Tianjin University

Kangda Hao

Yongdian Han

Lianyong Xu

Lei Zhao

Zhaowei Xue

Wenjing Ren

Hongyang Jing

Hao Wang

Tianzhu Wang

Molin Su

Yuan Li

Jiajun Shao

Shifang Zhong

Yongle Shi

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.

High-heat-input combined welding method for thick-walled high-strength steel

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.

Welding method for sea pipe with high efficiency and comprehensive performance under shaking of pipe-laying ship

An automatic welding production line for a large complex workpiece includes a base station, a welding robot, a displacement worktable, an auxiliary robot, a feeding system and a blanking system. The displacement worktable has multi degrees of freedom, the position and angle of the workpiece can be flexibly adjusted during welding to meet the welding requirements of any position and angle of the welding equipment, thereby realizing the welding operation of large complex special-shaped three-dimensional components, and multi-point welding at any point can be realized through the cooperation of the welding robot and the auxiliary robot. The control system controls the robot and the feeding and blanking system to cooperate with the displacement worktable to realize automatic feeding, welding and blanking operations, the welding parameters and operations can be automatically adjusted for the special components of the structure, to realize integration and intelligence, improve production efficiency and reduce production costs.

Automatic welding production line for large complex workpiece and production method

A feeding device for subway grille main reinforcement conveying includes two-layer chain plate conveyor arranged at an upper and a lower interval, and the chain plate conveyor is a climbing structure with one end high and one end low, two ends of the chain plate conveyor are fixedly connected to a support frame, and the chain plate conveyor is erected on a working plane through the support frame. The chain plate conveyor provides power through a motor reducer connected to a drive sprocket of the chain plate conveyor, and a higher end of the chain plate conveyor is provided with a position detection sensor. The position detection sensor can detect the position of the main reinforcement, and control the start and stop of the motor reducer and the grasping of the main reinforcement by a manipulator through feeding back the position of the main reinforcement to a main control system.

Feeding device for subway grille main reinforcement conveying

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.

Simplified method for welding 5G position filler layer of marine riser and product thereof

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.

Method for establishing hydrogen charging model for pipeline steel in equivalent wet hydrogen sulfide environment and application thereof

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.

Rapid and comprehensive method for evaluating pitting resistance of stainless steel pipe welds

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.

High-strength, high-toughness, and corrosion-resistant welding method for TKY nodes in deepwater jacket

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.

Method and system for predicting critical floating time of reinforcing phase

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.

Method of automatically welding welded seam of saddle line for saddle-type T joint

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.

CMT automatic overlaying method for opening in side wall of bimetallic composite pipe

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 Tφmodel for characterizing the propagation of short cracks and long cracks, where the Tφmodel is used for representing the growth rate of short cracks and long cracks.

Approach for characterizing propagation of metallic short cracks and long cracks

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: S, 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 S, 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 &#x3c3;of the sample. According to the method, a rigid restraint crack test is applied to evaluation of sensitivity of welding transverse cracks, so that external restraint conditions borne by a welding joint can be accurately simulated, a stress state of the welding joint in an actual working condition can be truly reflected, the overall evaluation precision is greatly improved, and a foundation is laid for accurately evaluating sensitivity of welding cold cracks in a tube joint. Furthermore, a welding technology (base material, welding material, welding process and restraint level) is designed to restrain cold cracks from cracking, and the method has important theoretical significance and engineering value.

Growing community of inventors

Tianjin, China

Kangda Hao