Environmental Cracking of X-60 Pipeline Steel
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Abstract Environmentally assisted crack (EAC) growth mechanisms affecting the external surface of API X-60 pipeline steel has been investigated. Low frequency cyclic tests at 4.63x10−4 Hz were conducted in simulated groundwater (NS4 solution) under near neutral (pH ≈7) conditions, similar to those for buried natural gas pipelines. The crack morphology and amount of growth were determined for two stress ratios, R (minimum/maximum stress) 0.5 and 0, at Kmax=25.5 MPa√m under both constant and variable amplitude loading conditions. Examination of EAC was carried out using optical, scanning electron, focused ion beam (FIB) and transmission electron microscopy. Transgranular stress corrosion cracking (SCC) occurred at the higher R-ratio of 0.5. The crack was relatively wide, filled with corrosion product. By contrast, corrosion fatigue had taken place at R=0. The crack was also transcrystalline. Its tip was extremely sharp, and the amount of growth was greater. For the sample subjected to variable amplitude loading conditions, the crack was less sharp, but significantly sharper than that of the sample under constant load at R=0.5. The crack was open in many places, and the majority of the crack path was transgranular. Applying the superposition model to the variable amplitude test showed that the SCC growth rate accelerated when a single cycle at R=0 was combined with 159 cycles at R=0.5.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.026 | 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 it