Corrosion Fatigue Performance of Materials in Delayed Cokers and Coker Blowdown Piping System
Bibliographic record
Abstract
Abstract Very often the current body of knowledge and literature of fatigue performance in coke drums and blowdown piping system are linked to fatigue testing performed in air or in water. This paper summarizes the test results that were conducted using process fluids collected from a delayed coker. Both fatigue crack growth rate (FCGR) tests and stress/strain – cycle fatigue endurance tests in sour water at 200°F (93°C) or in a hot oil mix at 460°F (238°C), with gas mixture containing H2S were conducted. Carbon steel, Alloy 625 and their corresponding weld metal specimens were tested. The test results indicate remarkable impact of environment on fatigue behavior. Frequency scanning FCGR tests in sour water environment showed that FCGR increased with decreasing load frequency, particularly with high ΔK (32 ksi·√in or 35 MPa·√m). When ΔK was between 12 ksi·√in (13MPa·√m) and 36 ksi·√in (40 MPa·√m), FCGR of all specimens in sour water are higher than the mean + 2 SD (Standard Deviation) curve of carbon steel in air. Fatigue endurance tests in both sour water and hot oil environments showed various ranges of knock-down factors compared to test results in air. This testing program provides a better definition of the corrosion fatigue cracking mechanism of materials in delayed coker process. It also helps in the inspection planning of delayed coker equipment and in decisions on material selection.
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How this classification was reachedexpand
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) | 0.000 | 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 teacher head, 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".