Abstract: A detection device includes a frame body and a main pipe positioning assembly, a branch pipe positioning assembly, and a first driving assembly disposed on the frame body. One side of the frame body is provided with an opening. The branch pipe positioning assembly is disposed inside the opening. The first driving assembly adjusts the branch pipe positioning assembly, so that the branch pipe positioning assembly is adapted to positions of the two branch pipes. During detection, the branch pipes are located in the opening, the main pipe positioning assembly connects two ends of the main pipe, and the branch pipe positioning assembly connects the two branch pipes. Two limiting members are slidably disposed on the frame body to open and close the opening, and the limiting members abut against an outer wall of the main pipe, such that the main pipe is located inside or outside the opening.

Abstract: A welding method for improving quality of 5G all-position welding of a marine riser and a product thereof are provided, and the disclosure belongs to the technical field of welding. The welding method specifically includes the following. welding the marine riser in 5G all positions using a unified welding mode; reducing a predetermined voltage or reducing predetermined inductance in an overhead welding position to improve directivity and stability of an arc; and meanwhile increasing an arc swing width in the overhead welding position to eliminate a lack-of-fusion defect. In the disclosure, a unified welding mode suitable for flat welding is applied to marine riser welding. The process of 5G all-position welding of the marine riser is effectively simplified. The welding quality of 5G all-position welding of the marine riser is thereby effectively improved.

Abstract: A simplified method for welding a 5G position filler layer of a marine riser and a product thereof are provided, and the disclosure belongs to the technical field of welding. The method specifically includes the following. performing filler welding on the marine riser using an oscillation scanning laser-GMAW hybrid welding process; performing welding on each layer using same process parameters, then reducing gravity of a molten pool and increasing an arc force through interaction between laser and an arc, meanwhile expanding a range of a welding molten pool through an oscillation scanning behavior of the laser beam. A lack-of-fusion defect is prevented from being generated. A 5G position filler layer welding process of the marine riser is effectively simplified in the disclosure. Further, laser beam scanning also expands the range of the welding molten pool and prevents generation of the lack-of-fusion defect on a side wall.

Abstract: A method for determining the filling welding parameters of large deformation pipeline steel based on secondary regulation method includes: welding specimens to be welded for secondary welding thermal simulation experiments based on a thermal simulation to obtain samples after thermal simulation; processing the samples after thermal simulation into CTOD samples and calculating fracture toughness parameters; pre-loading of specimens requiring pre-strain after thermal simulation by uniaxial tension, and then processing samples before and after pre-strain after thermal simulation, conducting slow strain rate tension tests and calculating stress corrosion cracking susceptibility parameters; comparing the change in elongation of the samples before and after pre-strain and calculating the pre-strain sensitivity parameters; determining secondary thermal simulation parameters; converting the secondary thermal simulation parameters into welding heat input parameters; determining welding parameters based on welding heat

Abstract: The present disclosure relates to a method and system for predicting the critical floating time of a reinforcing phase. According to the method, a particle concentration processing model, a half-life processing model, an agglomeration kinetics model, and a floating time processing model are combined to obtain the critical floating time of a reinforcing phase particle according to an initial particle size of the reinforcing phase particle, a density of the reinforcing phase particle, a mass fraction of the reinforcing phase of a composite soldering material, and a density of the composite soldering material. The method and system can accurately predict the critical floating time of the reinforcing phase particle.

Abstract: The disclosure discloses a creep lifetime prediction method for a P92 main steam pipeline welded joint, which includes the following. Based on the minimally invasive sampling technology and the microstructure characterization equipment, the microstructure of the P92 steel welded joint after service is obtained. An area with a most significant degradation of the P92 steel welded joint is determined by performing grading processing on the microstructure of the welded joint. The maximum main stress of the structural component is obtained through the finite element technology and the actual service pressure of the P92 steel welded component. Through the maximum main stress and the microstructure after grading, based on the temperature-related Larson-Miller creep lifetime prediction method, the creep lifetime of the welded joint under the condition is determined.

Abstract: Disclosed is a deepwater platform welded joint testing system. The testing system comprises a host unit, a hydraulic unit and a control unit, wherein the control unit is connected with the host unit and the hydraulic unit respectively; the host unit comprises a bearing frame placed on a bearing base, biaxial tension/compression loading oil cylinders mounted on the bearing frame, a lateral force resistant mechanism connected to the front ends of the biaxial tension/compression loading oil cylinders, counter-force supports fixed to the top end of the bearing frame and biaxial bending loading oil cylinders mounted on the counter-force supports.

Abstract: A method of automatically welding a welded seam of a saddle line for a saddle-type T joint belonging to the technical field of welding is provided, including: establishing a groove cross-sectional model, solving a variation law of a groove cross-sectional area, and planning a welding bead and a welding process parameter according to the groove cross-sectional area; establishing a welding torch pose mathematical model and obtaining a pose homogeneous transformation matrix T of a welding torch; establishing a three-dimensional model of a main pipe and a branch pipe, building a welding system through offline software, importing welding spot pose information, and generating welding torch pose offline command through the offline software; and performing automatic welding of the welded seam of the saddle line for the saddle-type T joint according to the planned welding bead and the welding process parameter and the generated welding torch pose offline command.

Abstract: The invention belongs to the field of welding technology and discloses a CMT automatic overlaying method for opening in side wall of bimetallic composite pipes. The method includes: establishing a mathematical model of the opening in a side wall to be welded; Based on the mathematical model, determining the trajectory of the saddle line during overlaying; dividing the trajectory of the saddle line into several welding runs, all of which adopt the downslope welding process; establishing a three-dimensional model of the opening in the side wall to be welded and a CMT overlaying system simulation model; Based on the simulation model, planning the overlaying path of the CMT overlaying, and generating an overlaying offline instruction; Based on the offline instruction, performing CMT overlaying on the opening in the side wall to be welded according to the overlaying sequence, so as to obtain a weld overlay.

