Shielding Gas and Inclusion Content Effects on Impact Toughness and Tensile Properties of 410NiMo Steel Welds
Bibliographic record
Abstract
The effect of shielding gas on the mechanical and microstructural characteristics of ER410NiMo martensitic stainless steel weldments was investigated. Three weldments with various inclusion contents were manufactured using different shielding gas compositions and welding processes: gas metal arc welding (GMAW) with 100% argon (Ar), GMAW 85% Ar/15% carbon dioxide (CO2), and flux cored arc welding (FCAW) 75% Ar/25% CO2. The inclusions in each weldment were characterized by means of scanning electron microscope observations and energy-dispersive spectroscopy analysis. The weldments underwent postweld heat treatment, after which the chemical composition and reformed austenite proportion were measured to account for microstructural effects. Hardness measurements, tensile tests, and impact toughness tests using the Charpy method were performed. The results showed that the Charpy V-notch (CVN) absorbed energy decreases with increasing inclusion content. The highest CVN absorbed energy, 195 J, was obtained for the GMAW 100% Ar weld, which had the lowest inclusion content. GMAW 85% Ar/15% CO2, with four times more inclusions than the former, had a CVN absorbed energy of 63 J. The current manufacturing process, FCAW 75% Ar/25% CO2, was found to have an inclusion content three times higher than the GMAW 100% Ar weld but a CVN absorbed energy of 66 J, which is close to the GMAW 85% Ar/15% CO2 weld. The results showed that using GMAW 100% Ar as a replacement to FCAW 75% Ar/25 % CO2 would lead to a three-fold improvement in terms of absorbed impact energy. The effect of inclusions on tensile properties, which was not clearly identified as several factors, in addition to inclusion content, affects the weld strength and elongation. Overall, the yield and ultimate tensile strengths differed slightly: 724 and 918 MPa for GMAW 100% Ar, 746 and 927 MPa for GMAW 85% Ar/15% CO2, and 711 and 864 MPa for FCAW 75% Ar/25% CO2, respectively.
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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".