Near-Threshold Fatigue Crack Growth and Fatigue Strength of ER70S-6 Steel Processed by Wire Arc Additive Manufacturing
Loading...
Files
Size: 8.88 MB, File format: Adobe PDF
Date
Authors
Chen, Zhan Wen
Wang, Yuanming
Davidson, Karl Peter
Jackson, Benjamin
Supervisor
Item type
Degree name
Journal Title
Journal ISSN
Volume Title
Publisher
Springer Science and Business Media LLC
Abstract
In this work, fatigue crack growth (FCG) tests were conducted to determine the threshold stress intensity factor (ΔKₜₕ) of ER70S-6 steel processed by wire arc additive manufacturing (WAAM). Samples were orientated with the crack direction (CD) both parallel (//) and normal (⊥) to build direction (BD). In addition, tests were conducted to obtain data of S–N fatigue strength and cycles to failure (Nf). Following S–N testing, the sizes of defects were determined. The resulting S–N data, together with the measured defect sizes and ΔKₜₕ values, were subsequently analysed using the Kitagawa–Takahashi (K–T) diagram approach. Applying R = 0.1, the ΔKₜₕ value for CD//BD samples at ~ 4.5 MPa √m has been found to be slightly lower than the ΔKₜₕ value for CD⊥BD samples at ~ 5.0 MPa √m. Some elongated α-ferrite grains orientated close to BD have been identified, suggesting that the cementite containing pearlite colonies may be locally aligned with the BD, reducing fatigue crack resistance along BD and thereby lowering ΔKₜₕ. For both CD//BD and CD⊥BD samples, the effect of the defect size up to 520 μm affecting Nf can be explained using the K–T diagram approach. It is also shown that, when the effect of defects is excluded, the endurance limit of CD⊥BD samples is slightly higher than that of CD//BD samples, consistent with ΔKₜₕ (CD⊥BD samples) > ΔKₜₕ (CD//BD samples).
Description
Keywords
4014 Manufacturing Engineering, 40 Engineering, Additive manufacturing defects, Damage tolerance, Build orientation effect
Source
Progress in Additive Manufacturing, ISSN: 2363-9512 (Print); 2363-9520 (Online), Springer Science and Business Media LLC, 1-17. doi: 10.1007/s40964-026-01908-0
Publisher's version
Rights statement
Open access
Permanent link
Endorsement
Review
Supplemented By
Referenced By
Creative Commons license
Except where otherwise noted, this item's license is described as Creative Commons Attribution CC BY 4.0