|
|
|
| Microstructure and properties of simulated heat affected zone of TMCP processed E500 heavy plate steel for offshore platform |
| CHEN Huan-de，LIU Dong-sheng |
| Institute of Research of Iron and Steel of Jiangsu ProvinceShasteel， Zhangjiagang 215625， Jiangsu， China |
|
|
|
|
Abstract Heavy steel plates (max thickness， 80 mm) for offshore platform with yield-strength greater than 500 MPa have been produced by thermomechanically controlled process (TMCP). Continuous cooling transformation in the simulated coarse-grained heat-affected zone (CGHAZ) was investigated. The influence of heat input[E]on the microstructure and mechanical properties of the CGHAZ with and without second reheating peak temperature[(t2p)]was studied by means of metallographic analysis， hardness testing， instrumented impact testing and electron backscatter diffraction (EBSD). The microstructure of the CGHAZ changes from lath-like Bainite (LB) to granular Bainite (GB) as[E]increases， resulting in decreased hardness， impact energy， and the fraction of large-angle grain boundaries (＞15°). The predominant microstructure of the CGHAZ is refined LB when[E]is lower than 50 kJ/cm. Coarsened martensite-anstenite constituents (MA) are formed in the intercritically (reheatedCGHAZ) with[t2p]at 750 ℃. This leads to decreased impact toughness showing brittle fracture regardless off the variation of heat input. When[E]is smaller than 50 kJ/cm and[t2p]is higher than 850 ℃， the fraction of high angle grain boundaries increases and the impact toughness is largely improved showing ductile fracture.
|
|
Received: 06 December 2014
Published: 08 September 2015
|
|
|
|
| [1] |
WANG Bingxing，ZHU Fuxian，WANG Chao，LOU Haonan，. Application of oxide metallurgy in high heat input welding steels[J]. Iron and Steel, 2019, 54(9): 12-21. |
| [2] |
WANG Yunan，JIANG Xiaofang. Investigation on inclusions and microstructure of #br#
offshore steel for high heat input welding[J]. Iron and Steel, 2019, 54(8): 209-215. |
| [3] |
QIAO Gui-ying,,HAN Yang,HAN Xiu-lin,GU Yu,ZHAO Bo,XIAO Fu-ren. Microstructure and Mechanical Properties of Welding Heat Affected Zone of a High-Nb High Strength Pipeline Steel[J]. Chinese Journal of Iron and Steel, 2014, 26(10): 40-45. |
| [4] |
JIANG Qing-mei,ZHANG Xiao-qiang,CHEN Li-qing,SUN Wei-hua. SH-CCT Diagram, Microstructures and Properties of Heat-Affected Zone in a 1000MPa Grade Extra High-Strength Steel[J]. Chinese Journal of Iron and Steel, 2014, 26(1): 47-51. |
| [5] |
ZHAI Zhan-jiang1,WEI Jin-shan2,PENG Yun2,GAO Yi-fei3,LUAN Pei-feng1. Thermal Simulation Research on Welding Heat Affected Area of X80 Pipeline Steel[J]. Chinese Journal of Iron and Steel, 2012, 30(5): 7-13. |
| [6] |
. Effect of Boron on Microstructure and Mechanical Property of Welding-Induced Coarse Grain Heat-Affected Zone of V-N Microalloyed Steel[J]. Iron and Steel, 2010, 45(7): 85-85. |
|
|
|
|
2015, Vol. 50 
