Study On The Heat Treatment Process And Matching Electrode Of 1Ni9 Steel

Though welding materials were largely produced and consumed in our country,it still needed to develop.The products of welding material was very limited,especially in high strength steel,low temperature steel,heat-resistant steel,stainless steel and special steel,the corresponding matching welding material of them were very rare.Many kinds of welding material have to rely on imports from foreign country in high price.In order to provide reference and guidance for the research and development of 1Ni9 steel welding consumables in China,and to expand the scope of application of 1Ni9 steel,it was presented to be very meaningful to systematically investigate the properties of 1Ni9 steel and to develop its matching welding materials,and to ensure the weld and base material having similar strength and toughness matching.The paper,basing on investigation of heat treatment process,microstructure analysis,mechanical property,and its walkability of low temperature ductile material 1Ni9,developed a matching welding material for 1Ni9 using uniform design method,the welding material matching with 1Ni9 steel can get excellent ductile weld.By suitable heat treatment,1Ni9 steel,after quenching at 800℃ plus quenched at+670℃ and+570℃ tempering,has a good impact property,the impact absorbing energy can be up to 125J at-196℃,from SEM images can be seen,the impact fracture surface showing a ductile fracture with dimples after heat treatment in dual phase region;Through the research on slag detachability of developed welding electrode,in the low hydrogen electrode,the iron alloy highly affected slag detachability of electrode.In the composition range determined by test,with the increase of ferromanganese,ferrosilicon,titanium iron,the slag microstructure of CaTiO3 and Ca2SiO4 melt phase showed a shape of fishbone,most of them arranged orderly,and basically the same direction,which were played an important role in slag removal of electrode;in testing of arc stability property for developed electrode,it was found that the welding electrode had an best arc stability welding property electrode,it was found that the welding electrode had an best arc stability welding property when the alkalinity of electrode coating was about 2.0;in practical welding with the developed welding electrode,the microstructure of weld zone was single phase austenite,which mainly consisted of a gamma phase solid solution and precipitation phase;the grain of weld fusion zone was crystalized and grown up basing on grain of overheated base metal,the orientation of many unit cell arranged to a cluster and separated with large angle to another cluster unit cell,formed the interface,and then composed of columnar grain boundaries;the microstructure of weld fusion line of base metal side were tempered martensite plus retained austenite.Finally,the mechanical properties test can be seen,the plasticity and toughness of welding electrode j oint was effectively improved at-196 ℃.The 1Ni9 steel have good low temperature performance by heat treatment,the matching electrode has excellent welding performance,compared with the existing imported welding electrode ENiCrMo-3,in the same welding condition,the strength of welded joints is basically the same,but there were more obvious improvement in the joint impact toughness at low temperature.