Upset bulging as a preforming operation for hot metal gas forming of 22MnB5 tubes

Abstract

Hot Metal Gas Forming (HMGF) is a coupled process of gas forming and quenching of tubes. This process allows to obtain complex and accurate geometry due to the elimination of springback and high mechanical properties due to the formation of martensite, as a result, the weight of the parts can be reduced. HMGF is widely used in the aerospace and automotive industries to make critical parts from high hardenability steels such as 22MnB5. A typical hot stamped component has 1000 MPa yield stress and 1500 MPa ultimate tensile strength. The main challenge of HMGF process is a significant material thinning and cracking due to the biaxial tension stress state. The paper proposes a preforming method for increasing the forming limits of HMGF by the cold upset bulging of tubes by means of the additional volume of material in the deformation zone. This method allows to obtain one or several waves in the cross section of the tube, which helps to increase the minimum workpiece wall thickness after the forming process by more than 40% and to reduce a probability of the crack formation.

Recent advances in mitigating fusion zone softening during laser welding of Al-Si coated 22MnB5 press-hardened steels

“…22MnB5 steel is considered a suitable alternative to traditional high-strength low-alloy steels and other advanced high strength steels (AHSSs), as it offers superior mechanical properties, exceptional formability, while being relatively cost-effective for producing structural parts and components with tailored properties. The chemistries of various boron-alloyed press-hardened steels have been reported extensively in the literature [52][53][54][55][56][57][58][59][60], with the bulk composition of the 22MnB5 steel discussed in the manuscript given in table 1:…”