Weldability Studies of AISI 409 Ferritic Stainless Steel Thick Plates Using Electron Beam Welding Process

Abstract

In the present research, attempts have been made to weld 18 mm thick AISI 409 ferritic steel plate in a single pass with electron beam welding process. The welded joint was investigated for macrostructure, microstructural, microhardness, impact toughness, and tensile strength. The coarse ferritic grains of base metal were converted into fine equiaxed and columnar grains in the weld zone. The microhardness results revealed that for fusion zone and heat affected zone had 28% and 41% higher microhardness than the base metal. Further, post weld heat treatment at 550ºC/75 minutes resulted in 5% rise in ultimate tensile strength, 10% rise in yield strength, and 31% rise in impact toughness as compared to as welded specimens. The fractography of impact and tensile specimens revealed brittle mode of fracture and changed to ductile mode after post weld heat treatment.

Metallurgical and Mechanical Properties Variation Along the Thickness of Electron Beam Welded Ferritic Stainless Steel Joints After Postweld Heat Treatment

“…The rise in microhardness of weld zone and HAZ might be attributed to the electron beam welding process that imposed high energy density beam [23,49,54]. The absorbed high energy density at low heat input and rapid solidification helped to achieve higher microhardness in the joints [1,55]. Lakshminarayanan et al [23] also experienced rise in the microhardness of the weld zone after welding AISI409M FSS using EBW process.…”

“…The microhardness increased to 208HV at middle section and 229HV at bottom section. The change in hardness between the various weld zone sections was directly linked to the attained microstructure [29,56]. The heat input is the main considerable factor that affects the microhardness of the weld joint.…”