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针对空冷器用低碳10钢管扩孔过程中产生的开裂,借助直读光谱仪,SEM、EDS和OM等设备对开裂钢管原材料的化学成分,显微组织和物相进行分析,并测试原材料的力学性能(抗拉强度、屈服强度和伸长率)。结果表明,在开裂钢管断口附近存在大量非金属夹杂物,显微组织中在铁素体晶界处存在较多未溶的渗碳体,导致钢管的脆性增大、韧性降低,直接引起钢管在扩孔过程中产生开裂。通过严格控制原材料品质,降低10钢管在正火热处理过程中的冷却速度,可以避免10钢管在使用中产生开裂。
In view of the cracking of the low carbon steel 10 during the reaming process of the air cooler, the chemical composition, microstructure and phase of the raw material of the cracked steel pipe were analyzed by means of direct reading spectrometer, SEM, EDS and OM etc. The mechanical properties (Tensile Strength, Yield Strength and Elongation). The results show that there are a lot of non-metallic inclusions near the fracture of the cracked steel pipe. There are many undissolved cementite in the microstructure at the ferrite grain boundaries, which leads to the increase of the brittleness and the decrease of the toughness of the steel pipe, Cracking during reaming. By strictly controlling the quality of raw materials and reducing the cooling rate of 10 steel pipes in normalizing heat treatment, cracking of 10 steel pipes can be avoided during use.