The Influence of Weld Heat-Affected Zone on Stress Corrosion Cracking of Pipeline Steel in Near-Neutral PH Environment
Bibliographic record
Abstract
Abstract Colonies of stress corrosion cracks are often seen around weld heat-affected zones (HAZs) in pipelines that are operating in the field in contact with near-neutral pH (NNPH) environment. Research on stress corrosion cracking (SCC) of welded line pipe steel can contribute knowledge that is important in establishing pipeline integrity. In the project reported in this paper, samples that had been machined from a large-diameter welded gas transmission pipe were subjected to slow strain rate testing (SSRT) at different strain rates in a soil solution and in NS4 solution, both purged with 5% CO2/balance N2 gas mixture. There were many more quasi-cleavage areas on the fracture surfaces of the weld HAZ specimens than on the fracture surfaces of the base metal. The increased SCC susceptibility of the weld HAZ samples compared to the base steel was attributed to the coarse-grained, non-uniform microstructure of the HAZ samples as well as the higher residual stress. SCC propensity increased with decreasing loading rate and with more negative potentials. SCC initiation was associated with pitting corrosion.
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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".