关于洁净钢的若干基本问题

CERTAIN BASIC SUBJECTS ON CLEAN STEEL

洁净钢是针对客户提出的质量要求,钢厂不断改进工艺、装备后,逐步提高洁净度的各类钢.介绍了典型钢种的洁净度要求及近半个世纪来商用钢中杂质能达到的最低水平.钢中总氧量对钢的洁净度至关重要,列举了国内外主要钢厂精炼、凝固过程中钢中总氧量的变化及降低总氧量的相关理论.减少钢中夹杂物数量及控制其形态也是洁净钢的重要任务,讨论了脱氧产物、脱氧剂再氧化及顶渣与耐火材料成分的影响,对430系不锈钢中夹杂物控制及精炼时最佳搅拌强度作了介绍,简述了钙处理使铝镇静钢夹杂物转形的基础理论.对超低磷、超低硫钢生产的冶金原理作了重点阐述,介绍了抗氢致开裂(HIC)的管线钢中超低硫和硫化物的形态控制.对钢中其它杂质元素去除的可能途径也进行了讨论.

Clean steel is a general designation of certain types of steel with higher cleanness upgraded gradually by steel factories with promotion of process and equipment step by step according to the customer demands on product quality. The requirements for cleanness of typical steel and the possible lowest level of impurity in commercial steel since last half century were introduced. The total oxygen content in steel is extremely important for its cleanness. Relevant theories of changes and decreases of total oxygen content during refining and solidification processes used by major steel factories at home and abroad were enumerated. Decreasing the inclusion amount and controlling its shape are also key tasks for clean steel production. The influences of deoxidization products, re oxidation of deoxidizer as well as top slag composition and refractory materials on the cleanness were mentioned separately, inclusion control in stainless steel series 430 and optimum stirring intensity in refining process were introduced, the theory foundation of inclusion transformation in aluminum-killed steel treated by calcium was briefly outlined, the metallurgical principles of ultra-low phosphorus steel and ultra-low sulphur steel productions were emphasized, ultra-low sulphur and sulphide shape control which are required by anti HIC of linepipe steel was introduced, the possible ways of removing other impurities from steel were also discussed.