【摘要】 SUS30 4钢盐浴歧化反应渗铬后炉冷 ,渗层由碳化物、α相 (Fe Cr)和弥散分布的粒状σ相组成 ,无显微裂纹 ;基体晶界碳化物呈网状分布。水冷可抑制基体中的碳化物及渗层σ相的形成 ,但使渗层出现显微裂纹。空冷时基体晶界碳化物析出较少 ,渗层无显微裂纹 ,而且渗层中的σ相粒径比较小。渗铬炉冷后的试样经 10 50℃固溶处理 ,基体晶界网状碳化物及渗层中的σ相消失 ,但渗层碳化物增多且向表层富集 ,渗层的铬浓度和硬度均随固溶加热时间的延长而下降更多还原

【Abstract】 When the specimens of SUS304 steel were cooled in the furnace after chromizing at 950℃ for 3h in the molten salt, the chromizing layer is crackfree,and consists of Cr carbides, rich chromium α (Fe Cr) and dispersed granular σ phase, but network carbides would precipitate at the grain boundaries of the substrate. Although the water cooling could inhibit the carbides precipitation in the substrate and prevent the σ phase from forming, it also causes the microcracks to present clearly in the chromizing layer. As to the air cooling, the specimens have finer granular σ phase,no crack in chromizing layer and have comparatively few carbides precipitated at grain boundaries of the substrate than furnace cooled. Solution treatment at 1050℃ can remove the σ phase in the chromizing layer and the carbides of the substrate, but it also makes the carbides in to the chromizing layer,and further concentrate to the surface layer. Both the Cr concentration and the hardness of the chromizing layer decrease markedly with the increase of solution treatment time.更多还原