Phase transformation and impact toughness in HAZ of micro alloyed X80 line pipe steel
IR@NML: CSIR-National Metallurgical Laboratory, Jamshedpur
View Archive Info| Field | Value | |
| Title |
Phase transformation and impact toughness in HAZ of micro alloyed X80 line pipe steel
|
|
| Creator |
Singh, M
Kumar, R Shukla, D K Arora, K S |
|
| Subject |
Steel Metallurgy
|
|
| Description |
In the present work, phase transformation behavior and structure-property correlation in X-80 steel was analyzed at three distinct austenitizing peak temperatures (1250 °C, 1030 °C and 950 °C). Dilation studies and simulations of Charpy size samples were carried out using Gleeble 3800 thermal simulator. Dilation studies indicated that the dissolution of Nb rich carbides occurred at 1020 °C. During cooling from 1250 °C, mixed microstructure of bainitic ferrite and martensite formed at fast (200 °C s−1 −80 °C s−1) and medium (50 °C s−1–40 °C s−1) cooling rates. For slow cooling rates (20 °C s−1–0.5 °C s−1), ferrite/pearlite microstructure was obtained. For lower peak temperatures 1030 °C and 950 °C, mixed microstructure of bainitic ferrite and martensite was observed for fast cooling rates. Whereas, ferrite/pearlite with small fraction of bainitic ferrite nucleated in the microstructure at medium and slow cooling rates. Highest area fraction of M-A (8%) was observed at medium cooling rates (50 °C s−1–40 °C s−1) for 1250 °C peak temperature. Charpy size samples simulated for a 1250 °C peak temperature, exhibited the minimum notch toughness at 12.5 °C s−1, due to deleterious effect of granular bainite and M-A constituents. Simulated samples at lower peak temperatures 1030 °C and 950 °C exhibited higher notch toughness due to a mixed microstructure of bainitic ferrite and ferrite-pearlite.
|
|
| Publisher |
IOP Publishing Ltd.
|
|
| Date |
2019
|
|
| Type |
Article
PeerReviewed |
|
| Relation |
https://doi.org/10.1088/2053-1591/aaf156/meta
http://eprints.nmlindia.org/7990/ |
|
| Identifier |
Singh, M and Kumar, R and Shukla, D K and Arora, K S (2019) Phase transformation and impact toughness in HAZ of micro alloyed X80 line pipe steel. Materials Research Express, Volume 6, Number 2, 6(2) .
|
|