FEM-Based Thermogram Correction for Inconel 625 Joint Hardness Clustering

Abstract

Assessing the temperature of the joint in on-line mode is a vital task that is demanded to characterize the formations of terns formations that are taking place in a joint and result in reaching necessary properties of the joint. Arc welding generates a high amount of heat that is reflected by the metallic surface of the welded object. In the paper, a temperature measurement credibility increase method is described and evaluated. The proposed method is used to reduce the influence of the reflected temperature of the hot torch and the arc on the temperature distribution observed on the surface of the welded joint using an infrared camera. The elaborated approach is based on comparison between infrared observation of the solidifying weld and precisely performed finite element method (FEM) simulation. The FEM simulations were calibrated according to the geometry of the fusion zone. It allows to precisely model heat source properties. The best-reflected temperature correction map was selected and applied to obtain a temperature representation that differs from the FEM baseline by less than 10 °C. Precise temperature values allowed us to cluster welded joints in 3D feature space (temperature, hardness, linear energy). It was found that by using the k-means clustering method it is possible to distinguish between correct and faulty (in terms of too low mechanical properties) joints.

Thermal Profile Modeling and Microstructural Evolution in Laser Processing of Inconel 625 Plates

“…Examining thermal and microstructure evolution through processing parameters via numerical and analytical modeling continues to increase in popularity. Thermal history and microstructural evolution (grain morphology, grain size, and texture) considering time history of material phase transformation and fluid dynamics with materials have rarely been studied [22][23]. Youseff et al [55] developed a three-dimensional finite-difference analysis model to predict thermal and clad layer morphology and geometry evolution of laser powder cladding of Ti6Al4V alloy.…”

The Structure and Properties of Laser-Cladded Inconel 625/TiC Composite Coatings

“…Surface engineering technologies are widely used to enhance surface properties such as corrosion or wear resistance without compromising favorable properties of the processed material core (e.g., mechanical and plastic properties) [ 1 , 2 ]. Nickel-based superalloys are widely used as coating materials due to their high corrosion resistance in aggressive environments as well as because of their fatigue strength, high-temperature toughness and ductility [ 3 , 4 ]. The positive influence of Inconel 625 coatings on the corrosion resistance of various grades of low-alloy and stainless steels was reported in the publication [ 5 ].…”

Determination of the Preload of Bolts for Structural Health Monitoring of a Multi-Bolted Joint: FEM Approach

“…These activities, in relation to already maintained structures, consist of health monitoring of various joints. This applies especially to systems with such structural nodes as bolted [1,2], riveted [3,4], or welded joints [5,6]. These issues are commonly defined as structural health monitoring (SHM) [7].…”