The properties of sintered and heat-treated steels produced from the Catamold 8740 material by powder injection molding were examined. Parts made of the Catamold 8740 low-alloy mild carbon steel are used in the military, automotive, and other industries where high reliability and resistance to dynamic loads are required. The Catamold 8740 chemical homogeneity was studied as a function of powder injection molding parameters: heating rate, sintering temperature, holding time, and subsequent heat treatment. Microscopic analysis showed that Catamold 8740 was a mechanical mixture of powders in various sizes (carbonyl iron, nickel, Fe–Mo, Fe–Cr, Fe–Si-Mo, Fe–Si). When the heating rate of the Catamold 8740 powder mixture increased from 2 to 5 °C/min, the microstructural heterogeneity caused by uneven compaction decreased and the alloy formation process activated at 900–1340°C. The impact strength of Charpy V-notch test samples changed from 10.39 to 11.52 J/cm 2 with higher sintering temperature and heating rate increasing from 2 °C/min (1270°C) to 5 °C/min (1340°C). When holding time increased from 30 to 90 min at a sintering temperature of 1340°C, the material became denser, the pores rounded, and the ferrite matrix homogeneous. However, the impact strength decreased by a factor of 1.4 because of coarser grain sizes and brittle fracture. Heat treatment processes reduced the impact strength after sintering. The results obtained were used to optimize the powder injection molding parameters. The influence of chemical and dimensional inhomogeneity of the starting Catamold 8740 powders and sintering kinetics on the structure and mechanical properties of parts operating under impact loads was established.

中文翻译：

---

粉末注射成型材料烧结参数的优化

研究了由 Catamold 8740 材料通过粉末注射成型生产的烧结和热处理钢的性能。由 Catamold 8740 低合金低碳钢制成的零件用于军事、汽车和其他需要高可靠性和抗动态负载能力的行业。Catamold 8740 化学均匀性作为粉末注射成型参数的函数进行研究：加热速率、烧结温度、保温时间和随后的热处理。显微分析表明 Catamold 8740 是各种尺寸（羰基铁、镍、Fe-Mo、Fe-Cr、Fe-Si-Mo、Fe-Si）粉末的机械混合物。当 Catamold 8740 粉末混合物的加热速率从 2°C/min 增加到 5°C/min 时，由不均匀压实引起的显微组织不均匀性降低，合金形成过程在 900-1340°C 激活。夏比 V 型缺口试样的冲击强度从 10.39 变到 11.52 J/cm 2，烧结温度升高，加热速率从 2°C/min (1270°C) 增加到 5°C/min (1340°C)。在1340°C的烧结温度下，保温时间从30分钟增加到90分钟，材料变得更致密，气孔变圆，铁氧体基体均匀。然而，由于晶粒尺寸变粗和脆性断裂，冲击强度降低了 1.4 倍。热处理工艺降低了烧结后的冲击强度。所得结果用于优化粉末注射成型参数。