关键词: 钢脚, 淬火裂纹, 原因分析

Abstract: Cracks of steel foot were analyzed by means of metallographic microscope, Brinell hardness tester and inductively coupled plasma emission spectrometer. The results show that the steel foot has fewer non-metallic inclusions, the metallographic structure is quenched and tempered sorbite, which is consistent with the heat treatment process, and the chemical composition meets the requirements of GB/T 3077—2015.The fracture morphology is fine porcelain like, without any fatigue cracking characteristics. No decarburization, oxidation or folding morphology is observed on both sides of the entire crack, indicating a typical quenching crack morphology. The reason for cracking is that the large and small workpieces are treated in the same furnace, causing the cooling rate of small workpieces to be too fast and the stress to be too high, leading to crack.

Key words: steel foot, quenching crack, cause analysis