Effect of Heat Input on M-A Constituent and Toughness of Coarse Grain Heat-Affected Zone in an X100 Pipeline Steel
- PDF / 15,567,993 Bytes
- 12 Pages / 593.972 x 792 pts Page_size
- 19 Downloads / 177 Views
ASM International 1059-9495/$19.00
Effect of Heat Input on M-A Constituent and Toughness of Coarse Grain Heat-Affected Zone in an X100 Pipeline Steel Xiao-Nan Wang, Yan-Jun Zhao, Peng-Fei Guo, Xiao-Nan Qi, Hong-Shuang Di, Min Zhang, and Chang-Jun Chen (Submitted January 19, 2018; in revised form October 24, 2018; published online February 14, 2019) The joining of 14.8 mm thick pipeline steels was achieved with developments in high-power fiber laser by laser welding or hybrid laser arc welding. However, there were few studies on the effects of single-pass welding heat input on the M-A component and impact toughness of the heat-affected zone. In this study, single-pass welding thermal cycle was performed on Gleeble 3800 thermal simulation tester; the effect of heat input on microstructure, M-A constituent, hardness, toughness and corrosion resistance of coarsegrained heat-affected zone of X100 pipeline steel was studied. The results showed: The microstructure was lath martensite with a heat input of less than 8 kJ/cm. When the heat input was 26-36 kJ/cm, the microstructure was granular bainite. The heat input had not obvious effect on hardness (only 16% hardness reduction in this heat input arrange). However, the impact toughness was strongly influenced by heat input, with an 88% hardness reduction compared to base metal, due to M-A constituent and prior austenite grain size. Few finer M-A constituent dispersing in austenite was obtained instead of necklace-like M-A constituent at the prior austenite grain boundary when the welding heat input was less than 15 kJ/cm, which was beneficial to improve the impact toughness and corrosion resistance of welded joints of X100 pipeline steels. Keywords
impact toughness, M-A constituent, microstructure, pipeline steel, welding thermal cycle
1. Introduction With the consumption of energy source such as petroleum and natural gas increasing, the extraction has been extended from inland to offshore, deep sea and frigid Arctic (Ref 1). Under long-distance and high-pressure conditions, pipeline transmission was one of the most important ways to deal with the above issues, and it developed toward high strength and large diameter in order to save the operation costs and improved transmission efficiency (Ref 2). Relevant studies showed that natural gas transmission capacity was increased from 100 to 300 million to 30 billion cube/year and reduced the operation costs by 30% using ultra-high strength X100 instead
Xiao-Nan Wang, Ministry-Province Jointly-Constructed Cultivation Base for State Key Laboratory of Processing for Non-Ferrous Metal and Featured Materials, Nanning 530004 Guangxi, Peoples Republic of China; and Shagang School of Iron and Steel, Soochow University, Suzhou 215021, Peoples Republic of China; Yan-Jun Zhao, Ministry-Province Jointly-Constructed Cultivation Base for State Key Laboratory of Processing for Non-Ferrous Metal and Featured Materials, Nanning 530004 Guangxi, Peoples Republic of China; Peng-Fei Guo, Min Zhang, and Chang-Jun Chen, Shagang School of Iron and St
Data Loading...
