Welding distortion investigation of rotary drill rig pipe with radial loading transition bars

• Published in: The International journal of pressure vessels and piping 2022-10, Vol.199, p.104704, Article 104704
• Main Authors: Song, Wei, Xia, Xiaolei, Yang, Feng, Shi, Duanhu, Song, Meijuan
• Format: Article
• Language: English
• Subjects: Drilling rig pipe; TEP deformation Theory; Welding distortion; Welding sequence
• ISSN: 0308-0161; 1879-3541
• DOI: 10.1016/j.ijpvp.2022.104704

Cylindrical drilling pipe is an essential component of the rotary drilling rig, and its fabrication accuracy will significantly affect the machine performance and service reliability. The paper investigates the fabrication distortion of drilling pipes during the welding processing. Given the effects of welding distortion induced by material heterogeneity and pipe diameters, the welding deformation of simplified drilling pipe components with a single long bar was first studied to clarify the mechanism of dimensional variation and determine the inherent strain by the Thermal Elastic-Plastic (TEP) method. The deduced inherent strain results were employed to estimate the welding distortion of complex welding drilling pipe structures. To mitigate the welding distortion of the drilling pipe, the influence of the welding sequence on the local deformation is examined in the hoop direction. Moreover, the discrepancy of distortion under each welding pass was demonstrated. Different welding strategies (rotate and symmetry) for the next welded bar are employed according to the pipe rolling action after one welding. The distortion results show an optimization welding sequence by the characteristics distribution of welding distortion. [Display omitted] •Welding distortion of rotary drill rig pipe is systemically investigated by the inherent strain method.•Expansion coefficients for the inherent deformation method were determined by the TEP method.•Welding sequences on distortion were evaluated considering the rolling pipe and torch distances.•The distortion evolutions of different welding strategies were exhibited.