Comparative analysis of continuous cooling transformation behaviour in CGHAZ of API X-80 and X-65 line pipe steels
IR@NML: CSIR-National Metallurgical Laboratory, Jamshedpur
View Archive Info| Field | Value | |
| Title |
Comparative analysis of continuous cooling transformation behaviour in CGHAZ of API X-80 and X-65 line pipe steels
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| Creator |
Singh, M P
Arora, K S Shajan, N Pandu, S R Shome, M Kumar, R Shukla, D |
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| Subject |
Steel Metallurgy
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| Description |
Continuous cooling transformation diagrams were obtained for a simulated coarse-grain heat-affected zone of API X-80 and X-65 steels using Gleeble-3800 thermo-mechanical simulator. Dilatometry results showed that variable cooling rates have significant effect on phase transformation behaviour and microstructure of the steels. For X-80 steel, a mixture of bainite/martensite at fast and medium cooling rates and ferrite/pearlite at slow cooling rates was obtained and confirmed by microhardness measurements between 340 and 240 HV, whereas, for X-65 steel soft phase such as ferrite was nucleated along with bainite at moderate (15–100 °C s−1) and pearlite at slow cooling rates (3–10 °C s−1). Dilatometry curve comprises inherent noise, and Loess computational filter was used to filter background noise in the curves. Martensite/bainite and ferrite/pearlite coexisted for most cooling rates, which made it difficult to distinguish transformation kinetics of individual phases. In the first derivative analysis d/dT {(ΔL/Lo)} of dilatometry curves, peaks of individual phases were clearly observed. Peaks of individual phase were separated according to their transformation temperature range, and peak rate temperatures were determined. It was confirmed that the first derivative d/dT {(ΔL/Lo)} analysis described phase transformation behaviour precisely and aided in identification of the transformed phases.
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| Publisher |
Springer
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| Date |
2019-08
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| Type |
Article
PeerReviewed |
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| Relation |
https://doi.org/10.1007/s10973-019-08023-z
http://eprints.nmlindia.org/8000/ |
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| Identifier |
Singh, M P and Arora, K S and Shajan, N and Pandu, S R and Shome, M and Kumar, R and Shukla, D (2019) Comparative analysis of continuous cooling transformation behaviour in CGHAZ of API X-80 and X-65 line pipe steels. Journal of Thermal Analysis and Calorimetry, 137(4) . pp. 1155-1167.
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