The present investigation is aimed to reduce the cost of production of various components fabricated by using cold rolled C250 marageing steel in the aerospace applications like landing gears of aeroplane and spacecraft. As cast C250 marageing steel was forged and solution annealed as per the specification of the customer. Forged C250 steel was cold rolled from 15 to 300%. Microstructure analysis revealed that grains got refined and elongated in the direction of cold working. Cold drawing increases the hardness, tensile strength and yield strength. However, loss in ductility and impact strength was observed. Scanning electron microscope fractographs of tensile and impact samples showed elongation of the dimples in cold working direction. The increase in cold working reduces the size of dimples indicating the transformation of fracture nature from the ductile-to-brittle regime. At higher cold working, >170% led to intergranular tearing and resulted in a loss of impact and mechanical properties of the steel. Further, cryogenic treatment of cold rolled C250 steel delayed ageing causing increase in tensile and yield strength with a marginal loss in ductility. The cost estimation of C250 steel revealed a significant cost saving (Indian Rupees [INR] 7500/1000 kg) for components made from different diameters of cold rolled steel over the solution annealed steel.

本研究旨在降低在航空航天应用（例如飞机和航天器的起落架）中使用冷轧C250马氏体时效钢制造的各种组件的生产成本。根据客户的要求铸造C250马氏体时效钢并对其进行固溶退火。锻造的C250钢从15％冷轧至300％。显微组织分析表明，晶粒向冷加工方向细化和拉长。冷拔可提高硬度，抗拉强度和屈服强度。然而，观察到延展性和冲击强度的损失。拉伸试样和冲击试样的扫描电子显微镜分形仪显示，在冷加工方向上的凹痕伸长。冷加工的增加减少了酒窝的尺寸，表明了断裂性质从韧性转变为脆性。在较高的冷加工下，> 170％会导致晶间撕裂，并导致冲击和机械性能的损失。此外，C250冷轧钢的低温处理延迟了时效，从而导致拉伸强度和屈服强度增加，而延展性略有下降。C250钢的成本估算表明，与固溶退火钢相比，由不同直径的冷轧钢制成的零件可节省大量成本（印度卢比[INR] 7500/1000公斤）。C250冷轧钢的深冷处理延迟了时效，从而导致拉伸强度和屈服强度增加，延展性略有下降。C250钢的成本估算表明，与固溶退火钢相比，由不同直径的冷轧钢制成的零件可节省大量成本（印度卢比[INR] 7500/1000公斤）。C250冷轧钢的深冷处理延迟了时效，从而导致拉伸强度和屈服强度增加，延展性略有下降。C250钢的成本估算表明，与固溶退火钢相比，由不同直径的冷轧钢制成的零件可节省大量成本（印度卢比[INR] 7500/1000公斤）。