonance auxiliary direct deposition process of the metal wire is completed; the control system can adjust the amplitude and frequency of ultrasonic vibration, the electromagnetic induction heating temperature, the wire feeding speed, the substrate preheating temperature and the working frequency of the shear strain device according to actual conditions. According to the device, direct deposition of the high-melting-point metal wire is achieved through electromagnetic induction heating, high-frequency ultrasonic vibration can greatly reduce the flow stress of the material, a large number of dislocations are generated, atomic diffusion is promoted, and metallurgical bonding of adjacent metal units is achieved.

The invention relates to the technical field of leisure chair processing, in particular to a special perforating device for leisure chair processing, which comprises a mounting frame and an operating table, the operating table is positioned under the mounting frame, an anti-overflow groove is formed in the top end of the operating table, and the special perforating device further comprises a first suspension mechanism and a second suspension mechanism; the first hanging mechanism and the second hanging mechanism are located on the two sides of the mounting frame correspondingly and used for hanging a to-be-machined U-shaped pipe and hanging a machined U-shaped pipe correspondingly. According to the U-shaped pipe machining device, continuous drilling machining of the U-shaped pipe can be achieved, automatic feeding, discharging and alignment before and after machining of the U-shaped pipe can be achieved, the situation that the U-shaped pipe is manually taken for feeding, discharging and then alignment are conducted is not needed, and therefore the machining efficiency of the U-shaped pipe can be effectively improved, and due to the fact that the feeding and discharging steps of the U-shaped pipe can be synchronously conducted, the machining efficiency is improved. And therefore, the machining efficiency of the U-shaped pipe is further improved, and the machining efficiency of the leisure chair is effectively improved.

The application discloses a Cr3C2-BN nickel-based ultra-high-speed laser cladding composite coating and a preparation method thereof. In the cladding raw material powder, the mass percentage of the nickel-based powder is 65-75%, the mass percentage of the Cr3C2 powder is 20-30%, and the mass percentage of the h-BN powder is 2-10%. The main steps for preparing the coating are as follows: the three kinds of powders are uniformly mixed and then are put into a laser cladding device; and the laser cladding machine is started to perform laser cladding on a 40Cr rod material rotating appropriately with Ar gas as a protective gas. In the obtained coating, the hard phase particles are mainly Cr3C2 particles; the addition of BN promotes the melting of the Cr3C2 powder, enhances the uniformity of the coating, improves the forming quality of the coating, and generates dendritic networks around the Cr3C2 particles to optimize the mechanical structure of the coating. The coating prepared by the method has good surface morphology and excellent wear resistance and corrosion resistance; the application has simple process, excellent performance of the obtained product and is convenient for industrial application.

The present invention relates to the technical field of metal material welding, and is a welding wire deposition method and welding process based on ceramic particles, comprising the steps of selecting welding wire; cleaning the welding wire by ultrasonic wave; placing the cleaned welding wire on a rotating bracket; preparing a ceramic particle coating on the surface of the rotating welding wire by a ceramic particle generator; after the ceramic particles adhere to the surface of the welding wire to form a coating, the bracket stops rotating and the welding wire is removed from the bracket. The welding wire deposition method of ceramic particles of the present invention is that the welding wire is placed on a rotating bracket after being cleaned by ultrasonic wave, and a ceramic particle coating is prepared on the surface of the rotating welding wire by a ceramic particle generator, so that when the bracket rotates, the ceramic particle generator located on one side of the welding wire can realize rapid and uniform attachment of ceramic particles to the surface of the welding wire, thereby allowing the ceramic particles to adhere to the surface of the welding wire to form a coating.

This invention relates to the field of casting technology and discloses a casting process for marine engine blades, comprising: preparing three types of molding sand with different compositions: surface molding sand, intermediate molding sand, and back molding sand; sequentially filling the surface of the pattern with surface molding sand, intermediate molding sand, and back molding sand using a layered compact molding method to form a gradient structure mold; introducing CO2 gas to harden the mold; applying a silica sol coating to the surface of the mold cavity; drying the surface to form a siliceous glassy film from the silica sol; pouring molten metal into the mold after closing the mold, and pouring at high temperature to decompose the organic pore-forming agent in the back molding sand to create pores in situ; and demolding after solidification and cooling to obtain the casting. This invention, through its gradient layered structure and surface sealing treatment, reduces the mold expansion rate while establishing a permeability gradient from the surface to the back layer, preventing molten metal penetration and promoting gas expulsion, effectively solving the problems of hot cracking, porosity defects, and surface sand adhesion in the casting of marine engine blades.

This invention discloses a robotic arm based on rotary friction welding and its manufacturing method. The robotic arm includes an arm body and a first flange. The arm body has a tubular structure, and the first flange is connected to the end of the arm body. The two are welded together by rotary friction welding. This invention experimentally screened 6061-T6 aluminum alloy or 7075-T6 aluminum alloy as suitable materials for the robotic arm. Through process debugging, rotary friction welding process parameters that enable reliable welding of the arm body and the first flange were obtained. This effectively solves the technical problems of insufficient strength, low precision, large welding deformation, softening of weld joints, and poor production economy in the manufacturing and application of existing industrial robotic arms. By fully utilizing the material advantages of 6061-T6 aluminum alloy or 7075-T6 aluminum alloy, the invention significantly improves the structural strength, stiffness, and fatigue performance of the robotic arm while achieving lightweight design, ensuring dimensional and assembly accuracy, and improving the structural reliability and service life of the robotic arm.

The invention discloses a method for repairing a swing laser welding hot crack, which comprises the following steps of: 1, designing a light path: designing two paths of laser, placing one laser beam on a fixing device for fixing, and placing the other laser beam on swing equipment for swinging as an auxiliary; secondly, parameter adjustment is conducted, wherein parameter setting is conducted on the swing amplitude and swing frequency of swing laser welding; step 3, optimizing temperature field distribution; according to the method, the fixing device and the swing equipment are arranged, one laser beam is fixed through the fixing device, the other laser beam is fixed through the swing equipment, double-beam laser welding is carried out on a product, then surface machining is carried out, a low-angle grain boundary is formed along a fusion line, grains are refined at a welding center, and the welding quality of the product is improved. And therefore, internal hot cracks are reduced by adjusting microscopic structures of base metal and welding metal, the use requirements of people are met, and the practicability is high.

The invention relates to the technical field of surfacing electrodes, and provides a surfacing electrode for gear wear repair and a preparation method of the surfacing electrode. A surfacing welding rod for gear abrasion repair comprises a welding core and a welding skin wrapping the welding core, and the welding skin comprises 35-40 parts of marble, 10-20 parts of fluorite, 30-40 parts of high-carbon ferrochrome, 5-8 parts of magnesium nitride, 15-30 parts of titanium nitride, 1-3 parts of vanadium and 2-5 parts of zinc oxide; the welding core is composed of the following components of 0.05%-0.10% of C, 0.2%-0.5% of Mn, 0.5%-0.8% of Ni, 0.3%-0.6% of Cr, 0.2%-0.4% of Mo, 0.1%-0.3% of Zr, 0.001%-0.005% of S, 0.001%-0.005% of P and the balance iron and inevitable impurities. The problem that the hardness and the impact resistance of the gear repaired by the surfacing welding rod in the related technology are poor is solved.