Experimental and numerical investigation of the effective parameters on the flow forming process of special high-strength steel used in the aerospace industry

Tube flow forming is one of the most economical production methods for simple cylindrical tubes with external and internal protrusions with or without flanges. The purpose of flow forming operation for body production is to use more raw materials and increase mechanical properties due to hard work on the part instead of raw machining of tubes. Due to the high strength of these tubes, it is one of the most important methods of manufacturing cylindrical bodies in the aerospace industry. In this research, the formability of high-strength maragining steel has been experimentally investigated by the three-roller flow forming process and finite element analysis. The effect of changes in flow forming process parameters such as mandrel rotation speed, feed rate, and angle of attack on dimensional and geometric accuracy as well as surface quality of the produced product was investigated experimentally and numerically. The results showed that the surface roughness of the final product increases up to 62% as the feed rate increases. Increasing the feed rate also leads to the reduction of out-of-roundness by more than 50%, thus improving the geometric quality of the final part. Increasing the rotation speed of the mandrel leads to a decrease in the surface roughness up to 30%. Also, increasing the rotation speed leads to an increase in the non-rotation of the product. Increasing the angle of attack of the roller from 15 to 30 degrees leads to an increase of about 30% in surface roughness and a decrease in non-roundness and a decrease in diameter growth.