Abstract: The disclosure belongs to the field of advanced manufacturing technology and discloses a multi-field-assisted laser melting deposition composite additive manufacturing system. The system includes a vacuum chamber atmosphere protection module, a laser melting deposition module, an ultrasonic shock peening module, a workpiece transfer module, an auxiliary thermal field induction heating module, a laser shock peening module, and an integrated control module. The vacuum chamber atmosphere protection module, the laser melting deposition module, the ultrasonic shock peening module, the workpiece transfer module, the auxiliary thermal field induction heating module, and the laser shock peening module are electrically connected to the integrated control module individually and are collaboratively controlled by the integrated control module.

Abstract: A method and device for predicting long-term creep data based on short-term creep data. The method comprises: obtaining steady-state creep rate data of a material under different stress levels through a step-loading method for multi-stage stress based on short-term creep data; determining first fitting parameter values of a creep deformation performance model through nonlinear fitting; determining the creep stress exponents under different stress levels based on the steady-state creep rate data and creep stress; determining the creep damage parameters under different stress levels based on the creep stress exponents and a creep damage parameter model; determining the second fitting parameter values of a creep deformation prediction model through nonlinear fitting to predict the long-term creep deformation of the material; and determining the third fitting parameter values of a creep life prediction model based on the second fitting parameter values to predict the long-term creep life of the material.

Abstract: A backing welding process curve based on a narrow-gap U-groove and its application and product are provided. The backing welding process curve is used for welding the narrow-gap U-groove. On the basis of a CMT reference curve, at least one current pulse is introduced before and after the short-circuiting phase respectively, to increase the root weld width and avoid root concavity. Meanwhile, the peak current and cycle time are increased to enhance welding heat input, while the peak current rise rate and peak current fall rate are reduced to prolong the peak current action time.

Abstract: This disclosure relates to a welding method for improving the stress corrosion resistance of a welded joints of a riser pipe and a product thereof. The welding method including: using CMT to weld SCR riser pipe under a shielding gas of 80% Ar+20% CO2. The welding current for the root pass and fill pass is 180 A to 200 A, and the welding voltage is 20 V to 23 V, and the welding speed is 400 mm/min to 500 mm/min; the welding current of the cover pass is 130-150 A, the welding voltage is 13-15 V, and the welding speed is 245 mm/min to 255 mm/min.

Abstract: A method and system for evaluating the performance of metallic materials based on creep-fatigue interaction, comprising: based on elastic-plastic property data and creep property data of metallic materials, calculating the monotonic crack tip opening displacement and cyclic crack tip opening displacement caused by plasticity or creep of short cracks under maximum far-field stress and far-field cyclic stress, respectively; using the linear superposition method to obtain the total monotonic crack tip opening displacement and cyclic crack tip opening displacement of short cracks under the combined creep-fatigue action; by calculating the short crack growth rate of the metallic material under creep-fatigue interaction, the performance of the metallic material is evaluated. The invention solves the problems of traditional methods, such as relying on a large amount of crack growth experimental data and insufficient consideration of creep-fatigue short crack effects.

Abstract: The disclosure belongs to a technical field of a stress corrosion cracking test, and specifically discloses a quantitative evaluation method and system for stress corrosion susceptibility of a pipeline steel welding connector. Through the disclosure, bending tests in a hydrogen sulfide environment is combined with a slow strain rate tensile test to obtain a limit value/range of the stress corrosion susceptibility of the welding connector. Resistance of the welding connector to stress corrosion cracking is unqualified when it is greater than the limit value/exceeds the limit range, otherwise it is qualified.

Abstract: A high-heat-input combined welding method for thick-walled high-strength steel includes following steps. First, a steel plate to be welded is machined into an asymmetric double-sided V-groove, with a depth of a front groove ranging from 30 mm to 40 mm. Then, electrogas welding is used to fill and weld the front groove, with a single-pass heat input controlled below 300 KJ/cm. Finally, a back groove is filled and welded, ensuring that the single-pass heat input for the back groove does not exceed that of the front groove. By adopting an asymmetric double-sided V-groove, the steel plate to be welded is divided into front and back sections. The depth of the groove is restricted to limit the heat input during filling welding.

Abstract: Fully automatic welding forming equipment for a special-shaped three-dimensional workpiece and a welding method is provided. The welding forming equipment includes a base station, a welding robot, a displacement worktable, an auxiliary robot, and a hopper. The welding robot, the auxiliary robot and the hopper are arranged on the base station, and the displacement worktable is arranged between the base stations. The displacement worktable adopts the structure of main and sub double frames and main and sub double rotary power, which has multiple degrees of freedom, and can flexibly adjust the position and angle of the welded parts, realize the welding requirements of any position and angle, and meet the welding operation requirements of complex special-shaped three-dimensional components without manual repair welding operation, and the multi-point welding can be realized through the cooperation of welding robot and auxiliary robot to improve the welding efficiency and quality.

