Wear progress and mechanisms in high temperature sieves

摘要

Sieves for high temperature (HT) environment are necessary for screening of iron oxide sinter in steel industry. Sinter is produced at temperatures of similar to 1000 degrees C, crushed and screened for usage as raw material in blast furnaces. To determine the critical cause that leads to sieve cavity widening and subsequent productivity loss of the steel plant, a comprehensive damage analysis was undertaken. Sieves are equipped with plates covered by a hypereutectic hardfacing for wear protection. Cavities are cut by oxygen plasma cutting. Long-term wear investigation was done using replica samples taken from cavities after defined time intervals during the sieve's lifetime. Thereby differences in wear progress due to asymmetric material flow, position and alignment of cavities were studied. Additional temperature measurements were conducted via thermography of the sieve while in operation to identify service temperatures. Furthermore cross-sectional and microscopic analyses were carried out after end-of-life of the sieve to investigate wear mechanisms and microstructural changes.