含不烧镁橄榄石的镁质中间包涂料对汽车板钢洁净度的影响

采用市售镁质中间包涂料和添加20%(w)不烧镁橄榄石颗粒的镁质中间包涂料分别制备坩埚试样,将汽车板钢样置于坩埚孔中,在真空碳管炉中于氩气保护下经1 600℃分别热处理1 h或2 h,以研究含不烧镁橄榄石的镁质中间包涂料对钢中Al、Si、Mn、P和T. C、T. O、T. N、T. S的含量,以及钢中夹杂物尺寸、形貌和成分的影响。结果表明:钢样在1 600℃下与两种中间包涂料作用后,钢中Si含量均降低,P、Al含量均增加,Mn含量变化不大,T. N、T. S含量均增加;而T. O含量在与两种涂料作用1 h后略有降低,但延长至2 h后,T. O含量又增加,且以添加不烧镁橄榄石的增加明显。钢中的夹杂物尺寸在与两种涂料相互作用后均有所增大,且以未加不烧镁橄榄石的增大明显,夹杂物的成分从原始钢样中较为单一的Al_2O_3、Mn O以及TiO_x等变化为成分复杂的(P,Si) O-MnS、SiO_2-Al_2O_3以及MgO-Mn(O,S)-(Al,Ti,Si) O等复合氧化物。

Effects of unburned forsterite containing magnesia tundish coating on cleanliness of auto sheet steel

Crucibles were prepared using commercially available magnesia tundish coating and magnesia tundish coating with 20 mass%unburned forsterite particles as starting materials.Auto sheet steel samples were placed in the two sets of crucibles,and then they were placed in a vacuum carbon tube furnace under argon atmosphere at 1600℃for 1 h or 2 h.The effects of unburned forsterite containing magnesia tundish coating on the contents of total carbon,total oxygen,total nitrogen,total sulfur and Al,Si,Mn and P in steel and morphology,composition and size of the inclusions in steel were studied.The results show that after reaction with the two coatings at 1600℃,the steel has decreased Si content,increased P and Al contents,and little changed Mn content;the contents of total nitrogen and total sulfur in the steel increase,and the content of total oxygen decreases slightly after 1 h smelting test but increases when the duration prolongs to 2 h;the increase is more significant in the coating with unburned forsterite;the size of the inclusions in the steel increases after smelting in the two coatings and the increase is more obvious in the coating with forsterite.The composition of inclusions changes from the single-component inclusions such as Al2O3,MnO and TiOx to composite oxides inclusions as(P,Si)O-MnS,SiO2-Al2O3 and MgO-Mn(O,S)-(Al,Ti,Si)O.