关键词: 矿用接链环, 23MnNiCrMo54钢, 回火, 碳化物, 疲劳循环次数

Abstract: Due to technical transformation of the equipment, the quenching medium of the the 23MnNiCrMo54 steel mining link was replaced, and the fatigue life of the mining link after quenching and tempering according to the original process could not meet the technical requirements of the drawing standards. Through adding a second second tempering after the first, it is found that the fatigue cycle number of the mining link significantly increases and reaches the technical requirements of the drawing standard. The phenomenon that second tempering improves the fatigue life of the mining link parts is verified and confirmed, and no abnormality is found in observation of microstructure and inclusions of the mining link under different tempering conditions. When using the scanning electron microscope to observe and analyze the carbide distribution, alloy element distribution and carbide morphology of the tempered specimen, the results show that the carbides after the the first tempering at 420 ℃ and double tempering at 380 ℃+420 ℃ have different morphologies and structures. The carbide boundary after the first tempering is clear, and the number of carbides is small. The carbide boundary after the second tempering is fuzzy, and the amount of carbides is large. The carbide morphology under the second tempering state corresponds to a higher fatigue life.

Key words: mining link, 23MnNiCrMo54 steel, tempering, carbide, fatigue cycle number