Effect of post-weld heat treatment on the joint of friction-welded 1MnCrMoNi steel

Abstract

The microstructural evolution, mechanical and electrochemical properties of the rotary friction welding joint of 1MnCrMoNi maraging steel were investigated after post-weld heat treatment (PWHT). The joint could be divided into two zones: weld zone and thermo-mechanically affected zone. After PWHT, the parallel alignment of the laths turned 'blurred'; sub-grain and cell structure appeared; M23C6 and ε-Cu precipitated, respectively; the joint was softened. But the microhardness was still higher than that of base materials and distributed unevenly. The closer it was to the weld centre, the higher the microhardness was. No deformation occurred in the joints during tensile test, indicating the excellent bonding strength. PWHT process slightly reduced the impact toughness and corrosion resistance of the joint.

Effect of Ni interlayer on the microstructure, mechanical and corrosion properties of the dissimilar 1MnCrMoNi/X70 steels friction welding joint

“…The microstructural distribution of both joints can be divided into four characteristic zones: the thermo-mechanically affected zone in the 1MnCrMoMi steel (TMAZ-1MnCrMoNi) (Figure 3(b,f)), the weld zone in the 1MnCrMoMi steel (WZ-1MnCrMoNi) (Figure 3(c,g)), the weld zone in the X70 steel (WZ-X70) (Figure 3(c,g)), and the thermo-mechanically affected zone in the X70 steel (TMAZ-X70) (Figure 3(d,h)). The microstructural characteristics of WZ-1MnCrMoNi and TMAZ-1MnCrMoNi are similar to that of joints welded using the same materials, as previously reported and discussed [19]. The WZ-X70 of both joints is composed of fine-grained polygonal ferrite and pearlite clusters.…”

“…The TMAZs are farther from the joint interface than the WZs, leading to a lower temperature and higher torque resistance. Therefore, the TMAZs experienced partial deformation and generated a lower amount of dislocation, leading to partial DRX [19]. During the upset stage, the incompletely recrystallised microstructure flowed along the radial direction to form parallel bands of TMAZ-1MnCrMoNi and TMAZ-X70.…”

Studying the STA effects on aluminium alloy joints by friction welding

“…The temperature of the welded specimens, particularly those close to the weld zone, is raised to the solutionizing temperature during FW due to frictional heat created during joint formation. This causes the strengthening precipitates to become coarser and the tensile characteristics to deteriorate [28,29]. The recovery of the loss in tensile strength of FW joints requires the PWHT process [30,31], and the efficiency of the recovery of joints is greatly influenced by the size, volume fraction, and even distribution of the precipitates [32][33][34].…”