Comparison of Hydrogen Environment Assisted Cracking Susceptibility of Alloy 825/625 Welds to Duplex Stainless Steel 2205/2209 Welds In Reactor Effluent Air Cooler Vessels
Bibliographic record
Abstract
Abstract Hydro-processing reactor effluent air cooler (REAC) systems are exposed to startup, in-service, and shutdown operating conditions that can promote sulfide stress cracking (SSC) and hydrogen environment assisted cracking (HEAC). Welds are the primary cracking location for both damage mechanisms. Typical weld consumables used in REAC systems include duplex stainless steel (DSS), carbon steel (CS), and Alloy 825/625 consumables. SSC occurs after some period of service while HEAC failures have reportedly occurred shortly after startup as well as after some period of in-service operation. This paper will focus on key factors associated with these failure mechanisms in REAC systems. In addition, the paper will discuss results from a series of slow strain rate tensile (SSRT) tests carried out on duplex stainless steel weldments extracted from operating REACs and Alloy 825/625 weldment from new REACs. The SSRT tests were performed under high pressure hydrogen gas with test temperatures, hydrogen absorption, and flux rates designed to simulate start-up vessel operation. The results will be presented, trended, and ranked to characterize susceptibility to hydrogen embrittlement with respect to strength, ductility, and failure surface morphology for each alloy and test condition. The outcome of this work provides valuable insight and guidance for optimizing the design, fabrication, maintenance and operation of REACs to minimize HEAC damage mechanisms. Preliminary results show that Alloy 825/625 weldments have lower UTS values but higher ductility when compared to DSS 2205/2209. These tests were conducted at temperatures of 10, 22, and 50 Celsius (50, 72, and 122 Fahrenheit) in a total pressure of 12.2 MPa (1770 psig) composed of 90% H2 and 10% Argon
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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 | 0.001 | 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".