Tianjin University

Hongyang Jing

Lianyong Xu

Yongdian Han

Lei Zhao

Kangda Hao

Wenjing Ren

Yi Miao

Shifang Zhong

Yuan Li

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 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

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.

Quantitative evaluation method for sensitivity of welding transverse cold cracks in typical joint of jacket

The present invention published a large walled field conditions P92 long pipeline local heat treatment processes. Firstly, according to the specific conditions for the on-site grade heat-resistant steel (P92 pipe), combining of the finite element method and test, the Heated Band (HB) width and Gradient Control Band (GCB) was calculated. The pipe was then locally heated using the flexible ceramic resistive heater. When the temperature reaches 80-100&#xb0; C., the pipe was heated to constant temperature at 80-100&#xb0; C. for 2 h. The pipe was heated to 300&#xb0; C. at the rate of 150&#xb0; C./h. When the temperature reaches 300&#xb0; C., rising the temperature to 765&#xb0; C. at the rate of 80&#xb0; C./h. Holding time is calculated by the wall thickness (5 min/mm, no less than 4 h). Lowering the temperature to 300&#xb0; C. at the rate of 100&#xb0; C./h and then natural cooling to room temperature, finally removing the heating device. Finally, the local heat treatment process can be obtained. The present invention can effectively decrease the temperature difference between the outer and inner wall, the residual stress in the welded joints. Thus the service properties can be guaranteed.

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Tianjin, China

Hongyang Jing