Development And Application On The High-performance Submerged Arc Sintered Flux

As the "West to east gas pipeline project" construction of X80pipeline steel has been successfully applied to the second line of west-east gas project", the matching of welding materials is developed;"Three line of west to east gas pipeline project" has been started, X100pipeline steel pipeline steel is used, and some domestic steel mills have been successfully developed, matching of submerged arc welding with welding wire entered the stage of experiment research, and has achieved initial results, but to match the sintered flux is relatively lag, current production of sintered welding flux SJ101-G cannot have satisfied mechanical properties of high-strength X100pipeline steel welding joint and welding process requirements, so you need to develop a new kind of conform to X100pipeline steel welding technology, welded joint mechanical properties such as sintering flux.This article main content by changing the flux SJ101-G of manganese, wollastonite silicate composition, agent and adding alloy Ti-Fe, Mn-Fe, borax, TiO2, etc., to match the same H08C welding wire welding experiment, through the analysis of the welding technology of different flux, welding joint organization and mechanical properties, to develop a new type of X100pipeline steel sintered flux provides the basis.Through metallographic microscope, scanning electron microscopy (SEM) and other test means of the welding joint microstructure, impact fracture surface morphology and the chemical composition of deposited metal carries on the observation and analysis, the following conclusions:(1)Through the analysis of composition of sintered welding flux SJ101-G, developed a new type of high-performance submerged arc sintering flux, its main chemical composition content is:SiO2≤15%、MgO≤30%、Al2O3≤20%. CaF2≤25%、MnO≤8%、CaO<12%, the total of15to20%of the binder. (2) Based on high performance submerged arc sintering flux composition, optimized flux composition design, developed a new type of high performance conforms to the sintering flux of X100pipeline steel, the main chemical composition content is:SiO2<13%、MgO≤30%、 Al2O3≤20%、CaF2≤25%、MnO≤6%、CaO≤10%、TiO2≤8%、Mn-Fe≤5%、Si-Fe≤5%,the total of15to20%of the binder.(3) High performance sintered flux welding test result shows that after welding the weld metal strength can reach680～720MPa, low temperature impact toughness reaches about110J, the test results can satisfy the X100pipeline steel welding joint and mechanical performance requirements. Optimize flux components developed in line with the X100pipeline steel welding joint of high strength, high toughness and corrosion resistance properties of the sintered flux.Through the choice of sintered welding flux slag system, the control of alkalinity and adding alloy agent and flux composition change aspects of consideration, develop a conform to the X100pipeline steel high performance of the submerged arc welding with sintered flux.