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 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.