Analysis of erosion morphology and causes of 2 600 m3 casting type blast furnace hearth
WANG Fengmin1, ZHAO Hongbo1, ZHANG Fu1, CHI Chenhuan1, MENG Zhaowei1, ZHANG Jianliang2, SONG Mingbo2
1. Technical Center, Bengang Group Corporation, Benxi 117000, Liaoning, China; 2. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
Abstract：In order to clarify erosion characteristics and erosion mechanism of casting hearth, erosion morphology and erosion causes of a 2 600 m3 blast furnace were studied. By means of damage investigation, the casting hearth was measured and sampled after furnace shutdown. In the process of damage investigation, the hearth was dismantled layer by layer, and the residual thickness of the side wall castables in the hearth was measured manually. The castables embrittlement was found in the joint area of castables and carbon bricks, and the embrittlement layer of castables was measured and sampled. Obvious iron infiltration erosion was found in the hot surface castable of the hearth. The castables after service were studied by means of electron microscope, XRD and other detection methods, and the erosion causes for casting hearth of blast furnace were clarified. The results show that the most eroded castables on the side wall of the hearth are located at the position of No.1 iron taphole and No.2 iron taphole, and are concentrated at 0.5-1.5 m below the iron taphole in height, among them the castable residual thickness of 17th layer and 18th layer of carbon bricks at the position of No.1 iron taphole is the minimum, which is 180 mm. A embrittlement layer with thickness of 50-180 mm is found at the interface between the castable and the carbon brick. The average thickness of the embrittlement layer of castable at the iron taphole orientation is less than that at the non-iron taphole area. The results of electron microscopy show that the erosion of hot surface castables is mainly caused by the penetration of high temperature slag iron, and the formation of castable embrittlement layer is the result of comprehensive action of high temperature phase transition and the erosion of harmful elements. The emergence of embrittlement layer on the side wall of castable hearth makes the air gap appear in the joint area of castables and carbon bricks on the side wall of castable hearth, which destroys the heat transfer system of the hearth, and intensifies the erosion of castable hearth. The research results can provide reference for realizing the long life of casting hearth.
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2023, Vol. 33 
