Research Of Welding Quality Testing And Standared On Stainlless Steel Clad Welded Pipe

Design of clad pipe is to meet the requirement of its use and cost saving. As the main body, the prime layer is to meet the requirement of basic property index and low cost; the top layer contacts medium is to meet the demand of anti-corrosion and service life etc.Stainless Steel Clad Pipe (SAWH) is three-roller helically formed using carbon steel and stainless steel hot-rolled coil, then welded by SAW process,mainly for drinking water, weakly corrosive medium transmission etc.The main purpose and achievements of the essay are as following:a) With Q235B+SUS304 Clad coil, wire CHW-S1,CHW-398L and flux CHF411,CHF117, "Y" groove and optimized welding parameters, successfully trial-produced one lot stainless steel clad pipe by spiral forming for the stainless top layer and SAW for the carbon steel prime layer, which can prove the process is feasible.b) Inspect and test stainless steel clad pipes including chemical composition analysis (spectrum and energy spectrum),metallgraphic examination (macro and micro), Vickers hardness test, tensile test, guided-bend test for the weld, charpy-V impact test, bond strength, intergranular corrosion etc.,discuss the result in detail. The result indicates under the optimized raw material and process parameters discussed by the article, over-all property can meet the requirements of drinking water and weakly corrosive medium transmission, furthermore, the article proposes that lower the alloy element dilution rate of welding jointer and improve the over-all property of the weld and HAZ, optimize the welding process is necessary..c) Propose suitable inspection and test methods refer to API SPEC 5LD etc.,initially set up quality inspection and test system after analysis and conclusion, make a brief introduction of the inspection methods and inspection items and evaluation criteria and test frequency.