Self‐Piercing Riveting of Hot Stamped Steel and Aluminum Alloy Sheets Base on Local Softening Zone

Abstract

Self‐piercing riveting (SPR) has been used to joint steel to aluminum alloy sheets in multimaterial car body. It is a challenge to joint high strength steel to aluminum alloy by SPR process, especially for materials with high strength and large thickness. Herein, the SPR process for 1500 MPa hot stamped steel and aluminum alloy sheets is studied by experiment and simulation method. The laser heat treatment process is applied to the hot stamped steel sheet before joining. The relationship between heat treatment process and hardness distribution is studied and the softening zone with hardness less than 300 HV is obtained. Furthermore, the local softening zone is joined to an aluminum alloy sheet by SPR process. In the process, the rivets with high hardness are used to pierce the steel sheet. The failure mode and maximum tensile shear force of the joint are studied. At the same time, the joints without laser heat treatment are compared. The results show that the interlock and the maximum shear force for laser heat treatment increase by 91% and 26%, respectively.

Effects of the Intermediate Precooling Parameters on the Mechanical Properties of a Tailored Press‐Hardened Component in Advanced High‐Strength Steel

“…[12] Furthermore, the presence of some ductile areas is also important to simplify the assembly phase since the components obtained from the classic press hardening process are difficult to rivet due to the high strength. [16,17] To integrate ductile areas on the press-hardened component, the state of the art reports several tailored technologies that can be divided into two main classes: tailored blank technologies and tailored process technologies. [1] The tailored blank technologies include: 1) tailored rolled blanks (TRB), [18] 2) tailored welded blanks (TWB), and [19] 3) patchwork blanks.…”

“…[ 12 ] Furthermore, the presence of some ductile areas is also important to simplify the assembly phase since the components obtained from the classic press hardening process are difficult to rivet due to the high strength. [ 16,17 ]…”

Performance analysis of similar and dissimilar self-piercing riveted joints in aluminum alloys

“…9 Zhang et al investigated the mechanical properties of the SPR joint with the local softening zone. 10 Liao et al proposed a new joining process called double-sided self-piercing riveting which uses tubular rivets of simple geometry placed between the two parts to be joined. 11 Li et al studied the influence of local friction on the rivet insertion process, joint properties, and static lap shear strength by modifying the local surface of the top sheet around the rivet piercing site with different impression tools.…”