The effects of the heat treatment on the microstructure of Inconel 625/steel bimetal joint obtained by explosive welding

Abstract

In this investigation steel P355NH was successfully clad with Inconel 625 through the method of explosive welding. Explosively welded bimetal was subjected to the two separated heat treatment processes: stress relief annealing (at 620oC for 90 minutes) and normalizing (at 910oC for 30 minutes). In order to identify the microstructure of the joint and to investigate the influence of the heat treatment on it, the light and scanning electron microscope observations and microhardness analysis have been performed. In order to investigate the diffusion zone microstructure the scanning transmission electron microscope observation have been performed. It was stated that obtained joint has characteristic wavy-shape geometry with the presence of the melted zones and severe deformed grains of both joined materials. Strengthening of materials in joint zone was established with microhardness analysis. In both of the heat treatments the changes in the grain structure have been observed. The normalizing heat treatment has the most significant impact on the microstructure of the joint as well as the concentration of the chemical elements in the joint zone. It was reported that due to normalizing the diffusion zone has been formed together with precipitates in the joint zone.

Enhancing Corrosion Resistance in Explosive Welding

“…The process used explosive called ammonium nitrate (V) and Vd was 2700 m/s. This resulted in welding P355NH and Inconel 625 alloy [4].…”

“…Corrosive wear indicates a significant problem in the consumption of any equipment such as in chemical industry in addition to geothermal power plants [4]. The usage of alloys which are resistive to corrosion is generally associated with its cost.…”

The Influence of the Post-Weld Heat Treatment on the Microstructure of Inconel 625/Carbon Steel Bimetal Joint Obtained by Explosive Welding

“…An approach worth considering is the use of relatively inexpensive material (e.g., non-alloy steel) and cladding it with layer of corrosion resistant alloy, such as stainless steel or nickel alloy providing potentiality of operating in the aggressive environment. This solution allows to reduce the material cost of industry equipment significantly depending on used manufacturing technique [3][4][5]. As an example of such bimetal clad plate Inconel/steel system can be given, in which steel is a load-bearing component while Inconel provides resistance to an aggressive environment.…”

The Analytical Model of Stress Zone Formation of Ti6Al4V/AA1050/AA2519 Laminate Produced by Explosive Bonding

“…It is an important complement to traditional plating production methods, such as welding or rolling mill. Bimetals obtained this way, and multilayered composites consisting of more than two materials, have unique structural properties [1,2]. They are characterized by high strength, corrosion resistance and, in case of the association of appropriate materials, also a large ballistic resistance.…”