A Semi-Analytical Model for the Heat Generation during Hybrid Metal Extrusion and Bonding (HYB).

Francesco Leoni,Paolo Ferro,Filippo Berto,Øystein Grong

doi:10.3390/ma14010170

Abstract

Hybrid Metal Extrusion and Bonding (HYB) is a novel solid-state welding method for metals and alloys that utilises continuous extrusion as a technique to enable aluminium filler metal additions. In the present study, a new semi-analytical model for the heat generation during aluminium butt welding is presented. As a starting point, the classical Rosenthal thin plate solution for the pseudo-steady-state temperature distribution around a fully penetrating line source is invoked. Then, the associated heat generation is calculated by considering the individual contributions from the tip of the rotating pin, the pin shoulder, and the filler metal additions on the net power input. In a calibrated form, the model yields thermal efficiency factors that are in close agreement with those obtained from more sophisticated finite element analyses but with considerably less computational effort.

Highlights

The term solid-state joining covers a vast number of processes including diffusion welding, explosion welding, hot pressure welding, forge welding, ultrasonic welding, cold pressure welding, roll welding, friction stir welding, and conventional friction welding [1,2]
A new solid-state joining method for metals and alloys has been developed, known as the Hybrid Metal Extrusion and Bonding (HYB) process [10,11,12,13,14]. This method, which is based on the principles of continuous extrusion, allows joining to be performed using aluminium filler metal (FM) additions similar to that done in gas metal arc welding (GMAW) but without any melting involved
The present heat generation model is deemed to exhibit the required degree of predictive power to make it useful in combination with more advanced numerical models for simulation of the thermal, microstructure and residual stress fields, where the thermal efficiency factor is an essential input parameter [24]. Since both HYB and friction stir welding (FSW) are friction-driven processes, the heat generation problem in a butt welding situation can be treated in a similar manner using the same physical framework

Summary

Introduction

The term solid-state joining covers a vast number of processes including diffusion welding, explosion welding, hot pressure welding, forge welding, ultrasonic welding, cold pressure welding, roll welding, friction stir welding, and conventional friction welding [1,2]. Materials 2021, 14, 170 Materials 2021, 14, 170 joint line at a constant travel speed, while the rotating pin with its moving dies is sub‐ merged between the plates This enables the extrudate to flow downwards in the axial direction and mix with the base metal (BM) in the groove under the conditions of high anpdremssixurweiathndthseebvaesreempleatsatlic(BdMef)oirnmthaetiognro. Based on a best-fit comparison between predicted and measured thermal cycles for two different positions within the HAZ, a thermal efficiency factor of 0.28 was obtained for the HYB PinPoint extruder [24] This means that only a minor fraction of the heat being generated, as calculated from the torque acting on the rotating drive spindle, is absorbed by the base plates in a real joining situation. This makes the approach attractive in the HYB case for reasons that will be obvious from the arguments provided below

How the HYB Process Control System Works

Coupling of Models

Materials and Experimental Conditions

Conclusions