Al-Ti脱氧对非调质钢中MnS析出行为及组织的影响

Effects of Al-Ti Deoxidation on MnS Precipitation and the Microstructure of Non-Quenched and Tempered Steel

通过试验研究了含碳量为0.35%(质量分数,下同)的非调质钢加入不同含量的Al、Ti脱氧后,钢中含MnS夹杂物的形貌、成分、尺寸分布情况以及钢的铸态组织。用激光共聚焦高温扫描显微镜在线观察了不同碳含量的钛脱氧非调质钢试样在1 350℃保温10min后,以2℃/s速率冷却的过程中奥氏体晶内针状铁素体的生成过程。结果表明:钢中铝含量大于0.04%时,不利于形成细小、弥散、球状的MnS,也不利于针状铁素体的生成;钢中铝含量小于0.011%时,向钢中加入0.02%的钛,可以生成细小、弥散的球状MgO-Al2O3-TiOx-SiO2-MnS复合夹杂物,这种复合夹杂物有利于非调质钢中晶内针状铁素体的形成。碳含量影响钛脱氧非调质钢中针状铁素体的形成,钛脱氧钢增碳后针状铁素体比例减少。

The morphology, composition and sizes of MnS containing inclusions in a non-quenched and tempered steel containing 0.35 % of carbon deoxidized with different contents of aluminium and titanium were investigated. The generation of acicular ferrite in austenite grain for the samples with different carbon content was observed on line with a cooling speed of 2 ℃/s after 10min heating at 1350℃ by a confocal laser high temperature scanning microscope. The results show that aluminum content in the steel more than 0.04 % is not beneficial to the forma- tion of fine, disperse and spherical MnS. Adding 0.02 % Ti to steel could form the complex inclusions of MgO- A12 03-TiOx-SiO2-MnS which is fine, dispersed and spherical when the aluminum content in the steel is low. The complex inclusions of MgO-Al2 O3-TiOx-SiO2 MnS are beneficial to the generation of acicular ferrite in the non- quenched and tempered steel. Carbon content effects the generation of acicular ferrite in Ti-deoxidized non- quenched and tempered steel, after C-addition, the ration of acieular ferrite would decrease in Ti-deoxidized steel.