Aluminium-steel plating by press welding

Dan Dobrotă,Florin Ciofu,Valentin Petrescu,N.F Cofaru,M Inţă

doi:10.1051/matecconf/202134303013

Abstract

A series of researches related to aluminium-steel plating by press welding are presented in the paper. In this sense, the influence of the roughness of the aluminium and steel test samples was taken into account, but also of the post-welding heat treatment on the characteristics of the joints made. S355 steel specimens and AlMgSi0.7 F27 aluminium specimens were analyzed. The samples were processed and roughness Ra = 2.51-51.09 µm were obtained. Also, after making the joints, a postwelding heat treatment was applied which consisted of a heating at a temperature of 425 °C with a duration of 6.5 hours and a slow cooling to room temperature. Six distinct samples were made in terms of surface roughness in the joint area. After making the joints and applying the heat treatment, the samples were analyzed in terms of metallographic structure, the thickness of the interface layer and the hardness of the material in it. Thus, it was found that both the roughness of the test tube surfaces and the post-weld heat treatment have a substantial influence on the metallographic structure and the hardness of the material in the interface layer. The highest hardness of the material in the interface layer and its lowest thickness were obtained for the samples with the lowest roughness of the joint surfaces.

Highlights

At present, cold pressure welding offers the most satisfactory way to achieve cladding with aluminium or copper without the appearance of brittle inter-metallic compounds
In the first stage of the research, the samples were cut longitudinally so that the area of the interface layer could be observed and, at the same time, an analysis of the metallographic structure and a hardness measurement for the material in the interface layer could be performed. These analyzes were performed for the 6 samples presented in Table 4, following the influence of the roughness of the sample surfaces both on the metallographic structure and on the hardness of the material in the interface layer
The researches demonstrated that both the roughness of the samples surfaces and the postwelding heat treatment have a substantial influence on the metallographic structure and the hardness of the material in the interface layer

Summary

Introduction

Cold pressure welding offers the most satisfactory way to achieve cladding with aluminium or copper without the appearance of brittle inter-metallic compounds. This cold plating avoids the appearance of the head affected zone (HAZ) which can have a number of unsuitable properties [1, 2]. In particular, deformations of crystal lattice substantially influence the diffusion process. Distortions of crystal lattice caused by plastic deformation accelerate diffusion. The diffusion along marginal dislocations possesses a lower activation energy and is important in the case of processes that take place at relatively low temperatures. The diffusion along marginal dislocations possesses a lower activation energy and is important in the case of processes that take place at relatively low temperatures. [3, 4]

Methods

Results

Conclusion