Cause Analysis of Turbine Shaft Ultrasonic Flaw Detection Disqualification
American Journal of Mechanical and Materials Engineering
Volume 3, Issue 1, March 2019, Pages: 20-24
Received: Nov. 20, 2018;
Accepted: May 27, 2019;
Published: Jun. 18, 2019
Views 150 Downloads 26
Wang Yongsheng, Department of Chief Engineer’s Office, Dongbei Special Steel Group, Dalian, China
Sun Shengyu, Department of Chief Engineer’s Office, Dongbei Special Steel Group, Dalian, China
Sun Xin, ESR Plant of Dongbei Special Steel Group, Dalian, China
Guo Libo, Central Laboratory of Dongbei Special Steel Group, Dalian, China
Follow on us
Heavy forging is a kind of large or deformed-size forge, used on marine, roller or power station roter. etc, which are fabricated by free forging or hydraulic compressor. The turbine shaft products, steel grade ASTM668E, rejected during ultrasonic inspection. Aiming at the problem of ultrasonic flaw detection disqualification, through Positioning saw cutting, the macroscopic test, SEM and Micrographic examination are taken out. The main cause of the disqualification were found out. The results show that, because of the exist of unbalance crystallization, highly grade general loosen happened in the cycle area, which cause the energy of ultrasonic are weakened a lot, then lead to the central quality of the forging cannot be detected clearly. What’s more, the manganese sulfide precipitated at the grain boundary because of the selective crystallization occurs in the central of the ingot. The tensile stress on the interface between steel and inclusion separate the steel, caused the cracks which couldn’t be welded as the plastic deformation happened in forging press, then cause the cracks. Reduce the molten steel’s overheat and the freezing time can improve the defect of general loosen and the gartering of low-melting ingredients. Increase the compression ratio can take out too in the hot work process to solve the problem.
Heavy Forging, ASTM668E, UT, General Loosen, Manganese Sulfide
To cite this article
Cause Analysis of Turbine Shaft Ultrasonic Flaw Detection Disqualification, American Journal of Mechanical and Materials Engineering.
Vol. 3, No. 1,
2019, pp. 20-24.
Copyright © 2019 Authors retain the copyright of this article.
This article is an open access article distributed under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/
) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
YAO Ze-kun. Forging Technology [M]. XI AN: Press of Northwestern Polytechnic University, 1998: 77.
MA Qing-xian, et al. Study on Mechanism of Defects Originated from Inclusions in Processes of Heavy Forgings, [J]. China Mechanical Engineering. 2001, 12 (8):943-945.
DONG Lan-feng, ZhongYue-xian, et al. Research on the Dynamic Recrystallization Behavior of 20SiMn, [J]. China Mechanical Engineering. 2008, 19 (10):1245-1249.
GB/T1979-2001, Grading Diagrams for Macrostructure and Defect of structural steels [S].
LI Dai-zhong. Nonmetallic Inclusion in Steel [M], Peking: Science Press, 1983.
SHEN Cai-fang, SUN She-cheng, CHEN Jian-bin, et al. Technology and equipment of EAF Steel making [M], Peking: Metallurgical industry Press, 2001.
LIU Xue. Precipitation Behavior of MnS Inclusion in the steel [D]. Thesis for Master’s Degree of Northeastern University, June 2012.
Γ. M. Iczkovits. Deoxidation and Modifying Technology of Inclusion in Steel [M], Peking: Metallurgical industry Press, 1986.
Luu W C, Wu I K. Effects of sulfide inclusion on hydrogentmnsport in steels [J], Materials Letters, 1995, 24 (2):175-179.
Li Wei-liao. Nonmetallic Inclusion in Steel [M], Peking: Science Press, 1988.
Diederichs R, Bite R, Pariser G, et al. Modelling of manganese sulphide formation during solidification, Part i: Correlation of solidification and MnS formation [J], Steel Research International, 2006, 77 (4):256-264.
XU Jian-bing, YU Ji-xing, SU Kai. The Effect of Sulphide on Fatigue Crack Initiation of Cold Ring-Rolling Mandrel [J], China Metal Forming Equipment & Manufacturing Technology, 2006 (4):80-81.
YANG RANG. Lectures foundation of High Strength Low Alloy(HSLA) SteelsⅡ [M], Peking: China Metallurgy society, 1986.
REN Xue-chong, LI Gao-yang, et al. Effects of Inclusions and Grain Size on Impact Toughness of a Cleaning Wheel steel at Room Temperature [J]. PTCA (PART A: PHYS. TEST), 2012, 48 (4):207-212.
XIA Zhi-xin, YE Wen-bing, YANG Zhuo-yue, et al. Effect of Morphology of MnS Inclusions on Toughness of Ultra-High Strength Steel Produced by Different Smelting Processes [J], Journal of Iron and Steel Research, 2009, 21 (3):13-14.