连铸结晶器水量对40Cr钢方坯表面裂纹的影响

为了改善湘钢2号连铸机产出的40Cr钢铸坯表面裂纹问题,特对不同结晶器水量下铸坯表面质量的变化进行研究。结果表明,随着结晶器水量增加,热流密度先增加后降低,铸坯表层的晶粒尺寸先减小后增大。当结晶器水量小于2250 L/min时,铸坯表层存在数量较多的异常长大奥氏体晶粒组织,晶粒度不均匀,铸坯表层裂纹主要沿着晶界扩展。当结晶器水量大于2333.33 L/min时,随着结晶器水量增加,热流密度降低,铸坯表层晶粒尺寸开始增加,铸坯表层没有出现裂纹。当结晶器水量为2333.33 L/min时,靠近结晶器壁侧钢水形核率最大,铸坯表层晶粒度最细小均匀,获得了最有利于抵抗应力开裂的晶粒组织。这种分析方法为解决铸坯表面裂纹问题提供了新思路。

200系连铸坯边部纵裂原因及控制

针对复产后广东省高端不锈钢研究院有限公司200系不锈钢连铸板坯出现批量头坯边裂的问题,通过观察表面缺陷类型、边裂形貌特征,结合连铸工艺条件、钢水质量以及连铸机结晶器状况,分析了板坯边部纵裂的主要原因,提出了改善结晶器水宽窄面水量,调整钢水过热度以及浸入式水口插入深度等改善铸坯边裂的措施,取得了明显的效果,铸坯表面边裂得到了有效控制,发生率从80%降低到25%以内,产品质量大幅提高。

Experimental research on influence of emulsifier on crystallization quantity of emulsion explosives under dynamic pressure

Dynamic pressure was applied on emulsion explosive by using an underwater explosion measuring apparatus, and the crystallization quantity was measured by dissolution method after emulsion explosive was pressed; the influence of emulsi- fier content and type was analyzed. The experimental results show that emulsifier content and type have an important effect on crystallization quantity of emulsion explosive. The crystallization quantity will reduce with Span-g0 content from 2% to 4%, so the demulsification and crystallization will decrease if the emulsifier content improves appropriately and the dynamic pressure resistance will increase. For emulsion explosive emulsified by T-152 and Span-g0, the crystallization quantity with T-152 is less than that of Span-g0 under the same dynamic pressure. This shows that the emulsifying effect ofT-152 is better than Soan-80.

板坯表面纵裂成因分析及预防措施

针对涟钢210转炉厂1号连铸机生产线上实际生产情况,分析了板坯的表面纵裂形成的原因,认为连铸板坯表面纵裂与结晶器冷却强度、钢水成分、拉坯速度、液位波动等诸多因素相关,通过采取相应的措施后,铸坯的表面纵裂纹比例由4.99%下降到0.05%以下。