Methanol-induced Internal Stress Corrosion Cracking in a Northern Petroleum Pipeline
Bibliographic record
Abstract
Abstract In early 2012, a metallurgical investigation was performed on a section of pipe that leaked in service. The pipeline transports crude oil and is located in Northern Canada. The investigation concluded that internal stress corrosion cracking (I-SCC) was the primary mechanism by which a crack initiated and propagated 96% through-wall, following an intergranular path. The remaining 4% of the wall thickness failed due to fatigue crack propagation. While I-SCC is extremely rare in underground petroleum pipelines, all other plausible cracking mechanisms were eliminated through a detailed metallurgical analysis. Methanol was suspected to be the agent responsible for the I-SCC . Following the completion of the investigation, a laboratory research program was initiated to confirm the mechanism of methanol-induced I-SCC using slow strain rate (SSR) testing under simulated environmental and physical conditions. In addition to the SSR testing, the circumferential, radial and axial distributions of residual stresses along the girth welds of two pipe sections removed from the pipeline were quantified. Residual stresses in the vicinity of the girth welds were found to be a contributing factor to the cracking identified in the investigation. This paper provides an overview of the comprehensive laboratory research program and details the efforts to replicate the atypical cracking mechanism in controlled methanol environments.
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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".