Fracture failure analysis and improvement of engine exhaust valve

doi:10.13251/j.issn.0254-6051.2024.12.048

Abstract

Abstract: During the reliability validation process of a specific natural gas engine, a fracture of the exhaust valve occurred. The fracture cause was analyzed by using methods such as morphology observation, chemical composition analysis and hardness testing, and improvement measures were proposed. The results indicate that the chemical composition and hardness of the exhaust valve material meet the requirements of GB/T 12773-2021. The hardness test shows that the maximum actual working temperature of the exhaust valve is 725-735 ℃. The oxide layer generated on the valve stem under high temperature extends to the substrate and forms microcracks on the surface of the valve stem. High temperature causes layered precipitates to precipitate along the grain boundary, further accelerating the propagation of microcracks along the grain boundary, and gradually developing into deeper cracks, ultimately leading to fatigue fracture of the valve stem. It is recommended that reducing the operating temperature of the exhaust valve through optimizing the combustion system parameters, or alternatively, selecting NCF 3015 or Inconel 751 materials with superior temperature resistance can ensure the exhaust valve meets the operational requirements.

Key words: natural gas engine, exhaust valve, fracture, failure analysis

CLC Number:

TG162.79

Luo Changzeng, Zeng Xiaoxiao, Yao Yajun, Xu Deshi, Li Xucong, Ma Zongqiao. Fracture failure analysis and improvement of engine exhaust valve[J]. Heat Treatment of Metals, 2024, 49(12): 301-305.

References

[1]尧命发, 闫博文, 郑尊清, 等. 点燃式重型天然气发动机燃烧技术的发展及其应用[J]. 天然气工业, 2017, 37(10): 79-86.
Yao Mingfa, Yan Bowen, Zheng Zunqing, et al. The development and application of combustion technologies for spark ignition heavy-duty natural gas engines[J]. Natural Gas Industry, 2017, 37(10): 79-86.
[2]马义, 王晓辉, 李红洲, 等. 欧Ⅵ天然气发动机关键技术研究[J]. 车用发动机, 2016, 223(2): 71-75.
Ma Yi, Wang Xiaohui, Li Hongzhou, et al. Key technologies of EuroⅥ natural gas engine[J]. Vehicle Engine, 2016, 223(2): 71-75.
[3]刘敬平, 杨汉乾, 王树青, 等. 改善增压天然气发动机排放特性的途径[J]. 中南大学学报(自然科学版), 2012, 43(1): 143-150.
Liu Jingping, Yang Hanqian, Wang Shuqing, et al. Approach of improvement in emission characteristic of turbocharged CNG engine[J]. Journal of Central South University (Science and Technology), 2012, 43(1): 143-150.
[4]袁卫波, 陈本林, 王舒, 等. 基于国六排放标准的天然气发动机试验研究[J]. 汽车工程学报, 2019, 9(3): 193-200.
Yuan Weibo, Chen Benlin, Wang Shu, et al. Experimental study of natural gas engines based on China VI emission standards[J]. Chinese Journal of Automotive Engineering, 2019, 9(3): 193-200.
[5]罗长增, 曾笑笑, 魏东博, 等. 基于双辉技术的气门盘锥面TiN涂层制备和高温摩擦行为[J]. 金属热处理, 2024, 49(7): 195-199.
Luo Changzeng, Zeng Xiaoxiao, Wei Dongbo, et al. Preparation and high-temperature friction behavior of TiN coating on valve disc cone surface based on dual glow technology[J]. Heat Treatment of Metals, 2024, 49(7): 195-199.
[6]崔立英, 陈玉珍, 刘莎, 等. 船用柴油机排气阀断裂原因分析[J]. 金属热处理, 2012, 37(8): 122-125.
Cui Liying, Chen Yuzhen, Liu Sha, et al. Failure analysis of a broken exhaust valve for marine diesel engine[J]. Heat Treatment of Metals, 2012, 37(8): 122-125.
[7]吴桂涛, 魏海军. 船用柴油机排气阀的断裂失效分析[J]. 金属热处理, 2007, 32(4): 86-88.
Wu Guitao, Wei Haijun. Rupture failure analysis of marine diesel exhaust valve[J]. Heat Treatment of Metals, 2007, 32(4): 86-88.
[8]GB/T 12773—2021, 内燃机气阀用钢及合金棒材[S].
[9]余式昌. 微合金化奥氏体气阀钢的组织和性能研究[D]. 南京: 东南大学, 2006.
Yu Shichang. Study on the microstructure and performance of austenitic valve steel by micro-alloying[D]. Nanjing: Southeast University, 2006.
[10]余式昌, 吴申庆, 宫友军, 等. 6Cr21Mn10MoVNbN钢热变形显微组织研究[J]. 金属热处理, 2008, 33(3): 23-27.
Yu Shichang, Wu Shenqing, Gong Youjun, et al. Hot deformation microstructure of steel 6Cr21Mn10MoVNbN[J]. Heat Treatment of Metals, 2008, 33(3): 23-27.
[11]贾思钰. 高速重载柴油机Ni30气门-ST30座圈的高温摩擦磨损特性研究[D]. 广州: 华南理工大学, 2022.
Jia Siyu. Research on high-temperature tribological performance of Ni30 valve-ST30 valve seat of high-speed and heavy-duty diesel engine[D]. Guangzhou: South China University of Technology, 2022.

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