Fatigue Properties and Life Prediction of 8630 Cast Steel in the Presence of Weld Repair and Porosities
Bibliographic record
Abstract
The objective of the this work is to study the effect of weld repair and macro-porosities on fatigue properties and fatigue life of AISI 8630 cast steel subjected to bending cyclic loads. Test specimens were cut from a cast steel component that contains macro-porosities. To regain the structural integrity, the component is typically excavated and weld repaired. In this study, weld repairs are simulated by machining a cylindrical groove across the width of the specimen then the groove is welded using different weld rods and various pre and post weld heat treatment conditions. All specimens were examined by radiography (X-Ray) in accordance with ASTM E446 before depositing the weld in order to verify the quality of the samples. After welding, the quality of the welded grooves was examined using ultrasonic testing (UT) and magnetic particle inspection (MPI) in accordance with ASTM A609 and ASTM E709 standards, respectively. Qualified samples were then machines to the final dimensions. The fatigue test was performed under pure bending conditions using four-point bend set up. This set up allows localizing stresses at the sites where weld repairs were applied. Experimental results show that specimens with stronger weld material tested under no heat treatment conditions have comparable fatigue performance to those heat treated specimens with lower strength weld material. Furthermore, it was found that the fatigue test results are highly affected by the presence of micro-porosities within the cast steel material. Therefore, an analytical approach to predict the fatigue life is also presented in this work. A good agreement is achieved between the predicted fatigue lives and the experimental results. Generally, the results show that for porosities with width to depth ratios between 0.25 to 1 and width size smaller than or equal to 1 mm the life is reduced by up to 1.5 orders of magnitude while the endurance limit was reduced by a factor of 1.57. Similarly for porosities with ratios between 1.5 and 2.5 and width greater than 1.5 mm the life was reduced by 2.5 orders of magnitude and the endurance limit was reduced by a factor of 2.2.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".