Title: A novel method for flame bending of thick-walled pipes

Authors: Seyed Ehsan Chavoshi; Vahid Badali; Seyed Ebrahim Moussavi Torshizi

Addresses: Department of Mechanical and Energy Engineering, Shahid Beheshti University, Tehran, Iran ' Department of Automotive Engineering, Iran University of Science and Technology, Tehran, Iran ' Department of Mechanical and Energy Engineering, Shahid Beheshti University, Tehran, Iran

Abstract: In the flame bending forming method, the thermal stresses caused by local heating lead to plastic deformation. Applying this method to thick and large diameter pipes leads to drastically low bending angle. The proposed methods for increasing the bending angle in these pipes require simultaneous control of two torches. In this study, a simple heating method is proposed that results in a significant increase in bending thick pipes. Also, a non-mechanical method is presented to create heating-induced pre-stress. Firstly, the heating within a longitudinal band (band heating) is investigated. Then, a heating step is added prior to the main band heating step to create pre-stress in the heating zone. Finite element method is used to investigate the deformation mechanism and the effectiveness of different heating methods. The effective parameters are optimised to achieve the maximum bending. Also, a heating test is carried out using a large perforated plate burner. There is 6 to 11% discrepancy between the numerical and experimental results. [Submitted 21 August 2019; Accepted 5 December 2019]

Keywords: flame bending; pipe straightening; line heating; forming; finite element method.

DOI: 10.1504/IJMR.2021.117843

International Journal of Manufacturing Research, 2021 Vol.16 No.3, pp.241 - 261

Received: 21 Aug 2019
Accepted: 05 Dec 2019
Published online: 04 Oct 2021 *

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