New Technology and Experimental Research on Thick-Walled Tube Fatigue Impact Loading Precision Separation

Traditional separation methods for thick-walled metal tubes include turning and sawing, which suffer from wasted raw material and low efficiency. In view of this, this paper proposes a new process of using impact load to promote crack generation and tube separation. Based on the principles of radial...

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Bibliographic Details
Published in:Metals (Basel ) 2022-05, Vol.12 (5), p.837
Main Authors: Zhao, Ren-Feng, Gao, Wei-Cheng, Zhang, Dong-Ya, Xiao, Xu-Dong, Liu, Yan-Wei, Pan, Run-Ze
Format: Article
Language:English
Subjects:
control curve
Crack initiation
Crack propagation
Efficiency
Fatigue cracks
Fatigue failure
Impact loads
Load
Metal fatigue
Microcracks
New technology
Propagation
Quality assessment
Raw materials
repeated impact load
Repeated loading
Sawing
Separation
Steel tubes
Stress concentration
stress concentration effect
Thick walls
thick-walled tube
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Summary:Traditional separation methods for thick-walled metal tubes include turning and sawing, which suffer from wasted raw material and low efficiency. In view of this, this paper proposes a new process of using impact load to promote crack generation and tube separation. Based on the principles of radial repeated impact load, stress concentration effect and fatigue fracture, the rapid initiation and stable expansion of tube fatigue crack are promoted. In addition, the crack initiation mechanism of the tube V-notch root cracks under radial repeated load when the tube is in a restrained state. For the experimental study of the GCr15 steel tube, a multistep decline frequency time tube separation control curve with an initial frequency from 4 Hz to 31 Hz and termination frequency from 1 Hz to 8.5 Hz was designed, and the precision tube separation device is loaded by pneumatic fatigue shock to achieve tube precision separation. In addition, a tube fracture quality evaluation method is proposed. According to the test results, the stress concentration effect of V-notch can significantly reduce the average stress in the process of tube fatigue separation and accelerate the generation of microcracks. Under the continuous action of repeated impact load, the loading method of multistep decline can effectively control the rapid crack initiation and stable expansion of the GCr15 tube V-notch root crack. Moreover, the tube final fracture region has relatively small defects, which can obtain good fracture quality.
ISSN:2075-4701
2075-4701
DOI:10.3390/met12050837