The decarburization behaviour of 60Si2MnA in atmospheres containing 0–21% O 2 , < 20 ppm–17%H 2 O, and with or without 8%CO 2 , at 700–1000 °C, was investigated. The new findings of the current study were: (a) severe decarburization was associated with the formation of wüstite (FeO) scale on the steel surface, (b) the carbon activity at the steel–FeO interface was most likely determined by the reaction equilibrium between FeO and dissolved carbon in steel, (c) when a ferrite layer was able to form, the decarburization tendency was determined by the relative carbon permeability (defined as the product of carbon concentration difference at the two interfaces of the ferrite layer and carbon diffusivity) through the ferrite layer, and therefore, (d) the decarburization tendency at 800 °C was greater than those at 700 and 900 °C as the relative carbon permeability at 800 °C was the greatest. If FeO was absent when heating in dry O 2 -containing gases, however, possibly as a result of the formation of a SiO 2 layer at the steel surface, decarburization was very much alleviated or avoided. At 1000 °C, the decarburization tendency was alleviated even when FeO was able to form because formation of a ferrite layer was not possible and carbon diffusivity in austenite was much lower than that in ferrite. A preformed oxide scale was effective in providing decarburization protection only when the steel was exposed to dry O 2 -containing atmospheres.

中文翻译：

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60Si2MnA 在 700–1000 °C 下含不同水平氧气、水蒸气和二氧化碳的气氛中的脱碳

研究了 60Si2MnA 在含 0–21% O 2 、< 20 ppm–17%H 2 O 和含或不含 8%CO 2 的气氛中，在 700–1000 °C 下的脱碳行为。当前研究的新发现是：(a) 严重脱碳与钢表面方铁矿 (FeO) 氧化皮的形成有关，(b) 钢-FeO 界面的碳活性很可能由反应平衡决定FeO与钢中溶解碳之间的关系，(c)当能够形成铁素体层时，脱碳趋势由相对碳渗透率决定（定义为铁素体层两个界面处碳浓度差与碳扩散率的乘积） ) 通过铁氧体层，因此，(d) 800°C 的脱碳趋势大于 700 和 900°C 的脱碳趋势，因为 800°C 的相对碳渗透率最大。然而，如果在干燥的含 O 2 气体中加热时不存在 FeO，可能是由于在钢表面形成了 SiO 2 层，脱碳会大大减轻或避免。在 1000 °C 时，即使能够形成 FeO，脱碳趋势也有所减轻，因为不可能形成铁素体层，而且奥氏体中的碳扩散率远低于铁素体中的扩散率。仅当钢暴露于干燥的含 O 2 气氛时，预先形成的氧化皮才能有效地提供脱碳保护。可能由于在钢表面形成了 SiO 2 层，脱碳得到了很大的缓解或避免。在 1000 °C 时，即使能够形成 FeO，脱碳趋势也有所减轻，因为不可能形成铁素体层，而且奥氏体中的碳扩散率远低于铁素体中的扩散率。只有当钢暴露在干燥的含 O 2 气氛中时，预先形成的氧化皮才能有效地提供脱碳保护。可能由于在钢表面形成了 SiO 2 层，脱碳得到了很大的缓解或避免。在 1000 °C 时，即使能够形成 FeO，脱碳趋势也有所减轻，因为不可能形成铁素体层，而且奥氏体中的碳扩散率远低于铁素体中的扩散率。仅当钢暴露于干燥的含 O 2 气氛时，预先形成的氧化皮才能有效地提供脱碳保护。