镁处理对钢中夹杂物以及HAZ组织和性能的影响  

Effect of magnesium treatment on inclusions and HAZ microstructure and properties of steel plate

作　　者：杨健 蔡文菁 YANG Jian;CAI Wen-jing(School of Materials Science and Engineering,Shanghai University,Shanghai 200444,China)

机构地区：[1]上海大学材料科学与工程学院,上海200444

出　　处：《钢铁》2021年第7期13-24,共12页Iron and Steel

基　　金：国家自然科学基金钢铁联合研究基金重点资助项目(U1960202);省部共建高品质特殊钢冶金与制备国家重点实验室、上海市钢铁冶金新技术开发应用重点实验室和上海市科学技术委员会资助项目(19DZ2270200)。

摘　　要：近年来镁处理的氧化物冶金技术研究非常活跃,为了总结镁处理氧化物冶金研究的最新成果,综述了镁处理对钢中夹杂物以及HAZ组织和性能的影响研究。通过镁处理形成的微米级含镁氧化物和硫化物复合夹杂物可以诱导晶内针状铁素体析出;镁处理过程中形成的纳米析出物,通过对奥氏体晶界的钉扎作用可以抑制原奥氏体晶粒长大,钉扎粒子多为300nm以下的TiN、在MgO表面析出TiN形成的MgO+TiN复合夹杂和镁的氧化物或硫化物及其复合夹杂物。这两种氧化物冶金作用机理都有助于提高厚钢板的大线能量焊接热影响区的低温冲击韧性。镁处理可以同时对钢中氧化物和硫化物进行改性,改变了硫化物的组成和形态,生成以含镁夹杂物为核心,外围包裹MnS的复合夹杂物抑制了树枝状MnS的生成,促进钢中生成细小、球状分布的MnS夹杂物,进而改善钢的可加工性能;并且形成的含镁复合夹杂物之间的作用力约为Al_(2)O_(3)夹杂物之间作用力的1/10,作用距离约为Al_(2)O_(3)夹杂物最大作用距离的2/5,呈现弥散分布状态。The research on oxide metallurgy with magnesium treatment is very active in recent year.In order to summarize the latest achievements of the research on oxide metallurgy with magnesium treatment,the effect of Mg treatment on inclusions and HAZ microstructure and properties of steel plate was reviewed.The microscale Mg-containing oxide and sulfide inclusions formed by Mg treatment can induce the formation of acicular ferrite.The results show that the nano precipitates formed during Mg treatment can inhibit the growth of original austenite grains by pinning the austenite grain boundaries.The pinning particles are TiN below 300 nm,MgO + TiN complex inclusions formed by TiN precipitation on MgO surface,and Mg oxides or sulfides and their complex inclusions.These two kinds of oxide metallurgy mechanisms are helpful to improve the low-temperature impact toughness of heat-affected zone(HAZ)of steel plate after high heat input welding.Mg treatment can modify oxide and sulfide in steel at the same time,change the composition and morphology of sulfide,form complex inclusions with magnesium oxide as the core surrounding MnS to inhibit the formation of dendrite MnS,promote the formation of fine and spherical MnS inclusions in steel,and improve the machinability of steel.Moreover,the force between the magnesium-containing inclusions is about 1/10 of the force between the Al_(2)O_(3) inclusions,and the action distance is about 2/5 of the maximum action distance of the Al_(2)O_(3) inclusions,so that the Mg containing complex inclusions can be dispersed in the steel.

关 键 词：镁处理 氧化物冶金 夹杂物 HAZ 低温冲击韧性 

分 类 号：TG142.1[一般工业技术—材料科学与工程]