Experimental investigations for electric heating rotary stretch bending process of extruded Ti-6Al-4V alloy profile with T-section

Titanium alloys stand out primarily due to their high specific strength and excellent corrosion resistance, they have higher mechanical strength to weight ratio but are 40% lighter than steel. It is widely used in aero-engines, gas turbines and aero-space structures and titanium products increased during the last decade. However, it is well known that titanium alloy is difficult to be formed at room temperature. Therefore, hot stretch bending (HSB) process was developed to create bent parts of extruded Ti-6Al-4V titanium alloy profile, thus reducing the cost impact of raw material and finished machining. In the present paper, a new force-controlled electric heating rotary stretch bending (HRSB) process was developed. In order to obtain the precise bending of titanium alloys extrusion, experimental investigations for extruded Ti-6Al-4V Alloy profile with T-section are carried out. Firstly, experimental method of HRSB and electric heating tension are proposed. Secondly, the HRSB process of Ti-6Al-4V Alloy extrusion at different forming temperatures and tension forces was investigated. Lastly, microstructures of Ti-6Al-4V Alloy formed in different conditions are investigated using SEM, TEM and EBSD method. The results show that: (1) When initial temperature of Ti-6Al-4V titanium alloy profile ranges from 700 to 750^°C, and temperature of die surface ranges from 100 to 200^°C, the forming quality and precision are higher. (2) Increasing post-stretching force can reduce the angle springback of Ti-6Al-4V titanium alloy profile. The results may help to provide the basis for the determination and optimization of hot stretch bending of Ti-6Al-4V titanium alloy profile.