The Research Of The Effect Of Welding Material On Weld Structure And Properties Of X100Pipeline Steel

With the increasing demand for oil and gas,the more and more high requirements for the pipeline steel, X70, X80grade pipeline steel has been unable to meet their requirements, a higher level of X100grade pipeline came into being,,but its research and development of welding materials has remained relatively stagnant.The current production of X70, X80grade pipeline steel submerged arc welding wire and flux have been unable to meet the mechanical properties, welding technology and other needs of high-strength X100pipeline steel welded joints, therefore, a new submerged arc welding material was needed to develop to meet the welding process, the mechanical properties of X100pipeline steel welded joints and other requirements.In this topic,accoring to the welding mechanies demandment of X100pipeline, Mn-Ni-Cr-Mo was choosed as the alloy systems of X100pipeline submerged arc welding wire.While according to the requirements of welded joints, alkali fluoride slag system of the agglomerated flux was choosed. Then the welding materials were tested and analysised.By research the microstructure and properties of welded joints of X100pipeline steel mechanisms and laws affecting,the main conclusions were obtained:(1) Acicular ferrite and granular bainite were obtained for the optimal design of the Mn-Ni-Cr-Mo system wire of X100.(2) A new kand of agglomerated flux was obtained for the X100pipeline steel by optimization of flux composition.Its main composition as follows:18to25%of fluorite,17to22%of bauxite,4to8%of manganese dioxide,3to7%of wollastonite,5to9%of fire clay,23to30%of crude magnesia,1to4%of ferrosilicon,2to4%of ilmenite,2to6%of zircon powder,3to6%of titanium dioxide, The yield strength reached643MPa,the tensile strength reached732Mpa, low impact energy reached33J (-20℃) by welding test of X100pipeline steel.(3) From the test results, acicular ferrite and granular bainite mixed microstructure were obtained by agglomerated flux designed to match the the wire of X100pipeline steel.Through the research of the effect of welding materials on weld Structure and properties of X100pipeline steel, a new kind of submerged arc welding material was obtained.It can meet the demand of high strength, high toughness, corrosion resistance and other properties of the X100pipeline steel welding joint.