Fatigue strength improvement of welded joints by means of shot peening and clean blasting

Author:  Thomas Nitschke-Pagel, Klaus Dilger, Hamdollah Eslami Institut für Füge- und Schweißtechnik, Technische Universität Braunschweig,Germany
Source:  ICSP14 Milan
Doc ID:  2022061
Year of Publication:  2022
Abstract:  
Shot peening is a well established state of the art mechanical surface treatment to improve the fatigue strength of metallic components, clean blasting a familiar process and used frequently in welding practice. The main difference is the peening media used and the minor or missing parameters of clean blasting. The clean blasting process is not yet qualified to optimize fatigue enhancement although it holds similar potential as regular shot peening. Clean blasting is usually applied with the purpose of surface preparation for application of corrosion protection. This article presents results of regular shot peened DV-butt welds made from construction steels S355N and S960QL, The peening parameters are varied widely. The effect of coverage and intensity is investigated to test the robustness of the peening processes. The data is completed with industrially clean blasted welds representing typical workshop conditions. The overall objective of this work is to demonstrate the fatigue strength potential of several variations of peening processes. The results indicate a high robustness of the applied process variations. This indicates high potential of shot peening and clean blasting for fatigue strength enhancement. If clean blasting is accompanied by a simple process control in terms of coverage and intensity the fatigue strength benefit is obvious- Keywords: Welded joints, fatigue strength, shot peening, clean blasting, residual stresses