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采用OM、TEM和XRD对深层渗碳处理后H13钢的显微组织进行观测,研究了深层渗碳对H13钢显微组织和硬度的影响。结果表明:渗碳后完全退火试样与渗碳后球化退火试样的渗碳层厚度均在3 mm以上,组织细密均匀,硬度提高30%~60%;渗碳后球化退火试样的晶粒更细小,基体上碳化物弥散分布并存在较多的亚结构,且表面硬度稍高于渗碳后完全退火试样。最佳深层渗碳处理工艺为1000℃下固体渗碳4 h,接着进行球化退火(840℃保温4 h,炉冷到740℃再保温4 h,炉冷到500℃后空冷到室温),然后进行1030℃淬火10 min,最后进行560℃回火2次,每次2 h。
The microstructure of H13 steel after deep carburization was observed by OM, TEM and XRD. The effect of deep carburizing on the microstructure and hardness of H13 steel was studied. The results show that the thickness of carburized layer of fully annealed sample after carburizing and spheroidized annealed sample after carburizing is more than 3 mm, the microstructure is fine and uniform, the hardness is increased by 30% -60% Of the grains are finer and the carbides are dispersed and distributed in the matrix with more sub-structures, and the surface hardness is slightly higher than that of the completely annealed samples after carburization. The best deep carburizing treatment was solid carburizing at 1000 ℃ for 4 h, followed by nodular annealing (840 ℃ for 4 h, furnace cooling to 740 ℃ for 4 h, cooling to 500 ℃ and air cooling to room temperature) Then quenching 1030 ℃ 10 min, the final tempering 560 ℃ 2 times, each 2 h.