Abstract: A rotary translational positioner with multiple degrees of freedom includes support frames, a main rotary dynamic structure, a main frame, an auxiliary dynamic structure, an auxiliary frame, and a worktable, where the main frame is arranged between the support frames, the main rotary dynamic structure is arranged at the end of the main frame and is located between the main frame and the support frame, the auxiliary frame is arranged in the main frame through the auxiliary dynamic structure, the auxiliary dynamic structure is arranged at the front end and the rear end of the auxiliary frame, and the worktable is arranged on the auxiliary frame. A main and auxiliary double frame structure is adopted, the main frame can adjust the position and angle of the whole welding workpiece, and the auxiliary frame can adjust the position and angle of the welding parts.

Abstract: In a field of welding technology, a welding method for a sea pipe with high efficiency and comprehensive performance under shaking of a pipe-laying ship is specifically disclosed. The welding method is as follows: performing ultra-short arc GMAW all-position welding on the sea pipe within a range of heat input of 0.2 kJ/mm˜0.3 kJ/mm, while setting a peak current, setting a peak current descent rate to 50 A/ms˜70 A/ms, and setting the necking time to 3 ms˜7 ms in the GMAW waveform to 285 A˜370 A. A welding effect of overall low heat input and partial high heat input is formed, and the stability of all-position welding of the sea pipe is guaranteed, which realizes stable welding of the sea pipe under the condition of pipe-laying ship shaking, and improves the fatigue resistance and corrosion resistance of the sea pipe.

Abstract: The disclosure belongs to the field of advanced manufacturing technology and discloses a multi-field-assisted laser melting deposition composite additive manufacturing system. The system includes a vacuum chamber atmosphere protection module, a laser melting deposition module, an ultrasonic shock peening module, a workpiece transfer module, an auxiliary thermal field induction heating module, a laser shock peening module, and an integrated control module. The vacuum chamber atmosphere protection module, the laser melting deposition module, the ultrasonic shock peening module, the workpiece transfer module, the auxiliary thermal field induction heating module, and the laser shock peening module are electrically connected to the integrated control module individually and are collaboratively controlled by the integrated control module.

Abstract: The disclosure provides a method for establishing a hydrogen charging model for pipeline steel in an equivalent wet hydrogen sulfide environment and an application thereof, which belongs to the field of corrosion electrochemistry. The method includes the following steps: using a cathode hydrogen charging method and a wet hydrogen sulfide environment method respectively to perform hydrogen charging on each sample to be tested under different reaction conditions to obtain several first hydrogen charging samples and second hydrogen charging samples; measuring the hydrogen content of each of the first hydrogen charging sample and the second hydrogen charging sample; performing curve fitting on the variables in the two methods respectively according to the obtained hydrogen content, and the hydrogen charging model for pipeline steel in the equivalent wet hydrogen sulfide environment is obtained according to the fitting result.

Abstract: The disclosure relates to a rapid and comprehensive method for evaluating pitting resistance of stainless steel pipe welds. Weld samples are collected from different positions of one or more welds on the stainless steel pipe to obtain the surface oxide inclusion density and critical pitting temperature of each weld sample, the surface oxidation inclusion density is taken as an independent variable and the critical pitting temperature is taken as a dependent variable to obtain a fitting function formula between the surface oxidation inclusion density and the critical pitting temperature. The surface oxide inclusion density obtained by adopting the same welding process on the stainless steel pipe to be tested is substituted into the fitting function formula to obtain a standard critical pitting temperature of the weld to be tested. The pitting resistance of the weld of the stainless steel pipe to be tested can be evaluated rapidly, accurately, and comprehensively.

Abstract: The disclosure provides a method for establishing a hydrogen charging model for pipeline steel in an equivalent wet hydrogen sulfide environment and an application thereof, which belongs to the field of corrosion electrochemistry. The method includes the following steps: using a cathode hydrogen charging method and a wet hydrogen sulfide environment method respectively to perform hydrogen charging on each sample to be tested under different reaction conditions to obtain several first hydrogen charging samples and second hydrogen charging samples; measuring the hydrogen content of each of the first hydrogen charging sample and the second hydrogen charging sample; performing curve fitting on the variables in the two methods respectively according to the obtained hydrogen content, and the hydrogen charging model for pipeline steel in the equivalent wet hydrogen sulfide environment is obtained according to the fitting result.

Abstract: A high-strength, high-toughness, and corrosion-resistant welding method for TKY nodes in a deepwater jacket includes the following steps: preheating T/K/Y nodes at a predetermined temperature according to a wall thickness of a base material; setting different welding parameters for different welding processes; and performing rooting weld on the preheated T/K/Y nodes through an electrode arc welding process, then performing filling weld through a gas metal arc welding process, and finally performing capping weld through the gas metal arc welding process. A corresponding electrode is selected for the rooting weld, a welding wire is selected for the capping weld according to low-strength matching, a welding wire is selected for the filling weld according to an equal-strength matching principle, and diffusible hydrogen contents of any electrode and any of the welding wires are all less than or equal to a predetermined diffusible hydrogen content.

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 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 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: 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.