Abstract: A method for characterizing propagation of metallic short cracks and long cracks includes: acquiring crack tip opening displacement in a metallic notched sample under cyclic loading; acquiring crack tip opening displacement amount caused by a single monotonic tensile in the notched sample, and crack tip opening displacement caused by monotonic tensile in the notched sample under a maximum far-field stress; and based on an original Shyam model, constructing, according to the crack tip opening displacement amount and the crack tip opening displacement by obtaining yield strength of metals, a Tm?c model for characterizing the propagation of short cracks and long cracks, where the Tm?c model is used for representing the growth rate of short cracks and long cracks.

Abstract: A method for characterizing propagation of metallic short cracks and long cracks includes: acquiring crack tip opening displacement in a metallic notched sample under cyclic loading; acquiring crack tip opening displacement amount caused by a single monotonic tensile in the notched sample, and crack tip opening displacement caused by monotonic tensile in the notched sample under a maximum far-field stress; and based on an original Shyam model, constructing, according to the crack tip opening displacement amount and the crack tip opening displacement by obtaining yield strength of metals, a Tm?c model for characterizing the propagation of short cracks and long cracks, where the Tm?c model is used for representing the growth rate of short cracks and long cracks.

Abstract: The present invention discloses a method and system for predicting a creep-fatigue life of a structural part of a thermal power unit. The method includes: constructing a life prediction model; acquiring a stress relaxation curve in a strain control creep-fatigue test through pure creep data to calculate an initial creep damage; acquiring a cyclic hardening coefficient, an elasticity modulus and other related material constants through the pure fatigue data to calculate an initial fatigue damage; and acquiring a difference between strain energy densities in upper and lower parts of creep-fatigue mean stress, making the difference between strain energy densities less than a set threshold through dichotomy iteration to acquire a final creep damage, a final fatigue damage and an oxidative damage under such a circumstance, and predicting the creep-fatigue life of the high-temperature structural part based on the life prediction model.

Abstract: Disclosed is a deepwater platform welded joint testing system. The testing system comprises a host unit, a hydraulic unit and a control unit, wherein the control unit is connected with the host unit and the hydraulic unit respectively; the host unit comprises a bearing frame placed on a bearing base, biaxial tension/compression loading oil cylinders mounted on the bearing frame, a lateral force resistant mechanism connected to the front ends of the biaxial tension/compression loading oil cylinders, counter-force supports fixed to the top end of the bearing frame and biaxial bending loading oil cylinders mounted on the counter-force supports.

Abstract: A method of predicting low-cycle fatigue crack initiation and propagation behaviors under a multi-scale framework includes the following steps: S1, providing a calculation method for low-cycle fatigue crack initiation and propagation damages under a multi-scale framework; S2, determining a slip system where a maximum damage is located and an accumulated damage of all slip systems by calculation using the calculation method in S1; S3, a crack initiating and propagating in a direction towards the slip system where the maximum damage is located when the accumulated damage reaches a critical value; and S4, conducting calculation repeatedly until a predicted crack length reaches a fracture length of a low-cycle fatigue specimen under test conditions.

Abstract: The present invention discloses a quantitative evaluation method for sensitivity of welding transverse cold cracks in a typical joint of a jacket, including following steps: S1, performing macroscopic analysis, metallographic analysis, fracture analysis and hardness analysis on cracks of a failed component to obtain main causes of cold crack failure; and S2, designing and processing a dedicated sample, and performing rigid restraint crack tests on the dedicated sample at different preheating temperatures to obtain a cracking/non-cracking critical restraint stress ?1cr of the sample.

Abstract: The present invention discloses a quantitative evaluation method for sensitivity of welding transverse cold cracks in a typical joint of a jacket, including following steps: S1, performing macroscopic analysis, metallographic analysis, fracture analysis and hardness analysis on cracks of a failed component to obtain main causes of cold crack failure; and S2, designing and processing a dedicated sample, and performing rigid restraint crack tests on the dedicated sample at different preheating temperatures to obtain a cracking/non-cracking critical restraint stress ?1cr of the sample.

Abstract: The present disclosure relates to a method and system for predicting the critical floating time of a reinforcing phase. According to the method, a particle concentration processing model, a half-life processing model, an agglomeration kinetics model, and a floating time processing model are combined to obtain the critical floating time of a reinforcing phase particle according to an initial particle size of the reinforcing phase particle, a density of the reinforcing phase particle, a mass fraction of the reinforcing phase of a composite soldering material, and a density of the composite soldering material. The method and system can accurately predict the critical floating time of the reinforcing phase particle.

Abstract: This invention discloses a method for preparing a kind of Sn-based silver-graphene lead-free composite solder, including mixing a certain amount of graphene with sodium dodecyl sulfate, then adding a certain amount of dimethylformamide, sonicating for 2 hours, adding a certain amount of silver nitrate to the mixture, continuing the sonication and finally obtaining the homemade. The solders matrix powder is weighed according to different silver-graphene mass fraction required, then poured into a ball-milling tank milling for 5 h. The powder is poured into a stainless steel mold after drying, then placed under hydraulic pressure to 500 Mpa for pressure forming. Later, the cold-pressed cylinder is placed in a high vacuum tube resistance furnace and sintered at 175° C. for 2 hours. After cooling to room temperature, it is formed into a cylinder under the hydraulic press.