Experimental Investigation of Springback of Locally Heated Advanced-High Strength Steels

Abstract

Sheet metal bending is one of the important metals forming processes at ambient temperature. The usage of high-strength steel is one of the stronger materials for the construction of components in the automotive industries. However, for complex shapes, cold forming is not always sufficient, and heating the workpiece plays a major role in manufacturing these shapes. Bendability may increase with increasing forming temperature and currently, hot forming of advanced high strength steels (AHSS) is becoming more attractive. While hot forming of AHSS is beneficial for high formability, subsequent quenching is required to maintain final strength. This procedure extends the production time. In this study, temperature gradients, bending loads, and springback after V-bending were investigated. The experimental study was carried out on a 2 mm thick Docol 1500M steel at various temperatures by using a speed-controlled servo press machine. The bending regions of the specimens were locally heated to 200, 300, 400, 500, and 600oC by using a high-frequency induction heating device. The results show that; punch loads were significantly lowered with increasing the local heating temperature during bending. There were no cracks observed on the specimens. The amount of spring back is decreasing with the bending temperature and around 500oC almost no springback was measured. Negative spring back was observed for the bending temperatures higher than 500oC

The effects of laser-assisted heat treatment on warm formability of dual-phase materials

“…It has been observed that the rate of ferrite in the material increases with the increase in temperature in locally applied heat treatments when various studies in the literature are examined. In this way, it has been observed that the amount of springback could be reduced and the formability feature could be increased [6][7][8][9][10][11][12][13][14][15][16][17][18]. During the forming of high-strength sheet metal materials at room temperature, dimensional forming errors which are called springback may also occur in addition to difficulties such as crack formation and breakage.…”

Numerical Simulation and Experimental Study of Cold and Hot Composite Forming of Sharp-Edged High-Strength Steel Sections

“…It can also overcome defects such as corner cracking and thickness reduction produced by rolls. Obaidi and Eyercioglu et al [21,22] found that localized heating can reduce spring back and improve the accuracy of sheet bending. Yan [23] suggested using induction heating to study the warm roll forming of highstrength steel.…”