TY - JOUR

T1 - Influence of deep rolling on surface layer condition and fatigue life of steel welded joints

AU - Dänekas, C.

AU - Heikebrügge, S.

AU - Schubnell, J.

AU - Schaumann, P.

AU - Breidenstein, B.

AU - Bergmann, B.

N1 - Funding Information: The research project IGF 19537N/DVS 09.073 “Fatigue life improvement of cyclic loaded welded joints steel and aluminum alloys by means of deep rolling” from the German Society of Welding (DVS), is supported by the Federal Ministry of Economic Affairs and Energy through the German Federation of Industrial Research Associations (AiF) as part of the program for promoting industrial cooperative research (IGF) on the basis of a decision by the German Bundestag. The project is carried out at the Fraunhofer Institute for Mechanics of Materials Freiburg. The research project IGF 20626N/P 1389 “Deep rolled welds – Increased fatigue strength of welded joints in wind energy by deep rolling” from the Research Association for Steel Application (FOSTA), Düsseldorf, is supported by the Federal Ministry of Economic Affairs and Energy through the German Federation of Industrial Research Associations (AiF) as part of the program for promoting industrial cooperative research (IGF) on the basis of a decision by the German Bundestag. The project is carried out at the Institute for Steel Construction and at the Institute of Production Engineering and Machine Tools, Leibniz University Hannover.

PY - 2022/9

Y1 - 2022/9

N2 - Deep rolling is an established mechanical surface treatment method to modify surface and subsurface properties and increase the wear- and fatigue strength of metallic parts and components. However, until now, deep rolling has not been considered for use as a post treatment method of welded joints to extend fatigue life of steel constructions. In this study, butt joints made of construction steels S355J2+N and S355G10+M were treated by means of hydrostatic deep rolling with tool diameter. The surface and subsurface properties after treatment were quantified by roughness-, hardness and residual stress measurements. Reduced roughness of 50–80%, increase of surface near hardness of up to 45% and compressive residual stresses of up to -1,000MPa were determined after deep rolling. Furthermore, the stress concentration factor of the weld toe was evaluated for each specimen based on surface scans. Due to the comparable low contact force of the deep rolling tool-process parameter combinations investigated, the stress concentration of the weld toe was mostly unaffected by deep rolling. However, a significant fatigue life improvement by deep rolling was determined for all test series, showing a maximum increase of FAT-class of approximately 60%. A tendency is shown that a higher tool diameter leads to higher fatigue life improvement.

AB - Deep rolling is an established mechanical surface treatment method to modify surface and subsurface properties and increase the wear- and fatigue strength of metallic parts and components. However, until now, deep rolling has not been considered for use as a post treatment method of welded joints to extend fatigue life of steel constructions. In this study, butt joints made of construction steels S355J2+N and S355G10+M were treated by means of hydrostatic deep rolling with tool diameter. The surface and subsurface properties after treatment were quantified by roughness-, hardness and residual stress measurements. Reduced roughness of 50–80%, increase of surface near hardness of up to 45% and compressive residual stresses of up to -1,000MPa were determined after deep rolling. Furthermore, the stress concentration factor of the weld toe was evaluated for each specimen based on surface scans. Due to the comparable low contact force of the deep rolling tool-process parameter combinations investigated, the stress concentration of the weld toe was mostly unaffected by deep rolling. However, a significant fatigue life improvement by deep rolling was determined for all test series, showing a maximum increase of FAT-class of approximately 60%. A tendency is shown that a higher tool diameter leads to higher fatigue life improvement.

KW - Deep rolling

KW - Fatigue

KW - Notch stress

KW - Post weld treatment

KW - Residual stress

KW - Stress concentration factor

UR - http://www.scopus.com/inward/record.url?scp=85130403709&partnerID=8YFLogxK

U2 - 10.1016/j.ijfatigue.2022.106994

DO - 10.1016/j.ijfatigue.2022.106994

M3 - Article

AN - SCOPUS:85130403709

VL - 162

JO - International journal of fatigue

JF - International journal of fatigue

SN - 0142-1123

M1 - 106994

ER -