镁处理对钢中夹杂物以及HAZ组织和性能的影响

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300 n...

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

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 Al₂O₃ inclusions, and the action distance is about 2/5 of the maximum action distance of the Al₂O₃inclusions, so that the Mg containing complex inclusions can be dispersed in the steel.