The Study Of Efficient Repair Of 316L Bimetallic Composite Pipe

Due to the relatively high cost performance of the bimetallic composite pipe,bimetallic composite pipes are widely used in the oil and gas transportation industry today.However,due to the large difference in physical and chemical properties between the lining and the substrate of the bimetallic composite pipe,in the application process,various types of corrosion perforation will inevitably occur.In particular,the mechanically conforming bimetallic composite pipe has a gap between the two layers of materials,and the gap may contain impurities such as gas,solution,and the like.The weld is the most vulnerable part of the bimetallic composite pipe.If the pipe would be replaced,the weld is the most important part;Most of the existing active bimetallic composite pipes with defects do not need to be replaced with new ones.Therefore,this paper first verified the reliability and feasibility of welding technology of the new welding process.Then,different repair plans were developed for various defect situations,and their reliability was verified.For the verification of the new tube changing process,this paper firstly uses the ray detection method and the ultrasonic detection method to perform defect inspection on the weld.The results are as follows: no obvious defects are found.Then the impact test,the chemical composition analysis test,the side bend test,tensile test,the hardness test,the corrosion resistance test,the crystal phase test,the grooving test,etc.were carried out to test the physical and chemical properties of the sample.Corrosion resistance tests were carried out on the welds.The corrosion rates were 0.0004 mm/a,0.0006 mm/a and 0.0010 mm/a under three conditions,all of which were slightly corroded,indicating that the welding process has excellent corrosion resistance.Then,the pressure-holding test was carried out for the repairer and B-type sleeve repair method,and the experimental result was that no leakage occurred under the pressure of 22.5 MPa,indicating that the method is reliable.Then,the pressure holding test of the grease filling jig was performed.The experimental results show that no leakage occurred under the cyclic pressure of 5MPa-10MPa-15 MPa twice,indicating that the method is reliable.