Abstract

The variation of the morphology and distribution of cementite particles in different prior structures with spheroidizing annealing process has been proceeded in this paper. It is found that the dissolution and coarsening progresses of various initial structures in spheroidizing annealing process are quite asynchronous due to the different interlamellar spacing. The dissolution rate of degenerated pearlite (D-P) with finer interlamellar spacing is faster. The granular cementite in the spheroidized microstructure is fine, uniform and dense. The mean diameter of spherical cementite is refined to 233 nm. However, the initial structure of degenerated pearlite (D-P) is highly sensitive to the austenitization temperature. The cementite is easy to be coarsened under high austenitizing temperature. The coarsening is accompanied by the gradual increase of the Cr content in the cementite, which increases the stability of the cementite. Therefore, the optimal austenitizing temperature for degenerated pearlite (D-P) is suggested to be 770 °C.

Graphic Abstract

The dissolution rates of cementite in spheroidized structures are related to the initial pearlite interlamellar spacing and the austenitizing temperature. A detailed experimental research and analysis are needed on the evolution of different initial structures during spheroidizing annealing treatment.

中文翻译：

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先验显微组织对高碳钢亚临界退火过程中渗碳体溶解行为的影响

摘要

本文研究了球化退火过程中不同结构中渗碳体颗粒形态和分布的变化。发现由于不同的层间距，球化退火过程中各种初始组织的溶解和粗化进程是相当不同步的。层间距越细的退化珠光体（DP）的溶解速度越快。球化显微组织中的粒状渗碳体细小、均匀、致密。球形渗碳体的平均直径细化到 233 nm。然而，退化珠光体（DP）的初始结构对奥氏体化温度高度敏感。渗碳体在高奥氏体化温度下容易粗化。粗化伴随着渗碳体中Cr含量的逐渐增加，增加了渗碳体的稳定性。因此，建议退化珠光体 (DP) 的最佳奥氏体化温度为 770 °C。

图形摘要

渗碳体在球化组织中的溶解速率与初始珠光体层间距和奥氏体化温度有关。需要对球化退火处理过程中不同初始结构的演变进行详细的实验研究和分析。