Reasons For Refractory Material Damage Of Converter Working Lining
The mechanism of refractory material damage in converter working lining is very complicated, generally speaking, under the combined action of physical, chemical and thermal stress conditions, oxygen converter will endure mechanical abrasion, scouring, molten erosion, thermal pall, etc and finally causes the damage of working lining. Because the working condition differs largely in different parts of working lining, the damages to different parts are diverse. There are high requirement for the performance of refractory materials used in working lining.
Furnace mouth and cover: This part mainly suffers high temperature gas scouring, slag spraying and usually adheres slag and metals. When cleaning the adhered material, mechanical strike can do damage to it, meanwhile, the thermal shock between two smelting will also play a role for the damage. So, refractory material used here should have high thermal shock resistance, slag corrosion resistance, molten slag proof and high temperature gas scouring proof and won’t easily adhere steel, so high strength magnesia carbon brick is an good choice for this part.
Feeding side of furnace lining: This part will not only endure liquid steel erosion and slag erosion, but also endure severe strike when feed scrap steel and scouring during pouring into iron liquid. Thus, the masonry refractory material used here should have good high temperature strength, good thermal shock resistance and have good slag resistance. Magnesia carbon brick which has excellent erosion resistance and thermal shock resistance are usually used here.
Tapping side of furnace lining: Thermal shock is smaller at this part, but steel liquid thermal scouring is very strong, so same class of material used in feeding side can be adopted, but the thickness can be smaller.
Slag line: Contacting with slag for a long time, is the severest part of slag erosion. Slag line at tapping part changes according to tapping time and is not significant, but at slagging side, due to slag erosion and other physicochemical function, erosion is sever. High corrosion resistant magnesia carbon brick is suitable for this part.
Molten bath: Although suffers steel liquid scouring, the damage is slighter compared with other parts, moreover, slag spraying operation will generally raise furnace bottom and so ordinary magnesia carbon brick can be used.
Tapping hole: High temperature steel liquid scouring and slag erosion is happened here, added with drastic temperature change, the damage is very severe, so scouring and corrosion resistant and high oxidation resistant magnesia carbon brick is needed. Usually, integral magnesia carbon brick or combined magnesia carbon brick can be used, and should be mended or changed after used for certain times.
