Common slide gate plate damage phenomenon and analysis 常见滑板损毁现象及分析

常见滑板损毁现象及分析 1.1热冲击破坏 滑板使用前温度很低，而在浇注过程中，滑板在短时间内与高温钢水接触，由此产生的巨大温差对滑板本体会产生强烈的热冲击作用。此时在滑板浇注孔外部产生了张应力，一旦此应力超过滑板材料的强度，就会形成辐射状微裂纹。此类裂纹有利于外来钢水、熔渣和氧气的扩散、聚集、渗透，成为加剧化学性侵蚀的诱因。 1.2热化学侵蚀 滑板在使用过程中接触高温钢水和熔渣，会发生一系列化学反应，造成热化学侵蚀。这类侵蚀容易造成滑板工作面高温耐磨性变差，表面层脱落，导致滑板吻合性不良，缝隙增大，进而导致吸气，进一步氧化侵蚀，上述过程交替作用后，严重时会导致滑板漏钢等重大事故。 1.3操作因素 通过实践总结，对滑板造成损坏的操作因素可以归纳为滑板安装、浇注控流及水口烧氧三大类。 (1) 滑板安装不合理。当滑板在安装到滑动机构内时没有严格放平，出现翘动，或者滑板夹持松动，就会在使用过程中产生很大的外来应力，从而导致滑板的整体破坏。 (2) 生产中浇注控流不合理。在浇注过程中控流操作不合理时，容易导致滑板工作面的剥落、侵蚀、夹钢等现象。总结生产中的控流操作，发现容易造成滑板损坏的主要原因是滑板动作幅度过大，或动作过于频繁，特别是手动控流时造成的滑板破坏数量多于计算机自动控流的，说明操作中的人为因素也是造成滑板损坏的重要原因。 (3) 烧氧操作不合理。钢包整备操作或者在浇注过程中不下流时，均要对钢包水口进行烧氧，一旦烧氧操作不当，就会产生严重的烧氧侵蚀。造成滑板损毁的不当烧氧操作包括:滑板没有完全对眼即吹氧，造成氧气直接冲击滑板工作面;引流砂未完全流出时吹氧，则很难烧开，从而造成吹氧时间过长;氧气管与流道不平行，造成氧气流冲刷滑板孔边壁，形成扩孔等。另外，其他操作不当因素还包括钢包周转时间不合理，导致钢包整体温度下降，再使用时引起的热冲击大;滑板用火泥配比不当，搅拌不均匀，有杂质等。 Common slide gate plate damage phenomenon and analysis 1.1 Heat shock damage The temperature of the slide gate plate is very low before use, and in the pouring process, the slide gate plate contacts with the high temperature of water steel in a short time, and the resulting huge temperature difference has a strong thermal impact on the experience of the slide gate plate . A tension stress occurs outside the slide gate plate pouring hole, and once this stress exceeds the strength of the slide gate plate material, a radial microcrack forms. Such cracks are conducive to the diffusion, aggregation and penetration of external water of molten steel, slag and oxygen, and become the inducement to aggravate chemical erosion. 1.2 Thermochemical erosion In the use of high temperature steel and molten slag, will occur a series of chemical reactions, causing thermochemical erosion. This kind of erosion is easy to cause the slide gate plate working face high temperature and wear resistance deterioration, the surface layer falls off, resulting in poor slide gate plate anastomosis, gap increase, and then lead to inhalation, further oxidation erosion, the above process of alternating action, serious will lead to slide gate plate steel leakage and other major accidents. 1.3 Operating factors Through practical summary, the operation factors caused by damage to the slide gate plate can be summarized into three categories: slide gate plate installation, pouring and flow control, and water inlet oxygen burning. (1) Skate-board installation is unreasonable. When the slide gate plate is not strictly flat in the sliding mechanism, warping, or the slide gate plate clamp loose, will produce great external stress in the process of use, leading to the overall damage of the slide gate plate . (2) Unreasonable pouring and flow control in production. When the flow control operation is unreasonable in the pouring process, it is easy to lead to the flaking, erosion and steel clip of the slide gate plate working face. Summarize the flow control operation in the production, it is found that the main reason that can easily cause slide gate plate damage is that the slide gate plate action range is too large, or too frequent action, especially the number of slide gate plate damage caused by manual flow control is more than the computer automatic flow control, indicating that the human factors in the operation are also an important cause of slide gate plate damage. (3) Oxyburning operation is unreasonable. When the steel package preparation operation or does not flow during the pouring process, the steel package water outlet should be burned for oxygen. Once the oxygen burning operation is improper, it will produce serious oxygen erosion. Improper oxygen burning operation causing slide gate plate damage includes: the slide gate plate does not blow oxygen completely eye to eye, causing oxygen to directly impact the slide gate plate working face, it is difficult to burn oxygen, causing too long oxygen blowing time; the oxygen pipe is not parallel to the flow channel, causing oxygen flow to wash the edge wall of the slide gate plate hole, forming hole expansion. In addition, other improper operation factors include the unreasonable turnover time, resulting in the overall temperature drop, the heat impact; improper ratio of slide gate plate mud, uneven mixing, impurities, etc.