Research On Manufacturing Technology Of X90 High Strength Steel Heating Bend

With the demand for energy in the world,oil and gas resources are mainly transported by long-distance pipelines.Long-distance pipelines are welded by straight and curved pipe,and the curved pipe are divided into heating and cold bending pipes according to the area to be laid.Heating bending pipe is usually located at steep slopes,steep ridges and horizontal corners,which will withstand more complex stresses,so extremely important and weak it is linking in long-distance pipelines.At present,the highest steel grade heating bending pipe used in China is X80.In order to improve the pipeline construction level,reduce the wall thickness of the steel pipe,increase the pipeline transportation pressure,thereby reducing construction and operating costs,so urgent it is to study the X90 high-strength steel heating bending pipe.But there is no relevant research and development experience in China.However X90 high-strength steel heating bending pipe is an important part of X80 steel transition to X100/X120 ultra-high strength steel grade,showing high application value and scientific significance.In this paper,two different specifications X90 high-strength steel double-sided submerged arc straight seam welded steel pipe customized by various manufacturers are application for thermal simulation test.And trial production of heated bending pipe,in-depth studying of raw material composition.Manufacturing process parameters are determined by thermal simulation test.Through the coMParative analysis of the whole process heating and local heating process,the performance of each part of the trial heating bend is studied.Finally,the verification test and hydrostatic pressure test were carried out,the manufacturing process specifications for X90 high-strength steel heating bending pipe is formulated,which provided a reference for the next step of officially producing X90 high-strength steel heating bending pipe.Because of the strong practicality involving in material properties,the research work need to be combined with field practice and based on a large number of experimental tests to enable research results to be truly applied to engineering.The results of this study are listed below:(1)From the theoretical aspect,study the microstructurechange of raw material X90 high-strength steel and test the properties ofsteel.The technical parameters of the study are directly affected by external factors on the heating elbow,including cooling water flow,heatingtemperature,heat treatment temperature and pushing speed.Etc.,master thevarious processing parameters to control the microstructure performance in theheated bend.(2)Based on experimental data such as trial heating bendand thermal simulation,the best process parameters are obtained.(3)After coMParing the various processing techniques,theheating elbow has uniform organization and higher performance,ensuring theprocessing quality of the heated elbow,and achieving the expected X90 highsteel grade heating elbow performance index.(4)Adjusting the heating and bending unit from the aspectof adaptability,re-adjusting the type of the intermediate frequency inductionheating coil,enhancing the cooling capacity of the transformer,improving thewater exchanger-increasing the transformer water,etc.,to ensure a certainstability during the heating and bending stage.After the intermediatefrequency transformer adjustment mechanism is modified,it is ensured that thewhole temperature is maintained uniformly when the elbow is heated;thecompressed air air ring is added,and the cooling water and the water mist canbe blown off during the production stage,so as to ensure the stability anduniform heating of each equipment in the production stage of the elbow.Themain way of sex.