Research On Safety Assessment Technology Of Fully Automatic Welded Girth Weld Of 0.8 Design Factor Gas Transmission Pipeline

In recent years,social safety accidents often occur,which cause great waste to so cial economy and public resources.The safe operation of pipeline is very important for the public society and the pipeline industry.As the 0.8 coefficient section of the west third line is the first high-steel pipeline with automatic welding in China,there is no relevant test data on the weld quality in China,especially the mechanical properties a nd anti-defect extension parameters of automatic girth weld in real service in the fiel d,the current domestic no relevant test data,especially the real service defects automa tic girth weld mechanical properties and resistance to extension of parameters.Fracture assessment is based on the existing materials of X60 and X65 and X70 and semi-auto matic welding procedure,welding and manual welding does not include X80 welding a nd automatic welding,automatic welding process under the girth weld of factors with different main failure is not fusion defects.So this paper in order to design coefficient0.8 period of fully automatic welding welding technology of girth weld containing defe cts under more accurate evaluation,west of three line of west-east gas after serving fo r a long time the actual pipeline girth weld as the research object,through the R6 do uble criterion method was carried out on the actual service piping materials to build n ew failure assessment curve of water pressure blasting tests are carried out.in addition,hydraulic pressure blasting test is carried out to verify the new failure assessment curv e.The bearing capacity of the actual service section is studied,and the relevant mec hanical properties are tested.The mechanical properties of girth weld under different w elding methods were studied.The research results include the following aspects:(1)Study on the safety assessment curve of girth weld defects in 0.8 design coefficient section using automatic welding process;(2)It is verified by physical hydraulic blasting test that it is applicable to the safety assessment method of full-automatic welding with defects in 0.8 design coefficient section;(3)Comparative analysis of mechanical properties of girth weld of automatic welding and that of semi-automatic welding.Pipeline is the most easily damaged part in the oil and gas industry,and girth weld cracking is also an important factor of pipeline failure.Therefore,the research results have important guiding significance for the accuracy of service suitability evaluation of girth welddefects and for the economic and safe operation of automatic welding of high steel grade gas transmission.pipeline with 0.8 design coefficient.