摘要
Abstract
The microstructure characteristics of LDX2101 steel joints involving high strength matched weld metals were reviewed.The results show that the principle of"quasi-composition matching"can be adopted in the selection of welding consumables for lean duplex stainless steel LDX2101,that is,the kinds of elements added in the weld are the same as those of the base metal,but the contents of each element may change greatly,so as to ensure proper phase equilibrium in the deposited metal and obtain satisfactory comprehensive properties.Under the same thermal cycling conditions,the microstructure of the joint mainly depends on the chemical composition,that is,Creq/Nieq ratio.In a certain range,with the decrease of Creq/Nieq ratio,the solid solution temperature of ferrite is increased,and δ→γ transformation occurs at higher temperature,and more austenite is obtained.With the increase of heat input,the content of γ-austenite in all weld metals increases,and the content of γ-austenite is higher than that of δ-ferrite.In HAZ,with the increase of heat input,the content of γ austenite increases.In the 650℃aging specimen,the microstructure change of the welded joint is mainly Cr2N precipitation.When aged at 650℃for 15 min,the main precipitation is Cr2N within the ferrite grains.When aging at 650℃for 90 min,Cr2N is precipitated on the grain boundaries of the three regions of the joint.The change of ferrite content is 37%in weld,40%in HAZ and 45%in base metal.关键词
双相不锈钢LDX2101/显微组织/高强匹配/铁素体和奥氏体相平衡/Cr2N析出物Key words
duplex stainless steel LDX2101/microstructure/high strength matching/phase equilibrium of ferrite and austenite/Cr2N precipitates分类
矿业与冶金
