Investigation of local brittle zone in multipass welded joint of NiCrMoV steel with heavy section
- PDF / 942,511 Bytes
- 12 Pages / 584.957 x 782.986 pts Page_size
- 49 Downloads / 228 Views
Zhipeng Caia) Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China; State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China; and Collaborative Innovation Center of Advanced Nuclear Energy Technology, Tsinghua University, Beijing 100084, China
Kejian Li and Jiluan Pan Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
Xia Liu Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China; and Shanghai Turbine Plant of Shanghai Electric Power Generation Equipment Co. Ltd., Shanghai 200240, China
Lingen Sun and Peng Wang Technology Development Department, Shanghai Turbine Plant of Shanghai Electric Power Generation Equipment Co. Ltd., Shanghai 200240, China (Received 9 October 2017; accepted 4 December 2017)
Welding was successfully used in the fabrication of low pressure steam turbine rotors for nuclear power plants. In this paper, the local brittle zone of the welded joint in NiCrMoV steel with heavy section was investigated by cross-zone fracture toughness test and the effect of martensite–austenite constituent in the simulated reheated zone of welds with different second peak temperature on toughness was analyzed. The results showed that the crack propagated in unstable manner in the reheated zone of welds where the martensite–austenite constituent promoted the initiation and propagation of the crack. The fine structure of martensite–austenite constituent contained retained austenite, martensite, and martensite–austenite mixture microstructure. The impact toughness deteriorated drastically in the incomplete phase transition zone for the simulated reheated zone of welds related to the formation of mixture microstructure in which large blocky martensite–austenite constituent at prior austenite grain boundaries and inside the grains were distributed in the shape of network.
I. INTRODUCTION
Nuclear power acting as a kind of clean energy attracts much more attention attributing to its efficiency, reliability, and economic feasibility.1,2 It is worth to point out that the first demonstration nuclear power plant of the most advanced pressurized water reactors (PWRs) in the world have been constructing in China including Advanced Passive PWR 1000 MW (AP 1000), Advanced China PWR 1400 MW (ACP 1400, also named Hua-Long 1#), European Pressurized Water Reactor (EPR) et al.3 Steam turbine rotors are the key components of the power plant and can affect power plants’ efficiency and safety. With the development and application of large capacity in future turbines, higher strength and toughness are required for the steam turbine rotors, and their safety Contributing Editor: Jürgen Eckert a) Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2017.467
under service must also be improved. NiCrMoV steels used as plant structural component applications have been used to manufacture low pressure (LP) rotors in steam turbine rotors.4,5 Since the rotor shaft is more than 13 m long and the maximum d
Data Loading...
